Benefits of Crop Diversification to Sustain Yields, Soil Quality and Biodiversity

The use of crop rotations, multiple cropping or intercropping associated with sustainable agricultural practices (conservation agriculture, nutrient management, integrated pest management, etc.) can achieve higher land productivity than mono-cropping. This is due to the effect of crop diversification in increasing the resilience of the agroecosystem to perturbations (drought, flooding, diseases, pests, nutrient availability, pollution) by complementary use of resources and transfer of nutrients by plant roots. With diversified cropping systems, dependence on a single crop is avoided, so that variability in prices, market, climate, and pests/diseases will not have such drastic effects on local economy. However, to ensure increases in land productivity, the establishment of suitable crop associations, cultivars, densities and patterns is essential.

Crop diversification can enhance the delivery of ecosystem services such as increases in above and belowground biodiversity, decreases in soil erosion and greenhouse gas emissions, decreases in soil/water pollution and increases in carbon sequestration. It can also reduce the consumption of fertilisers, pesticides, water and energy, improving the long-term sustainability of agro-ecosystems. Crop rotation, multiple cropping and intercrops can promote water retention (by improved soil structure and higher soil cover) and mitigate pest/disease pressures (by competence, repellence, allelopathy, and development of natural enemies). Crop diversification can reduce the use of fertilisers with use of associations with different requirements for soil nutrients in time and space. For example, legumes, as crops that fix atmospheric nitrogen can increase the production of the other crops through increments in soil fertility by higher microbial activity and release of available nitrogen. The inclusion of several crop species can increase biodiversity, since they provide refuge for more species. Selecting opportunities for pest control in combination with crop diversification that are specific to the particular area (e.g. selective non-persistent pesticides, barriers, minimisation of irrigation, mulching, suitable timing of crops) will limit the input of persistent pesticides to the soil and water, with optimised pest and disease control.