长期施肥对水稻土酶活性及理化特性的影响

为了明确不同施肥种类对水稻土土壤肥力与酶活性的影响，以30年（1981年至今）长期定位试验地为基础，研究不同施肥处理（CK，N，P,K，NPK，2倍NPK，NPK＋猪粪）水稻田耕层（0-20cm）土壤酶活性与养分的变化趋势及其相关性。结果表明：1）施P（配施或单施）增加土壤全P、速效P含量，平衡施肥配施有机肥（NPK＋猪粪处理）土壤的有机质、全P、速效P、全N、速效N均显著增加，所有施肥处理间pH值差异均不显著；2）除了NPK处理土壤脲酶活性最高外，平衡施肥配施有机肥土壤转化酶、酸性磷酸酶、过氧化氢酶活性均较其他处理显著增加；3）酸性磷酸酶活性与土壤全P量呈负相关，过氧化氢酶、脲酶、转化酶与全N、有机质、速效N、速效P呈显著或极显著正相关；因此，水田土壤长期平衡施肥配施有机肥，能显著提高土壤肥力，增加土壤酶活性，有益于土壤生产力的持续提高。

Effect of long-term fertilization on enzyme activities and chemical properties of paddy soils

In order to understand the relation between soil enzyme activity and soil chemical properties in paddy soil under different fertilizer treatments, we conducted a study to determine the effects of inorganic fertilizer and combination of pig manure and inorganic NPK on soil chemical and biological properties in a more than 30 a long term fertilization experiment. The treatments as the following： no fertilization （CK）, N, P, K, NPK, double NPK, NPK ＋ pig manure. The results showed, P fertilizer（ only applied P fertilizer or applied P fertilizer with other chemical fertilizer） could increase total P and availabel P of paddy soils. Soil organic matter, total P, available P, total N and available N in NPK＋pig manure treatment all increased significantly compared with no fertilization（CK） and mineral fertilization treatments（ N, P, K, NPK and 2NPK）. Except for the highest urease activity was NPK treatment, the soil invertase, acid phosphatase and catalase activities were all significantly higher than those in other fertilization treatments. Acid phosphatase activity negatively correlated with soil total P. Catalase, urease and invertase activities were significant and dramatically significant positively correlated with total N, organic matter, available N, available P. So, co-application of manure and mineral fertilizers not only increased the soil fertility, but also enhaced significantly soil enzymes activities, thus could inprove paddy soil sustainable productivity.