Effects of mineralization of apple ring (Faidherbia albida) foliage and urea fertilizer on soil microbial biomass on an Alfisol in Northern Guinea Savanna of Nigeria

Abstract

The role of mineralized Apple-ring (Faidherbia albida) foliage and urea fertilizer on soil microbial biomass in a Northern Guinea Savanna Alfisol, Nigeria was assessed in the screen house using maize (Sammaz 32 variety) as the test crop. The treatments consisted of five Apple-ring (AR) tree foliage levels (0, 2, 4, 6 and 8 tonsha-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 equivalent to 0, 0.13, 0.23 and 0.46 g pot-1 respectively) laid out in a completely randomized design with three replications. Results of the plant analysis showed that apple ring foliage contained 428.3 g kg-1 organic carbon (OC), 29.8 g kg-1 nitrogen (N), 1.94 g kg-1 phosphorus (P), 37.5 g kg-1 potassium (K), 17.1 g kg-1 calcium (Ca). The C: N ratio of the foliage was found to be low indicating apple ring ability for improving and sustaining soil health and crop productivity even under long term crop production. The highest yield of microbial biomass carbon (MBC) (80.43 mg C kg-1) and microbial biomass nitrogen (MBN) (47.13 mg N kg-1) were observed with application of 8 tons ha-1 apple ring + 120 kg Nha-1 , having a C: N of 1.96 which is statistically the same with the C: N ratios of 2 tons ha-1 apple ring + 120 kgNha-1 (2.03) and 6 tons ha-1 apple ring + 120 kg Nha-1 (2.05), indicating that decomposition will be fastest due to higher carbon and nitrogen contents and 8 tons ha-1 apple-ring + 120 kg Nha-1 (urea) would be the best treatment combination for sustainable maize production under continuous intensive cultivation.