和田地区绿洲外围防护林体系的防风阻沙效益

Protection Against Wind and Blocking and Intercepting Sand Effects of Shelterbelt Forests System Outside Oasis in Hotan Area

通过对2010年和2011年和田地区策勒县、皮山县、和田县吉亚乡3个绿洲外围靠近沙漠边缘的防护林防风阻沙效益进行野外实地调查及对防护林内小气象站和配套积沙仪定点观测数据分析,发现和田地区绿洲外围防护林体系树种较单一,由于垦荒天然防护林面积在日益缩小,导致新的幼小新疆杨防护林防风阻沙效果不是很理想;在相同的水分灌溉条件下,沙拐枣防护林生长较新疆杨、梭梭、柽柳防护林成活率高,并且生长迅速,需水量少,且疏透度较小,防风阻沙效果更为理想。为有效提高和田地区绿洲外围防护林防护效益,应合理垦荒保护好绿洲-沙漠过渡带的天然植被,从流沙前沿至绿洲内部合理设计天然草灌带-人工防护林带-农田小方格防护网,防护林树种的选择不仅需考虑其耐水性、疏透度,还应适当考虑防护林经济效益。通过对和田县吉亚乡防护林示范区BSNE积沙仪不同高度水平输沙量、输沙率及其粒度样分析,表明从流沙前沿进入防护林内不同高度的输沙量都有很大程度的降低,并且风蚀沙粒平均粒径变细,随高度增加输沙沙粒分选性变差,峰态变窄,引起新开垦农田地表风蚀沙粒主要为极细沙。

Through field surveying on benefits of analyzed datum of weather stations and matching counties of shelterbelt forests in Cele, Pishan and wind protection, blocking mobile dunes and blown sand, passive collectors based on the margin of desert in three Hotan. Results show that peripheral shelterbelt forests of oasis varieties of protection trees are single. Because area of reclaimed wasteland is enlarged, it led to in- creasingly reduction of natural shelterbelt forests, which led to be unsatisfied effects of young Xinjiang pop- lars on protecting wind and blocking mobile dunes. However, at the same irrigation condition, higher rate of survival and faster growing with less water of Calligonum herb compared with Xinjiang poplar trees and Sac- saoul and Tarnarix rarnosissirna shelterbelts, and Calligonurn herb has small porosity with dense branches and leaves and which is ideal to protect wind and block mobile dunes. In order to enhance effectively protec- tion effects of shelterbelt forests outside oasis in Hotan area, natural vegetation should be preserved in rea- sonable reclamation. Net of natural shrubs belts-man-made shelterbelt forests-small square shelterbelt for- ests in farmland should be reasonably designed from mobile sandy land to oasis. The choice of species of shel- terbelt forests should be not only taken resisting water and porosity into account, but also economics effec- tiveness. Through analyzing horizontal sand transportation quantity and particle size at different heights of passive collectors in protection demonstration plot of Jiya country in Hotan county, the results show that the sand transportation quantity and sand transportation rate at different heights decreased sinificantlv frcrnmobile sandy land to shelterbelt forests. became much narrower. The main sand very fine sand particles. Mean grain size became particles resulted in wind finer, and sorting became worse. Kurtosis erosion in new reclamation farmland were .