Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

or strip cropping along contour bunds. Species planted include Grevillea, Sesbaniasesban, Calliandra calothyrsus, Leucaena diversfolia and L. leucocephala. Agroforestry is alsopractised around homesteads to demarcate boundaries, to serve as woodlots, andfor intercropping, relay cropping and sometimes as alley cropping (fig. 3). Nowadaysmany farmers have realized the importance of planting multipurpose trees andthey are doing it themselves.Figure 3. Agroforestry systems practised in the study area.Crop rotationCrop rotation is not common due to limited land or lack of knowledge. However, asfrom 2000, a few farmers have been rotating wheat with lablab and maize. Wheatand barley are grown in pure stands, while for other crops intercropping is the mostcommon practice.5 Land degradation in Karatu and justificationfor conservationEnvironmental degradation in Karatu District began long ago, during the colonialera (Rohde and Hilhorst 2001). About 80% of Karatu District was considered goodfor agriculture because it had suitable rainfall and fertile soils (Meindertsman andKessler 1997). Mechanized and tractor-based agriculture was introduced as earlyas in the 1960s when settlers 2 cleared more land to allow farming and livestockrearing, which accelerated environmental degradation. By 1976, there were about370 tractors in Karatu, with their use contributing significantly to degradationproblems such as soil compaction. In turn, this resulted in soil erosion, especially onslopes such as in Manyara Basin (COPEC 2003).2 People come from Mbulu to settle in Karatu because of its agricultural potential.Karatu District 69