The prospects for integrated nutrient management for sustainable rainfed lowland rice production in Sukumaland, Tanzania

The possibilities of integrated nutrient management for sustainable rice cultivation are investigated for rainfed, lowland rice in Sukumaland, northwestern Tanzania. Typical, hardpan rice soils in Sukumaland have rather low levels of organic matter, total nitrogen and available phosphorus, and a low to medium amount of exchangeable potassium. Consumption of mineral fertilizers in rice is, however, very low due to availability problems and sharply increased prices of fertilizers. Use of locally available resources for soil fertility improvement is hampered by the additional inputs of farm household labour involved. High labour inputs per hectare without increases in capital inputs lead to lower marginal and average products per hour of labour. Furthermore, in semi-arid Sukumaland biomass production of green manures is seriously restricted by climate. The amount of kraal cattle manure is insufficient and half the households have no easy access to it. Using rice straw as cattle feed and thatching material has priority over soil fertility improvement. Some farmers indicate that at present there is not yet an urgent need for improved integrated nutrient management in Sukumaland rice cultivation. Adoption of integrated nutrient management based technologies depends on conducive socio-economic, agro-ecological and public policy circumstances. Farmer investment in learning and a favourable policy environment are thus no guarantee for worldwide adoption of these technologies by farm households.