How does crop rotation and mixed cropping help in improving the nutrient content in the soil
Answers
Advantages of Crop Rotation -
1. Increases soil fertility
Prolonged planting of the same crop type leads to depletion of specific nutrients in the soil. Each crop type has a different nutrient interaction with the soil, they each release and absorb different types of nutrients. Because of this, crop rotation increases soil fertility by controlling deficient or excess nutrients because it replenishes nutrients that are not available or absorbing nutrients that are in abundance.
It also increases the soil organic matter caused by the micro-organisms left behind by each type of crop planted. Animals that also graze on land left to fallow contribute to adding manure to the ground that fertilizes the soil. Biomass left behind when harvesting also improves the fertility of the soil as it is purely green manure.
2. Increases crop yield
Crop rotation increases the harvest obtained from a single seasonal harvest. Not only does one get a variety of crops after each season because of the incorporation of different crop types, but also a generally bounty harvest. The availability of nutrients from the soil provide abundant nourishment to all plants, therefore, ensuring success in the yield produced.
Most farmers are advised to practice crop rotation when the land becomes still and does not produce as much as it should further demonstrating the advantage of crop rotation. Notably, the practice has been seen to be successful in increasing the fertility of the land over a period of time.
3. Increase in soil nutrients
As earlier stated, crop rotation allows the land to regenerate and rejuvenate its self-nutrients without having to apply more nutrients through the use of fertilizers. Leaving the land bare for a season allows the land to regenerate the soil nutrients lost through absorption by plants harvested in the previous season.
By planting crops like legumes, for example, one is able to increase nitrogen in the soil as they contain nitrogen fixing bacteria that fixes nitrogen naturally into the soil. Each crop type adds up or absorbs different soil nutrients to the soil, therefore, it needs a mix up of a variety of plants to make them more balanced. Knowing the type of plants to grow after a rotation is imperative to avoid either excessive buildup of nutrients or excessive absorption of nutrients from the soil.
4. Reduces soil erosion
Soil erosion is the carrying away of the most important top soil layer by wind or water. When the soil is constantly covered by plants, the top soil layer is not carried away by water during heavy rainfall. A layer of crawling plants or cover crops like beans and peas works well to prevent erosion by giving the ground full crop cover unlike standalone crops like maize that leave land exposed to the soil erosion elements.
Crop rotation also helps reduce rain drop impact to the soil and general erosion by water because the roots of the plants hold the top layer soil together. Trees planted together with crops in the farms also assists in preventing soil erosion.
5. Limits concentration of pests and diseases
Similar plants tend to have the same pathogens, therefore, crop rotation intercepts the pest life cycle and their habitat. A cycle entails similar events that happen in constant rotation, meaning that the infestation of pests and diseases happens in season.
As a farmer, when aware of the kinds of pests and diseases that break out at a given time of the year and the crops affected, you can plant the host plant at a different season when the chances of infestation are low. This lowers the risk of plants getting infested and equally allows the farmer to grow crops each season without using pesticides, which is good for the environment.
6. Reduces the stress of weeds
Crop rotation is a traditional weed control technique that involves maintaining field conditions such that weeds are less likely to grow and/or increase in number. In other words, crop rotation allows the crops to crowd out weeds during competition of nutrients and other resources.
Weeds are a constant nuisance to any farmer and control can be done through tillage or mowing. They are a major enemy to crops as they bring competition of nutrients. Crop rotation thus reduce the population of weed or better yet, denies them an opportunity to grow. This in the long-run allows the farmer not to use tillage on the ground as it is a harmful technique of weed management to the soil structure.