Talk:Crop rotation

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The following are the bits not covered (and some not deserving of coverage) by my rewrite:

It is the greatest possible mistake to think that the temporary diminution of fertility in a field is chiefly owing to the loss of the decaying vegetable matter it previously contained: it is principally the consequence of the exhaustion of potash and soda, which are restored by the slow process of the more complete disintegration of the materials of the soil. It is evident that the careful tilling of fallow land must accelerate and increase this further breaking up of its mineral ingredients. Nor is this repose of the soil always necessary.
Because plants require for their growth different constituents of soil, changing the crop from year to year will maintain the fertility of that soil (provided it be done with judgment) quite as well as leaving it at rest or fallow. In this we but imitate nature. The oak, after thriving for long generations on a particular spot, gradually sickens; its entire race dies out; other trees and shrubs succeed it, till, at length, the surface becomes so charged with an excess of dead vegetable matter, that the forest becomes a peat moss, or a surface upon which no large tree will grow. Generally long before this can occur, the operation of natural causes has gradually removed from the soil substances, essential to the growth of oak leaving others favorable and necessary to the growth of beech or pine. So, in practical farming, one crop, in artificial rotation with others, extracts from the soil a certain quantity of necessary materials; a second carries off, in preference, those which the former has left.
One hundred parts of wheat straw yield 15 1/2 of ashes; the same quantity of barley straw, 8 1/2; of oat straw, only 4; and the ashes of the three are chemically, of about the same composition. Upon the same field, which will yield only one harvest of wheat, two successive crops of barley may be raised, and three of oats. We have in these facts a clear proof of what is abstracted from the soil and the key to the rational mode of supplying the deficiency.
A field, which has become unfitted for a certain kind of produce, may not, on that account, be unsuitable for another; and upon this observation a system of agriculture has been gradually formed, the principal object of which is to obtain the greatest possible produce in a succession of years, with the least outlay for manure.
because, during the interval, the soil will have been, by the action of the atmosphere, and the solution of vegetable and animal substances decaying upon or in it, again rendered capable of yielding what the wheat requires. Whether this process can be artificially anticipated, by supplying the exhausted ingredient to the soil, is a further and most interesting and important inquiry.
We could keep our fields in a constant state of fertility by replacing, every year, as much as is removed from them by their produce. An increase of fertility may be expected, of course, only when more is added of the proper material to the soil than is taken away. Any soil will partially regain its strength by lying fallow. But any soil, under cultivation, must at length (without help) lose those constituents which are removed in the seeds, roots and leaves of the plants raised upon it. To remedy this loss, and also increase the productiveness of the land, is the object of the use of proper manures.
Land, when not employed in raising food for animals or man, should, at least, be applied to the purpose of raising manure for itself; and this, to a certain extent, may be effected by means of green crops, which, by their decomposition, not only add to the amount of vegetable mould contained in the soil, but supply the alkalies that would be found in their ashes. That the soil should become richer by this burial of a crop, than it was before the seed of that crop was sown, will be understood by recollecting that three-fourths of the whole organic matter we bury has been derived from the air: that by this process of ploughing in, the vegetable matter is more equally diffused through the whole soil, and therefore more easily and rapidly decomposed; and that by its gradual decomposition, ammonia and nitric acid are certainty generated, though not so largely as when animal matters are employed. He who neglects the green sods, and crops of weeds that flourish by his hedgerows and ditches, overlooks an important natural means of wealth. Left to themselves, they ripen their seeds, exhausting the soil, and sowing them annually in his fields: collected in compost heaps, they add materially to his yearly crops of corn.

— Preceding unsigned comment added by Koyaanis Qatsi (talkcontribs) 20:56, 2 April 2002‎

Irrellevant passage (as currently written) moved to talk

This section moved from page. It is simply continuous cropping without reference to the principles of crop rotation:

Crop rotation is widely practiced in vegetable production, where it is possible to grow a cool-season crop (such as lettuce) in the spring, follow with a warm-season crop (such as tomatoes) in the summer, and then grow a winter crop (such as mache) harvested in early spring.

