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Jai Ganesh

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Crop Rotation

Crop Rotation

Gist

Crop rotation is a farming technique where different crops are grown in a sequence on the same land over a period of time. This practice helps improve soil health, control pests and diseases, and enhance overall crop yields. By alternating crop types, farmers can minimize the build-up of specific pests and diseases, improve soil fertility, and reduce the need for synthetic fertilizers.

Crop rotation is a systematic approach to farming where different crops are grown in the same field sequentially over time. This practice helps improve soil health, manage pests and diseases, and potentially increase crop yields. It involves planting a sequence of crops, with each crop having different nutrient requirements, rooting depths, and disease/pest susceptibilities, to optimize resource utilization and minimize negative impacts on the soil and environment.

Summary

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.

Growing the same crop in the same place for many years in a row, known as monocropping, gradually depletes the soil of certain nutrients and promotes the proliferation of specialized pest and weed populations adapted to that crop system. Without balancing nutrient use and diversifying pest and weed communities, the productivity of monocultures is highly dependent on external inputs that may be harmful to the soil's fertility. Conversely, a well-designed crop rotation can reduce the need for synthetic fertilizers and herbicides by better using ecosystem services from a diverse set of crops. Additionally, crop rotations can improve soil structure and organic matter, which reduces erosion and increases farm system resilience.

Planning a rotation

There are numerous factors that must be taken into consideration when planning a crop rotation. Planning an effective rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc. Moreover, a crop rotation must consider in what condition one crop will leave the soil for the succeeding crop and how one crop can be seeded with another crop. For example, a nitrogen-fixing crop, like a legume, should always precede a nitrogen depleting one; similarly, a low residue crop (i.e. a crop with low biomass) should be offset with a high biomass cover crop, like a mixture of grasses and legumes.

There is no limit to the number of crops that can be used in a rotation, or the amount of time a rotation takes to complete. Decisions about rotations are made years prior, seasons prior, or even at the last minute when an opportunity to increase profits or soil quality presents itself.

Details

Crop rotation is the successive cultivation of different crops in a specified order on the same fields, in contrast to a one-crop system or to haphazard crop successions.

Throughout human history, wherever food crops have been produced, some kind of rotation cropping appears to have been practiced. One system in central Africa employs a 36-year rotation; a single crop of finger millet is produced after a 35-year growth of woody shrubs and trees has been cut and burned. In the major food-producing regions of the world, various rotations of much shorter length are widely used. Some of them are designed for the highest immediate returns, without much regard for the continuing usefulness of the basic resources. Others are planned for high continuing returns with protected resources. The underlying principles for planning effective cropping systems began to emerge in the middle years of the 19th century.

Early experiments, such as those at the Rothamsted experimental station in England in the mid-19th century, pointed to the usefulness of selecting rotation crops from three classifications: cultivated row, close-growing grains, and sod-forming, or rest, crops. Such a classification provides a ratio basis for balancing crops in the interest of continuing soil protection and production economy. It is sufficiently flexible for adjusting crops to many situations, for making changes when needed, and for including go-between crops as cover and green manures.

A simple rotation would be one crop from each group with a 1:1:1 ratio. The first number in a rotation ratio refers to cultivated row crops, the second to close-growing grains, and the third to sod-forming, or rest, crops. Such a ratio signifies the need for three fields and three years to produce each crop annually. This requirement would be satisfied with a rotation of corn, oats, and clover or of potatoes, wheat, and clover-timothy. Rotations for any number of fields and crop relationships can be described in this manner. In general, most rotations are confined to time limits of eight years or less.

The acreage devoted to sod-forming, or rest, crops should be expanded at the expense of row crops on soils of increasing slopes and declining fertility. This will provide better vegetative covering to protect sloping land from excessive erosion and supply organic matter for improving soil productivity on both sloping and level lands. With lessening slope and increasing fertility, the row crops may be expanded, but this should not be done with too much reduction in the sod-forming crops. The differing effects of crops on soils and on each other and in reactions to insect pests, diseases, and weeds require carefully planned sequences.

Broadly speaking, cropping systems should be planned around the use of deep-rooting legumes. If too little use is made of them, productivity will decline; if too much land is devoted to them, wastes may occur and other useful crops will be displaced. Rotations depending wholly on green-manure legumes should be confined to the more level and fertile lands. It is desirable to include legumes alone or in mixtures with nonlegume sod-forming crops as a regular crop in many field rotations. In general, this should occur about once in each four-year period. Short rotations are not likely to provide the best crop balances, and long rotations on a larger number of fields may introduce complications. With a moderate number of fields, additional flexibility can be provided by split cropping on some fields.

The usefulness of individual field crops is affected by regional differences in climate and soil. A major crop in one region may have little or no value in another. In each region, however, there are usually row, grain, and sod, or rest, crops that can be brought together into effective cropping systems.

In addition to the many beneficial effects on soils and crops, well-planned crop rotations also provide the business aspects of farming with advantages. Labour, power, and equipment can be handled with more efficiency; weather and market risks can be reduced; livestock requirements can be met more easily; and the farm can be a more effective year-round enterprise.

Additional Information

Crop rotation is the practice of planting different crops sequentially on the same plot of land to improve soil health, optimize nutrients in the soil, and combat pest and weed pressure.

For example, say a farmer has planted a field of corn. When the corn harvest is finished, he might plant beans, since corn consumes a lot of nitrogen and beans return nitrogen to the soil.

A simple rotation might involve two or three crops, and complex rotations might incorporate a dozen or more.

Crop rotation is the practice of growing a series of dissimilar/different types of crops in the same area in sequential seasons. Judiciously applied (i.e. selecting a suitable crop) crop rotation can improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants. In turn this can reduce erosion and increase infiltration capacity, thereby reducing downstream flood risk. It gives various benefits to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals and other crops. Crop rotation also mitigates the build-up of pathogens and pests that often occurs when one species is continuously cropped. However, as crop rotation has been traditionally practiced for agronomic reasons rather than to achieve environmental and water objectives, new practices may be required to ensure water retention benefits can be achieved. Some crops such as potatoes carry greater risks of erosion due to formation of ridges and the greater area of bare soil. Some crops such as potatoes carry greater risks of erosion due to formation of ridges and the greater area of bare soil. Crop rotation can be used in combination with other measures when these are compatible with crop choice.

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