遮荫对冷季型混播草坪土壤呼吸速率、温度及生物量的影响

以草地早熟禾、多年生黑麦草和高羊茅组成的冷季型混播草坪为研究对象,测定了树冠遮荫41%和全光照下的草坪的土壤呼吸速率、叶绿素和地上生物量等指标。试验结果表明：（1）遮荫下混播草坪在白天的土壤呼吸速率低于光照充足下的草坪,尤其在14∶00时有着显著差异（P〈0.05）;（2）从土壤温度和土壤水分的日变化分析,遮荫降低了混播草坪的土壤温度,到14∶00以后与全光照处理趋于一致;土壤水分含量的变化呈先降低,后升高的趋势,从8∶00～12∶00,遮荫下的土壤水分含量均高于全光照混播草坪;（3）全光照下草坪的土壤呼吸速率与土壤水分含量存在显著的正相关,但遮荫下二者的相关性不显著;（4）遮荫显著地提高了草坪草的叶绿素a、b及整个叶绿素含量,降低了地上部生物量。

Effects of shade on soil respiration,temperature and biomass in mixed cool season turf

The paper studied the effects of tree canopy shade （41%） on soil respiration rate,chlorophyll content and aboveground biomass in the mixed cool season turf with Kentucky bluegrass （Poa pratensis） ,perennialryegrass （Lolium perenne） and tall fescue （Festuca arundinacea）. The results showed that.l） The soil respiration rate of the mixed turf under tree canopy shade was lower than the turf under full sun light. There was significant difference in the soil respiration rate between two treatmens at 14.00 （P〈0.05）. 2） In term of daily change of soil temperature and soil moisture, the shade decreased soil temperature, however, the soil temperature was the same between two treatments after 14：00. However, the soil moisture in the turf under shade was higher than that in the turf under sunlight from 8：00～ 12：00.3） There was a significant positive correlation between the soil respiration rate and the soil moisture in the turf under the sunlight. However, there was no correlation between the two indictors in the truf under shade. 4）Shade significantly increased content of chlorophyll a and b,total chlorophyll of turf grass,while aboveground biomass was significantly decreased