摘要
为明确长期施肥和秸秆还田对稻田土壤生态系统氮素循环过程的影响,探索维持稻田土壤长期供氮潜力的途径,利用始于1990年的湖南红壤水稻土长期定位试验,研究了长期施肥和秸秆还田对水稻土剖面氮素迁移分布和C/N的影响,比较了不同温度下土壤氮素矿化曲线变化和不同施肥方式氮素矿化动态的差异,分析了氮素累积矿化量与有效积温的关系。结果表明,长期施肥或秸秆可以促进红壤水稻土氮素的积累,其主要影响0—20 cm土层,而化肥和秸秆配合施用作用更明显;长期施氮、磷、钾化肥使土壤C/N降低,而秸秆还田使土壤C/N明显升高。在两种温度下的土壤矿质氮含量和累积矿化量曲线比较相似,10℃下土壤矿化速率达到稳定所需的时间要比30℃下长;30℃下不同施肥处理之间的矿化过程存在显著差异,而10℃下的差异较小,其在56 d内矿化出来的矿质氮是10℃下的近两倍。NP(仅施化肥氮、磷)及NP+C(施化肥氮、磷+秸秆还田)处理均有较高氮素矿化量,秸秆还田对土壤氮素矿化的促进作用比仅施化肥明显。在30℃下,土壤积累矿化量与有效积温的关系较好地符合有效积温方程式(EATM)(p<0.01)。仅施化肥处理和对照方程中的矿化特征常数k值相差不大,而秸秆还田与化肥配施处理方程的k值则有增大趋势,NPK+C(施化肥氮、磷、钾+秸秆还田)处理的矿化潜力较大,且养分供应能力较强;秸秆配施化肥处理方程中n值的绝对值有减小趋势。随着培养时间延长,秸秆还田配施化肥处理土壤的累积矿化量保持在一个较稳定范围。
To clarify the effects of long-term fertilization and straw returning on nitrogen cycle of paddy soil ecosystem and the ways of maintaining soil nitrogen supplying potentials,a long-term fertilization experiment of paddy soils was setup in Taoyuan country,Hunan province from 1990.Distributions of soil nitrogen and C/N ratio in soil profiles,soil nitrogen mineralization curves and differences under different temperatures,and relationship between cumulative mineralization and effective accumulated temperature were studied.The results show that nitrogen accumulations in soil profiles are significantly improved under the long-term amendments of chemical fertilizer or crop straw,especially in 0-20 cm soil layer,and effects are better with combined application of fertilizer and straw.Curves of soil mineral nitrogen and cumulative mineralization are similar under the two temperatures.Soil mineralization rates at 10℃ may require more time to reach stable state those at 30℃;Compared with the 10℃ treatments,significant differences of all treatments are found at 30℃,and nitrogen cumulative mineralization at 30℃ during 56 d is about two times of 10℃.Higher cumulative mineralization is found in the NP（chemical N,P） and NP＋C（chemical N,P ＋ straw） treatments,demonstrates that a more contributive effect of crop straw and fertilizer than chemical fertilizer only.The relationship between cumulative mineralization and effective accumulated temperature well fit the effective accumulated temperature model（EATM）（p0.01） in all treatments at 30℃,and the k values are similar to those of EATM in chemical fertilizer treatments and CK,but increasing of k is found in the straw and fertilizer combined treatments.The NPK＋C treatment（chemical N,P,K ＋ straw） has higher mineralization potential and nutrient supplying capacity.Decrease of absolute values of n in EATM are found in the straw and fertilizer combined treatments,demonstrates that cumulative mineralization of these treatments maintain a stable range with incubation time.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2011年第4期898-905,共8页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金重点项目(41030640)
中国科学院知识创新工程重要方向项目(KZCX2-YW-407)资助
关键词
秸秆还田
施肥
水稻土
氮素
温度
矿化
straw returning
fertilization
paddy soil
nitrogen
temperature
mineralization
