Crop Rotation: The key to success?

Introduction: What is crop rotation and why is it important?

Crop rotation is a critical factor of all sustainable agriculture and cropping systems because it provides the basic mechanism for building healthy soils, a major way to control pests, diseases, and a variety of other benefits.

Crop rotation means changing the type of crop grown on a particular piece of land from year to year. Each field has its own rotation, and, consequently, each farmer manages a set of rotations.

Crop rotation is a very long term planning. So we will guide you on crop rotation: the key to success can be useful and beneficial to gain maximum yield over the years and protect your soil from loss of nutrients and diseases causing agents such as insect pests and soil borne diseases.

Crop rotation involves strategic planning but it does mean that you have to plan which crop to plant in the upcoming couple of years. This can be detrimental because there are different factors involved in this type of management (weather, change in market preference, and labor expenses). The major problem can be accumulation of soil borne diseases and soil nutrient imbalance.

Why crop rotation

For organic farming crop rotation is one of the most effective procedures. For farmers it is very important to know the importance of crop rotation. In the crop rotation you have to plan your crop design in such a way that you get economical benefit, increase the soil fertility or build up the soil capital.

It is important to get the expertise of the expert farmers and consultants. These kinds of expert groups help out the farmers with the decisions in the crop rotation plan, advice about changing in the plans of crop rotation considering all the factors such as the change in market, invasive insect pests and diseases.

Crop rotation is an ongoing annual process that involves the information and objective for many upcoming years. Many farmers do not use the basic cyclic rotation for every field, but in this case experts help them out to design, implement, and adapt the crop sequence.

Effects of crop rotation

The losses from the intensively and continuous tilled row crops can be restored; you can do that when the field is rotated into a perennial sod crop(corn). Firstly, high rate of organic matter decomposition from tillage must be stopped under sod crop. Then plant some plants that are able to spread a deep root system into the soil such as legumes and grasses.

Then you have to let these crops die off. These roots and plants would be the food source for the soil organisms that are mainly responsible for the building soil aggregation. The digestive material of earthworm and other beneficial organisms gets deposited on soil aggregates and thereby stabilizes them.

Therefore, these kinds of beneficial organisms need a continuous supply of organic matter. That is why legumes and grasses are the perfect source of organic material into the soil. The dense, fibrous, rooting system of perennial grasses and shallow-rooted legumes creates a very active biological zone near the surface.

Instead of using conventional row crops if you have such kinds of crops that have a longer period of active growth. For example, in a corn-soybean rotation, active growth occurs only 32 percent of the time, while in a dry bean–winter wheat–corn rotation, this period is 72 percent.

Crop rotation for soil fertility and nutrients:

Plant nutrients are mostly present in the organic soil and the soil particles. But these nutrients are not available for most of the crops. In case of crop rotation farmers provide these basic nutrients by different means such as mixing different crop residues, cycling among crops with different nutrient needs, using cover crops, and adding organic soil amendments.

Most crops deplete soil nutrients during their growth cycle. Some of these nutrients leave the farm as harvested products, and the rest return to the soil as crop residues. The microbial activity and soil aggregation can increase crop roots and residues.

This improves soil physical environment helps water infiltration, water holding capacity, aeration, and, ultimately, root growth and plant nutrient foraging.

Diseases control by crop rotation:

Crop rotation is a very cheap and effective method to control diseases. But you have to understand the life cycle of that pathogen that you are trying to eradicate from the soil of the field. The most common method is to plant those kinds of crops which are non-host for the pathogens.

In this way the pathogen dies in the soil or its level would decrease to such level that its damage would be below the threshold level.

To properly manage the pathogen from the field one must know following things:

• how long a pathogen can survive in the soil
• what are the other host plants of the pathogen
• other effective methods it can survive on other favorable crops
• what are the method of regenerations of the pathogens
• control method to manage other pathogen sources

Duration needed to eliminate disease from the soil can not be very precise due to addition of other external factors and lack of extensive research.

While these periods are based on research and observations from conventional production systems, they are generally applicable to organic systems because pathogen biology doesn’t change.

Planting Time and Insect Pests

Different pests such as corn flea beetle, crucifer, flea beetle, striped flea beetles, and cabbage maggots do the damage on the early stages of the plants (seedlings). This kind of damage can be avoided by planting the cover crops or sowing the crop after sometime.

By the use of biological control the small wasp called Pediobius foveolatus is used to control the insects by the early planting of its host plant (snap beans) and then releasing the wasps in these infested crops.

Using tall crops to reduce drought or heat stress of shorter crops

There are two methods that can be useful for reducing heat or heat stress for the shorter crop plants. These methods involve partial shading and reduction in wind speed. If we plant maize crops in well-space manners it can help in the reduction of heat stress from the spinach or lettuce.

In case of high speed windy areas tall crops can be very beneficial for the crop. One case of study showed that soybean yield increased up to 28% when it was planted in between the rows of corn.

Tips for sequencing crops

The actual steps for the sequencing crop is a very lengthy and detailed procedure. But here we have provided brief steps which can be still useful for planning crop sequences.

Just to remind you these are simplified steps for the detailed sequencing of crop planting you have to consider the factors that are given above and get advice from the expert farmers or agriculture officers in your area.

• Find and prioritize goals
• Write down your crop mix
• Check for excessive acreage of one family
• Identify crop couplets and short sequences that work well on your farm
• Make a crop rotation planning map
• Identify conditions that affect what crops can be grown on each management unit
• Plan next summer
• Plan the following year
• Plan fall-planted crops and cover crops
• Take your plans to the field