Growth and yield responses of rice, wheat and beans to Zn and Cu fertilizers in soils of Mbeya region, Tanzania

Low crop production in most arable lands is associated with soils highly depleted of nutrients. A study was conducted in selected physiographic units of Mbeya Region Tanzania, to investigate the levels of soil macro- and micronutrients effect on crops (rice, wheat and beans) performance. Soils were analyzed in the laboratory. Screen-house experiments with three levels of Zn (0, 7.5 and 15 mg kg -1 soil) and Cu (0, 5 and 10 mg kg -1 soil) in combination with N and P treatment in completely randomized design with three replications was conducted. The results showed that all soils were deficient in N, P and Cu, while 46% of soils had low Ca. Zn was low in 46% of the soils while K and Fe was sufficient in all soils. Application of 15 mg kg -1 Zn and 5 mg kg -1 Cu with N and P fertilizers gave significantly highest grain yield of rice (9.05 g pot -1 ), beans (5.80 g pot -1 ) and wheat (5.58 g pot -1 ). The control gave lowest grain yield in all crops. Zink rate of 15 mg kg -1 and Cu rate of 5 mg kg -1 was sufficient to increase yields in these soils. Field experiments are recommended to confirm Zn and Cu fertilizer recommendations