淮北砂姜黑土酶活性对长期不同施肥模式的响应

【目的】针对安徽淮北砂姜黑土“旱、涝、僵、瘦”等不良属性，通过探讨长期定位施肥对砂姜黑土酶活性的影响，揭示土壤酶对施肥模式的响应机制，为有效改善土壤生物化学环境、提高土壤质量、进而保证作物高产稳产提供理论支撑。【方法】以安徽省濉溪县杨柳试验基点长期定位培肥试验（1981至今）为基础，研究5种不同施肥模式下（不施肥、单施化肥、单施有机肥、有机肥与化肥配施（等氮）、有机肥与化肥配施（高氮））小麦-玉米轮作系统中耕层土壤（0—20 cm）脲酶、酸性磷酸酶、中性磷酸酶、过氧化氢酶以及蔗糖酶活性的变化趋势，并进行相关性分析和成对比较，分别阐明土壤酶间的相互关系及各酶活性的季节性变化规律。【结果】与长期不施肥相比，长期单施有机肥可显著提高砂姜黑土脲酶、过氧化氢酶和蔗糖酶的活性，小麦收获期和玉米收获期分别提高了130.5%和129.5%、11.4%和14.9%、31.4%和12.0%，但对酸性磷酸酶和中性磷酸酶活性无明显促进作用；长期单施化肥可有效增强土壤酸性磷酸酶与中性磷酸酶活性，同时明显抑制其他3种土壤酶的活性；在同等施氮水平下，有机肥与化肥配施可使5种土壤酶活性均保持较高水平，弥补了单施化肥或单施有机肥因施肥模式单一导致某种土壤酶活性较差的不足;高氮水平下，有机肥与化肥配施可显著提高酸性磷酸酶和中性磷酸酶活性，但对其他酶作用规律不明显。砂姜黑土不同土壤酶之间普遍存在显著相关关系：脲酶与过氧化氢酶、蔗糖酶之间以及过氧化氢酶与蔗糖酶之间存在显著正相关关系，而磷酸酶与其他3种酶之间存在此消彼长的关系。此外，砂姜黑土脲酶、酸性和中性磷酸酶、过氧化氢酶以及蔗糖酶酶活受季节的影响也因施肥不同而不同。【结论】同等施氮水平下，有机肥与化肥配施与单施化肥或单施有机肥相比，能使砂姜黑土脲酶、磷酸酶、过氧化氢酶及蔗糖酶均保持较高的活性，有利于改善土壤生物化学环境，进而提高土壤可持续生产力；土壤酶之间相关关系各有不同，呈显著正相关关系的有脲酶与过氧化氢酶、脲酶与蔗糖酶及过氧化氢酶与蔗糖酶，而磷酸酶与其他3种酶之间均呈显著负相关关系；砂姜黑土酶活性受季节影响的程度因酶种类与施肥方式不同而有所不同。

A Research on Response of Enzyme Activities to Long-term Fertilization in Lime Concretion Black Soil

【Objective】In order to provide a theoretical support for improving soil biochemical environment and soil quality, insuring high and steady yield of crops in view of the characters of “drought, waterlogging, concretion, leanness” in lime concretion black soil, the responsive mechanism of soil enzyme activities to fertilization in black soil was studied by the way of exploring effects of long-term fertilization on soil enzyme activities. 【Method】 Based on a 31 yeas long-term fertilization experiment in Yangliu of Anhui province, the change trend of activities of urease, acid phosphatase, neutral phospahtase, catalase and invertase in tilth soil (0-20 cm) was investigated with 5 patterns of fertilization (non-fertilization, application of single chemical fertilizer, application of single organic fertilizer, mixed application of organic and chemical fertilizer (with the same amount of nitrogen), mixed application of organic and chemical fertilizer (with the lager amount of nitrogen) in wheat-maize rotation system, as well as the correlation and paired comparison was analyzed to interpret the relationship among soil enzymes and seasonal variation, respectively. 【Result】 Compared with control, the activities of urease, catalase, and invertase increased significantly by 130.5% and 129.5%, 11.4% and 14.9%, and 31.4% and 12.0%, respectively, after wheat and maize harvested in the situation of long-term application of single organic fertilizer, while acid and neutral phosphatase were less affected. Long-term application of single chemical fertilizer effectively enhanced soil acid and neutral phosphatase activities, whereas other 3 enzymes activities were significantly inhibited in the same time. With the same amount of nitrogen, the activities of all the 5 enzymes were maintained at a higher level under mixed application of organic and chemical fertilizer, in which low activity of certain enzyme caused by unbalance fertilizing could be avoided. With the lager amount of nitrogen, mixed application of organic and chemical fertilizer increased acid and neutral phosphatase activities significantly, but the effect on urease, catalase and invertase activities was insignificant. There were mutual stimulations between urease and catalase, urease and invertase, catalase and invertase, though phosphatase had a negative correlation with other enzymes. In addition, the seasonal variation of urease, acid and neutral phosphatase, catalase, invertase activities in lime concretion black soil was significantly different in 5 fertilizer applications treatments. 【Conclusion】 With the same amount of nitrogen, mixed application of organic and chemical fertilizer was superior to application of single chemical or single organic fertilizer which made soil enzymes activities stay at a higher level and then will be beneficial to improvement of soil biochemical environment. The correlation of urease and catalase, urease and invertase, catalase and invertase was positive, but the acid and neutral phosphatase was negatively correlated with other enzymes. Seasonal variation of enzyme activities varied with types of enzyme and fertilizations.