压砂瓜连作对土壤酶活性及理化性质影响

对宁夏兴仁镇红圈子村连作1 a、3 a、5 a、7 a、10 a的压砂瓜田土壤酶活性和理化性质数据进行单因素方差分析、Pearson相关分析以及主成分分析,以探明随压砂瓜连作年限的增加砂田土壤质量的变化趋势,为提高宁夏中部干旱带砂田的可持续利用提供依据。结果表明:随连作年限的增加,土壤脲酶、蔗糖酶、中性磷酸酶和过氧化氢酶活性都逐渐下降,其中,脲酶、中性磷酸酶和过氧化氢酶活性与土壤容重呈极显著负相关,与土壤总孔隙度表现出极显著正相关关系。土壤物理性质随连作年限的增加呈逐渐恶化趋势,土壤水分状况在连作5 a最佳;土壤肥力状况也逐渐降低,土壤全盐含量明显降低。土壤质量综合主成分得分最高的是1 a砂田为0.96,10 a砂田得分最低为-0.8。连作5~7 a表现出明显的连作障碍。因此,在砂田耕作的过程中必须进行科学合理的施肥与耕作,以保证砂田的持续利用。

Investigation on the effects of continuous cropping of Xisha water melon on the soil enzyme activities and physical-chemical properties

In order to improve the sustainable use of gravel-sand mulched fields in the arid area in central Ningxia, the soil enzyme activities and soil physiochemical properties of continuous cropping (1 a, 3 a, 5 a, 7 a, 10 a) were examined in the soil cultivated with selenium-contained watermelon in Hong Juanzi Village, Xingren County of Ningxia Hui Autonomous Region. The resulting data was analyzed by the methods of One-Way ANOVA and Pearson correlation analysis and principal component analysis, providing the trend of sand soil quality upon the increase of years of continuous cropping. The results showed that activities of soil enzymes (urease, neutral phosphatase, invertase, and catalase) displayed declining trends with the increase of years of continuous cropping. Those of urease, invertase and catalase showed significant negative correlations with soil bulk density, but exhibited significant positive correlations with soil porosity. Soil physical properties turned to be poor quality gradually with the increase of years of continuous cropping, and soil moisture reached a maximum value in 5 years of continuous cropping. Soil fertility became decreased gradually and the contents of total salt were decreased significantly. The highest comprehensive score of soil quality was 0.96 in 1 year, and the lowest was -0.8 in 10 years. There was an obvious obstacle of continuous cropping between 5 years and 7 years. Therefore, to ensure the sustainable use of sand soil, scientific and rational fertilization and tillage needed to be carried out.