施肥对黄河三角洲区盐碱化土壤活性碳、氮的影响

Effects of fertilization on active carbon and nitrogen in saline-alkaline soils from the Yellow River Delta region

以黄河三角洲区低盐和高盐土壤为对象,采用盆栽棉花试验,分析不施肥(CK)、施化肥(NPK)、秸秆+化肥(S+NPK)、牛粪+化肥(M+NPK)处理下棉花生长期土壤微生物生物量碳、氮和溶解性碳、氮的含量,探讨施肥对其的影响。结果表明,NPK处理对低盐土壤微生物生物量碳和氮含量的影响较小,而S+NPK、M+NPK处理明显提高微生物生物量碳和氮含量,与CK相比增加幅度分别为10.4%-113.4%、45.7%-115.9%和56.9%-90.6%、69.2%-186.4%。NPK、S+NPK、M+NPK处理均明显提高了高盐土壤微生物生物量碳和氮含量,增加幅度分别为18.6%-62.1%、19.8%-106.3%、31.8%-220.0%和46.7%-115.1%、58.2%-131.2%、70.2%-146.0%。各施肥处理对两个土壤溶解性碳含量的影响均较小。尽管在棉花生长前期(5月、6月)NPK处理可明显提高土壤溶解性氮含量,与CK相比低盐和高盐土壤增加的比例分别为40.5%-60.7%和139.9%-229.2%,但在棉花生长后期(9月、10月)影响较小。研究阐明了有机-无机配合施肥有利于提高黄河三角洲地区盐碱地土壤微生物生物量碳、氮含量,特别是对于高盐含量的土壤效果更加明显。

A pot experiment was conducted in which cotton was grown in a light saline-alkaline soil and a heavy saline-alkaline soil from the Yellow River Delta region, and four fertilization treatments were established, including no fertilizer （CK）, chemical fertilizer （NPK）, straw ＋ chemical fertilizer （S＋NPK） and cow manure ＋ chemical fertilizer （M＋NPK）. Effects of fertilization on the microbial biomass carbon, microbial biomass nitrogen, soluble carbon and soluble nitrogen were investigated during the cotton growing season. In the light saline-alkaline soil, the NPK treatment did not increase the microbial biomass carbon and nitrogen, but S＋NPK and M＋NPK treatments increased the microbial biomass carbon by 10.4%-113.4% and 45.7%-115.9%, and increased the microbial biomass nitrogen by 56.9%-90.6% and 69.2%-186.4%. In the heavy saline-alkaline soil, the NPK, S＋NPK and M＋NPK treatments increased the microbial biomass carbon and nitrogen, the increase proportion of microbial biomass carbon was 18.6%-62.1%, 19.8%-106.3%, 31.8%-220.0%, and that of microbial biomass nitrogen was 46.7%-115.1%, 58.2%-131.2%, 70.2%-146.0%, respectively. The soluble carbon little responded to the fertilization treatments in two soils. The NPK treatment increased the soluble nitrogen by 40.5%-60.7% in the light saline-alkaline soil and by 139.9%-229.2% in the heavy saline-alkaline soil compared with the CK in the first stage of cotton growth （May and June）, and little influences was found in the later stage （September and October）. It suggested that the combine application of inorganic and organic fertilizer was beneficial to improve the microbial biomass carbon and nitrogen in the saline-alkaline soils in the Yellow River Delta region, and it was more obvious for the heavy saline-alkaline soil.