Cropping system

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The term cropping system refers to the crops, crop sequences and management techniques used on a particular agricultural field over a period of years. It includes all spatial and temporal aspects of managing an agricultural system. Historically, cropping systems have been designed to maximise yield, but modern agriculture is increasingly concerned with promoting environmental sustainability in cropping systems. [1]

Contents

Crop choice

Crop choice is central to any cropping system. In evaluating whether a given crop will be planted, a farmer must consider its profitability, adaptability to changing conditions, resistance to disease, and requirement for specific technologies during growth or harvesting. [2] They must also consider the prevailing environmental conditions on their farm, and how the crop will fit in with other elements of their production system. [2]

Crop organisation and rotation

Monoculture is the practice of growing a single crop in a given area, where polyculture involves growing multiple crops in an area. Monocropping (or continuous monoculture) is a system in which the same crop is grown in the same area for a number of growing seasons. Many modern farms are made up of a number of fields, which can be cultivated separately and thus can be used in a crop rotation sequence. Crop rotation has been employed for thousands of years and has been widely found to increase yield and prevent harmful changes to the soil environment that limit productivity in the long term. [3] Although the specific mechanisms regulating that effect are not fully understood, [4] they are thought to be related to differential effects on soil chemical, physical, and microbiological properties by different crops. [5] By affecting the soil in different ways, crops in a rotation help to stabilise changes in the properties. Another consideration is that many agricultural pests are species-specific and so having a given species present in a field only some of the time helps to prevent populations of pests from growing. [6]

The organisation of individual plants in a field is also variable and typically depends on the crop being grown. Many vegetables, cereals, and fruits are grown in contiguous rows, which are wide enough to allow cultivation (or mowing, in the case of fruits) without damaging crop plants. Other systems aim for maximum plant density and have no such organisation. Forages are grown in that manner since animal traffic is expected, and maximum plant density is required for their nutrition, as are cover crops, since their purpose of competing with weeds and preventing soil erosion depends largely on density. [7]

Residue management

Managing crop residues is important in most systems. Some of the nutrients contained in these dead tissues are made available to crops during decomposition, [8] reducing the need for fertiliser inputs. Leaving residues in place also increases the soil organic matter (SOM), which has a number of benefits. [9] Specific management practices can have a number of other impacts.

Tillage

Rice tillage. Valencian Museum of Ethnology. Arros, sequer (26462086444).jpg
Rice tillage. Valencian Museum of Ethnology.

Tillage is the primary method by which farmers manage crop residues. Different types of tillage result in varying amounts of crop residue being incorporated into the soil profile. Conventional or intensive tillage typically leaves less than 15% of crop residues on a field, reduced tillage leaves 15–30%, and conservation tillage systems leave at least 30% on the soil surface. [10] The differences observed across these systems are diverse, and there is still considerable debate concerning their relative economic and environmental impact, but a number of widely reported benefits have led to a major shift towards reduced tillage in modern cropping systems. [11]

In general, leaving residues on the soil surface results in a mulching effect which helps control erosion, [12] prevents excessive evaporation, and suppresses weeds, [13] but may necessitate the use of specialised planting equipment. [14] Incorporating residues into the soil profile results in rapid decomposition by soil microorganisms, [15] which makes planting easier and in some cases could mean that nutrients will be made available to plants sooner, but limited erosion control and weed suppression are provided.

Under reduced or no-tillage, limited exposure to soil microorganisms can slow the rate of decomposition thus delaying the conversion of organic polymers to carbon dioxide and increasing the amount of carbon sequestered by the system, [16] [17] [18] although in poorly aerated soils this may be offset in part by an increase in nitrous oxide emissions. [19]

Burning

In some systems residues are burned. This is a fast and cheap way to clear a field in preparation for the next planting, and can assist with pest control, but has a number of drawbacks: organic matter (carbon) is lost from the system, soil is exposed and becomes more susceptible to erosion, and the smoke produced is an atmospheric pollutant. [20] In many parts of the world, this practice is restricted or banned. [21]

Removal

Especially in developing countries, crop residues may be removed and used for human or animal consumption, or other purposes. [22] This provides a secondary source of sustenance or income, but precludes the benefits associated with leaving residues within the system.

Nutrient management

Nutrients are depleted during crop growth, and must be renewed or replaced in order for agriculture to continue on a piece of land. This is generally accomplished with fertilisers, which can be organic or synthetic in origin. A large component of the organic farming movement is a preference for organic-source fertilisers.

Excessive fertilisation is not only costly, but can harm crops and have a number of environmental consequences. [23] Therefore, there is considerable interest in developing nutrient management plans for individual plots which attempt to optimise fertiliser application rates.

