1. FARMS WITH HIGH EXTERNAL INPUT USE

The majority of intensively managed farms in Africa, Latin America and Asia that strongly rely on external inputs are larger farms. Such farms mostly grow a few annual or perennial cash crops relying heavily on the use of fertilizers for plant nutrition and pesticides and herbicides for pest, disease and weed control. On such farms crops are often grown without a planned rotation and farm animals are not integrated into the nutrient cycle. Diversification is usually low on these farms. Trees and bushes are mostly removed to facilitate extensive mechanization, and crops are mostly grown alone. (Figure 2-2).

Figure 2-2

Potential challenges in conversion of such farms (Figure 2-3):

• Establishing a diverse and balanced farming system with a natural ability to regulate itself usually takes several years. • Major efforts may be necessary to restore natural soil fertility by providing a considerable amount of organic matter to the soil. • Abandoning high input external fertilizers results in yield depression in the first years of conversion, before soil fertility is re-established and yields rise again. • New approaches and practices usually involve a lot of learning and intensive observation of crop development, and dynamics of pests, diseases and natural enemies.

Figure 2-3

However, the conversion process can be achieved, if the following practices are implemented:

• Diversify the farming system: Select appropriate annual crops for the area and rotate them in a planned sequence. Include legume crops such as beans or leguminous feed crops in the rotation to provide nitrogen to the subsequent crops. Plant hedges and flower strips to encourage natural enemies and to control pests. • Start recycling valuable farm by-products. Establish on-farm compost production based on harvest residues and manure, if available, and mix the compost with the topsoil. This will bring stable organic matter into the soil and improve its structure and its capacity to feed the plants and store water. Green manures can provide plenty of plant material to feed soil organisms and build up soil fertility (Figure 2-4). • Introduce farm animals into the system. Farm animals provide valuable manure and diversify farm income through additional animal products. • Grow cover crops. Cover crops or lay out mulches in perennial crops provide protection to the soil.

Figure 2-4