氮肥施用量对生菜产量、硝酸盐积累及土壤EC值、pH值的影响

研究了日光温室内不同氮肥用量对生菜产量、硝酸盐积累及土壤栽培环境的影响。结果表明:适当增施氮肥可提高生菜的产量,但过高又使产量下降;生菜中硝酸盐含量与施氮量呈显著的正相关性,相关系数为0.9914,过量施用氮肥是生菜中硝酸盐累积的主要原因;施氮量达300kg/hm2以上,各层次土壤EC值明显上升,pH值升高,对土壤环境造成污染。综合以上指标的测定,日光温室内栽培生菜施氮量不宜超过300kg/hm2。

Effects of N Application Rates on Yield, Nitrate Accumulation of Lettuce and EC, pH Value of Soil

Effects of N application rates on yield,nitrate accumulation of lettuce and the soil of planting were studied in greenhouse.The results showed that the application of suitable amount of N fertilizer could increase the yield of the lettuce,but excessively high N rates could decrease its yield;the nitrate accumulation of the selected vegetables was correlative with the N application rates signally,and the coefficient of correlation was 0.9914.The excessive N rates was the main reason for the nitrate accumulation of the lettuce.The EC and pH value of different stratums rose signally when the N application rates were more than 300kg/hm2,and the soil was polluted.The optimum N application rate was less than 300kg/hm2 in count of all indexes in greenhouse.