Differences among foraging, cultivation, domestication

Differences among foraging, cultivation, domestication

I am currently researching the transition from hunter-gathering bands to agricultural communities. I am coming across the word cultivation a lot. It's getting confusing, because sometimes the word cultivation seems to mean "gathering wild plants", like foraging. At other times it seems to mean "managing and controlling plant growth", like agriculture.

Dictionaries and encyclopedias aren't helpful, giving an overly broad discussion. I am beginning to wonder if cultivation is a term of art in this context. Was it a transitional phase? If so, that was a pretty big deal! Where is the line between foraging and cultivation? How about the line between cultivation and domestication?


There was definitely a transitional phase in areas that developed agriculture independently. For example, in the mid-east they started out grinding useful grasses. Mortar and pestle and sickle finds start to get more and more common for quite a while before the first full-blown river-valley societies are formed.

Likely they started "weeding" around the better strains, and slowly transitioned to expending more and more effort encouraging their growth (and getting higher and higher yields). A term I've seen in several places for this phase is incipient agriculture.

The anthropologists have their own term for this: Mesolithic. This is essentially defined as the period between Paleolithic (hunting and gathering) and Neolithic (farming).

Poking around, I also see there's the term "Protoneolithic". That could be exactly what you want, but I've never seen that word before just now on Wikipedia.

If you're not into talking about rocks, there's also the term "Horticulture":

Horticulture primarily differs from agriculture in two ways. First, it generally encompasses a smaller scale of cultivation, using small plots of mixed crops rather than large fields of single crops. Secondly, horticultural cultivations generally include a wide variety of crops, even including fruit trees with ground crops. Agricultural cultivations however as a rule focus on one primary crop.

I'm less fond of this distinction, as it seems to be used as a way to selectively dismiss the efforts of certain societies, who it could be argued were merely practicing sensible agricultural diversity and crop rotation practices*.

Of course a lot (most?) of the world did not independently develop agriculture, but rather acquired their techniques from nearby practitioners, along with their cereal crops and domesticated animals. These people generally didn't go through much of a noticeable transition period.

* - Native American societies in particular had to cultivate multiple crops, because their main cereal crop lacks an essential amino acid.


PLANT DOMESTICATION

The domestication of the plant was man’s crowning achievement. It allowed us to develop into the complex global society that we are today. We are arguably more dependent on those same crop species domesticated by early man up to 10,000 years ago than we ever have been. Whether early man joyfully embraced the new technology of agriculture is debatable, but once it caught on it spread quickly across continents. The hunter-gatherer systems of old were notoriously land inefficient. It took large acreages to support these early humans, and so agriculture arose from necessity and allowed more people to survive on fewer acres.

The process of man’s conversion to agricultural systems was spurred along by the warming of the earth and the scarcity of large land mammals previously hunted for food and clothing. The plants used to fill the void were less selected than they were chanced upon. Traits that made domestication possible were controlled by few genes. These traits were fixed quickly and we are left with those same original domesticated crops from antiquity. The crops have certainly evolved, but not as much as they did during those first centuries.

With domestication came some negative aspects such as reduced genetic diversity. The genetic bottle neck effect seen in modern crops is a product of man’s selection for desirable agronomic traits. Unfortunately modern crops are often susceptible to disease, insects, and abiotic stresses. To find resistance genes it is often necessary to go back to their wild ancestors and close relatives. This is can be problematic due to the setback in yields attained when crossing to wild relatives, but it necessary for advancement of the crop. An understanding of crop domestication can help the plant breeder in her pursuit of the next best plant.

Early humans lived as hunter gatherers, victims of the wax and wane of the ecosystem in which they inhabited. For those that lived in grassland systems, a nomadic existence, following the plants and animals they fed upon was necessary. Tropical forest dwellers or those that lived in ecosystems where food was available year-round could build more permanent homes. They all depended on that which sprang forth from the ground naturally for their sustenance however, which meant that their fates were not necessarily their own to choose. Food availability depended on what the ecosystem could provide, and searching for that food required a great deal of early man’s time and energies. Survival was a full-time job. This inherent lack of control over their fates changed roughly 5,000 to 10,000 years ago with the domestication of the plant species that would become the first agricultural crops (Smith and Pluciennik, 1995). The change did not occur abruptly (Anderson, 1956), and certainly did not resemble what we today would call agriculture for quite some time.

The domestication of the plant was arguably the single most important technological advance in our history, and allowed us to develop into the highly complex civilization we have become. As technologically advanced as we might be, we are still as dependent on plants as we have ever been. It could be argued, that with the current population and rate of growth, we are more dependent on these crops than ever. There were 6.1 billion humans on earth in 2000, and current population estimates for 2050 range from 7.4 billion to 10.6 billion (UN, 2004). Not only is that a lot of mouths to feed, but homes for 7 to 10 billion people covers large amounts of land. Much of that same land will be needed for food and fiber production.

It is interesting that the crops we grow globally today, to feed an ever growing society, in most cases were the same species our ancestors originally domesticated thousands of years ago. The beginnings of agriculture and plant domestication occurred at different times and places, with different plant species, for different societies around the globe (Flannery, 1973). It appears that some societies did this independently of each other, and for other societies the technology was introduced. An in-depth review of the archaeological evidence is beyond the scope of this chapter however, a discussion of plant domestication is impossible without an archaeological perspective.


Abstract

During the last two decades, new archaeological projects which systematically integrate a variety of plant recovery techniques, along with palaeoecology, palaeoclimate, soil science and floristic inventories, have started to transform our understanding of plant exploitation, cultivation and domestication in tropical South America. Archaeobotanical studies are providing a far greater appreciation of the role of plants in the diets of early colonists. Since ∼13ka, these diets relied mainly on palm, tree fruits, and underground tubers, along with terrestrial and riverine faunal resources. Recent evidence indicates two areas of precocious plant cultivation and domestication: the sub-Andean montane forest of NW South America and the shrub savannahs and seasonal forests of SW Amazonia. In the latter area, thousands of anthropic keystone structures represented by forest islands show a significant human footprint in Amazonia from the start of the Holocene. While radiocarbon date databases show a decline in population during the middle Holocene, important developments happened during this epoch, including the domestication of cacao, the adoption of maize and the spread of manioc across the basin. The late Holocene witnessed the domestication of rice and the development of agricultural landscapes characterised by raised fields and Amazonian Dark Earths (ADEs). Our multi-proxy analysis of 23 late Holocene ADEs and two lakes from southern Amazonia provides the first direct evidence of field polyculture agriculture including the cultivation of maize, manioc, sweet potato, squash, arrowroot and leren within closed-canopy forest, as well as enrichment with palms, limited clearing for crop cultivation, and low-severity fire management. Collectively, the evidence shows that during the late Holocene Amazonian farmers engaged in intensive agriculture marked by the cultivation of both annual and perennial crops relying on organic amendments requiring soil preparation and maintenance. Our study has broader implications for sustainable Amazonian futures.


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The biobehavioural profiles of wild and domestic animals in adulthood

Behavioural aspects

As indicated above, domestic guinea pigs derived from the wild cavy at least 3,000 years ago. From behavioural observations it appears that the repertoire of behavioural patterns is similar in domesticated and wild guinea pigs, as is the case in other domesticated animals and their wild counterparts. Thus, domestication has not resulted in the loss or addition of behavioural elements [27–29, 43, 55].

Distinct differences, however, occur in behavioural frequencies and thresholds ([27–29] see Table 1): domestic guinea pigs exhibit less aggressive behaviour and more sociopositive behaviour than their wild ancestors. Thus, the process of domestication has led to traits - reduced aggressiveness, increased tolerance of conspecifics - that are typical of other domesticated species (e.g. rats: [61] cats: Zimmermann cited in [62] mallard ducks: Desforges and Wood-Gush cited in [11]). This shift in biobehavioural profile of guinea pigs likely developed during domestication because of the immense increase in population densities: wild cavies live in large home ranges from 200 m² up to 1000 m² [49, 50] domestic guinea pigs, however, can be kept in 6 m² enclosures with up to 20 adult animals [63]. Housing at such high density is probably possible because early breeders of wild cavies chose and selected for the most agreeable individuals, that is those that were least aggressive toward conspecifics as well as humans.

