24. Sustainable Intensification of Maize and Rice in Smallholder Farming Systems Under Climate Change in Tanzania

Maize and rice are major staple food crops in Tanzania and constitute 31 % and 13 %, respectively, of total food production. The current productivity of the two crops (1.6 t/ha and 2.3 t/ha, respectively) will not match with the increasing demand for food created by population growth unless there is an expansion of cultivated land or intensification measures are imparted to smallholder farmers, who produce nearly 90 % of each crop in the country. Expansion of cropped areas is limited by increased land-use pressure. Under smallholder farming the same land is continuously cultivated without proper input to replenish the removal of nutrients with crop harvesting, which leads to a decline in the subsequent crop yield. The situation is exacerbated by the effects of climate change. The smallholder farmers lack agro-inputs, information and extension services, and are faced with erratic rainfall. Therefore, a public-private partnership comprising two public universities and two multinational companies dealing with fertilizer and crop protection was initiated in December 2010, aiming at demonstrating sustainable intensification of maize and rice production in smallholder farmers’ fields. Five farms for maize and four for rice crops in different villages and districts were selected, and their soils were sampled for physical and chemical analysis. Two treatments were imposed on each farm. The treatments were farmers’ practice (control) and improved practice, which includes the proper use of fertilizer, crop protection inputs and recommended crop seed variety. Generally, the soils of most farms were acidic with low phosphorus, potassium, magnesium, sulphur, copper and zinc values. On average, maize and rice grain yield 14 % moisture content ranged from 2.5 to 5.4 t/ha in farmers’ practice and 6.6–8.5 t/ha in improved practice. Maize and rice stover/straw biomass ranged from 5.33 to 15.4 t/ha for improved practice and 2.11–9.13 t/ha for farmers’ practice. It can be concluded that improved agricultural practices, including plant nutrition, plant protection, improved seeds and conservation agriculture measures (e.g., crop residue recycling), enable sustainable intensification of smallholder crop production. Crop yields are improved, soil fertility is maintained, and family income is increased all at the same time. Therefore, public-private partnerships are needed to put this concept into practice and to make knowledge and technology available to smallholder farmers.