ABSTRACT

To clarify the changes of root traits, soil biological characteristics and yield after applying fertilizers for 39 years, a long-term located fertilization experiment (1981-) was conducted. Compared to NPK (inorganic fertilizer) and M (organic fertilizer), 0.8NPKM (80% of NPK plus 80% of M) and 0.5NPKM (50% of NPK plus 50% of M) obviously improved root traits. The number of bacteria, fungi, actinomycetes in 0.8NPKM and 0.5NPKM were significantly higher than that in NPK, M and CT (no fertilizer). Compared to NPK, M increased soil microbial quantity. Soil microbial biomass carbon and nitrogen, organic carbon and total N in M were higher than that in NPK. The activities of phosphatase, dehydrogenase and urease in M were significantly higher than that in NPK. Compared to NPK and M, 0.8NPKM and 0.5NPKM enhanced above-mentioned soil enzymes activities. The differences in wheat and maize yields between 0.5NPKM and 0.8NPKM were insignificant, and the harvest index in 0.5NPKM was the highest. Soil microbial quantity, microbial biomass carbon and nitrogen were positively correlated with enzymes activities and root traits. Thus, appropriate combined application amount of organic and inorganic fertilizer might be an effective way to improve root traits, rhizosphere soil micro-biological environment and crop yield.AbbreviationsCT No fertilizer addedNPK Inorganic fertilizer onlyM Organic fertilizer only0.5NPKM Organic fertilizer plus inorganic fertilizer (50% of NPK plus 50% of M)0.8NPKM High application ratio of inorganic and organic fertilizers (80% of NPK plus 80% of M)

摘要

为明确施肥39年后根系性状、土壤生物学特性及产量的变化，进行了长期定位施肥试验（1981-）。与NPK（无机肥）和M（有机肥）相比，0.8NPKM（80%的NPK加80%的M）和0.5NPKM（50%的NPK加50%的M）明显改善根系性状。0.8NPKM和0.5NPKM的细菌、真菌、放线菌数量显着高于NPK、M和CT（不施肥）。与 NPK 相比，M 增加了土壤微生物数量。M中土壤微生物生物量碳氮、有机碳和全氮均高于NPK。M中的磷酸酶、脱氢酶和脲酶活性显着高于NPK。与NPK和M相比，0.8NPKM和0.5NPKM增强了上述土壤酶的活性。0.5NPKM和0.8NPKM小麦、玉米产量差异不显着，0.5NPKM收获指数最高。土壤微生物数量、微生物生物量碳氮与酶活性和根系性状呈正相关。因此，适量的有机无机肥配施可能是改善根系性状、根际土壤微生物环境和作物产量的有效途径。缩写CT 不加肥 NPK 仅施无机肥 M 仅施有机肥0.5NPKM 有机肥加无机肥（50%的NPK加50%的M）0.8NPKM 无机肥和有机肥的高施用比例（80%的NPK加80%的M）