【摘要】 通过研究寒地黑土耕作15年(2002—2017年)后的土壤养分、生态化学计量特征及酶活性的变化,探究寒地黑土土壤养分分配力和保持力,为寒地黑土的合理开发和持续利用提供理论依据。结果表明:1)与2002年相比,2017年土壤有机质、全氮含量显著降低(P <0.05),土壤全磷含量显著增加(P <0.05);土壤C∶N无显著变化,土壤C∶P、N∶P和C∶N∶P显著降低(P <0.05)。2)与2002年相比,2017年土壤过氧化氢酶活性显著增加(P <0.05),土壤转化酶、脲酶、硝酸还原酶和磷酸酶活性显著降低(P <0.05),土壤总体酶活性指数无显著变化。3)土壤全磷含量在2002年和2017年都是主要肥力因子;在2002年土壤C∶P、N∶P和C∶N∶P为主要肥力因子,2017年土壤有机质、脲酶、转化酶为主要肥力因子。综合来看,长期耕作15年后,虽然土壤C、N含量以及相关的酶活性均显著降低,但土壤碳氮平衡并没有变化,建议在今后的生产中继续加强有机碳肥和氮肥的配合施用,同时适当减少磷肥的施用来维持土壤养分分配格局。更多还原

【Abstract】 [Background]Relying on the fertile black soil resources,northeastern China has developed the biggest grain base. The practice of agricultural development has proved that the level of soil fertility and the rational use of fertilizer are the key factors in sustaining grain production. Therefore,there is great practical significance to master the soil nutrient status,fertility level in order to effectively maintain and protect the quality of cultivated land and to ensure grain security in grain production in the black soil area of northeastern China. [Methods] To explore the variation of soil nutrients, ecological stoichiometrics and enzyme activities after long-term cultivation of black soil,34 research samples were set up in the typical cold land black soil cultivation area. Based on the experiment in 2002,the global positioning system( GPS) was reused to confirm the sample points in 2017. The variability of soil fertility quality and other indicators in the topsoil( 0-20 cm) in the northeastern area of China during last 15 years were revealed with completion GPS and statistics. [Results]1) Compared with results in 2002,the content of soil organic matter( OM),total nitrogen( TN),C∶ P,N∶ P,C∶ N∶ P decreased significantly and total phosphorus( TP) content increased significantly( P < 0. 05) in 2017,while it had no significant change in soil C∶ N. 2) Compared with results in 2002,soil catalase( CAT) activity increased significantly( P < 0. 05) and the activities of soil invertase( INV),nitrate reductase( NR),urease( URE) and phosphatase( PHO) decreased significantly( P < 0. 05) in 2017. Meanwhile,it had no significant change in soil total enzyme activity index( ETEI). 3) Compared with results in 2002,the correlation among soil nutrient, ecological stoichiometric characteristics and soil enzyme activities changed a lot in 2017. 4) The principal component analysis of soil nutrient,ecological stoichiometric characteristics and related enzyme activities showed that TP was the main fertility factor in 2002 and2017,soil C∶ P,N∶ P,C∶ N∶ P accounted for the main proportion of fertility factors in 2002 and soil OM,URE,INV accounted for the main proportion of fertility factors in 2017. [Conclusions] In conclusion,during the period in 15 years from 2002 to 2017,although the soil C,N content and related enzyme activities were significantly reduced,there was no change in soil carbon and nitrogen balance. It was suggested that the application of organic carbon fertilizer and nitrogen fertilizer should be increased in the future production,while the application of phosphorus fertilizer should be reduced appropriately to maintain the soil nutrient distribution pattern.更多还原