Crop rotation is less common with field crops because the timing is difficult to manage, particularly since most crop-growing regions experience a good deal of rainfall during the late spring and early summer season, which interrupts fieldwork. Pollinator 07:47, 22 February 2006 (UTC)

Where is the above passage quoted from ? it sounds old fashioned. N.B. harvestng of crops depletes the soil because the harvested grain etc. contains minerals from the soil, but similar amounts of minerals are also leached from the soil and lost to the atmosphere (in the case of Nitrogen) as a result of cultivation of the soil. The author is right to emphasise the importance of weeds on the edges of fields and especially along ditches, but wrong to say that left to themselves they exhaust soil, in fact, soil under weeds invariably grows richer (unlike land under continuous cultivation ). Cutting back weeds on field margins and removing the cutings for hay, mulch or compost is a very good idea to improve nutrient use efficiency as these weeds will be thriving on surplus nutrients lost from nearby crops. Cutting them back will also reduce the problem of weed seeds.Pignut (talk) 20:58, 4 February 2011 (UTC)
Seasonal timing is important, but crop rotation usually means growing different crops in different years e.g. one year field 1 has maize, field 2, beans, field 3 potatoes. the next year field 1 has beans, field 2 has potatoes, field 3 has maize and so on. In this hypothetical example there are only warm season crops, so it would be good to grow some green manures over the winter. Pollinator is mistaken. There are many different climates in crop growing regions worldwide, and crops and rotations have been developed to suit these local conditions. Rotation of field crops is common worldwide. in a place with wet spring/early summer weather, a sequence of winter cereals could, for instance, be grown, each one planted in autumn and harvested late summer. — Preceding unsigned comment added by Pignut (talkcontribs) 21:28, 4 February 2011‎

Crop rotation in the fourteenth century was considerably more widespread after John Lloyd invented the patent crop rotator.

Funny - 21:04, 11 February 2007 (UTC)

True. But I got rid of it. — Preceding unsigned comment added by (talkcontribs) 07:14, 26 February 2007‎

Some dutch translation.

te laat = to late I think it either has to do with the seasons or not being on time with planting/seeding the new crops after harvest.

onkruid = weeds

brouwgerst = barley with the intention of using it for brewing beer. As opposed to regular barley. brouwen = brewing

koolzaad = rapeseed (looked on the English companion to the Dutch page on koolzaad). It can be used for biodiesel (alternative fuel). My father sowed it once in the nineties, I believe there was also some European subsidies involved, but he did not harvest it. He used it as nutrition for the soil.

JulesVanLaar 02:58, 4 July 2007 (UTC)

If I knew anything about farming, I wouldn't be reading the wiki page on it ;) But I confirmed and made all the corrections. Some of the original plants were a little over specific (eg brewer's barley, tribe broad beans), so I simplified those. Thanks Jules, and if someone could explain what I meant by "late" (once that's decided), that'd be nice. Bagsc 26 July 2007

it is a crime

— Preceding unsigned comment added by (talkcontribs) 08:38, 10 October 2007

 ?? crop rotation is legal everywhere I think, but intercropping is a sin according to leviticus ch19 v19 :) — Preceding unsigned comment added by Pignut (talkcontribs) 11:26, 5 February 2011 (UTC)

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Erosion section

The information on erosion was added as part of a class project at the University of Kentucky by a student enrolled in a soil management class. —Preceding unsigned comment added by (talk) 17:36, 4 December 2008 (UTC)

History needs to be expanded?

Growing up in the 50s/60s in (upstate NY?? and) Indiana, crop rotation was a staple of the curriculum. In recent years I have become aware that what I was taught in school, and that I never heard farmers my family socialized with say was BS, is no nolonger the common practice in the US or elsewhere in the world. The article mentions the move away from crop rotation, but I wish an aggriculture specialist or student would fill in how the standard practice promoted by government farm extension programs seemingly suddenly vanished from recommended practice. I heard or read a brief comment that pointed to Earl Butts as the key figure, and I do recall he was controversial, but I never understood the issues over Earl Butts. As the abandonment of crop rotation occurred worldwide, what were the forces driving it. And what can be said about the efforts to return to the old methods? Mulp (talk) 18:41, 6 January 2009 (UTC)

Naked fallows

Naked fallows are mentioned in poetry by Robert Louis Stevenson, but not in this article. In trying to find a definition: I found this in Papers and Articles OSV Research Paper, author Jay Adams, 1978

The major attitudes that I would ascribe to progressive farmers are: 1) a belief in intensive rather than extensive agriculture; 2) a commitment to the spirit of scientific inquiry; 3) support for and participation in agricultural societies and the farm press; and 4) a conviction that farmers deserved a higher place in society. On the farm, these attitudes were brought to life by adoption of some or all of the following practices: manuring, draining, deep plowing, alternating crops, root culture, row culture, the use of clover, and the substitution of fallow crops for naked fallows. --Notes on Progressive Agriculture
--Pawyilee (talk) 13:41, 9 August 2010 (UTC)

