Effects of animal manures on enzymes activities and physico-chemical properties of a degraded humid ultisol

Abstract

Application of animal manures for soil amendment plays a major role in the improvement of soil properties and enzymatic activities of a degraded Ultisol. This study assessed the effects of poultry manure (PM) and swine manure (SM) on the activities of catalase and urease enzymes and some soil properties. The PM and SM were applied at the rate of 30 t ha^–1 each on experimental plots arranged in a randomized complete block design with three replicates. Soil samples were collected at day 0, 14, 28, 42, 56, 70 and 84 from 0-15 and 15-30 cm depths and analyzed for catalase and urease enzymes and some soil properties using standard procedures. The results showed increase in soil pH (in H₂O) from 4.0 to 5.4 following manure application. At 0-15 cm soil depth, PM and SM recorded 28.1 and 28.8% increases in soil pH (in H₂O), respectively. Soil organic carbon was highest (2.6 g kg^–1) at 0-15 cm depth for soil amended with SM while the lowest value of 1.1 g kg^–1was obtained at 15-30 cm depth for soil unamended with SM. In PM-amended soil, catalase activities ranged from 1.32 to 6.77 mg g^–1 while its activities in SM-treated soil significantly (p < 0.05) varied between 1.55 and 8.11 mg g^–1. Urease showed ranges of 0.72-3.90 mg g^–1 and 0.96-4.71 mg g^–1 in PM-amended and SM-treated soils, respectively. The results uphold that animal manures improve soil properties and are enzymatically controlled.