Study On The Effect Of Biomass Carbon Modified Aeolian Sandy Soil On Adsorption And Desorption Of Nitrogen,Phosphorus And Potassium

The area of desertified soil in China is relatively large.The research on aeolian sandy soil area mostly focuses on how to prevent wind and sand,how to use planting structure to improve soil quality,and there are relatively few studies on using biochar to improve soil quality of aeolian sandy soil.It takes a long time to improve the soil quality,and because of the irreversibility of applying biochar into the soil,there is no clear conclusion about the suitable concentration level of biochar applied to different types of soil,and the improvement methods and methods need to be further explored.This paper takes Horqin sandy land as the research object,and uses field and indoor simulation experiments to study the improvement effect of biochar on the nutrient conditions of aeolian sandy soil.In the field trial,five different amounts of peat,charcoal and straw charcoal were applied to the aeolian sandy soil.Then the soil tested in the field was subjected to an indoor simulation experiment to determine the effective nitrogen,phosphorus and potassium contents of the soil samples and the adsorption and desorption effects.The adsorption experiment used exogenous nitrogen,phosphorus and potassium methods to carry out 12 hour adsorption equilibrium treatment of 8 different concentrations.Among them,the concentration of exogenous nitrogen and exogenous potassium is twice that of exogenous phosphorus.The desorption experiment was performed by taking the adsorption test sample subjected to the maximum concentration treatment for 8 consecutive 30 minutes of desorption.Finally,the Langmuir equation and the Freundlich equation fitting analysis were performed to calculate the soil adsorption desorption amount.(The amount of carbon applied is respectively: 1kg/?,2kg/?,3kg/?,4kg/?,5kg/?.The concentration of exogenous phosphorus in turn is as follows:0mg/L,5mg/L,10mg/L,15mg/L,25mg/L,40mg/L,50mg/L,100mg/L.The concentrationof exogenous nitrogen and potassium is twice as high as that of exogenous phosphorus.)Through the above series of experiments,the following conclusions are drawn:The aeolian sandy soil modified by straw charcoal has the best adsorption and desorption effect on NPK;Straw charcoal has better sustained release properties of external nitrogen,phosphorus and potassium;The adsorption effect of NPK is consistent with the Langmuir equation and the Freundlich equation.The desorption effect of potassium accords with the Langmuir equation.When the concentration of exogenous NPK was C4~C6(P-15mg/L~40mg/L,N/K-30mg/L~80 mg/L),the correlation of adsorption and desorption of straw charcoal was moresignificant.When the cumulative amount of carbon in the aeolian sandy soil increases,the straw charcoal can still maintain the balance of nutrients in the soil;After the improvement,the demand for fertilizer in the aeolian sandy soil decreased by about 1/3.