Conserving soil and water Food and （保护土壤和食物和水）.PDFVIP

8 Conserving soil and water Conservation Agriculture ROSION AND lack of rainfall are problems that many African farmers face. EConservation agriculture can help overcome both by conserving soil and by storing water in the soil. If erosion is severe, you can combine conservation agriculture with other techniques to control erosion. In drier areas, you can combine it with water-harvesting methods to make more water available to the crop. This chapter describes various erosion control and water management meth- ods that you can combine with conservation agriculture. It does not describe these approaches in detail. You can find this information in many other manu- als (see, for example, Critchley et al., 1991 – full details in the Resource materi- als section in Chapter 14) Measures that control erosion and conserve soil almost always help to con- serve water too. And techniques designed to conserve water may help reduce soil erosion. Choose from the techniques below, and combine and adapt them to suit your needs. Soil conservation techniques Erosion can be a severe problem in conventional farming, especially on steep slopes. Conservation agriculture helps control erosion in several ways: Protective cover Cover crops and mulch on the surface protect the soil against heavy rain. They prevent rainsplash from dislodging fine particles and from forming a surface crust. Soil structure Undisturbed by ploughing, the soil structure stays intact. Organic matter holds the soil particles together, making it harder for water to carry them off, or for wind to blow them away. Roots bind the soil and hold it in place. Less runoff More water sinks into the soil through cracks and pores, so less runs off and causes erosion. Ripping and planting along the contour helps prevent