Assessment of enzymatic activity differentiation when using waste-free processing technologies in agro-chernozem layers

The objective of the study is to identify the effect of no-till technologies for processing agrochernozems on the heterogeneity of the compared soil layers in terms of protease and urease enzyme activity. The studies were carried out under the conditions of a production experiment laid out in the Shilinskoye agricultural production cooperative in the Krasnoyarsk forest-steppe located within the Chulym-Yenisei denudation plateau of the southwestern outskirts of Central Siberia (56°37' N and 93°12' E). The soil of the experimental plot was leached high-humus medium-deep light clayey chernozem on red-brown clay. The experimental soil was characterized by: humus content of 5.9 %, neutral reaction of the environment (pHH2O 6,8). The sum of absorbed bases was from 60 to 62 mg-eq/100 g of soil. In production crops, soil samples were taken three times during the vegetation season from the 0-5 and 5-20 cm layers using the snake method. The sample size was 15 individual samples. The norm, in accordance with the WMO regulations, was calculated for a 30-year period (1981-2010). The experimental design consisted of the following variants (processing methods): 1 - zero; 2 - minimum; 3 - moldboard (st). A significant differentiation of the studied agrochernozem layers was revealed when using minimum tillage technologies. Periods with a deficit of atmospheric moisture had a significant effect on the amount of proteolysis. An increase in moisture was accompanied by a decrease in proteolytic activity (r = -0.5 ... -0.63) when using surface disking, whereas under no-till conditions a direct effect of moisture on the level of hydrolysis of nitrogen-containing organic compounds was found (r = 0.61 ... 0.68). An increase in protease activity was accompanied by a significant decrease in difficult-to-hydrolyze nitrogen-containing compounds when using surface disking (r = -0.57 ... -0.71). During periods with excess moisture, significant differences in the level of urease activity were also found, mainly when using minimum tillage technology. The transformation of easily hydrolysable nitrogen-containing organic compounds was associated with the level of urease activity.