摘要
田间试验研究了多年生苜蓿草地轮作为农田后2年内土壤矿质氮和全氮的变化,结果表明,与苜蓿连作相比,土壤全氮在苜蓿翻耕后迅速下降,土壤硝态氮和铵态氮在耕作下层出现大量累积,土壤氮素有效性提高。不同轮作方式对土壤氮素变化有显著影响,轮作第2年种植玉米或马铃薯可以增加硝态氮在土壤中的累积,种植春小麦则增加了铵态氮和总矿质氮累积量,休闲土壤矿质氮变化幅度居中。与轮作春小麦相比,轮作玉米显著增加了对土壤全氮的消耗,因此多年生苜蓿草地轮作农田后应避免种植玉米等耗肥量较大的作物以维持土壤氮素平衡。
The responses of soil nitrogen to the conversion of cropland from perennial M. sativa grassland in the semi-arid loess area was investigated in two years of field experiments. Compared with M. sativa grassland, soil total nitrogen decreased rapidly and soil mineral nitrogen increased in the two years after the conversion. The crop phase in the rotation had a significant effect on the soil nitrogen changes. In the second year after the conversion, planting Zea rnays or Solarium tuberosurn increased the soil NO3^--N accumulation, while planting Triticurn aestivurn increased the soil NH4^＋-N and total mineral nitrogen, while fallow was intermediate between them. Z. mays significantly reduced soil total nitrogen compare with T. aestivum consequently Z. mays should be avoided after the conversion of perennial M. sativa grassland to cropland in the semi-arid loess area.
出处
《草业学报》
CSCD
2006年第5期32-37,共6页
Acta Prataculturae Sinica
基金
国家重点基础研究发展规划项目(2005CB121102)
国家自然科学基金项目(30500077)资助
关键词
土壤氮素
苜蓿
轮作
半干旱黄土区
soil nitrogen
Medicago sativa
rotation
semi-arid loess area
