Overstory #215 - Agroforestry benefits for tropical organic farming
An agroforestry system approach
Conventional farming focuses on maximizing yields of a specific crop. It is based on a simple presumption: crop yields are increased by nutrient inputs and by controlling pests, diseases and weeds. Organic agriculture is a holistic way of farming: besides production of goods of high quality, an important aim is the conservation of natural resources such as fertile soil, clean water and rich biodiversity. The art of organic farming is to make the best use of ecological principles and processes. Organic farmers can learn a great deal from studying the interactions in natural ecosystems such as forests.
Trees and other plants take up nutrients from the soil and incorporate them in their biomass. The nutrients return to the soil when leaves or branches fall or plants die. Part of the biomass is consumed by various animals (including insects), and their excrement returns the nutrients to the soil. In the soil, a huge number of soil organisms are involved in the decomposition of organic material which makes nutrients available to plant roots again. The dense root system of forest plants collects the released nutrients almost completely. Forests host a high diversity of plant varieties of different size, root systems and requirements. Animals are also part of the system. In a healthy, diverse system, if one organism drops out, it is immediately replaced by another that fills the gap. Thus space, light, water and nutrients are used near-optimally. The result is a very stable system.