Effects Of Conservation Tillage On Soil Enzymatic Activities In Slope Farmland Of Middle Gansu Region Of Loess Plateau

The paper focuses on Chinese medicinal materials in genuine and spring wheat in strip cropping, combines the measures of contour tillage and strip protective cropping, measures catalase, urinary enzyme, invertase, alkaline phosphatase, protease in loess plateau of middle Gansu, discusses the influence of conservation tillage technology farmland to the soil enzyme activity, and forms a suitable model of conservation tillage in slope farmland in loess plateau of middle Gansu.There were 6 treatments: intercropping pattern of isatis and glycyrrhiza and intercropping pattern of glycyrrhiza and spring wheat in the model of conventional tillage; intercropping pattern of isatis and glycyrrhiza and intercropping pattern of glycyrrhiza and spring wheat in the model of no-till with not cover tillage; intercropping pattern of isatis and glycyrrhiza and intercropping pattern of glycyrrhiza and spring wheat in the model of no-till with straw cover tillage. The changes of 5 kinds of the soil enzyme activity showed that:1. The changes of the soil enzyme activity in different treatmentsThe NTS treatment of soil enzyme activity of catalase, urinary enzyme, invertase, alkaline phosphatase, and protease is stronger than the one of NT, T treatments and NT treatment is stronger than T treatment. Therefore, no-tillage and no-till with straw cover can increase the soil enzyme activity in slope farmland on loess plateau of middle Gansu and also improve the soil fertility status in slope farmland.2. The dynamic changes of soil enzyme activity in different treatments.The dynamic distribution of the activity of catalase, urinary enzyme, invertase, alkaline phosphatase, and protease showed inconsistency. Soil enzyme activity changed with the variation of time. In all, the maximum time of 5 kinds of soil enzyme activity appeared May or June and the minimum occurred March and July.3. The changes of vertical section in different oil enzyme activities treatmentsWith the depth increases of soil layer, the vertical profiles of catalase ,invertase, alkaline phosphatase and protease showed: surface (0⁵ cm)> subsurface (5¹0 cm)>deep (10³0 cm), but vertical section of urinary enzyme in NTS_WL,NTS_IL, T_WL and T_IL treatments showed: subsurface (5¹0 cm)>deep (10³0 cm) > surface (0⁵ cm) and with the depth increasing of soil layer, the activity of urinary enzyme increased in NT_WL,NT_IL.4. The changes of soil enzyme activities in different crops beltThe strong (weak) and correlation of various soil enzyme activities showed different between distinct crops. The order of catalase in the three crops is: isatis >glycyrrhiza> spring wheat. The order of urinary enzyme is: spring wheat> glycyrrhiza> isatis. The order of invertase is: glycyrrhiza>isatis>spring wheat. The order of alkaline phosphatase is: glycyrrhiza>spring wheat> isatis. The order of protease is: isatis >spring wheat> glycyrrhiza.5. The change of soil enzyme activities in different intercropping patternThe 5 kinds of soil enzyme activities in intercropping pattern of different soil layers showed inconsistency. The activity of catalase, invertase, alkaline phosphatase and protease of intercropping pattern of isatis and glycyrrhiza is higher than the intercropping pattern of spring wheat and glycyrrhiza, not including urinary enzyme of intercropping pattern of isatis and glycyrrhiza in NTS treatment. Therefore, soil enzyme activities of intercropping pattern of isatis and glycyrrhiza is better than intercropping pattern of spring wheat and glycyrrhiza.6. Correlation analysis of 5 kinds of soil enzyme activitiesCorrelation analysis by determination of the 5 kinds of soil enzyme activities found that: the correlation among urinary rnzyme, invertase, alkaline phosphatase and protease is very significant, not including Catalase.7. Comprehensive evaluation of soil enzyme activities of different treatmentsComprehensive evaluation of soil enzyme activities in different treatments of by using Fuzzy mathematical theory was showed that: the order of soil enzyme activities in different treatments is NTS_IL>NTS_WL>NT_IL>NT_WL>T_IL>T_WL. Therefore, soil enzyme activities of no-till with straw cover treatments in intercropping pattern is better than no-till and conventional tillage treatments, and the values of soil enzyme activities of intercropping pattern of isatis and glycyrrhiza is highest. The paper analyzed the soil enzyme activities by Cluster analysis and showed that: when class separation distance equal to 5, soil enzyme activities in different treatments can be divided into three or four levels, NTS_IL for one level, NTS_WL, NT_WL, NT_IL for a level, T_WL, T_IL for a level or NTS_IL for one level, NTS_WL for one level, NT_WL NT_IL for one level, T_WL T_IL for a level. The result of cluster analysis and comprehensive evaluation of soil enzyme activities in different treatments is consistent and it also illustrated that the result of this comprehensive evaluation of soil enzyme activities in different treatments is reasonable.