施用氮磷钾对黄土丘陵区山地红枣林土壤酶与土壤肥力的影响

Effects of N,P and K fertilization on soil enzyme activities and soil fertility in mintane Jujube forest of hilly loess region

采用野外试验与室内分析，研究了连续4 a施氮磷钾肥对黄土丘陵区山地枣园土壤酶活性及土壤养分含量的影响。结果表明：连续4 a NPK 施肥处理能够明显增强土壤脲酶、磷酸酶、过氧化氢酶和蔗糖酶的活性，提高土壤有机质、全氮、速效氮、速效磷和速效钾含量；在土壤剖面中总的趋势是土壤酶活性和土壤速效氮、速效磷和速效钾含量随土层深度加深而降低。土壤晦活性与土壤养分因子的相关分析表明，在0～20 CIn土层，磷酸酶与有机质、速效磷，过氧化氢酶与有机质、全氮呈显著或极显著性正相关。在20～40 cm，脲酶与有机质、全氮、速效氮，磷酸酶与速效钾，过氧化氢酶与速效磷，蔗糖酶与有机质、速效钾呈显著或极显著性正相关。在40 60 cm，脲酶与全氮、速效磷，磷酸酶与有机质、速效氮，过氧化氢酶与速效磷，蔗糖酶与有机质、全氮、速效磷呈显著或极显著正相关。

Soil enzymes play an essential role in catalyzing reactions necessary for decomposition of organic matter and nutrient cycling in ecosystems, involving a range of plants, microorganisms, animals and their debris. Field experi- ment and laboratory analysis were carried out to investigate soil enzyme activities and soil fertility affected by successive 4- year N, P, K fertilization in montane jujube forest of hilly loess region. The results showed that successive NPK1 fertiliza- tion could significantly increase the soil activities of urease, phosphatase, catalase and invertase. Similarly, the contents of organic matter, both total N and available N, P and K were increased. From surface layer to in-depth layer, the soil enzyme activities and the contents of available N, P and K reduced in turn. The relative analysis suggested that there was a significantly positive correlation between soil phosphatase activity and the contents of organic matter, available P, cata- lase activity and the contents of organic matter and total N in 0 - 20 cm soil layer. In 20 - 40 cm soil layer, the positive correlation of soil urease activity with the contents of organic matter, total N, available N, phosphatase activity with the contents of available K, catalase activity with the contents of available P, invertase activity with the contents of organic matter, available K were significant. In 40 ~ 60 cm soil layer, positive correlation was found between urease activity with the contents of total N, available P, phosphatase activity with the contents of organic matter, available N, atalase activity with the contents of available P, invertase activity with the contents of organic matter, total N and available P.