Other behavioural changes included an increase in the expression of overt courtship behaviour and in the tendency to vocalize in domestic guinea pigs (Table 1). Furthermore, domestic guinea pigs are less attentive to their physical environment than are wild cavies as indicated by, for instance, the incidence of rearing ([28, 29] Table 1). This reduction of alertness and sensitivity to environmental change is a further trait typical of domesticated animals [14, 21]. Wild forms of rats [64], dogs [21], pigs [65], and ducks [66] also direct greater attention to the environment than do their domestic counterparts. This is not surprising since a selection against overactive and nervous animals exists during domestication, and sensitivity confers no obvious selective advantage in captivity [67, 68].

Similarly, domestic guinea pigs show less exploratory behaviour than do wild cavies ([29] Table 1). A decline in exploration seems to be a general character of domestication that is also found in dogs, rats and mice ([69, 70] but see also [71]). In wild animals, exploratory behaviour is crucial for surviving in their natural habitat [72, 73]: animals have to explore to obtain access to vital resources such as food, water, shelter and mates. However, exploring new environments can be very risky and dangerous. For instance, in the natural habitat of the wild cavy Cavia aperea predation can be so severe that mortality rates of up to 50% are observed in a five month period [49]. In a second wild cavy species, Cavia magna, very high mortality rates also have been shown [74]. In contrast to this situation in the wild, domestication is characterised by a removal of dangerous and challenging environmental factors [14]. In man-made housing systems, guinea pigs are usually provided with all relevant resources and thus the selection pressure for high levels of exploration and risk-taking is removed.

Concerning learning and memory, Lewejohann et al. [30] tested wild and domestic guinea pigs in the Morris Water Maze, a frequently used test for the assessment of spatial learning in rodents (e.g. in guinea pigs: [75, 76]). Both wild cavies and domestic guinea pigs were able to learn the task. However, male as well as female domestic guinea pigs showed more-rapid acquisition of the task than did their wild conspecifics ([30] Table 1). In a discrimination task, domestic guinea pigs also performed better than wild cavies [77]. Furthermore the former learned an association and reversal more-rapidly than did the latter [78]. These findings are comparable to those in rats, in which the domestic form shows equivalent or even better performance in learning and memory tasks than their wild ancestor [79]. Thus, artificial selection and breeding does not necessarily lead to degenerated domestic animals with impaired cognitive abilities.

However, one should always be careful in claiming one form as being superior to the other in learning and memory. Performance can depend on the origin of the animals as well as the type of cues used in the tasks. Domesticated and wild gerbils both born in captivity showed similar performance in an auditory discrimination learning task, whereas gerbils caught in the wild performed more poorly [80]. Wild foxes were less able to learn using human gestures as cues compared with domesticated foxes however, in a control task using non-social cues, the wild foxes were found to be more skilled [81]. A comparison between dogs and wolves revealed that domestication improved performance in animal-human cooperative interactions [82], whereas wolves outperformed dogs in an imitation task: wolves learned quickly to open a box after a conspecific had demonstrated how to succeed in contrast, dogs were not able to solve the task [83].

Hormonal aspects

A series of experiments has been conducted to compare the endocrine profile of wild and domestic guinea pigs: while resting, cortisol levels of domestic guinea pigs and cavies in their familiar home enclosure are not different. Wild cavies respond with a larger magnitude increase of their serum cortisol concentrations when exposed to a novel environment than do domestic guinea pigs ([28, 29] Table 1). Furthermore, serum concentrations of epinephrine and norepinephrine are distinctly higher in the wild than in the domesticated form in response to removal from their homecages ([27–29] Table 1). Overall, domestic guinea pigs respond to stressors with a smaller response of the hypothalamo-pituitary-adrenocortical (HPA)- and the sympathetic-adrenomedullary (SAM)-systems than their wild counterparts. In addition, significantly lower cortisol levels in response to adrenocorticotropic hormone (ACTH) application indicate a reduction in adrenocortical sensitivity in domestic guinea pigs ([27–29] Table 1). In general, this lower responsiveness can be regarded as a physiological correlate of the reduced alertness, nervousness, and sensitivity of the domesticated animals compared to their wild counterparts. The lower stress response would seem to be sufficient for domestic animals maintained in artificial housing conditions. Wild animals, however, live in much more challenging environments and thus higher endocrine responsiveness to stressors appears to have evolved for this reason [28]. The activation of each of these systems provides the organism with energy and shifts it into a state of heightened reactivity that is a prerequisite for responding to environmental challenges in an appropriate way. Finally, guinea pigs have higher basal plasma testosterone levels than do wild cavies ([28] Table 1). As mentioned above, guinea pigs also show higher levels of courtship behaviour. There might be a causal relation between higher frequencies of courtship behaviour and higher testosterone concentrations in guinea pigs though the direction of this putative relation is unclear. That is, social interactions including courtship behaviour can result in increased testosterone titers [84–87] and elevated testosterone can increase courtship behaviour [88, 89].


Future Research

Recent research on the initial development and subsequent expansion of domestication and agricultural economies in the Mediterranean Basin provides a clear roadmap for future research. This is especially true for the Fertile Crescent where recent advances are transforming our understanding of the origins of plant and animal domestication in this key heartland region. Traditional approaches to documenting domestication relied on the appearance of genetically driven morphological change (i.e., the development of nonshattering seed heads in cereals and body size reduction in animals). The development of new analytical approaches has, however, provided a window into the preceding processes of human interaction with target plant and animal species and the genetic responses to this interaction that eventually resulted in morphological change. Researchers in the Fertile Crescent are detecting early signs of human ecosystem engineering aimed at encouraging plant production (24, 25) they are able to document the manipulation of herd structure to promote a secure and predictable yield of animal products (7, 8, 10, 11). In both plants and animals these new indicators precede the manifestation of traditional morphological markers of domestication by hundreds, if not thousands, of years. Estimating exactly when during this extended coevolutionary process a plant or animal species crossed the domestic threshold is now more a semantic issue than a substantive research question (20, 93). Although some researchers may require the appearance of specific morphological traits before conferring domestic status, others may be more willing to consider a managed animal or a cultivated plant as having achieved this status. Regardless of where one chooses to draw the line between wild and domestic, recent advances have provided researchers with powerful new tools capable of examining the entire process of domestication, not just its morphological impacts which, if they occur at all, only appear after the process is well underway.

Just how far back this process of active human resource management goes or how widespread it was in the Fertile Crescent is, at this point, an open question. The early dispersal of an integrated economy based on crop plants and managed animals to Cyprus at least 2,000 years before the apparent crystallization of agricultural economies on the mainland, however, suggests that our understanding of plant and animal domestication and agricultural emergence on the mainland is, at best, incomplete. Researchers working in this area are only just beginning to realize the potential of these newly available analytic tools. Additional even more effective analytical approaches will almost certainly be developed in the future as researchers embrace this broader concept of domestication and begin to exploit the many opportunities available in the Fertile Crescent region for documenting it.

Recent research has also shown that the dispersal of domesticates and the Neolithic way of life west across the Mediterranean Basin was much more complex and multifaceted than previous prime mover models could accommodate. To varying degrees, in different areas, this process involved elements of demic diffusion, local adoption, and independent domestication. But the outlines of this complex process are just beginning to come into focus. Maritime colonization of the Mediterranean clearly involved not one, but multiple unrelated seaborne migrations (52). The cultural context of these migratory movements, their causes, their routes, their timing, and their tempo all call out for additional investigation. The southern margin of the Mediterranean Basis along coastal North Africa is essentially terra incognita for understanding the course of Neolithic emergence and seems an especially promising region for future research (60).

