施氮对退化草甸植被结构和生物量及土壤肥力的影响

在围栏内采用施氮肥作为调控措施，与围栏内不施肥作对照，旨在寻求治理退化草甸的最佳途径。结果表明，施氮肥能够明显改善草地植物种群结构，增加牧草种类，提高草地生物量，显著改善020 cm土层土壤肥力。随着施氮肥量增加，不同处理与对照之间草层分层高度差异显著、地上生物量差异极显著、020 cm土层土壤肥力显著提高；不同施肥处理间随着施氮肥量增加草层高度增加、地上生物量增大、土壤肥力增强，当施肥量超过225 kg/hm2时，草层高度、地上生物量和土壤肥力变化不明显。施肥量225 kg/hm2时对退化草甸草地恢复具有明显的效果。在围栏封育的基础上采用切耙松土、施肥是治理退化草甸草地有效而且可行的措施。

Effect of nitrogen fertilization on the vegetation structure and biomass of degraded meadow and soil fertility

Nitrogen fertilizer was applied to the fenced meadow and it was aimed to find out the best way to management of degraded meadow.The results showed that N fertilizer application improved grassland plant population structure significantly,increased the biomass of forage grasses,and improved the soil nutrients content obviously.With the increase of application rate,the difference of vegetation structure and biomass between the treatment and the control was significant and the soil fertility in 0 to 20 cm layer...