Water management

Soil moisture content is an important factor in plant development, and must be maintained within a range throughout the growing period. The range of tolerable moisture conditions varies from crop to crop. Irrigation and fine-textured amendments can be used to increase soil moisture, whereas coarser-textured amendments and technologies such as tile drainage can be used to decrease it. [24] [25]

See also

Related Research Articles

<span class="mw-page-title-main">Tillage</span> Preparation of soil by mechanical agitation

Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shoveling, picking, mattock work, hoeing, and raking. Examples of draft-animal-powered or mechanized work include ploughing, rototilling, rolling with cultipackers or other rollers, harrowing, and cultivating with cultivator shanks (teeth).

<span class="mw-page-title-main">Crop rotation</span> Agricultural practice of changing crops

Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. This practice reduces the reliance of crops on one set of nutrients, pest and weed pressure, along with the probability of developing resistant pests and weeds.

<span class="mw-page-title-main">Conservation agriculture</span> Farming system to preserve and regenerate land capacity

Conservation agriculture (CA) can be defined by a statement given by the Food and Agriculture Organization of the United Nations as "Conservation Agriculture (CA) is a farming system that can prevent losses of arable land while regenerating degraded lands.It promotes minimum soil disturbance, maintenance of a permanent soil cover, and diversification of plant species. It enhances biodiversity and natural biological processes above and below the ground surface, which contribute to increased water and nutrient use efficiency and to improved and sustained crop production."

<span class="mw-page-title-main">Green manure</span> Organic material left on an agricultural field to be used as a mulch or soil amendment

In agriculture, a green manure is a crop specifically cultivated to be incorporated into the soil while still green. Typically, the green manure's biomass is incorporated with a plow or disk, as is often done with (brown) manure. The primary goal is to add organic matter to the soil for its benefits. Green manuring is often used with legume crops to add nitrogen to the soil for following crops, especially in organic farming, but is also used in conventional farming.

<span class="mw-page-title-main">Cover crop</span> Crop planted to manage erosion and soil quality

In agriculture, cover crops are plants that are planted to cover the soil rather than for the purpose of being harvested. Cover crops manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in an agroecosystem—an ecological system managed and shaped by humans. Cover crops can increase microbial activity in the soil, which has a positive effect on nitrogen availability, nitrogen uptake in target crops, and crop yields. Cover crops may be an off-season crop planted after harvesting the cash crop. Cover crops are nurse crops in that they increase the survival of the main crop being harvested, and are often grown over the winter. In the United States, cover cropping may cost as much as $35 per acre.

<span class="mw-page-title-main">Mulch</span> Layer of material applied to the surface of soil

A mulch is a layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving fertility and health of the soil, reducing weed growth, and enhancing the visual appeal of the area.

<span class="mw-page-title-main">Polyculture</span> Growing multiple crops together in agriculture

In agriculture, polyculture is the practice of growing more than one crop species together at the same time, in contrast to monoculture, which had become the dominant approach in the 20th century. Traditional examples include the intercropping of the three sisters, namely maize, beans, and squash, by indigenous peoples of Central and North America, and the rice-fish systems of Asia. Polyculture serves multiple functions in the ecology of agriculture, including controlling insect pests, plant diseases, and weeds. Polyculture can contribute to sustainable agriculture as unlike monoculture it does not rely on pesticides, requires less tillage, increases local biodiversity, and where legumes are involved, help to maintain soil nitrogen.

<span class="mw-page-title-main">Topsoil</span> Top layer of soil

Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs.

<span class="mw-page-title-main">No-till farming</span> Agricultural method which does not disturb soil through tillage.

No-till farming is an agricultural technique for growing crops or pasture without disturbing the soil through tillage. No-till farming decreases the amount of soil erosion tillage causes in certain soils, especially in sandy and dry soils on sloping terrain. Other possible benefits include an increase in the amount of water that infiltrates into the soil, soil retention of organic matter, and nutrient cycling. These methods may increase the amount and variety of life in and on the soil. While conventional no-tillage systems use herbicides to control weeds, organic systems use a combination of strategies, such as planting cover crops as mulch to suppress weeds.

<span class="mw-page-title-main">Nutrient management</span> Management of nutrients in agriculture

Nutrient management is the science and practice directed to link soil, crop, weather, and hydrologic factors with cultural, irrigation, and soil and water conservation practices to achieve optimal nutrient use efficiency, crop yields, crop quality, and economic returns, while reducing off-site transport of nutrients (fertilizer) that may impact the environment. It involves matching a specific field soil, climate, and crop management conditions to rate, source, timing, and place of nutrient application.