The subsequent inland transfer of domesticates, agriculture, and associated Neolithic lifeways from newly arrived colonists to indigenous populations around the Mediterranean Basin is another intriguing research area that will benefit from recent advances in our ability to detect and date domesticates in the archaeological record. Careful analysis of increasingly more precise radiocarbon dates will continue to be critical in discriminating between demic diffusion and selective adoption of Neolithic components in different parts of the Mediterranean (e.g., ref. 94). New demographic techniques for profiling prey strategies, morphometric techniques capable of tracking genetic and plastic responses to human management, isotopic analysis, and the increasing success of ancient DNA studies of domesticates will enhance our understanding of the ways in which both colonists and local populations adapted management strategies to these new environments.

There are also obvious opportunities for those interested in understanding the independent domestication of European wild species. Larson et al. (23), for example, suggest that European wild boar were domesticated only after the introduction of Near Eastern domestic swine, representing a case of apparent technology transfer rather than truly independent domestication. Local, culturally independent domestication of indigenous wild pigs, however, still cannot be ruled out. Application of enhanced archaeological and genetic techniques for detecting and dating domestication to both extant and yet-to-be-recovered assemblages is key to understanding patterns of indigenous domestication around the Mediterranean Basin.

Finally, although we may never be able to detect the final coup de grâce for endemic island faunas, the future holds considerable promise for a much fuller understanding of the human impact on Mediterranean biodiversity. As it has in the Gymnesic islands and on Cyprus, “carpet-dating” large numbers of archaeological materials by the small-sample atomic mass spectrometry radiocarbon method will certainly help refine the chronology of the disappearance of endemic island faunas and the arrival of human colonists. Application of demographic profiling techniques to the remains of these animals may make it possible to distinguish between natural-death accumulations and prey assemblages resulting from human predation. Similarly, recognition of the broader role of humans in shaping post-Neolithic environments is central to understanding how Mediterranean biodiversity evolved and how we might best work to conserve it. The archaeobiological sciences have a valuable role to play in providing greater time depth to biodiversity studies by monitoring the creation of anthropogenic ecosystems and tracing the development and impacts of both environmentally sustainable and destructive agricultural economies over thousands of years of human occupation.


MULTIPLE DOMESTICATION AND MULTIPLE ORIGINS OF DOMESTICATION TRAITS

A feature of crop domestication in the Americas is the number of examples of independent domestication of different species in the same genus, or occasionally of the same species (Table 2). New World crops are therefore potentially useful resources for investigating the still-unresolved question of whether similar changes have been selected independently, resulting in parallel or convergent evolution of the domestication syndrome, or whether different mutations have been selected in different regions, so that similar phenotypes are actually controlled by different genotypes.

Genera in which two or more species have been domesticated in the Americas and regions of domestication of the relevant species

Family/genus . Eastern North America . Mesoamerica . Andean region . Tropical lowland South America . Comments .
Amaranthaceae
Amaranthus A. cruentus A. hypochondriacusA. caudatus Still unclear whether there was more than one domestication from distinct wild progenitors or whether a single domestication was followed by speciation
Chenopodiaceae
ChenopodiumC. berlandieri ssp. jonesianumC. berlandieri ssp. nuttalliaeC. quinoa C. pallidicaule Not yet conclusively established that C. berlandieri was domesticated independently in North America and Mesoamerica
Cucurbitaceae
CucurbitaC. pepo ssp. oviferaC. pepo ssp. pepo C. argyrospermaC. ficifolia C. maxima Ancestry of C. moschata and hence whether it was domesticated more than once still uncertain
C. moschataC. moschata
Fabaceae
Arachis A. hypogaea A. villosulicarpa
Canavalia C. ensiformisC. plagiosperma C. ensiformis and C. plagiosperma are reported to produce fertile hybrids, so their status as distinct species and possible independent domestication need reinvestigation
Pachyrhizus P. erosusP. ahipaP. tuberosusP. erosus and P. tuberosus may be conspecific, hence possibly not independently domesticated. The wild progenitor of P. ahipa is not known.
Phaseolus P. vulgarisP. vulgaris
P. lunatusP. lunatus
P. coccineus
P. acutifolius
P. dumosus
Malvaceae
Gossypium G. hirsutumG. barbadense
Solanaceae
Capsicum C. annuumC. baccatumC. chinense
C. frutescensC. pubescens
Nicotiana N. rustica
N. tabacum
Physalis P. philadelphicaP. peruviana
Solanum
Sect. Basarthrum S. muricatum
Sect. Lasiocarpa S. quitoenseS. sessiliflorum
Sect. Petota S. tuberosum
Family/genus . Eastern North America . Mesoamerica . Andean region . Tropical lowland South America . Comments .
Amaranthaceae
Amaranthus A. cruentus A. hypochondriacusA. caudatus Still unclear whether there was more than one domestication from distinct wild progenitors or whether a single domestication was followed by speciation
Chenopodiaceae
ChenopodiumC. berlandieri ssp. jonesianumC. berlandieri ssp. nuttalliaeC. quinoa C. pallidicaule Not yet conclusively established that C. berlandieri was domesticated independently in North America and Mesoamerica
Cucurbitaceae
CucurbitaC. pepo ssp. oviferaC. pepo ssp. pepo C. argyrospermaC. ficifolia C. maxima Ancestry of C. moschata and hence whether it was domesticated more than once still uncertain
C. moschataC. moschata
Fabaceae
Arachis A. hypogaea A. villosulicarpa
Canavalia C. ensiformisC. plagiosperma C. ensiformis and C. plagiosperma are reported to produce fertile hybrids, so their status as distinct species and possible independent domestication need reinvestigation
Pachyrhizus P. erosusP. ahipaP. tuberosusP. erosus and P. tuberosus may be conspecific, hence possibly not independently domesticated. The wild progenitor of P. ahipa is not known.
Phaseolus P. vulgarisP. vulgaris
P. lunatusP. lunatus
P. coccineus
P. acutifolius
P. dumosus
Malvaceae
Gossypium G. hirsutumG. barbadense
Solanaceae
Capsicum C. annuumC. baccatumC. chinense
C. frutescensC. pubescens
Nicotiana N. rustica
N. tabacum
Physalis P. philadelphicaP. peruviana
Solanum
Sect. Basarthrum S. muricatum
Sect. Lasiocarpa S. quitoenseS. sessiliflorum
Sect. Petota S. tuberosum

Genera in which two or more species have been domesticated in the Americas and regions of domestication of the relevant species

Family/genus . Eastern North America . Mesoamerica . Andean region . Tropical lowland South America . Comments .
Amaranthaceae
Amaranthus A. cruentus A. hypochondriacusA. caudatus Still unclear whether there was more than one domestication from distinct wild progenitors or whether a single domestication was followed by speciation
Chenopodiaceae
ChenopodiumC. berlandieri ssp. jonesianumC. berlandieri ssp. nuttalliaeC. quinoa C. pallidicaule Not yet conclusively established that C. berlandieri was domesticated independently in North America and Mesoamerica
Cucurbitaceae
CucurbitaC. pepo ssp. oviferaC. pepo ssp. pepo C. argyrospermaC. ficifolia C. maxima Ancestry of C. moschata and hence whether it was domesticated more than once still uncertain
C. moschataC. moschata
Fabaceae
Arachis A. hypogaea A. villosulicarpa
Canavalia C. ensiformisC. plagiosperma C. ensiformis and C. plagiosperma are reported to produce fertile hybrids, so their status as distinct species and possible independent domestication need reinvestigation
Pachyrhizus P. erosusP. ahipaP. tuberosusP. erosus and P. tuberosus may be conspecific, hence possibly not independently domesticated. The wild progenitor of P. ahipa is not known.
Phaseolus P. vulgarisP. vulgaris
P. lunatusP. lunatus
P. coccineus
P. acutifolius
P. dumosus
Malvaceae
Gossypium G. hirsutumG. barbadense
Solanaceae
Capsicum C. annuumC. baccatumC. chinense
C. frutescensC. pubescens
Nicotiana N. rustica
N. tabacum
Physalis P. philadelphicaP. peruviana
Solanum
Sect. Basarthrum S. muricatum
Sect. Lasiocarpa S. quitoenseS. sessiliflorum
Sect. Petota S. tuberosum
Family/genus . Eastern North America . Mesoamerica . Andean region . Tropical lowland South America . Comments .
Amaranthaceae
Amaranthus A. cruentus A. hypochondriacusA. caudatus Still unclear whether there was more than one domestication from distinct wild progenitors or whether a single domestication was followed by speciation
Chenopodiaceae
ChenopodiumC. berlandieri ssp. jonesianumC. berlandieri ssp. nuttalliaeC. quinoa C. pallidicaule Not yet conclusively established that C. berlandieri was domesticated independently in North America and Mesoamerica
Cucurbitaceae
CucurbitaC. pepo ssp. oviferaC. pepo ssp. pepo C. argyrospermaC. ficifolia C. maxima Ancestry of C. moschata and hence whether it was domesticated more than once still uncertain
C. moschataC. moschata
Fabaceae
Arachis A. hypogaea A. villosulicarpa
Canavalia C. ensiformisC. plagiosperma C. ensiformis and C. plagiosperma are reported to produce fertile hybrids, so their status as distinct species and possible independent domestication need reinvestigation
Pachyrhizus P. erosusP. ahipaP. tuberosusP. erosus and P. tuberosus may be conspecific, hence possibly not independently domesticated. The wild progenitor of P. ahipa is not known.
Phaseolus P. vulgarisP. vulgaris
P. lunatusP. lunatus
P. coccineus
P. acutifolius
P. dumosus
Malvaceae
Gossypium G. hirsutumG. barbadense
Solanaceae
Capsicum C. annuumC. baccatumC. chinense
C. frutescensC. pubescens
Nicotiana N. rustica
N. tabacum
Physalis P. philadelphicaP. peruviana
Solanum
Sect. Basarthrum S. muricatum
Sect. Lasiocarpa S. quitoenseS. sessiliflorum
Sect. Petota S. tuberosum

