滇池流域蔬菜地土壤氮素分布与转移特征

选取滇池流域蔬菜设施保护地油麦菜（Lactuca sativa var.ramosa）种植区进行研究,分为高量组和低量组两个组别进行,每组分别设置9个施肥处理。试验结果表明：土壤总氮在各水平处理之间并没有规律性变化,在垂直梯度上（0-20、20-40、40-60cm）,土壤养分随深度增加而递减;高量组和低量组在生长期和成熟期,土壤总氮积累量和施氮量表现出了显著正向线性相关,相关系数R分别为0.9873、0.9901、0.9881和0.9880;适量施氮,土壤氮积累量表现出减少,而过量施氮则表现出了盈余;高量组氮损失量均大于低量组,且高量组在不同生育期的氮损失量与施氮量表现出极显著的线性正相关,相关系数R分别为0.9823、0.9719。高量组与低量组氮素损失率生长期均高于成熟期,而各处理之间未表现出明显的变化规律,最大损失率为39.79%,在适宜施肥量的处理中,损失率也达到了20%以上。

Distribution and transference characteristics of soil nitrogen in vegetable field in Dianchi lake basin

Lettuce vegetable areas of facilities vegetable soil in Dianchi Lake basin were selected for lettuce field experiment which were divided into high fertilization level and low fertilization level with 9 fertilizer treatments set.The results showed that：there was no regular change of soil total nitrogen among treatment levels.However,the soil nutrients decreased with depth decrements in the vertical gradient（0-20、20-40、40-60 cm）.In the growth period and maturity period of high fertilization level and low fertilization level,the total nitrogen accumulation was significantly positively linear related with the nitrogen application with correlation coeffi-cient R as 0.987 3、0.990 1、0.988 1 and 0.988 0 respectively.The soil nitrogen accumulation decreased in appropriate nitrogen application and increased in excess nitrogen application.Nitrogen losses of high fertilization level were generally greater than that of low fertilization level.In addition,the nitrogen losses of high fertilization level showed a highly significant correlation with the ni-trogen application during different periods with correlation coefficient R as 0.982 3、0.971 9.The nitrogen loss ratio of growth period was higher than that of maturity period in both the high fertilization level and the low fertilization level whereas the nitrogen loss ration showed no regular change among treatment levels with maximum loss ratio as 39.79%.The nitrogen loss ratio will be above 20% in the treatment with adequate fertilization amount.