摘要
以不同生长年限的苜蓿地为材料,研究了苜蓿在生长过程中土壤养分的变化趋势.结果表明:在苜蓿生长年限10～23a内,随着种植时间延长苜蓿生物量和体内养分累积量呈下降趋势.23a生苜蓿已进入衰败期,土壤肥力逐渐得到恢复,苜蓿根系养分含量随种植年限延长呈明显的增加趋势.不同生长年限苜蓿地土壤NO-3-N的含量变化趋势相同,2m以内土层生长年限越短,NO-3-N含量越少,2m以下变化趋势相反.NH+4-N含量变化规律不明显,表层高于下层,生长年限长的含量较低.
Based on the different growth years of alfalfa field in the gully region of the Loess Plateau, the distribution characteristics of N and the trend of fertilization were studied. The results showed that productivity and fertilization accumulation were descended according to the planting 10～23 years of alfalfa, but 23 years alfalfa entered into wane and soil fertilization was increased. The nutrient content of roots was improved according to the planting years of alfalfa. The trends of content of NO^-_3-N was the same to different years of alfalfa, in 0～2 m, the year shorter, the content of NO^-_3-N lower, soil layer below 2 m, the results was opposition. The change trend of content of NH^+_4-N was not significant, which is higher in upper layer soil than that of under layer soil, the year longer, the content of NH^+_4-N lower.
出处
《西北植物学报》
CAS
CSCD
2004年第6期1107-1111,共5页
Acta Botanica Boreali-Occidentalia Sinica
基金
中国科学院知识创新工程项目( KZCX2-413)
国家科技攻关项目 (2001BA508B18 )