Prior to the advent of molecular genetics, this question could be addressed only by crossing the related domesticates. If the F1 shows the wild-type phenotype, then the two domesticates are assumed to carry mutations at different, complementary, loci and thus to have evolved the trait in question independently. Cheng (1989) crossed a non-pungent bell pepper (Capsicum annuum) with a non-pungent accession of the closely related C. chinense, and found that the F1 had extremely pungent fruit. This suggests that the pathway to synthesis of the pungent principle, capsaicin, is blocked at a different point in each species and that different mutations to non-pungency have been selected in what are regarded, on morphological and cytological grounds, as independently domesticated taxa ( Pickersgill et al., 1979). Similarly, when the South American domesticate Chenopodium quinoa, which has pale seeds, was crossed with a pale-seeded accession of the Mesoamerican domesticate C. berlandieri ssp. nuttalliae, the F1 had black seeds ( Heiser and Nelson, 1979), so pale seeds are presumably controlled by mutations in different genes in the two species, supporting the view that each was domesticated independently.

Studies on crosses between the domesticated species of Cucurbita have given somewhat ambiguous results. Bush vs. wild-type vine habit has been reported to be controlled by a single gene, probably the same gene, in C. pepo and C. maxima ( Robinson et al., 1976). Whitaker (1951) showed that the hard rind of wild C. andreana is dominant to the soft rind of domesticated C. maxima and controlled by a single gene. Pearson et al. (1951) crossed cultivars of C. moschata and C. maxima with soft rinds and found that fruits of the F1 had hard rinds when the cross was made in one direction, but soft rinds in the reciprocal cross. On the other hand, when Piperno et al. (2002) crossed the more closely related C. argyrosperma and C. moschata, again using cultivars with soft rinds as parents, fruits of the F1 and F2 all had soft rind. Borchers and Taylor (1988) found that the F1 hybrid between non-bitter cultivars of C. argyrosperma and C. pepo had bitter fruit and carried dominant alleles at three loci governing synthesis of cucurbitacins. The C. pepo parent was homozygous recessive at one of these loci and the C. argyrosperma parent was homozygous recessive at the other two, so synthesis of cucurbitacins was blocked at different points in the two species, implying that non-bitterness had been selected independently in each species. These various studies therefore suggest that for some elements of the domestication syndrome the same phenotype has a different genetic basis in different domesticates, but for other traits human selection under domestication may have favoured independently occurring mutations in the same gene.

In grain amaranths, crosses between pale-seeded forms of the two Mesoamerican domesticates, A. cruentus and A. hypochondriacus, and between A. hypochondriacus and Andean A. caudatus, produced only pale-seeded F1s ( Kulakow et al., 1985). Kulakow et al. (1985) argued from this that pale seed evolved only once, supporting the hypothesis that grain amaranths were domesticated only once in the Americas and the three species differentiated after domestication. Against this is the finding of Hauptli and Jain (1978) that different traits are correlated with yield in the different domesticates. In A. hypochondriacus, seed yield correlates with length of the inflorescence, and the number of female flowers per flower cluster is relatively constant, while in A. cruentus and A. caudatus seed yield is not correlated with length of inflorescence but with the number of female flowers per cluster. This suggests that selection for increased yield has proceeded independently in the different domesticates.

The study of complementation between alleles controlling similar traits in different species depends on the ability to cross domesticates belonging to different species. Barriers to crossing and sterility of interspecific hybrids often impose severe limitations on such studies. The data may also be equivocal because gene expression may change in hybrid genotypes. Comparative studies of the molecular basis of single-gene mutants selected under domestication may therefore be more informative with regard to multiple origins of traits of the domestication syndrome. It is difficult to obtain interspecific hybrids between domesticated accessions in Capsicum ( Pickersgill, 1971), so it has not been possible to determine whether the homologous series of variants in fruit colour represent the same mutations in the same genes in each domesticate. Now, however, it would be relatively easy to amplify the gene coding for CCS from yellow-fruited accessions of each domesticate and determine whether the deletion present in C. annuum is responsible for yellow fruit in the other domesticated species. Similarly, the gene coding for capsaicin synthase, the enzyme that catalyses the final step in the synthesis of capsaicin, has recently been identified ( Prasad et al., 2006), so it should be possible to compare sequences for this gene from pungent vs. non-pungent accessions of the different domesticated species.

Sequencing studies may also constitute a useful tool for investigating possible multiple origins and spread of particular variants within a crop. Mangelsdorf (1974) considered that the sweet corns of Middle and North America were all derived from a single Peruvian race. All are homozygous recessive su1 su1, but Whitt et al. (2002) have shown that North American sweet corns carry a nucleotide substitution resulting in a single amino acid change in the gene product, whereas in Mexican sweet corns a transposable element has inserted into exon 1 of su1. The ‘sweet’ mutation has therefore arisen independently at least twice and the sweet corns of North America and Mexico cannot both result from northward spread of a South American sweet corn. This example suggests caution in accepting apparent homology of the pale-seeded mutation in the different species of grain amaranth as evidence for a single domestication. If different changes have occurred in the nucleotide sequence of the gene responsible for pale seeds in the different species, then lack of complementation in the F1 of a cross between two pale-seeded species does not prove identity of the underlying mutations even though the mutations are in the same gene.


Mathematical models vs. intuition

With little archaeological evidence available, the researchers depended on computer models to tackle the age-old question of agriculture's origins.

These models allowed them to manipulate various variables, or parameters, that could contribute to the emergence of farming.

"Fundamentally, we don’t know what the values of those parameters are," says Thomas. Bowles and Choi approached that challenge by manipulating them one at a time.

"We don’t like that approach," Thomas says.

So instead, their team varied all the parameters simultaneously, to see how the model was behaving overall, Thomas explains.

Their model identified which factors – group size, conservatism, property rights, but not field productivity – played key roles in the emergence of farming.

But the question of why comes down to intuition – which the mathematicians hold at arm's length.

"The whole point of modeling is to show things you can’t intuit," says Thomas. "Our intuitions trick us frequently. They shouldn’t always be trusted," he warns.

For example, it’s surprising that productivity may not have mattered to the shift to farming. While we might assume humans would choose to get food in the most efficient way possible, their models suggest otherwise.


