Effect Of Irrigation And Fertilization Pattern On N Balance Of Potato Field Based On Soil Columin Simulation

Applying excessive chemical N fertilizer in farmland is gradually causing environmental risk.Presently,the N use efficiency in China is far lower than the world average.In current study,a soil column simulation experiment was conducted to investigate the N leaching and balance for the potato fields.To be practical,through fields'survey we selected two typical farmlands from big farm,cooperatives and companies,respectively,to simulate the irrigation and fertilization pattern using the soil column.Through the determination of N in potato plants,soil and leachate in different growth stages,we concluded as follows:(1)After potato plants harvest,there was no significant difference in soil residual nitrogen in different irrigation and fertilization patterns.The total amount of leachate in the drip irrigation system is 471 mL,which is 19.6%of the irrigation rate.The total amount of leachate in the sprinkler system is 992mL,which is 28.8%of the irrigation amount.With the same N rate,the inorganic nitrogen leaching loss in drip irrigation and sprinkler irrigation were 2.2-4.5 mg and 7.7?14.2 mg,respectively,indicating that drip irrigation can improve water use efficiency than sprinkler irrigation,and reduce N leaching loss.(2)Applying organic fertilizer can increase soil fertility,increase the N uptake of potato plants,so that can reduce N leaching loss in farmland.(3)With the growth of potato plants,the concentration of N in the leaching solution showed a decreasing trend,the nitrogen leaching was higher in the seedling stage compare to the other growth stages.The result indicated that we should reduce the input of N fertilizer before planting,thus reduce the environmental pressure.(4)The N balance in different irrigation and fertilization ranged from 149 to 375 mg per column,indicating a surplus state in each soil column,which probably cause nitrate leaching.