长期不同施肥方式对黄潮土肥力特征的影响

依托黄潮土35 年长期定位试验,以2种土壤物理肥力指标、8种土壤化学肥力指标和5种土壤生物肥力指标进行主成分分析,最后将各主成分得分系统进行聚类分析.结果表明: 不同施肥方式对土壤肥力指标影响显著.施用有机肥处理(M、MN、MNP、MNPK)与NPK处理相比,土壤容重显著降低,而土壤孔隙度、有机质、全氮、碱解氮、全磷、有效磷、微生物生物量和过氧化氢酶、脲酶、碱性磷酸酶活性均显著增加;通过主成分分析可将原15个土壤指标降维,提取出2个主成分,反映了原信息量的85.5%,且无原变量丢失.土壤容重、孔隙度、有机质、全氮、碱解氮、全磷、有效磷、速效钾、微生物生物量、过氧化氢酶、脲酶、碱性磷酸酶、蔗糖酶活性在第1主成分上有较高因子负荷,全钾和pH在第2主成分上有较高因子负荷;以2个主成分得分为新指标进行聚类,得到长期不同施肥方式对黄潮土的培肥效果排序为MNPK＞MNP＞M、MN＞NPK＞N、NP＞CK.可见施用有机肥对黄潮土培肥效果更显著,以有机肥配施氮磷钾化肥方式效果最优.

Effects of long-term fertilization on soil fertility in yellow fluvo-aquic soil

Based on the long-term field fertilization experiment in yellow fluvo-aquic soil, this study selected 2 types of soil physical, 8 items of soil chemical, and 5 soil biological properties for principal component-cluster analysis to valuate comprehensively effects of long-term fertilization on soil fertility. Results showed that significant differences of soil properties were found among the fertilization treatments. Compared with no organic manure treatment (NPK), all treatments of organic manure (M) or its combination with inorganic fertilizers (MN, MNP, MNPK) significantly reduced soil bulk density, and increased soil total porosity, the contents of soil organic carbon, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, microbial biomass, and activities of catalase, urease, alkaline phosphatase and invertase. Two principal components that could reflect 85.5% of the original information quantity without losing any original variables were extracted from the initial 15 indices. Within the primary group of principal components, bulk density, total porosity, organic matter, total nitrogen, alkali-hydrolyzable nitrogen, total phosphorous, available phosphorus, available potassium,microbial biomass, catalase, urease, alkaline phosphatase and inver-tase were the major contributors, while among the secondary group of principal components, total potassium and pH were the major ones. Hierarchical cluster analysis of the new indices extracted based on scores of the two principal components revealed the effects of different patterns of long-term fertilization displayed an order of MNPK＞MNP＞M, MN＞NPK＞N, NP＞CK. In conclusion, organic fertilizer has the positive effect on improving soil fertility, and combined application of organic and N, P, K fertilizer is the best fertilizing model.