长期定位施肥对两种小麦耕作系统土壤肥力的影响

为寻求既能提高土壤肥力又能改善土壤环境的科学施肥模式,本研究以黄土高原长武30 a长期小麦连作和小麦–豌豆两个轮作系统为研究对象,以长期肥料定位试验(包括氮磷+有机肥配施NPM、氮磷配施NP、单施磷肥P、单施氮肥N、单施有机肥M和CK)土壤有机质、碱解氮、速效磷、速效钾、全磷和全钾为基础数据,应用土壤的综合肥力指标值(integrated fertility index,IFI)对长期定位施肥的土壤肥力进行定量综合评价。结果表明:①小麦-豌豆轮作系统在不同施肥处理下土壤养分含量普遍高于小麦连作系统,且在两种耕作系统下施用氮磷+有机肥各养分含量增幅明显。②各处理间土壤综合肥力指数表现为:小麦–豌豆轮作+NPM>小麦连作+NPM>小麦–豌豆轮作+NP、小麦连作+NP>小麦–豌豆轮作+P、小麦连作+P>小麦连作+M>小麦–豌豆轮作+不施肥>小麦连作+不施肥。③小麦连作系统有机质,全磷、全氮和速效磷与土壤综合肥力指数IFI之间呈显著相关关系,碱解氮和速效钾与IFI不相关;在小麦–豌豆轮作系统中,碱解氮与全磷对IFI呈显著正相关关系。综上,综合肥力指数能较好地反映土壤肥力状况,长期施用氮磷+有机肥相较单施氮磷肥、有机肥的土壤综合肥力要高,小麦–豌豆轮作系统土壤综合肥力优于小麦轮作系统,且不同耕作系统对土壤养分和土壤肥力的关系有一定的影响。

Effects of Long-term Fertilization on Soil Fertility Under Different Wheat Cultivation Systems

To find the scientific fertilization mode for improving soil fertility and environment, wheat continuous cropping and wheat-pea rotation in Changwu County of Shaanxi Province on the Loess Plateau were chosen as the research objects in this study. 30 a long-term fertilization experiments, including application of nitrogen, phosphorus and manure (NPM), application of nitrogen and phosphorus (NP), application of single nitrogen (N), application of single phosphorus (P), application of single manure (M), and no fertilization (CK), were carried out to monitor and determine the changes of soil organic matter, alkali nitrogen, available phosphorus and potassium, total phosphorus and potassium, as well as soil fertility represented by integrated fertility index (IFI). The results showed that:1)Soil nutrient contents in wheat-pea rotation were generally higher than those in wheat continuous cropping under different fertilization treatments. Application of nitrogen phosphorus and manure significantly increased nutrient contents under the two tillage systems. 2)IFI was in order of wheat-pea + NPM > wheat cropping + NPM > wheat-pea rotation + NP, wheat cropping + NP> wheat-pea + P, wheat cropping + P > wheat cropping + M > wheat-pea > wheat cropping. 3)IFI was significantly correlated with organic matter, total phosphorus and nitrogen, available phosphorus in wheat continuous cropping, while positively correlated with alkali solution nitrogen and total phosphorus in wheat-pea rotation. In summary, IFI can reflect soil fertility condition, soil fertility of NPM treatment is higher than single fertilization, soil fertility under wheat-pea rotation is higher than wheat continuous cropping, different tillage systems differently influence the correlation between soil nutrient and fertility.