Effects of Organic Amendments on Enzymes Activities in a Calcareous Sandy Soil

Abstract

This study was conducted to assess the impact of some organic amendments on enzyme activities and soil organic carbon (SOC) content of a Calcaric Regosol. The organic amendments included poultry manure compost (CM), sugarcane (Saccharum officinarum) bagasse biomass (SBB), and its biochar (SBBC). Chemical soil properties and some enzyme activities were analyzed after 2, 4, 8, and 12 months (M2, M4, M8, and M12, respectively) of soil incubation. Five treatments including Control soil, SBB, SBBC, CM, and the mixture of SBBC + CM in the ratio of 1 : 1 were considered. There were three levels of organic amendments: L1: 1.25%, L2: 2.5%, and L3: 5%. The results indicated a considerable increase in SOC content and enzyme activities following the addition of organic amendments to the soil. Both the SOC content and enzyme activities were impacted by the type of organic amendments, levels of input, and the duration of incubation (p < 0.001). Compared to the control (untreated soil), the activity of alkaline phosphatase significantly increased from 221.2 (CML1M2) to 1094% (SBBL3M12) and acid phosphatase activity varied from 108.2 (SBBCL3M2) to 1063% (SBBL3M12) in the treated soils. The CML3M12 treatment had the highest impact on β-glucosidase activity with a rise of 1256.5% in comparison with the control. Similarly, the SBBCL3M8 treatment led to the highest Invertase activity. Application of organic amendments would be considered as a guaranteed strategy of restoring and increasing SOC storage in calcareous sandy soils.