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| Relationship between the characteristics of transpiration of Larix principi-rupprechtii forest and soil water potential |
| Feng Yongjian1,Ma Changming1,Wang Yanhui2,Du Apeng2 |
| 1.Forestry College,Agricultrual University of Hebei,071000,Baoding,Hebei;2.The Research Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,100091,Beijing: China |
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Abstract Based on the field observation,the transpiration variation of Larix principi-rupprechtii forest in Diediegou Watershed in Liupan Mountain of Ningxia Province was studied from May to October in 2008.The results showed that the rainfall was the major factor impacting on the soil water potential.Soil water potential in different depth had the similar change tendency,but there were great differences among the variation range.Soil layer in 0-20cm,20-40cm,40-60cm had the biggest water potential gradient from June to September,and the soil water potential was lowest in August.The discending order in water consumption speed from May to October of Larix principi-rupprechtii was June,May,July,August,September,October,and the water consumption was 20.3%,25.4%,20.1%,18.6%,15.1%,10.7% of the growth season respectively.For Larix principi-rupprechtii forest,there was a distinct water shortage happened in earlier stage of growth season,and there was enough water at the later stage of growth season.There was a remarkable difference in water consumption speeds under the different soil water potential. The transpiration in the water enough conditions was higher than in the water shortage conditions significantly,besides,there was a significant relationship between the soil water potential at 20cm and 60cm depths and the sap flow change during the stage of water shortage.It could be concluded that the difference in transpiration consumption is caused by the soil water shortage,and the soil moisture at the earlier stage of growth season is very important for the growth of Larix princip-irupprechtii.
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Received: 22 June 2009
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