naked or bare fallow means maintaining a field bare of crops or weeds by regular ploughing. It was common in the middle ages in europe as a way to control weeds, fields could be bare fallowed for a whole year. It is however extremely detrimental to soil fertility and structure causing massive leaching of nutrients. In a medieval village some of these leached nutrients would have been recovered by the cutting of hay and rushes (for floor covering) from the riversides (These would have been fed by nutrient run off from higher ground, and the nutrients would return to the fields as animal manure and semi composted rushes). It is important to distinguish this from other kinds of fallow (growing green manures or simply letting the weeds grow). bare or naked fallow is certainly not "letting the land rest". Many farmers or gardeners nowadays still believe that there are benefits to cultivating soil in autumn and leaving it bare over winter (frost loosens clay soil and birds will eat slug eggs), but the considerable nutrient leaching during winter rains and the loss of humus will likely far outweigh any benefits -- user pignut —Preceding unsigned comment added by (talk) 20:31, 4 February 2011 (UTC)

Critique for HIST406

This article largely covers the most of the general information concerning crop rotations. It discusses what, exactly, crop rotation is, how it works, its history, and what affects crop rotation has on the environment. The writing style is simple and informal. It seems to me more like the authors are trying to have a conversation with the reader rather than lay out the information in a clear and concise manner. Not to say they are bad writers, the article is just wordier than it truly needs to be. Also, the illustrations and pictures are too few and unhelpful. They just show pictures of farms and large plots of land. That does not demonstrate anything about what crop rotation is. There need to be illustrations that actually showcase the process of crop rotations. The sources, also, need work. Wikipedia is an online reference database, used mostly for quick reference alongside actual research. Therefore, there needs to be some sort of accountability for each page, each article. This crop rotation article does not have ideal sources. The sources listed are good, they are accurate, but they are inconsistent with Wikipedia’s speed, i.e. they are not links. It is tough to determine the accuracy of this pages information when the references cannot be quickly accessed, and when that is the case, one might as well just bypass the Wikipedia page altogether. The page needs more sources that can be directly linked to so the reader can quickly determine the page’s validity. Also, the sources need to be cited inside the article, as is stated by the box at the beginning of the article. Basically, the article is sloppy. It has a lot of information; it’s just not organized very efficiently nor is it presented very well. One solid afternoon to find supplemental references, reorganize the information, and clean up the language should make this article much more useful.

HIST406-10msuterlo (talk) 14:48, 4 October 2010 (UTC)

Crop rotations and soil fertility

There has been a lot of wishful thinking and misconceptions regarding the effects of crop rotations on soil fertility, and sadly, many farmers have gone bankrupt, depleted their soil and grown disillusioned with crop rotation and organic farming techniques in general, as a result.

Arable crop rotation (as distinct from ley-arable rotation) is better than continuous monoculture of the same crop (for instance it reduces, pest and disease problems), but arable crop rotation is unlikely to be sufficient, by itself (without inputs of compost/manure, or periods growing green manures or ley) to maintain or improve the fertility of the soil under rotation.

It is often said that different arable crops remove different proportions of the essential nutrients and return different proportions in their crop residues (stubble, roots etc.), so a rotation of different crops prevents imbalances of nutrients that could occur in continuous monoculture. This is probably true although hard scientific evidence for this is surprisingly scarce (probably due to difficulties measuring small changes in soil nutrients: Soil is an ecosystem, hard to study without distubing it. At any point in time Some soil minerals will be available for plants to use, but far more will be locked away in humus, leaf litter, microbes, the bodies of animals such as earthworms or stuck to particles of clay etc.). However the quantities of nutrients removed in the harvested crop, and lost to groundwater and air as a result of soil cultivation are usually far greater than the quantities returned in crop residues.

Organic farming derives its name from Rudolf Steiner's concept of the farm as an organism, an interconnected whole. When a farmer says that a crop improves the "heart" or fertility of his land, many listeners will assume that the crop releases nutrients from its roots which enrich the soil it grows in. Few will consider the possibility that it might, for instance, allow the farmer to feed more animals from his land and thus get more, and richer, manure and compost.

19th century farmers considered turnips and potatoes to be soil improving crops, but the leaf and root residues left by a crop of potatoes are small. In fact, these root crops allowed the soil to be cleared of weeds, more animals to be fed over winter (before turnips were widely grown, many more animals had to be slaughtered in autumn), and the generous applications of manure thse crops received benefited subsequent crops. Potatoes and turnips do not themselves improve the land, but the act of growing them can!

