施肥措施对杨树二代林土壤理化性质、分形特征及酶活性的影响

Effects of Fertilization Measures on Soil Physicochemical Properties,Fractal Characteristics and Enzyme Activities of Second Rotation Poplar Plantations

为阐明施肥措施对杨树二代林土壤特征的影响,以配方施肥正交试验林为研究对象,分析了试验林土壤理化性质、分形特征及酶活性等指标,结果表明:不同施肥处理耕种层(0~20 cm)的土壤容重都低于对照,总毛管孔隙度、非毛管孔隙度、田间持水量和最大持水量都高于对照,其中14号作为正交试验中生长量最高的处理,对砂姜黑土物理性状改良的效果最好。土壤的分形维数在2.7479~2.8038之间,分形维数与土壤黏粒、粉粒含量呈显著正相关。施肥措施能够提高土壤的分形维数,使土壤结构趋于稳定。不同施肥处理下的脲酶、碱性磷酸酶、过氧化氢酶活性均随着土层深度增加呈逐步降低的趋势,施肥提高了土壤碱性磷酸酶活性,降低了过氧化氢酶活性,对土壤脲酶活性影响不明显。通过相关系数和通径分析可知,土壤酶活性与理化性质间存在复杂、紧密的联系且相关性很强,由决定系数可知,速效钾是3种土壤酶活性的主要促进因子,速效磷和全氮为主要抑制因子。

In order to clarify the effects of fertilization measures on soil characteristics of the second rotation poplar plantations,the orthogonal experimental forest of formula fertilization was taken as the research object,and the indicators of soil physicochemical properties,fractal characteristics and enzyme activities in the experimental forest were analyzed.The results showed that the soil bulk density of the tillage layer(0~20 cm)in different fertilization treatments was lower than that of CK,and the total capillary porosity,non-capillary porosity,field capacity and maximum water capacity were higher than those of CK.Among them,No.14 with the highest growth in the orthogonal test had the best improvement effect on the physical properties of lime concretion black soil.The fractal dimension of soil was 2.7479~2.8038,and was significantly positively correlated with clay and silt content.Fertilization could promote the soil fractal dimension,and stabilize the soil structure.The urease,alkaline phosphatase and catalase activities of different fertilization treatments decreased gradually with the increase of soil depth.Fertilization increased the alkaline phosphatase activity,decreased catalase activity,and had no significant effect on urease activity.Through correlation coefficient and path analysis,there was a complex and close relationship between soil enzyme activity and physicochemical properties,and the correlation was very strong.According to the determination coefficient,available K was the main promoting factor of three soil enzyme activities,and available P and total N were the main inhibiting factors.