Analysis And Research Of The Methods And Determination Of Key Factors Of Jujube Forestland Water In Loess Hilly Region

The forest water calculation include soil moisture and tree transpiration determination. The close planting jujube forest in loess hilly region which with large scale was emerged at the period of project of returnig farmland to forest and the related research was weak for the time of forest emergence was short. The water condition of jujube forest was the key that related to the forest quality, benefit and the sustainability. In order to master the water consumption pattern of mountainous jujube forest in semi-arid region, in this study, we concerned on the tree ages and soil texture that influence the jujube forest soil moisture and the determination method that influence the determination value. We evalued the two key indicators that related to jujuebe forest water consumprion from the correlation of ages of jujube forest, soil texture and the water in soil profile and on the other hand from trunk directions and depths to the calculation accuracy of water consumption in growth period by TDP(Thermal dissipation probe) monitoring value. For the more precise study of jujube forest water consumption pattern and provide technical and theoretical support to the water management in the construction and development of the jujube forest in loess hilly region in the future. The main results showed as bellow:1) The age of jujube tree is the dominant factor that lead to the soil desiccation in jujube forestland. There are significant differences among soil moisture of jujube forest at different ages and the soil moisture of jujube forestland were influenced significantly by the water consumption of jujube tree. The depth of water consumption of different jujube forest is 320 cm of 5a jujube forest and 560 cm of 15 a jujube forest. The soil particle is the key of the inherent water content of jujube forestland, and there was still exist low soil moisture distribute layer under the jujube roots and the low soil moisture distribute layer due to the particle in jujube forestland was in the range of 660~830cm.2) In 5a jujube forestland, the moderate desiccation layer appeared in the root water absorption range with the depth 100 cm from 300~400cm. A moderate desiccation layer with the depth 300 cm from 200~500cm and a severe desiccation layer with the depth 100 cm from 400~500cm appeared in 15 a jujube forestland.3) The water consumption in growth stage calculated by the monitored value of TDP installed at the north and with the depth of 20 mm was more accuracy in test area.