Tilth is a physical condition of soil, especially in relation to its suitability for planting or growing a crop. Factors that determine tilth include the formation and stability of aggregated soil particles, moisture content, degree of aeration, soil biota, rate of water infiltration and drainage. Tilth can change rapidly, depending on environmental factors such as changes in moisture, tillage and soil amendments. The objective of tillage is to improve tilth, thereby increasing crop production; in the long term, however, conventional tillage, especially plowing, often has the opposite effect, causing the soil carbon sponge to oxidize, break down and become compacted.

<span class="mw-page-title-main">Agroforestry</span> Land use management system

Agroforestry is a land use management system in which combinations of trees or shrubs are grown around or among crops or pastureland. Agroforestry combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy, and sustainable land-use systems. There are many benefits to agroforestry such as increasing farm profitability. In addition, agroforestry helps to preserve and protect natural resources such as controlling soil erosions, creating habitat for the wildlife, and managing animal waste. Benefits also include increased biodiversity, improved soil structure and health, reduced erosion, and carbon sequestration.

<span class="mw-page-title-main">Living mulch</span> Cover crop grown with a main crop as mulch

In agriculture, a living mulch is a cover crop interplanted or undersown with a main crop, and intended to serve the purposes of a mulch, such as weed suppression and regulation of soil temperature. Living mulches grow for a long time with the main crops, whereas cover crops are incorporated into the soil or killed with herbicides.

Soil biodiversity refers to the relationship of soil to biodiversity and to aspects of the soil that can be managed in relative to biodiversity. Soil biodiversity relates to some catchment management considerations.

<span class="mw-page-title-main">Strip-till</span> Soil conservation technique

Strip-till is a conservation system that uses a minimum tillage. It combines the soil drying and warming benefits of conventional tillage with the soil-protecting advantages of no-till by disturbing only the portion of the soil that is to contain the seed row. This type of tillage is performed with special equipment and can require the farmer to make multiple trips, depending on the strip-till implement used, and field conditions. Each row that has been strip-tilled is usually about eight to ten inches wide.

The environmental impact of agriculture is the effect that different farming practices have on the ecosystems around them, and how those effects can be traced back to those practices. The environmental impact of agriculture varies widely based on practices employed by farmers and by the scale of practice. Farming communities that try to reduce environmental impacts through modifying their practices will adopt sustainable agriculture practices. The negative impact of agriculture is an old issue that remains a concern even as experts design innovative means to reduce destruction and enhance eco-efficiency. Though some pastoralism is environmentally positive, modern animal agriculture practices tend to be more environmentally destructive than agricultural practices focused on fruits, vegetables and other biomass. The emissions of ammonia from cattle waste continue to raise concerns over environmental pollution.

Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance. It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.

<span class="mw-page-title-main">Natural farming</span> Sustainable farming approach

Natural farming, also referred to as "the Fukuoka Method", "the natural way of farming", or "do-nothing farming", is an ecological farming approach established by Masanobu Fukuoka (1913–2008). Fukuoka, a Japanese farmer and philosopher, introduced the term in his 1975 book The One-Straw Revolution. The title refers not to lack of effort, but to the avoidance of manufactured inputs and equipment. Natural farming is related to fertility farming, organic farming, sustainable agriculture, agroecology, agroforestry, ecoagriculture and permaculture, but should be distinguished from biodynamic agriculture.

<span class="mw-page-title-main">Soil regeneration</span>

Soil regeneration, as a particular form of ecological regeneration within the field of restoration ecology, is creating new soil and rejuvenating soil health by: minimizing the loss of topsoil, retaining more carbon than is depleted, boosting biodiversity, and maintaining proper water and nutrient cycling. This has many benefits, such as: soil sequestration of carbon in response to a growing threat of climate change, a reduced risk of soil erosion, and increased overall soil resilience.

<span class="mw-page-title-main">Carbon farming</span> Agricultural methods that capture carbon

Carbon farming is a name for a variety of agricultural methods aimed at sequestering atmospheric carbon into the soil and in crop roots, wood and leaves. The aim of carbon farming is to increase the rate at which carbon is sequestered into soil and plant material with the goal of creating a net loss of carbon from the atmosphere. Increasing a soil's organic matter content can aid plant growth, increase total carbon content, improve soil water retention capacity and reduce fertilizer use. Carbon farming is one component of climate-smart agriculture.

