| In the soil-crop system,ammonia(NH3)volatilization is one of the important ways to lose nitrogen fertilizer.It will not only reduce the fertilizer utilization rate,but also cause energy waste in the production of nitrogen fertilizer industry.At the same time,it will also cause environmental pollution that should not be ignored.Therefore,it is very important to understand the volatilization regularity of NH3 in farmland soil and provide effective agricultural measures to reduce NH3 volatilization.At present,the contradiction between land supply and demand has become increasingly prominent,so the prevention and development of saline-alkali land has attracted much attention.Improving saline-alkali land and expanding it to agricultural land resources can effectively solve the shortage of land supply and demand.Therefore,this study selected saline-alkali farmland in the Yellow River Delta as the soil for the test,and carried out the following series of experiments.In order to find out the basic law of NH3 volatilization in saline-alkali farmland soils in the Yellow River Delta,this study measured the recovery rate of NH3 volatilization in saline-alkali farmland soils by indoor continuous cultivation,and then explored the effects of fertilizer types,fertilizer concentration,soil water content and soil salt on NH3 volatilization rate and cumulative volatilization in saline-alkali farmland soils by single factor variable experiment.The results showed that the recovery of NH3 volatilization from ammonium sulfate as nitrogen source was as high as 99.21%-101.39%.The volatilization rate of NH3 was higher than that of ammonium sulfate granules and urea granules when ammonium carbonate granules were applied to soil,and the cumulative volatilization amount of NH3 was higher than that of urea granules and ammonium sulfate granules when ammonium carbonate granules were applied to soil.With the increase of fertilizer concentration,the volatilization rate and cumulative volatilization amount of NH3 increased.The NH3 volatilization rate and cumulative volatilization amount decreased significantly with the increase of soil water content.At the same time,in order to reduce NH3 volatilization caused by fertilization.this study further explored the effects of fertilizer granules and aqueous fertilizer solution on NH3 volatilization and the effects of biochar type.amount and fertilizer type on NH3 volatilization rate and total amount after addinu biochar.The results showed that NH3 volatilization was significantly reduced by applying fertilizer aqueous solution compared with surface application of fertilizer particles.Under the same amount of nitrogen application.NH3.volatilization was reduced by 60.29%,hen urea aqueous solution was applied compared with that when urea particles were applied.and NH3 volatilization was reduced by 61.40%when ammonium sulfate aqueous solution was applied compared with that when ammonium sulfate particles were applied.Compared with the blank treatment with ammonium sulfate solutioin without biochar.the total volatilization of NH3 decreased by 18.680%.16.16%.9.35%and 8.260%in the treatments with 0.5%biochar and the types of biochar applied were 300℃ rice biochar(RB-300).600℃ rice biochar(RB-600).300 ℃ cotton biochar(CB-300).and 600 ℃ cotton biochar(CB-600)respectively.and the volatilization rate of NH3 was the highest ithin 2 days after fertilization,accounting for the total volatilization rate.53.80%-64.02%of the total output.After addine biochar.the volatilization of NH3 decreased first and then increased with the increase of biochar contentThe basic data obtained in this study will provide a basis for reducing NH3 volatilization,improving nitrogen use efficiency and increasing crop yield in the application of biochar.selection of fertilizers and integrated management practice of water and fertilizer.Therefore,it can effectively reduce the non-point source pollution of nitrogen caused by fertilization of farmland soil. |
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