Responses Of Soybean Yield And Quality To Warming In Different Soil Types

The 14th Five-Year Plan puts forward the implementation of food security strategy for the first time,which reflects the importance of the CPC Central Committee to China’s food security.The impact of climate warming on agricultural production and food security is the focus of current research.Soybean is an important industrial crop in China,and soil is an important source of nutrients needed for crop growth and development.To further understand the response of soybean yield and quality to temperature increase in different soils,in this experiment,the spatial shift test was carried out at the Agrometeorological Experimental Station of Nanjing University of Information Science and Technology.The Free Air Temperature Increased(FATI)was used to mimic elevated temperature during whole growing season.The studied soils were sampled from Phaeozem,Burozem,Saline-alkali soil,Aeolian sand soil,Sierozem,Loess,Fluvo-aquic soil,Yellow brown soil,Vertisol,Krasnozem,Purple soil,and Latosol zone.The contents of the study were: soil enzyme activity and soil basic nutrients,soybean N,P and K utilization efficiency,yield and its composition,mineral elements and crude protein contents in grains.The main finds are as follows:(1)Increasing temperature had significant effects on soil available nutrients and enzyme activities.In terms of the physical and chemical properties of soil,the increase of temperature significantly reduced the soil water content,while the p H of acid soil: Yellow brown soil,Vertisol and Burozem decreased significantly.Soil available nitrogen and available potassium decreased by 7% and 10%,respectively,compared with a T.In terms of soil enzyme activity,Increasing temperature significantly decreased the activity of soil Catalase by 21%,while increased soil Invertase by 42%.The activity of soil Phosphatase was negatively correlated with p H,and positively correlated with available nitrogen and available phosphorus.The activities of soil Catalase,Urease and Invertase are positively correlated with p H.The activities of soil Urease and Catalase were positively correlated with available nitrogen.The comprehensive fertility of Yellow brown soil increased the most after warming,while the comprehensive fertility of Latosol decreased the most after warming.(2)In terms of nutrient absorption,the nitrogen,phosphorus and potassium uptake of soybean and the kernel potassium content of soybean increased by 35%,32%,33% and 6%,respectively,but the nitrogen,phosphorus and potassium contents of soybean straw decreased by 19%,27% and 14%,respectively,and the kernel nitrogen and phosphorus contents also decreased.In terms of nutrient use efficiency,increasing temperature decreased the unit nitrogen and phosphorus use efficiency,and increased the unit potassium use efficiency.(3)Increasing temperature significantly shortened the growth period of soybean,accelerated the development process,and significantly increased the plant height and yield per plant.The soybean yield,biomass,pod number per plant and grain number per plant were significantly increased in Yellow brown soil,Vertisol,and Krasnozem.Correlation analysis showed that the grain number per plant was the most direct factor affecting soybean yield.The yield of soybean was significantly positively correlated with biomass,grain number per plant,pod number per plant and the ratio of grain to stalk,but the correlation with plant height was weak.Increasing temperature increased soybean yield in Yellow brown soil and Vertisol the most,while increased soybean yield in Loess and Krasnozem the least.(4)Increasing temperature had significant effect on soybean quality.The protein of soybean grains decreased by 2%,while the mineral elements of soybean grains increased,and the contents of Fe,Zn,Mn and Ca increased by 19%,14%,14% and 12% compared with a T,respectively.Under the condition of increasing temperature,the protein content of Yellow brown soil and Vertisol decreased 3% and 7%,respectively,the Zn,Mn and Ca content of soybean also decreased significantly.Principal component analysis showed that the comprehensive quality of soybean in Sierozem,Phaeozem and Loess was improved greatly by increasing temperature,while the comprehensive quality of soybean in Yellow brown soil and Vertisol was decreased.Comprehensive analysis showed that warming conditions,Yellow brown soil,Phaeozem,Saline-alkali soil,Sierozem,Vertisol,and Loess fertility,nutrient elements have accumulated,so that the production increase,the mineral elements content is increased,but the grain protein content have weakened,thus the yield of soybean in Vertisol and Yellow brown soil increased too much,and the contents of Zn,Mn and Ca decreased to a certain extent.Under the background of climate change,the response of soybean yield and quality in different soil types to temperature increase still needs to be further explored in order to make a plan for soybean to cope with climate change.At the same time,the effects of temperature increase on soybean yield and quality as well as soil fertility should be comprehensively analyzed,so as to ensure high quality and high yield of soybean under continuous planting and guarantee national food security.