There are many management strategies for improving soil productivity. Crop rotation or cropping sequence is proven to be very effective in addressing concerns related to soil, water, and environment quality from long- or short-term perspectives. Producers who are innovative in diversifying their cropping systems and management strategies will be more successful than others who are not.
As producers search for better ways to achieve profitability, one management tool that has been largely overlooked for too long is a robust multiple-crop rotation management system. There are several proven benefits of a multiple-crop rotation system. Rotation is not only important for watching nutrient depletion, but also reducing the numbers of bacteria that attacks each type of vegetable family. Crop rotation is something of a lost art. It is a traditional method used to cleanse, protect and replenish the soil and involves growing different annual or perennial crops in the same area on a planned systematic basis. It is the opposite of continuous cropping, i.e. growing the same crop in the same area year after year.Crop rotation is useful in:
1. improving and maintaining good physical, chemical and biological soil conditions
2. reducing erosion
3. eliminating the need for nitrogen fertiliser by including legumes in the rotation
4. disrupting the build-up of insect populations and disease life cycles
5. discouraging weeds
6. encouraging healthy root systems which retrieve nutrients from the soil and minimize leaching
7. maximising use of nutrients e.g. following a nitrogen-fixing legume with a crop that needs high nitrogen soil content.
8. Crop rotation can improve yield and profitability over time, control weeds, break disease cycles, limit insect and other pest infestations, provide an alternative source of nitrogen, reduce soil erosion, increase soil organic matter, improve soil tilth, and reduce runoff of nutrients and chemicals, as well as the potential for contamination of surface water.
9. Crop rotation helps to create a biodivers soil which reduces the chance of soil bound organisms to get a pest and reducing the use of pesticides (see annexes)
10. Crop rotation helps to minimise the growth of herbs getting a weed that needs to be eradicated and so reducing the use of pesticides
11. Crop rotation helps getting a good soil structure (alternatively shallow and deep rooting roots), high organic matter, good water provision, especially in combination with conservation tillage, resulting in a higher yield
12. Crop rotation, especially performed with nitrogen-fixating rotation crops, will reduce the input of fertilizers and so reduce the pollution by nitrogen; a high nitrogen-supply will even contribute to soil organic matter depletion (S.A.Khan et al. J. Environ. Qual. 36:1821-1832, 2007: “The myth of nitrogen fertilization for soil sequestration”) pointing to the role of high N-fertilizer use as a reason for carbon depletion)
13. Crop rotation, especially combined with conservation tillage, will lead to higher soil-carbon content and so contribute to combating climate change ( proven in decade-long surveys in the US, Illinois, see Annex, and also by research, L.M.Vleeshouwers et al. Global Change Biology 8:519-530, 2002: “Carbon emission and sequestration by agricultural land use: a model study for Europe”).