秸秆还田与化肥减量配施对稻-菜轮作下土壤养分及酶活性的影响

Effects of Straw in Combination with Reducing Fertilization Rate on Soil Nutrients and Enzyme Activity in the Paddy-Vegetable Rotation Soils

以西南丘陵山区紫色土为研究对象,2013-2014年在重庆市江津区先锋镇布置田间试验,采用一年两熟,水稻-儿菜轮作制度,分析了秸秆还田与化肥减量配合施用对作物产量,土壤养分及酶活性的影响,为稻-菜轮作系统中养分资源优化管理的施肥方式提供科学依据,实现农业秸秆的循环利用.结果表明,秸秆还田与化肥减量配施处理能提高水稻和儿菜的产量,分别比常规施肥处理（F）增产3.0%-17.9%和12.2%-36.4%,经稻-菜轮作后,第二季（C3）的水稻产量比第一季（C1）水稻增加了820-1 240 kg·hm-2.与F处理相比,稻-菜轮作下连续秸秆覆盖与化肥减量配施的土壤pH提高了0.06-0.55个单位,特别是秸秆全量还田（AS）与70%-80%化肥（F）配施处理（70%-80%F＋AS）对土壤pH的改善效果最佳,同时80%F＋AS处理的土壤有机质最高,达到了41.01 g·kg-1.对土壤有效养分含量而言,80%F＋AS处理的土壤碱解氮（110-178 mg·kg-1）和有效磷（31.3-64.0 mg·kg-1）含量最高,但过多的秸秆还田量反而不利于土壤有效磷累积.秸秆还田与化肥减量配施提高了土壤酶活性,其中80%F＋AS和70%F＋AS处理对脲酶活性提高效果较为显著;80%F＋AS处理的过氧化氢酶在前两季度下活性均最高;随着耕种时间的增加,特别是C3季度下,70%F＋AS和80%F＋AS处理的磷酸酶活性较F处理显著提高了45.2%和48.2%.因此,西南丘陵山区紫色土在稻-菜轮作下,70%-80%F＋AS处理即秸秆全量覆盖还田与化肥减量20%-30%的配施方式是该地区的最优施肥方式.

The effects of straw returning combined the reducing application of chemical fertilizer for crop yield,soil nutrients and enzyme activity were studied in a typical southwestern hilly area of China in a rice-vegetable（ Brassica juncea var. gemmifera Lin.）cropping system. The purple soil was selected as the target type of soil,and the Pioneer Town,Jiangjin District,Chongqing,China was selected as the typical southwestern hilly area during 2013 and 2014. Scientific basis based on the optimized fertilization strategy and the recyclable utilization of straw was provided through a field in-situ experiment in this study. There were five treatments in the field experiment： F（ conventional fertilizer）,90% F ＋ AS（ 100% straw with 90% conventional fertilizer）,80% F ＋ AS（ 100% straw with 80% conventional fertilizer）,70% F ＋ AS（ 100% straw with 70% conventional fertilizer）,50% F ＋ DS（ 200% straw with 50%conventional fertilizer）,and the 100% straw was 7 500 kg·hm- 2. The results showed that the yields of rice and vegetable were all increased in straw with reduced fertilizer treatments（ 3. 0%-17. 9% in rice yield and 12. 2%-36. 4% in vegetable yield） compared with conventional fertilizer（ F） treatment. Moreover,the yield of rice in the second season was also increased by 820-1 240 kg·hm- 2.Soil pH values in straw with reduced fertilizer treatments raised by 0. 06-0. 55 compared with F treatment,especially in straw with 70%and 80% of conventional fertilizer dosage which increased by 6. 74-6. 88 and 6. 52-6. 84,respectively. The highest content of soil organic matter was 41. 01 g·kg- 1in straw with 80% of conventional fertilizer treatment. For the aspect of soil available nutrients,straw with 80% of conventional fertilizer treatment increased 110-178 mg·kg- 1content of soil available nitrogen and 31. 3-64. 0mg·kg- 1content of soil available phosphorus. However,the excessive application of straw had negative effect on the accumulation of soil available phosphorus. In the same cultivation period,the contents of soil urease increased significantly in straw with 70% and 80%of conventional fertilizer treatments,which increased by 13. 6%-76. 4% and 20. 1%-75. 0% compared with F treatment. The contents of soil catalase in straw with reduced fertilizer treatments were significantly higher than F treatment; in first two seasons,soil catalase contents increased by 0. 37 and 0. 31 m L·（ h·g）- 1relative to F treatment in straw with reduced fertilizer treatment（ 80% of conventional fertilizer）. With the increasing time of planting,the soil phosphatase content in the third season was higher than those infirst two seasons. Straw with 70% and 80% of fertilizer treatments increased the activity of soil phosphatase by 45. 2% and 48. 2%compared with F treatment. It was concluded that straw application with 70% or 80% dosage of conventional fertilizer could benefit the rice-vegetable rotation in the southwest hilly area of China.