等氮条件下化学肥料与有机肥连续大量施用下的环境风险

Environmental Risk Caused by Successive and Heavy Application of Mineral Fertilizer and Compost With the Same Amount of Nitrogen Applied

在充分调研当地农民小麦和水稻化学肥料施用量的基础上,确定等氮条件下有机肥的施用量,开展了3 a共6季的稻麦轮作田间试验,并采集了第3年水稻收获后耕作层(0~25 cm)土壤样品进行分析。结果表明:与对照(CK)相比,等氮条件下化学肥料(CF)和有机肥料(CP)的连续大量施用均可能引起环境风险。化学肥料易引起土壤酸化和硝酸盐的大量累积,而有机肥则导致土壤中磷和重金属(Zn、Cu、Cd和Ni)含量显著增加;另外,CF和CP处理均引起土壤微生物量碳含量/有机碳含量(SMBC/SOC)比值和生物量氮含量/总氮含量(SMBN/TN)比值及细菌多样性的下降,对土壤中病原微生物则无显著影响。

The environmental risk caused by successive and heavy application of mineral fertilizer has attracted wide attention,but scarce for that of compost. After fully investigation of the local fertilization rate of mineral fertilizer in winter wheat-rice cropping system,the dose of compost applied was determined according to the amount of total nitrogen contained in mineral fertilizers,and a 3-year( a total of six seasons) field experiment was carried out to study the environmental risk derived from compost heavy application. Soil samples were analyzed after the third year of rice harvested of the plough layer soil( 0-25 cm). It was found that mineral fertilizer and compost may both result in environmental risk after the 3-year successive and heavy application. In contrast to the untreated control( CK),heavy application of mineral fertilizer( CF) easily lead to soil acidification and nitrate accumulation,while soil phosphorus and heavy metals( Zn,Cu,CD and Ni) content increased significantly when manure-based compost carried the same amount of total nitrogen with mineral fertilizer was applied( CP); In addition,heavy application of mineral fertilizer and compost both caused significant decrease of SMBN/TN ratio,SMBC/SOC ratio and bacterial diversity. The results of this study may be conducive to the rational application of compost in the future.