Differences among foraging, cultivation, domestication - History

For roughly 90% of history, humans were foragers who used simple technology to gather, fish, and hunt wild food resources. Today only about a quarter million people living in marginal environments, e.g., deserts, the Arctic and topical forests, forage as their primary subsistence strategy. While studying foraging societies allows anthropologists to understand their cultures in their own right, the data from these studies provides us with an avenue to understanding past cultures.

General Characteristics

While the resources foraging groups utilize vary depending on the environment, there are some common characteristics among foragers:

  • Foragers generally make their own tools using materials available in the local environment, however, through the process of development and increasing contact with other groups of people, machine made tools are making their way into foraging societies.
  • There is a high degree of mobility as the group may follow migrating herds or seasonally available resources.
  • Group size and population density is small so as not to surpass the carrying capacity of the environment.
  • Resource use is extensive and temporary. In other words, foragers may use a wide-variety of resources over a large territory however, they leave enough resources so that the area can regenerate. Once the resources reach a certain level, the group moves on.
  • Permanent settlements are rare.
  • Production is for personal use or to share and trade.
  • The division of labor tends to be divided by age and gender.
  • Kin relations are usually reckoned on both the mother and father’s side.
  • There is usually no concept of personal ownership, particularly of land.
  • If left to follow traditional patterns, foraging as a subsistence strategy is highly sustainable.

Types of Foraging Groups

Haida village, Wrangel, Alaska circa 1902

Aquatic: Aquatic foragers, like the Ou Haadas, or the Haida, who live in the Queen Charlotte Islands, British Columbia, Canada, and Prince of Wales Island in Alaska, United States, rely primarily on resources from water. At the time of contact with Europeans, the Haidu utilized a wide variety of foods from the surrounding waters, including salmon, halibut, crabs, scallops, sea cucumber, sea lion, otters, and seaweed. They also hunted for land mammals like bear and deer and gathered wild plants such as rhubarb, fern, and berries.

Pedestrian: As the name implies, pedestrian foragers get their food by collecting on foot. The !Kung San are more properly known as the Zhu|õasi. They live in the Kalahari desert are one example of a pedestrian foraging group. The Zhu|õasi use about 100 species of animals and over 150 species of plants, although not all are used for food. The primary food source is the mongongo nut that is high in protein. The Zhu|õasi eat their way out of areas, starting with their favorite food and then the less desirable food. Once the resources get low, the group will move to a new area. The Zhu|õasi also move seasonally as resources become available. During the rainy season, the Zhu|õasi live in small groups of 2-3 families. In the dry season, large camps of 20-40 people are established near permanent water sources.

Equestrian: Equestrian foragers are the most rare type of foraging group, being identified only the Great Plains of North America and the pampas and steppes of South America. This type of foraging strategy emerged after contact with European settlers who reintroduced the horse to the Americas. The Aonikenks live on the Patagonian Steppes of South America. The Aonikenks, also called the Tehuelche or people of the south, hunted guanaco, an indigenous camelid, in seasonal rounds. They also ate rhea (sometimes referred to as the South American ostrich), roots, and seeds.


Contents

Origin hypotheses Edit

Scholars have developed a number of hypotheses to explain the historical origins of agriculture. Studies of the transition from hunter-gatherer to agricultural societies indicate an antecedent period of intensification and increasing sedentism examples are the Natufian culture in the Levant, and the Early Chinese Neolithic in China. Current models indicate that wild stands that had been harvested previously started to be planted, but were not immediately domesticated. [8] [9]

Localised climate change is the favoured explanation for the origins of agriculture in the Levant. [10] When major climate change took place after the last ice age (c. 11,000 BC), much of the earth became subject to long dry seasons. [11] These conditions favoured annual plants which die off in the long dry season, leaving a dormant seed or tuber. An abundance of readily storable wild grains and pulses enabled hunter-gatherers in some areas to form the first settled villages at this time. [12]

Early development Edit

Early people began altering communities of flora and fauna for their own benefit through means such as fire-stick farming and forest gardening very early. [13] [14] [15] Wild grains have been collected and eaten from at least 105,000 years ago, and possibly much longer. [1] Exact dates are hard to determine, as people collected and ate seeds before domesticating them, and plant characteristics may have changed during this period without human selection. An example is the semi-tough rachis and larger seeds of cereals from just after the Younger Dryas (about 9500 BC) in the early Holocene in the Levant region of the Fertile Crescent. Monophyletic characteristics were attained without any human intervention, implying that apparent domestication of the cereal rachis could have occurred quite naturally. [16]

Spontaneous grain collection seems to have progressed naturally to consciously planting grain. An example of this is the Natufian culture in what would someday be Jordan and Israel, which had been dependent upon grains gathered from natural grasslands for millenia. These grains were ground into flour and made into pita-like bread. They began clearing brush and planting grain about 10,000BC, around the time of the Younger Dryas, a thousand-year-long period of abnormally dry climate that may have endangered the natural grasslands, causing them to be outcompeted by dryland scrub.

Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin. [17] Some of the earliest known domestications were of animals. Domestic pigs had multiple centers of origin in Eurasia, including Europe, East Asia and Southwest Asia [18] and in Southeast Asia, [19] where wild boar were first domesticated about 10,500 years ago [20] while native pigs in Southeast Asia were domesticated 50,000 years ago. [21] Sheep were domesticated in Mesopotamia between 11,000 BC and 9000 BC. [22] Cattle were domesticated from the wild aurochs in the areas of modern Turkey and Pakistan around 8500 BC. [23] Camels were domesticated late, perhaps around 3000 BC. [24]

It was not until after 9500 BC that the eight so-called founder crops of agriculture appear: first emmer and einkorn wheat, then hulled barley, peas, lentils, bitter vetch, chick peas and flax. These eight crops occur more or less simultaneously on Pre-Pottery Neolithic B (PPNB) sites in the Levant, although wheat was the first to be grown and harvested on a significant scale. At around the same time (9400 BC), parthenocarpic fig trees were domesticated. [26] [27]

Domesticated rye occurs in small quantities at some Neolithic sites in (Asia Minor) Turkey, such as the Pre-Pottery Neolithic B (c. 7600 – c. 6000 BC) Can Hasan III near Çatalhöyük, [28] but is otherwise absent until the Bronze Age of central Europe, c. 1800–1500 BC. [29] Claims of much earlier cultivation of rye, at the Epipalaeolithic site of Tell Abu Hureyra in the Euphrates valley of northern Syria, remain controversial. [30] Critics point to inconsistencies in the radiocarbon dates, and identifications based solely on grain, rather than on chaff. [31]

By 8000 BC, farming was entrenched on the banks of the Nile. About this time, agriculture was developed independently in the Far East, probably in China, with rice rather than wheat as the primary crop. Maize was domesticated from the wild grass teosinte in West Mexico by 6700 BC. [32] The potato (8000 BC), tomato, [33] pepper (4000 BC), squash (8000 BC) and several varieties of bean (8000 BC onwards) were domesticated in the New World. [34]

Agriculture was independently developed on the island of New Guinea. [35] Banana cultivation of Musa acuminata, including hybridization, dates back to 5000 BC, and possibly to 8000 BC, in Papua New Guinea. [36] [37]

Bees were kept for honey in the Middle East around 7000 BC. [38] Archaeological evidence from various sites on the Iberian peninsula suggest the domestication of plants and animals between 6000 and 4500 BC. [39] Céide Fields in Ireland, consisting of extensive tracts of land enclosed by stone walls, date to 3500 BC and are the oldest known field systems in the world. [40] [41] The horse was domesticated in the Pontic steppe around 4000 BC. [42] In Siberia, Cannabis was in use in China in Neolithic times and may have been domesticated there it was in use both as a fibre for ropemaking and as a medicine in Ancient Egypt by about 2350 BC. [43]

In northern China, millet was domesticated by early Sino-Tibetan speakers at around 8000 to 6000 BC, becoming the main crop of the Yellow River basin by 5500 BC. [44] [45] They were followed by mung, soy and azuki beans.

