江河源区退化天然草地的恢复及其生态效益分析

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

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 (2 6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 12 6 )、对照 (2 819)、补播 +施肥 (1 4 94 ) ;均匀度指数大小依次为封育 +施肥 (0 90 2 )、对照 (0 86 5 )、补播 +施肥 (0 5 82 ) ;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 (46 0 6 5 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 92 0 37g/m2 )、补播 +施肥(14 5 8 96 g/m2 )、对照 (82 8 91g/m2 ) ;补播 +施肥 +封育处理优良牧草较对照提高近 5 0倍 ,杂草类减少82 81% ,封育 +施肥处理较对照良牧草比例提高 4 8倍 ,杂草类比例减少 80 4 6 %。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?

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