References

  1. ↑ Blanco, Humberto (2010). Principles of Soil Conservation and Management. Springer Science. pp. 167–193. ISBN   978-9048185290.
  2. 1 2 "Factors in Crop Selection". CropsReview.Com. Retrieved 2016-11-23.
  3. ↑ Bullock, D. G. (1992-01-01). "Crop rotation". Critical Reviews in Plant Sciences. 11 (4): 309–326. doi:10.1080/07352689209382349. ISSN   0735-2689.
  4. ↑ "Alianza SIDALC". www.sidalc.net. Retrieved 2016-11-23.
  5. ↑ "Why Is Crop Rotation Important?" . Retrieved 2016-11-23.
  6. ↑ Brueckmann, Dr. Stefan. "Crop rotation". www.oisat.org. Retrieved 2016-11-23.
  7. ↑ Brennan, Eric; Smith, Richard (2005). "Winter Cover Crop Growth and Weed Suppression on the Central Coast of California". Weed Technology. 19 (4): 1017–1024. doi:10.1614/WT-04-246R1.1. Archived from the original on 2017-03-05. Retrieved 2016-11-23– via NALDC.
  8. ↑ "The importance of soil organic matter". www.fao.org. Retrieved 2016-11-28.
  9. ↑ Bot, Alexandra (2005). "The Importance of Soil Organic Matter" (PDF). FAO. FAO. Retrieved November 23, 2016.
  10. ↑ "Tillage Type Definitions". www.ctic.purdue.edu. Archived from the original on 2016-11-24. Retrieved 2016-11-23.
  11. ↑ Huggins, David; Reganold, John (2008). "No-Till: The Quiet Revolution" (PDF). USDA. USDA. Retrieved 28 November 2016.
  12. ↑ Paul W. Unger (1994). Managing Agricultural Residues. CRC Press. p. 19. ISBN   978-0-87371-730-4.
  13. ↑ Amoroso, Gabriele; Frangi, Piero; Piatti, Riccardo; Fini, Alessio; Ferrini, Francesco (2010-12-01). "Effect of Mulching on Plant and Weed Growth, Substrate Water Content, and Temperature in Container-grown Giant Arborvitae". HortTechnology. 20 (6): 957–962. ISSN   1063-0198.
  14. ↑ "Residue management". wheatdoctor.org. Retrieved 2016-11-29.
  15. ↑ Coppens, Filip; Garnier, Patricia; Findeling, Antoine; Merckx, Roel; Recous, Sylvie (2007-09-01). "Decomposition of mulched versus incorporated crop residues: Modelling with PASTIS clarifies interactions between residue quality and location". Soil Biology and Biochemistry. 39 (9): 2339–2350. doi:10.1016/j.soilbio.2007.04.005.
  16. ↑ Abiven, Samuel; Recous, Sylvie (2007-02-07). "Mineralisation of crop residues on the soil surface or incorporated in the soil under controlled conditions" (PDF). Biology and Fertility of Soils. 43 (6): 849–852. doi:10.1007/s00374-007-0165-2. ISSN   0178-2762.
  17. ↑ Kahlon, Meharban Singh; Lal, Rattan; Ann-Varughese, Merrie (2013-01-01). "Twenty two years of tillage and mulching impacts on soil physical characteristics and carbon sequestration in Central Ohio". Soil and Tillage Research. 126: 151–158. doi:10.1016/j.still.2012.08.001.
  18. ↑ Bayer, C.; Martin-Neto, L.; Mielniczuk, J.; Pavinato, A.; Dieckow, J. (2006-04-01). "Carbon sequestration in two Brazilian Cerrado soils under no-till". Soil and Tillage Research. 86 (2): 237–245. doi:10.1016/j.still.2005.02.023.
  19. ↑ Rochette, Philippe (2008-09-01). "No-till only increases N2O emissions in poorly-aerated soils". Soil and Tillage Research. 101 (1–2): 97–100. doi:10.1016/j.still.2008.07.011.
  20. ↑ "Stubble Burning". Agriculture Victoria. 29 February 2016. Archived from the original on 6 October 2018. Retrieved 14 October 2016.
  21. ↑ "The Crop Residues (Burning) Regulations 1993". 1993.
  22. ↑ Prasad, Rajendra; Power, J. F. (1991-01-01). Stewart, B. A. (ed.). Advances in Soil Science. Advances in Soil Science. Springer New York. pp. 205–251. doi:10.1007/978-1-4612-3030-4_5. ISBN   9781461277682.
  23. ↑ "How Do Fertilizers Affect the Environment". Environment News South Africa. 2015-04-20. Retrieved 2016-11-29.
  24. ↑ "Agricultural Irrigation Systems". www.vandenbussche.com. Retrieved 2016-11-29.
  25. ↑ "Planning an agricultural subsurface drainage system : Agricultural Drainage : University of Minnesota Extension". www.extension.umn.edu. Archived from the original on 2016-11-29. Retrieved 2016-11-29.
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