中国西南喀斯特潮湿气候下干旱胁迫人工牧草地土壤水生态系统服务研究

Water services of soil ecosystem provided by introduced grassland at arid season under humidity climate of southwestern China Karst Area

文中质疑草地的"覆盖减少蒸散说",验证冷季型人工牧草地在西南喀斯特冬春旱季是否能发挥有益的土壤水调节功能。将盆栽草和原生土壤视为最小的可测量生态系统单元,通过差减法连续观察草类对土壤系统水分散失的影响。结果表明:冷季型人工草并不能保证生态系统具有比无覆盖土壤更好的水分保持能力,相反加速了土壤水散失。仅常态下10天内高密度高羊茅草地消耗1.11×10~4t/km^2和黑麦草地6.3×10~3t/km^2水,就远大于裸地消耗5.2×10~3t/km^2。"覆盖减少蒸散说"在西南喀斯特冬春少雨季节并不成立,反之短时裸土生态系统具有良好水调节能力,其季节性生态服务价值也较多年生草地生态系统更大。

Since we challenged the concept of ＂grass -covered soil performed better than uncovered soil for wa- ter conservation＂, so we regarded introduced grasses in pots with local soil as minimum ecosystem unit, a series of observations were carried out to reveal whether the grasses contribute to water conservation under the drought stress in arid season of southwest China Karst. Results show that grassland did not guarantee a better soil mois- ture condition. On the contrary, it accelerated water loss of soil ecosystem. Water consumption of introduced grass community had reached as high as 1.11 ×105t/km2and 6.3 × 104t/km2 within 10 days,which were much higher than uncovered grassland ecosystem as 5.2 × 104t/km2. Therefore, introduced grassland in winter in these area probably owns lower ecosystem services value than uncovered soil system.