Leguminous plants ('legumes'), (such as beans, peas, alfalfa, clover, gorse or acacia) can obtain (or "fix") some, or all of their nitrogen from the air with the aid of bacteria living in their roots, known as Rhizobia. The amounts of nitrogen they can obtain per hectare often far exceed the amounts commonly applied by farmers as nitrogen fertiliser. The fixed nitrogen is distributed throughout the legume plant, and contrary to popular belief, there is generally more fixed nitrogen in the leaves, flowers, stems and seeds of a legume plant than there is in their roots. As the legume plant flowers and makes seeds it transfers nitrogen from its leaves and roots into its flowers and seeds. An annual legume plant such as soya bean will transfer most of its nitrogen into its seeds, leaving comparatively little in its dry, dead, roots, stem and leaves at harvest time. Some fixed nitrogen leaks from the roots of legume plants, for instance, when roots die or decay. Neighbouring plants, such as grass growing with clover, or weeds growing with peas can benefit from this deposited nitrogen, as can successive crops, although much of the fixed nitrogen deposited this way will be lost to groundwater and the air before a successive crop can use it, especially if the soil is ploughed in the interim.

If a grain legume, such as soyabean, is harvested when the seeds are fully ripe, the soil it grew in will have about as much nitrogen in it as it did when the beans were planted. Some studies on this have found slight increases in soil nitrogen, others small decreases following a soya crop. Some fixed nitrogen has been deposited in the soil by the soya plant, some of this fixed nitrogen has been lost from the soil and some soil nitrogen has been taken up by the soy plant (legumes only fix nitrogen when they must. The Rhizobia receive sugar in exchange for nitrogen, so symbiotically fixed nitrogen costs the legume more than soil nitrogen). Most of the fixed nitrogen is in the harvested beans along with phosphate, potassium and other minerals from the soil.

If these soyabeans are fed to animals on the farm where they were grown and the resulting manure is used to feed crops, then the soyabeans will have helped the overall fertility of the farm. Likewise if they are eaten by people on the farm enlightened enough to use composting toilets, there will also be a benefit. If beans are picked green, the stems, leaves and roots will contain more of the fixed nitrogen (and the beans themselves proportionately less), which could significantly benefit the next crop (or make compost or provide high protein feed for animals and subsequently, nitrogen rich manure). If, however, the beans are exported from the farm, the meagre deposits of fixed nitrogen left in the beanfield will not be sufficient to supply the needs of a hungry crop like corn.

Alternating corn with soybeans and exporting the ripe harvest, (if fertilisers, manure or compost are not brought in from elsewhere), will deplete the soil of nitrogen and other minerals.

In a ley-arable rotation, a sequence of arable crops is followed by one or more years of ley (temporary grassland) for grazing by animals and/or cutting for hay/silage. It was this, rather than arable crop rotation which kick started the agricultural revolution of the 18th century. The ley usually contains leguminous plants such as clover as well as grasses (and hopefully herbs too), and these seeds may be undersown sown with the seeds of the preceeding arable crop (usually a cereal) reducing the crop yield a little, but sparing the soil another wasteful and destructive cultivation.

As explained earlier, leguminous plants leak some of their fixed nitrogen into the soil, and grasses growing alongside clovers will gain from this. A multi-species grassland is a jungle of fiercely competing plants, their roots entwined in a dense tangled mat, fighting for all the available nutrients. A field of vegetables or even cereals, in contrast, gets stripped bare of weeds annually. The seedlings grow, comfortably spaced apart, in unnaturally enriched soil free from competing weeds. The crop plants roots are often only just starting to efficiently exploit the soil when it is time for them to be harvested and the soil stripped bare ready for the next crop. Typically, arable crops utilise around half of the minerals fed to them as fertiliser, manure or compost. The rest is lost to groundwater and air.

The grasses in a ley continue to take up nitrogen in the winter, when the clovers etc. are dying back and consequently releasing more of their fixed nitrogen. In addition, grazing animals eat the leaves of leguminous plants and then transfer fixed nitrogen to grass and soil in their dung and urine. Grassland legumes such as clovers have evolved to thrive on this rough treatment. Grazing animals create a patchwork of high nitrogen patches where grasses, dominate and low nitrogen patches where legumes can thrive free from competing grasses. Under these conditions, legumes obtain almost all of their nitrogen from the atmosphere, taking little from the soil.