In southern China, rice was domesticated in the Yangtze River basin at around 11,500 to 6200 BC, along with the development of wetland agriculture, by early Austronesian and Hmong-Mien-speakers. Other food plants were also harvested, including acorns, water chestnuts, and foxnuts. [4] [44] [47] [48] Rice cultivation was later spread to Island Southeast Asia by the Austronesian expansion, starting at around 3,500 to 2,000 BC. This migration event also saw the introduction of cultivated and domesticated food plants from Taiwan, Island Southeast Asia, and New Guinea into the Pacific Islands as canoe plants. Contact with Sri Lanka and Southern India by Austronesian sailors also led to an exchange of food plants which later became the origin of the valuable spice trade. [49] [50] [51] In the 1st millennium AD, Austronesian sailors also settled Madagascar and the Comoros, bringing Southeast Asian and South Asian food plants with them to the East African coast, including bananas and rice. [52] [53] Rice was also spread southwards into Mainland Southeast Asia by around 2000 to 1500 BC by the migrations of the early Austroasiatic and Kra-Dai-speakers. [47]

In the Sahel region of Africa, sorghum was domesticated by 3000 BC in Sudan [54] and pearl millet by 2500 BC in Mali. [55] Kola nut and coffee were also domesticated in Africa. [56] In New Guinea, ancient Papuan peoples began practicing agriculture around 7000 BC, domesticating sugarcane and taro. [57] In the Indus Valley from the eighth millennium BC onwards at Mehrgarh, 2-row and 6-row barley were cultivated, along with einkorn, emmer, and durum wheats, and dates. In the earliest levels of Merhgarh, wild game such as gazelle, swamp deer, blackbuck, chital, wild ass, wild goat, wild sheep, boar, and nilgai were all hunted for food. These are successively replaced by domesticated sheep, goats, and humped zebu cattle by the fifth millennium BC, indicating the gradual transition from hunting and gathering to agriculture. [58]

Maize and squash were domesticated in Mesoamerica potato in South America, and sunflower in the Eastern Woodlands of North America. [59]

Sumer Edit

Sumerian farmers grew the cereals barley and wheat, starting to live in villages from about 8000 BC. Given the low rainfall of the region, agriculture relied on the Tigris and Euphrates rivers. Irrigation canals leading from the rivers permitted the growth of cereals in large enough quantities to support cities. The first ploughs appear in pictographs from Uruk around 3000 BC seed-ploughs that funneled seed into the ploughed furrow appear on seals around 2300 BC. Vegetable crops included chickpeas, lentils, peas, beans, onions, garlic, lettuce, leeks and mustard. They grew fruits including dates, grapes, apples, melons, and figs. Alongside their farming, Sumerians also caught fish and hunted fowl and gazelle. The meat of sheep, goats, cows and poultry was eaten, mainly by the elite. Fish was preserved by drying, salting and smoking. [60] [61]

Ancient Egypt Edit

The civilization of Ancient Egypt was indebted to the Nile River and its dependable seasonal flooding. The river's predictability and the fertile soil allowed the Egyptians to build an empire on the basis of great agricultural wealth. Egyptians were among the first peoples to practice agriculture on a large scale, starting in the pre-dynastic period from the end of the Paleolithic into the Neolithic, between around 10,000 BC and 4000 BC. [62] This was made possible with the development of basin irrigation. [63] Their staple food crops were grains such as wheat and barley, alongside industrial crops such as flax and papyrus. [62]

Indus Valley Edit

Jujube was domesticated in the Indian subcontinent by 9000 BC. [64] Barley and wheat cultivation – along with the domestication of cattle, primarily sheep and goats – followed in Mehrgarh culture by 8000–6000 BC. [65] [66] [67] This period also saw the first domestication of the elephant. [64] Pastoral farming in India included threshing, planting crops in rows – either of two or of six – and storing grain in granaries. [66] [68] Cotton was cultivated by the 5th–4th millennium BC. [69] By the 5th millennium BC, agricultural communities became widespread in Kashmir. [66] Irrigation was developed in the Indus Valley Civilization by around 4500 BC. [70] The size and prosperity of the Indus civilization grew as a result of this innovation, leading to more thoroughly planned settlements which used drainage and sewers. [70] Archeological evidence of an animal-drawn plough dates back to 2500 BC in the Indus Valley Civilization. [71]

Ancient China Edit

Records from the Warring States, Qin dynasty, and Han dynasty provide a picture of early Chinese agriculture from the 5th century BC to 2nd century AD which included a nationwide granary system and widespread use of sericulture. An important early Chinese book on agriculture is the Qimin Yaoshu of AD 535, written by Jia Sixie. [72] Jia's writing style was straightforward and lucid relative to the elaborate and allusive writing typical of the time. Jia's book was also very long, with over one hundred thousand written Chinese characters, and it quoted many other Chinese books that were written previously, but no longer survive. [73] The contents of Jia's 6th century book include sections on land preparation, seeding, cultivation, orchard management, forestry, and animal husbandry. The book also includes peripherally related content covering trade and culinary uses for crops. [74] The work and the style in which it was written proved influential on later Chinese agronomists, such as Wang Zhen and his groundbreaking Nong Shu of 1313. [73]

For agricultural purposes, the Chinese had innovated the hydraulic-powered trip hammer by the 1st century BC. [75] Although it found other purposes, its main function to pound, decorticate, and polish grain that otherwise would have been done manually. The Chinese also began using the square-pallet chain pump by the 1st century AD, powered by a waterwheel or oxen pulling an on a system of mechanical wheels. [76] Although the chain pump found use in public works of providing water for urban and palatial pipe systems, [77] it was used largely to lift water from a lower to higher elevation in filling irrigation canals and channels for farmland. [78] By the end of the Han dynasty in the late 2nd century, heavy ploughs had been developed with iron ploughshares and mouldboards. [79] [80] These slowly spread west, revolutionizing farming in Northern Europe by the 10th century. (Thomas Glick, however, argues for a development of the Chinese plough as late as the 9th century, implying its spread east from similar designs known in Italy by the 7th century.) [81]

Asian rice was domesticated 8,200–13,500 years ago in China, with a single genetic origin from the wild rice Oryza rufipogon, [4] in the Pearl River valley region of China. Rice cultivation then spread to South and Southeast Asia. [82]

Ancient Greece and Hellenistic world Edit

The major cereal crops of the ancient Mediterranean region were wheat, emmer, and barley, while common vegetables included peas, beans, fava, and olives, dairy products came mostly from sheep and goats, and meat, which was consumed on rare occasion for most people, usually consisted of pork, beef, and lamb. [83] Agriculture in ancient Greece was hindered by the topography of mainland Greece that only allowed for roughly 10% of the land to be cultivated properly, necessitating the specialized exportation of oil and wine and importation of grains from Thrace (centered in what is now Bulgaria) and the Greek colonies of southern Russia. During the Hellenistic period, the Ptolemaic Empire controlled Egypt, Cyprus, Phoenicia, and Cyrenaica, major grain-producing regions that mainland Greeks depended on for subsistence, while the Ptolemaic grain market also played a critical role in the rise of the Roman Republic. In the Seleucid Empire, Mesopotamia was a crucial area for the production of wheat, while nomadic animal husbandry was also practiced in other parts. [84]

Roman Empire Edit

In the Greco-Roman world of Classical antiquity, Roman agriculture was built on techniques originally pioneered by the Sumerians, transmitted to them by subsequent cultures, with a specific emphasis on the cultivation of crops for trade and export. The Romans laid the groundwork for the manorial economic system, involving serfdom, which flourished in the Middle Ages. The farm sizes in Rome can be divided into three categories. Small farms were from 18–88 iugera (one iugerum is equal to about 0.65 acre). Medium-sized farms were from 80–500 iugera (singular iugerum). Large estates (called latifundia) were over 500 iugera. The Romans had four systems of farm management: direct work by owner and his family slaves doing work under supervision of slave managers tenant farming or sharecropping in which the owner and a tenant divide up a farm's produce and situations in which a farm was leased to a tenant. [85]

