Nutrient Requirements of Tomatoes (Lycopersicon esculentum) in S.W. Nigeria. I. Effects of N, P and K on Yields

SUMMARY The response of tomatoes to applied N, P and K was determined in six trials in the forest and savannah zones of Nigeria. In the savannah area, N was the most deficient nutrient, with an optimum level of 60 kg. N/ha., while P and K were required at lower rates of between 20–60 kg. P 2 O 5 and K 2 O/ha. depending on initial soil nutrient status and moisture availability. In forest soils developed from sedimentary rocks, P requirement was high (120 kg. P 2 O 5 /ha.) and response to N was small, but K could be important on the well-drained soils in this area because of low K reserves (0·1 per cent total K) compared with soils from igneous rocks in the savannah with more than 0·6 per cent total K. The potential of the savannah for large-scale tomato production is discussed, as well as factors limiting yields in Western State of Nigeria.