All these processes enrich the ley with far more nitrogen rich organic matter than could ever be left behind by a field of beans. In addition fixed nitrogen from the legumes is going into the animals, becoming meat, milk and eggs (proteins are nitrogen compounds). Fixed nitrogen is also removed to other parts of the farm as hay or silage which are eventually converted into more meat and milk and into manure which can enrich soil anywhere on the farm. The removal of nitrogen from the ley in this manner, stimulates more nitrogen fixation by the legumes (as long as there is no other mineral deficiency). As the fixed nitrogen builds up in the ley, grass dominates at the expense of the legumes, and it is time to plough the ley and begin the cycle again with an arable crop. This ploughing causes the highet losses of nutrients of any stage in the rotation, so should be well timed with regard to the weather and season. Planting should be done as quickly as is practical. Leys can be managed as quick one or two year leys, primarily intended to enrich the soil where they grow, or as longer term leys to enrich the whole farm as well as the soil under the ley.

Green manures are crops grown to be ploughed or dug in to enrich the soil. They are especially useful in the absence of animals. They can also suppress weeds and pests. They may be legumes to enrich the soil with nitrogen or non-legumes to cover bare soil and prevent nutrient leaching. Deep rooting green manures can also bring nutrients up from the subsoil. Generally non-legumes are more useful than legumes for ground cover in cold winters as legumes don't fix nitrogen below around 7 degrees celsius, are less effective at stopping leaching and produce less biomass than many non-legume green manures. A mixture of legumes and non-legumes will usually fix slightly more nitrogen than a monoculture of the legume, produce more biomass and provide better groundcover. This is because Competition from a non-legume reduces the legume yield but forces the legume to fix a higher proportion of its nitrogen, by competing for the soil nitrogen. Legume green manures can also be undersown with crops, but more research is needed into this technique.

Green manure crops such as comfrey, alfalfa or grass can be grown as permanant stands, cut and used as compost or mulch. Trees can also be used to provide compost or mulch.

The increased nitrate and phosphate pollution of water in many areas over the last few decades is often blamed on synthetic fertilisers, which are a factor, but the main cause has been the conversion of mixed farms with permanant pastures, meadows, leys and trees, into entirely arable farms. An all arable farm using organic arable crop rotations or importing organic compost and manure to feed its crops, causes only slightly less nitrate pollution (per tonne of crop harvested) than an all arable farm using synthetic fertilisers. Both cause significantly more nitrate pollution than mixed farms (organic or not) where arable fields are interspersed with grassland. Much of this pollution derives from the breakdown of soil humus, which in a grassland or forest would remain stable for decades. Nitrate pollution and oher forms of eutrophication are natural capital going down the drain.

Conclusion: Rotations of arable cash crops will deplete soil nutrients and organic matter and are therefore unsustainable unless animal manures/compost are applied used, green manures used or (best of all) a ley phase included in the rotation. Tillage and bare soil increase losses of soil nutrients and soil organic matter, both should be minimised.Pignut (talk) 05:12, 5 February 2011 (UTC)

Nice essay, but in my opinion it only shows poor understanding of the principles of crop rotation from the farmers that went bankrupt. Crop rotation was never ment of being the holy grail of a manure/fertilizer/herbicide/pesticide-free practice. It was ment as a cost-effective way to achieve higher yields... The Banner talk 14:47, 7 October 2012 (UTC)

What is fallow?

I don't know what "fallow" is so I typed the word into wikipedia and it redirected me to this very article. Unfortunately the article uses the word fallow a lot but I couldn't see where it explains what fallow is. I still don't know. This article should either explain this, or the redirect should be removed. — Preceding unsigned comment added by (talk) 17:01, 4 August 2011 (UTC)

Fallow land = land ploughed and harrowed but left unsown. The Banner talk 15:46, 10 October 2012 (UTC)


What is "fallow" please? It redirects here, but I see no explanation in the lede, or indeed in the whole article. Thanks (talk) 14:03, 7 October 2012 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Crop rotation/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

I have assessed this article as Start-class and identified the following areas for improvement:
  • The article needs to be written in an enyclopedic tone
  • The article needs inline citations
  • The article needs references
Doug.(talk contribs) 05:59, 2 March 2008 (UTC)

Substituted at 21:21, 19 March 2016 (UTC)

Bold edits/significant updates

I am a new user looking to make bold edits of this page. I am most concerned with updating content, introducing more inline citations and scientific information from USDA and peer-reviewed sources. Please let me know if there is anything I should be aware of in advance. Thank you! — Preceding unsigned comment added by Sfs329 (talkcontribs) 22:17, 30 April 2016 (UTC)

"Proceed"? ... "precede", IMHO

It says, in "Planning a rotation", "For example, a nitrogen-fixing crop, like a legume, should always proceed a nitrogen depleting one". Shouldn't that be "precede"? --User:Haraldmmueller 07:27, 7 October 2016 (UTC)

helo — Preceding unsigned comment added by (talk) 06:27, 8 March 2018 (UTC)

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