Study On The Mechanism Of Carbon Conversion Under The Control Of Soil Enzymes Of Tartary Buckwheat From Pot Experiment

The ecological environment in the cold region of loess plateau is harsh and barren,which is one of the obstacles to agricultural development.Tartary buckwheat has high medicinal value and nutritional value,and has a good tolerance to fineness.It has become the main food crops,cash crops and relief crops planted on the loess plateau.However,"Buckwheat can bear both fineness and fineness".Reasonable application of fertilizer can effectively promote the growth of Tartary buckwheat,increase the yield and improve the quality.Under stress,soil enzymes play a more important role in regulating soil nutrient cycle than microorganisms.In order to study the dynamic change of soil carbon invertase activity of tartary buckwheat under low nitrogen stress and to provide theoretical basis for the mechanism of carbon transformation of tartary buckwheat rhizosphere soil.This study set up five kind of processing?CK1 and CK2,N1,N2,MJ?,two planted buckwheat varieties:the diqing?strong?and heifeng?weak?,respectively in seedling stage and flowering and maturity to collect soil samples,the soil invertase activities related to the physical and chemical properties and carbon are analyzed,and the main results were as follows:?1?Under low nitrogen stress,Tartary buckwheat with strong resistance to nitrogenpreferred the regulation of?-glucosidase enzyme.Under the same nitrogen treatment,the activity of?-glucosidase in the soil of tartary buckwheat increased first and then decreased.HF in the three stages was MJ>CK1,while DQ was just the opposite.In contrast,the activity of?-glucosidase in three stages was DQ>HF,while that in N2 and MJ was significantly higher than that in DQ.N1 was DQ>HF at seedling and flowering stage,while HF>DQ in mature stage.?2?Fertilization could make Tartary buckwheat root system and soil microorganismsecrete more sucrase enzyme,and provide more energy for the growth of Tartary buckwheat.In seedling stage,the sucrase activity of HF was MJ>N2>CK2>CK1>N1,and the activity of DQ was N1>MJ>N2>CK2>CK1 that of DQ.The activity of sucrase in flowering HF decreased with the increase of nitrogen application.The activity of sucrase increased with the increase of nitrogen application.There was no significant difference in sucrase activity among HF nitrogen treatments in the mature stage.DQ indicated that sucrase activity decreased with the increase of nitrogen application.?3?The nitrogen-tolerant Tartary buckwheat varieties showed stronger growthdominance and secreted more cellulase enzymes.At seedling stage,the cellulase activity of heifeng increased with the increase of nitrogen application.The activity of cellulase decreased with the increase of nitrogen application.At the flowering stage,the enzyme activities of both Tartary buckwheat showed a gradual increase with the increase of nitrogen application,and the enzyme activities were higher under the treatment of N1 and N2.In the mature stage,the cellulase activity of HF was N1>N2>MJ>control,while that of DQ increased with the increase of nitrogen application.The cellulase activities at seedling stage,flowering stage?except CK1?and mature stage?except CK?were all DQ>HF under the same nitrogen treatment,and the cellulase activities of MJ at the three stages were all lower than N1 and N2.?4?Nitrogen application could effectively improve the nutrient content in soil,andTartary buckwheat with strong nitrogen tolerance under low nitrogen stress had higher soil quality.1)Soil moisture content:in the seedling and flowering stages of Tartary buckwheat,the soil moisture content of DQ was lower than that of HF,and the soil moisture content of both Tartary buckwheat under the same nitrogen treatment was the lowest.2)Soil pH:the soil pH of both tartary buckwheat at seedling stage decreased with the increase of nitrogen application.The soil pH of the two tartary buckwheat under the same nitrogen treatment reached the maximum value at maturity stage.3)Soil organic carbon:DQ>HF was expressed in soil organic carbon at seedling stage under several treatments except sterilization.In the flowering stage,N1 is DQ>HF,while N2 is HF>DQ.In the mature stage,the soil organic carbon of N1 and N2 was also DQ>HF.4)Soil ammonia nitrogen:with the growth of tartary buckwheat,the ammonia nitrogen content of the two tartary buckwheat varieties increased first and then decreased,and the ammonia nitrogen content of the tartary buckwheat at seedling and flowering stage increased with the increase of nitrogen application.5)Soil nitrous content:nitrous content in HF of tartary buckwheat at seedling stage increased with the increase of n application,while nitrous content in DQ was N1 was the highest.N1 nitrate content of two kinds of tartary buckwheat in flowering stage was the highest,and that of DQ was higher than that of HF.The nitrate and nitrogen content of tartary buckwheat increased with the increase of nitrogen application.6)Soil total nitrogen:the total nitrogen of the two kinds of tartary buckwheat at seedling stage was N2>MJ>N1,the total nitrogen of the soil at flowering stage N1 was significantly higher than N2 and MJ,and the total nitrogen content of N2 in mature stage was significantly higher than MJ.7)Soil available phosphorus:the soil available phosphorus of two kinds of tartary buckwheat without fertilization in three periods was significantly lower than that of the other three treatments.8)Soil total phosphorus:under the three nitrogen treatments of N1,N2 and MJ,soil total phosphorus in DQ was higher than that in HF.9)Available k in soil:available k in DQ was higher than that in HF under low n and constant n in three periods.The available potassium of two kinds of Tartary buckwheat in three stages was lower than that of low nitrogen and constant nitrogen.10)Total k in soil:the total k in soil of DQ was higher than that of HF at seedling stage and flowering stage under low nitrogen,constant nitrogen and sterilization treatment,while the soil of HF was higher than that of DQ at maturity stage.?5?The results of RDA showed that among the environmental factors at seedlingstage,the ones that had the highest influence on carbon invertase were NO₃^--N,total potassium and NH₄⁺-N,the ones at flowering stage were NO₃^--N,NH₄⁺-N and total phosphorus,and the ones at maturity stage were water content,pH and NO₃^--N.Under low nitrogen stress,Tartary buckwheat roots at the early stage preferred someeasy to decompose such as monosaccharide enzyme and disaccharide enzyme for their growth and development,and later secreted more polysaccharide enzyme.Under different nitrogen treatments,the nitrogen-tolerant Tartary buckwheat showed the advantages of variety and had higher enzyme activity.Through the interaction of nitrogen,phosphorus and potassium,the transport and accumulation of nutrients were accelerated so as to gain stronger competitiveness.