临安区山核桃林地土壤水解酶活性空间分布特征及土壤肥力评价

Spatial distribution characteristics of soil hydrolase activities and soil fertility evaluation of Carya cathayensis forests in Lin’an District

【目的】探索山核桃Carya cathayensis产区土壤水解酶活性空间分布特征和土壤肥力状况。【方法】在浙江省杭州市临安区山核桃主产区选取了259个样地,测定了土壤α-葡萄糖苷酶(AG)、β-葡萄糖苷酶(BG)、纤维二糖水解酶(CBH)、木糖苷酶(XYL)、亮氨酸氨基肽酶(LAP)、N-乙酰-β-氨基葡萄糖苷酶(NAG)、酸性磷酸酶(PHOS)等7种水解酶活性和主要的肥力指标,并运用主成分分析、地统计分析、相关性分析、冗余分析等方法,分析了临安区山核桃林地土壤中7种水解酶活性的空间异质性、影响因素以及土壤肥力状况。【结果】AG、BG、CBH、LAP、NAG、XYL、PHOS活性的块基比C_(0)/(C+C_(0))分别为55%、42%、56%、49%、66%、47%、78%,全局莫兰指数(I_(g))均大于0。土壤中碱解氮、有效磷、速效钾、有机质位于丰富等级的样地数分别占64%、56%、23%、45%,平均pH为5.76。58.7%的样地土壤肥力低于平均水平,仅32.7%的土壤肥力为Ⅰ、Ⅱ等级,大部分土壤肥力处于Ⅲ、Ⅳ等级。【结论】7种土壤水解酶中,AG、BG、CBH、LAP、NAG、XYL具有中等空间自相关性,它们的变异情况受人为扰动和地形结构因素的共同影响。PHOS具有较弱的空间自相关,其活性空间分布主要受人为干扰的影响。7种水解酶活性均存在空间相关性,高低聚类情况相似。在岛石镇附近出现高值聚集,在清凉峰以及河桥、龙岗、昌化交界处附近出现低值聚集的情况,有机质、pH、碱解氮是影响水解酶活性高低值聚类的关键因素。土壤肥力指标分级和综合肥力得分结果表明:大部分林地土壤养分足以支撑山核桃林正常生长,但综合肥力还有待提高。

[Objective]This study aims to explore the spatial distribution characteristics of soil hydrolase activity and soil fertility in Caya cathayensis forests.[Method]259 sample plots were selected from the main C.cathayensis producing areas in Lin’an District of Hangzhou City,Zhejiang Province to determine the main fertility indicators and the activities of 7 hydrolases such asα-glucosidase(AG),β-glucosidase(BG),cellobiosidase(CBH),xylosidase(XYL),leucine amino peptidase(LAP),N-acetyl-glucosaminidase(NAG),and acid phosphatase(PHOS).Principal component analysis,geostatistical analysis,pearson correlation analysis,and redundancy analysis were used to analyze the soil fertility as well as the spatial variation of 7 hydrolase activities and their influencing factors.[Result]The spacial structure ratios[C_(0)/(C+C_(0))]of AG,BG,CBH,LAP,NAG,XYL,and PHOS were 55%,42%,56%,49%,66%,47%and 78%respectively,and the global Morans’I(I_(g))was greater than 0.Available N,available P,available K,and organic matter in the rich soil accounted for 64%,56%,23%and 45%,respectively,and the average pH was 5.76.The soil fertility of 58.7%of the sample plots was below average.Most of the C.cathayensis plots were in levelⅢandⅣ,while only 32.7%of the plots were in levelⅠandⅡ.[Conclusion]Among the 7 soil hydrolases,AG,BG,CBH,LAP,NAG,and XYL have moderate spatial autocorrelation,and their variation is jointly affected by human interference and topographic structure factors.PHOS has weak spatial autocorrelation,and its spatial distribution is mainly affected by human interference.The activities of 7 hydrolases have spatial correlations and similar high and low clustering.High value aggregation occurs near Daoshi town while low value clustering occurs near Qingliangfeng town and the boundary of Heqiao,Longgang and Changhua towns.Soil pH,organic matter and available N are the key factors affecting the high and low value clustering of hydrolase activity.The results of soil fertility index classification and comprehensive fertility score show that most soil nutrients are sufficient to support the normal growth of C.cathayensis forests,but the comprehensive fertility needs to be improved.