江河源区退化天然草地的恢复及其生态效益分析

根据天然草地退化程度的差异,采用松耙 补播 施肥 封育(退化较严重的草地)、封育 施肥(轻度退化草地)等措施,植物群落物种组成、多样性等特征值及其植被盖度发生明显变化.研究第2年结果表明,物种数封育 施肥处理最高(32种),对照居中(26种),补播 施肥处理最低(13种);多样性指数大小依次为封育 施肥(3.126)、对照(2.819)、补播 施肥(1.494);均匀度指数大小依次为封育 施肥(0.902)、对照(0.865)、补播 施肥(0.582);群落总盖度大小依次为封育 施肥(85.9%)、补播 施肥(79.7%)、对照(72.9%);补播 施肥 封育处理后地上生物量最大(460.65 g/m2),原生植被 封育 施肥处理居中(310.14 g/m2),对照最低(178.96 g/m2);地下生物量大小依次为封育 施肥(6 920.37 g/m2)、补播 施肥(1 458.96 g/m2)、对照(828.91 g/m2);补播 施肥 封育处理优良牧草较对照提高近50倍,杂草类减少82.81%,封育 施肥处理较对照良牧草比例提高48倍,杂草类比例减少80.46%.半人工草地通过灭除杂草和施肥相结合的示范试验表明:单纯进行灭杂,地上生物量减少,灭杂和施肥相结合不仅可提高地上生物量,而且可提高优良牧草的比例;不同处理区土壤养分含量各不相同,其中封育 施肥处理全氮、全碳、有机碳最高,对照居中,补播 施肥较低.

Recovery and benefit analysis of ecology on degraded natural grassland of the source region of yangze and yellow rivers

According to degradation degree of natural grassland,relevant treatments were used such as scarification +reseeding +enclosure (for heavily degraded grassland), enclosure +fertilize (for lightly degraded grassland). These treatments make plant community structure and plant cover change significantly. The results after two yeas recovery showed that the species number represented by enclosure +fertilize treatment (32 species) > Control (26 species) > reseeding +fertilize treatment (13 species). The species diversity index had the same trend with the species number. The evenness index represented by enclosure +fertilize treatment (0.902) > CK (0.865) > reseeding +fertilize treatment (0.582). The vegetation total cover decreased from enclosure +fertilize treatment (85.9%) to reseeding +fertilize treatment (79.7%) to Control (72.9%). The aboveground biomass decreased from reseeding +fertilize treatment (460.65 g/m~2) to natural grassland+enclosure +fertilize treatment (310.14g/m~2) to Control (178.96g/m~2). The underground biomass decreased from enclosure+fertilize treatment (6 920.37g/m~2) to reseeding +fertilize (1458.96g/m~2) treatment to Control (828.91g/m~2). The high-quality grasses in reseeding +fertilize treatment and enclosure +fertilize treatment were 50 and 48 times higher than that in Control. Forbs in reseeding +fertilize treatment and enclosure +fertilize treatment decreased by 82.21% and 80.46% compared to that in Control. Semi-artificial grassland established by killing forbs and fertilize, The results showed that the combination of killing forbs with fertilize treatment may increase not only above-biomass but also proportion of high quality herbage. But production can not be increased at only killing forbs treatment. The soil nurture change was enclosure +fertilize treatment > Control > reseeding +fertilize treatment