Responses of maize to nitrogen and phosphorus sources in guinea savanna zone of Nigeria

Abstract

Field experiments were conducted at Samaru in guinea savanna zone of Nigeria in 1998,1999 and 2000 to study the effect of N and two sources of phosphorus (single super phosphate and sokoto phosphate rock, SPR) on yield and N and P uptake of maize (Zea mays). The soil was low in organic matter, N, P and acidic. There was a control treatment, N, in three levels (60, 120, 180 kg ha^-1) as urea, and P at two levels, 60 kg P₂0₅ ha^-1 (as single super phosphate, SSP) and 180 kg P₂0₅ ha^-1) as SPR. There were 9 single and combined NP treatments. Application of NP fertilizers significantly increased N and P uptake, biomass, cob and grain yield of maize irrespective of P source. Addition of SSP (60 kg P₂0₅ ha^-1) and SPR (180 kg P₂0₅ ha^-1) to urea 180 kg N ha^-1 increased biomass, grain and cob yield, the grain N and P uptake increased by 30 and 20% respectively. Compared with SSP, relative agronomic efficiency for SPR was 33%. Biomass, cob and grain yield increased with level of applied N. Compared with control, 180 kg N ha^-1 increased maize biomass, cob and grain yield by 75, 159 and 176% respectively. The 180 kg N ha^-1 + 60 kg P₂0₅ ha^-1 (SSP), 120 kg N ha^-1 + 60 kg P₂0₅ ha^-1 (SSP), and 180 kg N ha^-1 + 180 kg P₂0₅ ha^-1 (SPR) gave highest grain yield. They increased yield by 259, 247 and 238% respectively. SPR maximized P uptake by maize.

Nigerian Journal of Soil Science Vol. 15 2005: 90-95