施肥对设施番茄-黄瓜养分利用与土壤氮素淋失的影响

Effect of fertilization on nitrogen leaching loss from soil and nutrients utilization by tomato and cucumber in greenhouse

以宁夏引黄灌区设施番茄-黄瓜为研究对象,利用田间定位试验,研究了不同施肥措施对蔬菜产量、养分吸收利用及淋溶水产生和氮素淋失动态的影响,并对氮素淋失量及淋失率进行了分析。结果表明,常规施肥和优化施肥间番茄和黄瓜果实产量差异都不显著,养分吸收量顺序为:K>N>P。两季蔬菜的氮、磷肥利用率都不到7%,而钾肥利用率最高仅12.3%。氮素淋失量与施肥灌水和蔬菜生育时期密切相关。同一施肥处理下,黄瓜季氮素淋失量高于番茄季;氮素淋失以硝态氮为主,占总氮比例70%以上。番茄季总氮、硝态氮淋失率分别为2.95%～6.65%和2.50%～5.56%;黄瓜分别为3.40%～6.96%和2.89%～5.70%。两季蔬菜铵态氮淋失率都低于1%。通过优化化肥用量和施用高C/N比有机肥或秸秆调节土壤C/N,有利于降低氮素的淋失量,从而减少氮素的损失。

Conventional fertilization and irrigation management caused soil nitrogen leaching loss and low fertilizer use efficiency in greenhouse vegetable growing system.In order to evaluate the effects of different fertilization on vegetable yield,nutrients uptake,dynamics of leachate and nitrogen leaching,and simultaneously determine how much nitrogen lost by leaching and the ratio of leaching N/fertilizer N.A field experiment with six treatments（no fertilizer,manure,conventional fertilization,optimal fertilization,conventional fertilization ＋ regulating soil C/N and optimal fertilization ＋ regulating soil C/N;represented by CK,M,CON,OPT,CON＋C/N and OPT＋C/N,respectively.） was carried out in greenhouse tomato and cucumber growing system in Yellow River Irrigated Region of Ningxia.The experimental design was the randomized complete block with three replications;each plot was 23.4 m2（6 m × 3.9 m）.The results indicated that the difference of fruit yield between treatment CON and OPT was not significant in tomato and cucumber season,nutrients uptake was KNP.Both of N and P fertilizer use efficiency was less than 7%,and the maximal K fertilizer use efficiency was 12.3% in two season vegetables.Nitrogen leaching was related to fertilization,irrigation and vegetable growing stage,and nitrogen leaching losses from soil in cucumber season was greater than that in tomato season under the same fertilization management practice.NO-3-N leaching loss accounted for more than 70% of total nitrogen leaching in both vegetable growing season.The ratio of total leaching N/fertilizer N and NO-3-N/fertilizer N in tomato season was 2.95%-6.65% and 2.50%-5.56%,respectively;and that of in cucumber season was 3.40%-6.96% and 2.89%-5.70%,respectively.The ratio of leached NH＋4-N/fertilizer N was far less than 1% in tomato or cucumber season.By reducing nitrogen rate and application of high C/N ratio manure or crop straw to regulate soil C/N ratio was benefit to decrease nitrogen leaching losses in greenhouse tomato-cucumber growing system.