Effect of long term fertilization on soil respiration and enzyme activities in floodplain soil

Abstract

In agricultural farming system organic manuring and inorganic fertilizer application are the most common agricultural practices. Different fertilizer application lead to differences in soil nutrients, pH, and microbial species, which in turn affect the transformation and decomposition of organic carbon by soil microorganisms. Therefore, a laboratory incubation study was carried out to investigate the influence of long term manuring and fertilization on soil respiration by means of C mineralization and enzyme activities. A parallel first- and zero-order kinetic model was used to describe observed C mineralization in soil. The annual carbon mineralization was found to be significantly influenced by different fertilizer. This result indicates that more stable organic matter was formed in NP treated soil which is less prone to decomposition if present crop management has been changed. Other ward, NP has the highest potentiality to soil for the purpose of carbon sequestration in floodplain soil compared to other fertilizer. Urease activities varied from 4.7µg NH4-N/g soil/2h in NK treatment to 25.7µg NH4-N/g soil/2h in N+FYM treatment. N treatment had a significantly higher urease activity compared to the respective controls. When P, K, S and PK applied separately with N then the treatments show low enzyme activity to control and other treatments (N, N+FYM and NPKSZn). There were no significant differences for Arylamidase activities among the treatments. The arylamidase activities decreased when S applied in combination with N. On the other hand arylamidase activity increased with the application of all other treatment.