Mesoamerica Edit

In Mesoamerica, wild teosinte was transformed through human selection into the ancestor of modern maize, more than 6,000 years ago. It gradually spread across North America and was the major crop of Native Americans at the time of European exploration. [86] Other Mesoamerican crops include hundreds of varieties of locally domesticated squash and beans, while cocoa, also domesticated in the region, was a major crop. [57] The turkey, one of the most important meat birds, was probably domesticated in Mexico or the U.S. Southwest. [87]

In Mesoamerica, the Aztecs were active farmers and had an agriculturally focused economy. The land around Lake Texcoco was fertile, but not large enough to produce the amount of food needed for the population of their expanding empire. The Aztecs developed irrigation systems, formed terraced hillsides, fertilized their soil, and developed chinampas or artificial islands, also known as "floating gardens". The Mayas between 400 BC to 900 AD used extensive canal and raised field systems to farm swampland on the Yucatán Peninsula. [88] [89]

South America Edit

In the Andes region of South America, with civilizations including the Inca, the major crop was the potato, domesticated approximately 7,000–10,000 years ago. [90] [91] [92] Coca, still a major crop to this day, was domesticated in the Andes, as were the peanut, tomato, tobacco, and pineapple. [57] Cotton was domesticated in Peru by 3600 BC. [93] Animals were also domesticated, including llamas, alpacas, and guinea pigs. [94]

Guaitecas Archipelago in Patagonia made up the southern limit of Pre-Hispanic agriculture, [95] as noted by the mention of the cultivation of Chiloé potatoes by a Spanish expedition in 1557. [96] The presence of maize in Guaitecas Archipelago is also mentioned by early Spanish explorers, albeit the Spanish may have misidentified the plant. [97]

North America Edit

The indigenous people of the Eastern U.S. domesticated numerous crops. Sunflowers, tobacco, [98] varieties of squash and Chenopodium, as well as crops no longer grown, including marsh elder and little barley, were domesticated. [99] [100] Wild foods including wild rice and maple sugar were harvested. [101] The domesticated strawberry is a hybrid of a Chilean and a North American species, developed by breeding in Europe and North America. [102] Two major crops, pecans and Concord grapes, were utilized extensively in prehistoric times but do not appear to have been domesticated until the 19th century. [103] [104]

The indigenous people in what is now California and the Pacific Northwest practiced various forms of forest gardening and fire-stick farming in the forests, grasslands, mixed woodlands, and wetlands, ensuring that desired food and medicine plants continued to be available. The natives controlled fire on a regional scale to create a low-intensity fire ecology which prevented larger, catastrophic fires and sustained a low-density agriculture in loose rotation a sort of "wild" permaculture. [105] [106] [107] [108]

A system of companion planting called the Three Sisters was developed in North America. Three crops that complemented each other were planted together: winter squash, maize (corn), and climbing beans (typically tepary beans or common beans). The maize provides a structure for the beans to climb, eliminating the need for poles. The beans provide the nitrogen to the soil that the other plants use, and the squash spreads along the ground, blocking the sunlight, helping prevent the establishment of weeds. The squash leaves also act as a "living mulch". [109] [110]

Australia Edit

Indigenous Australians were nomadic hunter-gatherers. Due to the policy of terra nullius, Aboriginals were regarded as not having been capable of sustained agriculture. However, the current consensus is that various agricultural methods were employed by the indigenous people. [111] [112] [113]

In two regions of Central Australia, the central west coast and eastern central Australia, forms of agriculture were practiced. People living in permanent settlements of over 200 residents sowed or planted on a large scale and stored the harvested food. The Nhanda and Amangu of the central west coast grew yams (Dioscorea hastifolia), while various groups in eastern central Australia (the Corners Region) planted and harvested bush onions (yauaCyperus bulbosus), native millet (cooly, tindilPanicum decompositum) and a sporocarp, ngardu (Marsilea drummondii). [13] : 281–304 [9]

Indigenous Australians used systematic burning, fire-stick farming, to enhance natural productivity. [114] In the 1970s and 1980s archaeological research in south west Victoria established that the Gunditjmara and other groups had developed sophisticated eel farming and fish trapping systems over a period of nearly 5,000 years. [115] The archaeologist Harry Lourandos suggested in the 1980s that there was evidence of 'intensification' in progress across Australia, [116] a process that appeared to have continued through the preceding 5,000 years. These concepts led the historian Bill Gammage to argue that in effect the whole continent was a managed landscape. [13]

Torres Islanders are now known to have planted bananas. [117]

From 100 BC to 1600 AD, world population continued to grow along with land use, as evidenced by the rapid increase in methane emissions from cattle and the cultivation of rice. [118]

Arab world Edit

From the 8th century, the medieval Islamic world underwent a transformation in agricultural practice, described by the historian Andrew Watson as the Arab agricultural revolution. [119] This transformation was driven by a number of factors including the diffusion of many crops and plants along Muslim trade routes, the spread of more advanced farming techniques, and an agricultural-economic system which promoted increased yields and efficiency. The shift in agricultural practice changed the economy, population distribution, vegetation cover, agricultural production, population levels, urban growth, the distribution of the labour force, cooking, diet, and clothing across the Islamic world. Muslim traders covered much of the Old World, and trade enabled the diffusion of many crops, plants and farming techniques across the region, as well as the adaptation of crops, plants and techniques from beyond the Islamic world. [119] This diffusion introduced major crops to Europe by way of Al-Andalus, along with the techniques for their cultivation and cuisine. Sugar cane, rice, and cotton were among the major crops transferred, along with citrus and other fruit trees, nut trees, vegetables such as aubergine, spinach and chard, and the use of imported spices such as cumin, coriander, nutmeg and cinnamon. Intensive irrigation, crop rotation, and agricultural manuals were widely adopted. Irrigation, partly based on Roman technology, made use of noria water wheels, water mills, dams and reservoirs. [119] [120] [121]

Europe Edit

The Middle Ages saw further improvements in agriculture. Monasteries spread throughout Europe and became important centers for the collection of knowledge related to agriculture and forestry. The manorial system allowed large landowners to control their land and its laborers, in the form of peasants or serfs. [122] During the medieval period, the Arab world was critical in the exchange of crops and technology between the European, Asia and African continents. Besides transporting numerous crops, they introduced the concept of summer irrigation to Europe and developed the beginnings of the plantation system of sugarcane growing through the use of slaves for intensive cultivation. [123]

By AD 900, developments in iron smelting allowed for increased production in Europe, leading to developments in the production of agricultural implements such as ploughs, hand tools and horse shoes. The carruca heavy plough improved on the earlier scratch plough, with the adoption of the Chinese mouldboard plough to turn over the heavy, wet soils of northern Europe. This led to the clearing of northern European forests and an increase in agricultural production, which in turn led to an increase in population. [124] [125] At the same time, some farmers in Europe moved from a two field crop rotation to a three field crop rotation in which one field of three was left fallow every year. This resulted in increased productivity and nutrition, as the change in rotations permitted nitrogen-fixing legumes such as peas, lentils and beans. [126] Improved horse harnesses and the whippletree further improved cultivation. [127]

Watermills were introduced by the Romans, but were improved throughout the Middle Ages, along with windmills, and used to grind grains into flour, to cut wood and to process flax and wool. [128]

Crops included wheat, rye, barley and oats. Peas, beans, and vetches became common from the 13th century onward as a fodder crop for animals and also for their nitrogen-fixation fertilizing properties. Crop yields peaked in the 13th century, and stayed more or less steady until the 18th century. [129] Though the limitations of medieval farming were once thought to have provided a ceiling for the population growth in the Middle Ages, recent studies have shown that the technology of medieval agriculture was always sufficient for the needs of the people under normal circumstances, [130] [131] and that it was only during exceptionally harsh times, such as the terrible weather of 1315–17, that the needs of the population could not be met. [132] [133]

