Water-saving And Yield-increasing And Soiland Water Conservation Effects Of Main Grain Crops On Sloping Farmlandwith Straw Biochar

Heilongjiang Province is an important grain production base in China.However,the shortage of water resources and the area of soil erosion are expanding,which seriously restricts the development of agriculture and economy in the region,threatens the balance of ecosystems and becomes an important factor restricting regional sustainable development and food security factor.Biochar as a new soil improver,can improve the soil,increase soil fertility,fixed carbon to mitigate climate change,comprehensive utilization of biochar can solve the sustainable development,energy saving,environmental protection and governance issues.In order to explore the effect of straw biochar on the water saving and soil and water conservation effect of the main grain crops in the sloping farmland of Heilongjiang Province,the experiment was carried out on the 3°slope farmland of Hongxing Farm in Beian City,Heilongjiang Province in 2015.Set up two test zones of corn and soybeans,The applied amounts of five treatments were 0,25,50,75 and 100 t/hm2.The data were collected by manual observation,TDR,runoff automatic recording system and sediment collection system.The effects of different crops on soil and water conservation and water saving and increasing yield under different biochar application rates were studied by the observation and analysis of the effects of rainfall,runoff,annual rainfall,sediment yield and soil water content,crop growth dynamics and yield and its growth factors.The grey relation projection model was used to evaluate the biochar application model of maize and soybean respectively,and the optimal biochar application scheme of maize and soybean was obtained in order to provide reference for the local area about the application of biochar.The preliminary conclusions are as follows:(1)The addition of biochar can improve the soil environment,and the effect is better when the more the amount of biochar applied.The effect of biochar application to maize and soybean test area was basically same.The application of biochar could reduce the soil bulk density,increase the water holding capacity in the field,increase the content of organic matter,available phosphorus and available potassium in soil,and the better the effect of biochar application,However,the effect of biochar on the content of ammonium nitrogen in soil was less.(2)The application of biochar had little effect on the rainfall runoff process,but it could reduce the rainfall runoff.The effect of biochar on subrainfall runoff was related to plant growth status and rainfall intensity during rainfall,and the runoff decreased with the increase of biochar application.The application of biochar could also reduce annual runoff.For maize test area,annual runoffamount of biochar is reduced with the increase of biochar application,while in the soybean test area,the annual runoff was the smallestwhen the amount of biochar application was 75t/hm2.(3)The application of biochar had little effect on the process of rainfall and sediment yield,but the right amount of biochar can reduce the soil erosion and nutrient loss caused by rainfall.Applying appropriate amount of biochar could reduce the annual sediment yield,for maize test area,the yield of sedimentwas the smallest when the amount of biochar application was 25t/hm2,and for soybean test area,the amount of sediment produced increases with the increase of biochar application.The application of biochar could reduce the loss of organic matter,ammonium nitrogen,available phosphorus and available potassium in the soil,but the effect of different biochar application on the reduction of nutrient loss was not obvious.(4)The change trend of dynamic of soil moisture was not significantly changed by biochar application,but it could increase the soil water content of 0 ~ 60 cm soil layer and improve soil water storage.The effects of biochar on the soil moisture were same in the maize and soybean test.The soil water content of 0 ~ 60 cm soil layer was higher than that of the control treatment in the each growth period,and soil water content increased with the increase of the amount of biochar.The results showed that the application of biochar had little effect on the soil water content of 60 ~ 100 cm soil layer.(5)The growth dynamics,yield and its components of maize and soybean could be improved by applying biochar,and the change regularity of each index is basically the same.When the amount of biochar was 50t/hm2,the indexes of maize were the best.When the amount of biochar was 75 t/hm2,the indexes of soybean were the best.(6)Application of biochar could improve water use efficiency of maize and soybean.Among them,when the application rate of biochar was 50 t/hm2,the water use efficiency of maize was the highest.When the application rate of biochar was 75 t/hm2,the water use efficiency of soybean was the highest.(7)The comprehensive evaluation of different biochar application schemes showed that the application rate of biochar was 25 t/hm2 in maize test area,and the application rate of biochar was 75 t/hm2 in soybean test area.