狼毒种群数量对青海环湖地区草地土壤肥力的影响

Effect of the number of Stellera chamaejasme L. populations on soil fertility in the grasslands around Qinghai Lake

狼毒（StellerachamaejasmeL．）型退化草地是青海省环湖地区常见的毒杂草退化草地。为了研究狼毒群数量对草地土壤肥力的影响，试验按狼毒盖度将草地划分为3类，分别为狼毒盖度〉0-≤10％、〉10％～≤20％、〉20％-≤50％，对不同狼毒盖度草地土壤的物理性质、养分变化规律进行研究。结果表明：不同狼毒盖度的土壤比重、pH值、容重差异不显著（P〉0．01）。狼毒盖度为〉10％-≤20％的土壤紧实度较低，土壤有机质、速效养分显著高于其他盖度（P〈0．01）。说明狼毒种群的数量维持在盖度为〉10％-≤20％水平对草地土壤肥力的提高和保护具有积极作用。

Degraded grasslands dominated by Stellera chamaejasme L. are common degraded grasslands with poisonous weeds around Qiughai lake. To study the number of Stellera chamaejasme L populations on soil fertility in the grasslands, the degraded grassland were divided into three kinds of groups according to the coverage of SteUera chamaejasme L. , including 〉 0 -≤ 10% , 〉 10% -≤20% , and 〉 20% -≤50% levels of the coverage of Stellera chamaejasme L. Physical properties and the variation law of nutrients in the grassland soils with different covera- ges of Stellera chamaejasme L. were investigated. The results showed that there were no significant differences （P 〉 0.01 ） in the soil specific gravity, pH and bulk density between different levels of the coverage of Stellera chamaejasme L. The soil compaction was lower in the grasslands with within 〉 10 -≤20% levels of the coverage of Stellera chamaejasme L. , and file contents of soil organic matter, and available nutrients were significantly higher （ P 〈 0.01 ） than those in the grasslands with other levels of the coverages of Stellera chamaejasme L. The results indicate that maintaining within 〉 10 - ≤20% levels of the coverage for the number of SteUera chamaejasme L. populations has a positive role in the improvement and protection of soil fertility in the grasslands.