Columbian exchange Edit

After 1492, a global exchange of previously local crops and livestock breeds occurred. Maize, potatoes, sweet potatoes and manioc were the key crops that spread from the New World to the Old, while varieties of wheat, barley, rice and turnips traveled from the Old World to the New. There had been few livestock species in the New World, with horses, cattle, sheep and goats being completely unknown before their arrival with Old World settlers. Crops moving in both directions across the Atlantic Ocean caused population growth around the world and a lasting effect on many cultures in the Early Modern period. [134] Maize and cassava were introduced from Brazil into Africa by Portuguese traders in the 16th century, [135] becoming staple foods, replacing native African crops. [136]

After its introduction from South America to Spain in the late 1500s, the potato became a staple crop throughout Europe by the late 1700s. The potato allowed farmers to produce more food, and initially added variety to the European diet. The increased supply of food reduced disease, increased births and reduced mortality, causing a population boom throughout the British Empire, the US and Europe. [137] The introduction of the potato also brought about the first intensive use of fertilizer, in the form of guano imported to Europe from Peru, and the first artificial pesticide, in the form of an arsenic compound used to fight Colorado potato beetles. Before the adoption of the potato as a major crop, the dependence on grain had caused repetitive regional and national famines when the crops failed, including 17 major famines in England between 1523 and 1623. The resulting dependence on the potato however caused the European Potato Failure, a disastrous crop failure from disease that resulted in widespread famine and the death of over one million people in Ireland alone. [138]

British agricultural revolution Edit

Between the 16th century and the mid-19th century, Britain saw a large increase in agricultural productivity and net output. New agricultural practices like enclosure, mechanization, four-field crop rotation to maintain soil nutrients, and selective breeding enabled an unprecedented population growth to 5.7 million in 1750, freeing up a significant percentage of the workforce, and thereby helped drive the Industrial Revolution. The productivity of wheat went up from 19 US bushels (670 l 150 US dry gal 150 imp gal) per acre in 1720 to around 30 US bushels (1,100 l 240 US dry gal 230 imp gal) by 1840, marking a major turning point in history. [139]

Advice on more productive techniques for farming began to appear in England in the mid-17th century, from writers such as Samuel Hartlib, Walter Blith and others. [140] The main problem in sustaining agriculture in one place for a long time was the depletion of nutrients, most importantly nitrogen levels, in the soil. To allow the soil to regenerate, productive land was often let fallow and in some places crop rotation was used. The Dutch four-field rotation system was popularised by the British agriculturist Charles Townshend in the 18th century. The system (wheat, turnips, barley and clover), opened up a fodder crop and grazing crop allowing livestock to be bred year-round. The use of clover was especially important as the legume roots replenished soil nitrates. [141] The mechanisation and rationalisation of agriculture was another important factor. Robert Bakewell and Thomas Coke introduced selective breeding, and initiated a process of inbreeding to maximise desirable traits from the mid 18th century, such as the New Leicester sheep. Machines were invented to improve the efficiency of various agricultural operation, such as Jethro Tull's seed drill of 1701 that mechanised seeding at the correct depth and spacing and Andrew Meikle's threshing machine of 1784. Ploughs were steadily improved, from Joseph Foljambe's Rotherham iron plough in 1730 [142] to James Small's improved "Scots Plough" metal in 1763. In 1789 Ransomes, Sims & Jefferies was producing 86 plough models for different soils. [143] Powered farm machinery began with Richard Trevithick's stationary steam engine, used to drive a threshing machine, in 1812. [144] Mechanisation spread to other farm uses through the 19th century. The first petrol-driven tractor was built in America by John Froelich in 1892. [145]

John Bennet Lawes began the scientific investigation of fertilization at the Rothamsted Experimental Station in 1843. He investigated the impact of inorganic and organic fertilizers on crop yield and founded one of the first artificial fertilizer manufacturing factories in 1842. Fertilizer, in the shape of sodium nitrate deposits in Chile, was imported to Britain by John Thomas North as well as guano (birds droppings). The first commercial process for fertilizer production was the obtaining of phosphate from the dissolution of coprolites in sulphuric acid. [146]

20th century Edit

Dan Albone constructed the first commercially successful gasoline-powered general purpose tractor in 1901, and the 1923 International Harvester Farmall tractor marked a major point in the replacement of draft animals (particularly horses) with machines. Since that time, self-propelled mechanical harvesters (combines), planters, transplanters and other equipment have been developed, further revolutionizing agriculture. [147] These inventions allowed farming tasks to be done with a speed and on a scale previously impossible, leading modern farms to output much greater volumes of high-quality produce per land unit. [148]

The Haber-Bosch method for synthesizing ammonium nitrate represented a major breakthrough and allowed crop yields to overcome previous constraints. It was first patented by German chemist Fritz Haber. In 1910 Carl Bosch, while working for German chemical company BASF, successfully commercialized the process and secured further patents. In the years after World War II, the use of synthetic fertilizer increased rapidly, in sync with the increasing world population. [150]

Collective farming was widely practiced in the Soviet Union, the Eastern Bloc countries, China, and Vietnam, starting in the 1930s in the Soviet Union one result was the Soviet famine of 1932–33. [151] Another consequence occurred during the Great Leap Forward in China initiated by Mao Tse-tung that resulted in the Great Chinese Famine from 1959-1961 and ultimately reshaped the thinking of Deng Xiaoping.

In the past century agriculture has been characterized by increased productivity, the substitution of synthetic fertilizers and pesticides for labour, water pollution, [152] and farm subsidies. [153] Other applications of scientific research since 1950 in agriculture include gene manipulation, [154] [155] hydroponics, [156] and the development of economically viable biofuels such as ethanol. [157]

The number of people involved in farming in industrial countries fell radically from 24 percent of the American population to 1.5 percent in 2002. The number of farms also decreased and their ownership became more concentrated for example, between 1967 and 2002, one million pig farms in America consolidated into 114,000, with 80 percent of the production on factory farms. [158] According to the Worldwatch Institute, 74 percent of the world's poultry, 43 percent of beef, and 68 percent of eggs are produced this way. [158] [159]

Famines however continued to sweep the globe through the 20th century. Through the effects of climactic events, government policy, war and crop failure, millions of people died in each of at least ten famines between the 1920s and the 1990s. [160]

The historical processes that have allowed agricultural crops to be cultivated and eaten well beyond their centers of origin continues in the present through globalization. On average, 68.7% of a nation's food supplies and 69.3% of its agricultural production are of crops with foreign origins. [161]

Green Revolution Edit

The Green Revolution was a series of research, development, and technology transfer initiatives, between the 1940s and the late 1970s. It increased agriculture production around the world, especially from the late 1960s. The initiatives, led by Norman Borlaug and credited with saving over a billion people from starvation, involved the development of high-yielding varieties of cereal grains, expansion of irrigation infrastructure, modernization of management techniques, distribution of hybridized seeds, synthetic fertilizers, and pesticides to farmers. [162]

Synthetic nitrogen, along with mined rock phosphate, pesticides and mechanization, have greatly increased crop yields in the early 20th century. Increased supply of grains has led to cheaper livestock as well. Further, global yield increases were experienced later in the 20th century when high-yield varieties of common staple grains such as rice, wheat, and corn were introduced as a part of the Green Revolution. The Green Revolution exported the technologies (including pesticides and synthetic nitrogen) of the developed world to the developing world. Thomas Malthus famously predicted that the Earth would not be able to support its growing population, but technologies such as the Green Revolution have allowed the world to produce a surplus of food. [163]

Although the Green Revolution at first significantly increased rice yields in Asia, yield then levelled off. The genetic "yield potential" has increased for wheat, but the yield potential for rice has not increased since 1966, and the yield potential for maize has "barely increased in 35 years". It takes only a decade or two for herbicide-resistant weeds to emerge, and insects become resistant to insecticides within about a decade, delayed somewhat by crop rotation. [164]

Organic agriculture Edit

For most of its history, agriculture has been organic, without synthetic fertilisers or pesticides, and without GMOs. With the advent of chemical agriculture, Rudolf Steiner called for farming without synthetic pesticides, and his Agriculture Course of 1924 laid the foundation for biodynamic agriculture. [165] Lord Northbourne developed these ideas and presented his manifesto of organic farming in 1940. This became a worldwide movement, and organic farming is now practiced in many countries. [166]