Intercropping and sustainability

Summary

Grain legume-cereal intercropping is a method to obtain greater and more stable crop yields, improve the plant resource utilisation (water, light, nutrients), increase the input of leguminous symbiotic nitrogen fixation (SNF) to the cropping system and reduce negative impacts on the environment. However, due to agricultural intensification of plant breeding, mechanisation, and fertiliser and pesticide use over the last 50 years, intercropping has disappeared from many European farming systems.
Motivations for reintroducing grain-legume-cereal intercropping relate to the problems faced by intensive farming systems. During the 1980s it became evident that West European agricultural production systems (often characterised by monocultures, nutrient surpluses, and large external input of fertilizer, pesticides and feed concentrates) are not sustainable in the long term. On the medium and long term this causes undesirable economic, ecological, environmental and social effects. Reduction of external inputs and increases of home-grown feed together with a more efficient nutrient use from leguminous SNF are important factors in increasing sustainability of these systems. Intercropping offers the potential for:
·generating more stable yields, due to self-regulation in the crop. This will give the farmer better insurance against crop failure and will safeguard the farmer’s earnings,
·improving product quality, e.g. greater protein content of cereals, via planned competition,
·providing an ecological method ¾ via competition and natural regulation mechanisms and planned biodiversity ¾ to manage weeds and pests, hence reducing the cost of energy for weed and pest control, and
·improving the synchrony between microbial immobilization-mineralization and crop N demand, due to differences in the quality of the residues and thereby aiding in the
conservation of N in the cropping system.