Effect of different tillage systems on the biological and enzymatic activity of soil

In recent years, the use of conservation tillage methods in the world has been widely considered and the use of conventional tillage methods has become obsolete in some parts of the world. Soil conservation tillage systems in arid and semi-arid usually runs. In semi-arid areas, the key to increasing the production of crops is to maximize the penetration of superficial waters. In addition, techniques that lead to a decrease in evaporation from the soil and increase the amount of water available to plants when drought occurs, they are very important. Conventional tillage methods, by increasing energy costs, lead to processes of degradation and reduction of water and soil resources, and long-term effects on soil properties produce undesirable effects and cause the formation of hard layers. The metabolic share and microbial contribution are among the ecophysiological indices that are evaluated to determine the microbial status of the soil.

This research was conducted in 2015 to investigate the effect of different tillage systems on soil biological activity in Golestan province. In this study, in the first stage, three regions were selected from Golestan province in the Gorganroud basin and in the cities of Gonbad, Kordkuy and Bandargaz. From each of these managements, 30 samples were taken at depths of 0-30 cm. Then biological soil properties such as soil microbial respiration, microbial biomass, urease, alkaline phosphatase, acid phosphatase, dehydrogenase and cellulase activity Measured. The experiment was conducted as a completely randomized block with three replications.

The results showed that the effect of tillage treatment in three areas of Gonbad, Kordkuy and Bandargaz on microbial respiration traits, alkaline phosphatase, acid phosphatase, urease, cellulase and dehydrogenase was significant, but there was no significant effect on microbial biomass in Gonbad region. The results of the comparison of mean values indicated that soil biological activity was affected by different tillage systems in the three studied areas. In all three studied areas, the rate of respiration in conventional tillage systems was higher than that of no-till and conservation tillage systems. While in the no-till system, due to reduced organic matter decomposition, the amount of microbial biomass was higher than the other two systems. Considering the differences in enzymatic activity in different regions in different systems, the results showed that alkaline and acid phosphatase enzymes activity, urease and cellulase activity in the Gonbad region in the conservation tillage system was higher than of two other systems While in the Kurdkuy region the activity of these enzymes in the conservation tillage system was less than the other two systems. In the Kurdkuy and Bandargaz regions, the activity of the dehydrogenase enzyme in the conservation tillage system was more than the other two systems, while in the Gonbad region the activity of this enzyme in the no-till system was more than the other two systems.

Different tillage systems affect the level of biological and enzymatic activity of the soil, which was also dependent on the area, so that the microbial biomass of the soil decreased with decreasing moisture content and soil organic matter. Also, according to the results of this study, it was determined that the conventional tillage s system in terms of biological and enzymatic activities in all three areas, especially the Gonbad area, had less efficiency and more efficient no-till and conservation tillage systems, although in areas the different situations were different. Key words: tillage, enzymatic activity, conservation tillage and organic matter