枯草层对草地早熟禾草坪水分利用的影响

Effects of thatch on water use of Kentucky bluegrass turf

对草地早熟禾Poa pratensis 草坪不同累积厚度下枯草层对水分的拦截程度及在水分充足供应和胁迫处理条件下的蒸散进行了测定,研究发现枯草层能大量截留外来水分,并随着厚度的增加,截留量增大;水分充足供应条件下,无枯草层累积的草坪蒸散量更大;在胁迫处理下,有枯草层累积的草坪相对蒸散率先表现出下降趋势,此时土壤水势为-40 kPa左右,无枯草层累积的草坪在土壤水势达-50 kPa时才开始下降,表明有枯草层累积的草坪更容易发生水分亏缺;当草坪出现明显胁迫症状后,无枯草层累积的草坪蒸散量较大。

The experiment that kentucky bluegrass turf thatch under different thickness intercepts water and affects ET was conducted. The results showed that: (a) thatch could intercept water greatly, and the rate increased with thickness; (b) Under non-limited water condition, the turf without thatch had a higher ET level; (c) under limited water condition, the relative ET of turf with thatch decreased firstly, which showed water deficit of it would take place more easily; (d) After the symptom of water stress occurred, ET of the turf without thatch was the biggest.