Effect of Straw Returning and Nitrogen Application Rate on Soil Enzymatic Activities

摘要

In order to study the effects of full corn straw returning and water and nitrogen regulation on straw decomposition, soil enzyme activity and microorganisms. The nylon mesh bag method was used. Seven treatments were set up according to soil moisture (SM) and nitrogen application (Napp). The experiment excluded interference factors such as crops and atmospheric environment. The results showed that water and nitrogen regulation significantly promoted the decomposition of straw, and straw decomposition rate was higher with Napp than without Napp. Soil sucrase activity, urease activity and cellulase activity first increased and then decreased. Soil sucrase activity was highest at 200 kg hm(-2) Napp and 60-70% SM. Under the same Napp, soil urease activity was highest at 70-90% SM soil cellulase activity at 200 kg hm(-2) Napp was higher than at 140 kg hm(-2) under 60-70% SM. The number of soil bacteria first increased and then decreased and it was highest at 70-90% SM under the same Napp. The number of soil fungi showed a gradually increasing trend, and it was highest at 70-90% SM under 200 kg hm(-2) Napp. The straw decomposition rate has significant positive correlation with the number of soil bacteria and fungi, and the three interacted with each other. There was an intrinsic link between sucrase and urease. The study was intended to provide theoretical reference and basis for water and nitrogen management under straw returning.