Assessment of nitrogen mineralization of <i>Faidherbia albida</i> and its effect on maize (<i>Zea mays</i> L.) growth on an Alfisol in Samaru, Northern Guinea Savanna of Nigeria

Abstract

This study was carried out to assess the effect of nitrogen mineralization of Faidherbia albida foliage and urea on maize growth in Samaru, Northern Guinea savanna Alfisols, Nigeria. A maize variety “Sammaz 32” was used as a test crop. The treatments consisted of five Faidherbia albida (FA) levels 0, 2, 4, 6 and 8 tons (t) ha-1 equivalent to 0, 3.56, 7.12, 10.67 and 14.22g pot-1 respectively and four urea fertilizer (0, 30, 60 and 120 kg N ha-1 represented as 0, ¼, ½ and FRR (full recommended rates) equivalent to 0, 0.13, 0.23 and 0.46 g pot-1 respectively) laid out in a completely randomized design with three replications. Result of the incubation study showed 49.16 of the N immobilized in the urea treatments, while all FA foliage mineralized in 63 days. Four (4 tons ha-1 FA gave the highest percentage of net N mineralization of 32.35%, while 8 tons ha-1 FA recorded the least net N mineralization percentage of 2.85%. Also, 4 tons ha-1 FA had the highest net mineralization rate of 10.55 mg kg-1 for NH4-N and 33.27 mg kg-1 for NO3—N with nitrification at 75% over ammonification, suggesting prevention of N loss through volatilization. The combination of 4 tons ha-1 FA + 30 kg Nha-1or + 60 kg Nha-1of urea gave the best treatment combinations for enhancing soil fertility though application of 120 kg Nha-1 gave the highest N value. Due to the negative impact of N fertilizer such as soil acidity resulting in poor soil quality and low yields, and to reduce production cost (fertilizer input cost) and maximize the profit, the use of 4 tons ha-1 FA + 30 kg Nha-1 is suggested for maize production in the Northern Guinea savanna of Nigeria.