One of the most important aspects of organic farming is the strict avoidance of monoculture, whether annuals or perennials. Besides the proverbial “putting all eggs into one basket”, monoculture systems are unhealthy for the ecosystem they are a part of. The prime requirement for any natural ecosystem to thrive and be healthy is diversity.
Traditional farmers till date follow the systems of crop rotation, multi-cropping, inter-cropping and polyculture to make maximum use of all inputs available to them, including soil, water and light, at a minimum cost to the environment. The home gardens of Kerala are an excellent example.
Crop rotation is the sequence of cropping where two dissimilar type of crops follow each other – a few examples include cereals and legumes, deep-rooted and short-rooted plants and where the second crop can make use of the manuring or irrigation provided some months earlier to the first crop (eg. rice + wheat, rice + cotton). The combinations possible are endless, and will depend to a great deal on the local situations.
Multi-cropping is the simultaneous cultivation of two or more crops. In Indian agricultural tradition, farmers have been known to sow as many as 15 types of crops at one time. An example of multi-cropping is Tomatoes + Onions + Marigold (where the marigolds repel some of tomato’s pests).
Inter-cropping is the cultivation of another crop in the spaces available between the main crop. A good example is the multi-tier system of coconut + banana + pineapple/ginger/leguminous fodder/medicinal or aromatic plants. While ensuring bio-diversity within a farm, inter-cropping also allows for maximum use of resources.
All these are forms of polyculture and biodiversity and help in keeping pest populations in control. Leaf fall and other crop residues in combination add more value to the soil or compost heap they become a part of, again because of the nutritional mix.