防护林沙拐枣人工平茬更新复壮效果分析

为保证古尔班通古特沙漠渠道防护林防护效益的持续性，对林中沙拐枣进行3种不同平茬数量规格的试验，即平茬沙拐枣的数量分别为样地中沙拐枣总量的50%、67%和78%，结果表明：① 人工平茬处理在一定程度上促进了沙拐枣根系对土壤水分的吸收。② 人工平茬后， 沙拐枣植株生长迅速，生长活力旺盛，平茬当年已经起到良好的防风固沙效果；③平茬增大了沙拐枣同化枝的有效表面积，生物量增加，提高了沙拐枣的生产力。3种平茬规格处理下，沙拐枣更新复壮都取得了显著的效果，在78%平茬数量规格下沙拐枣生长状况最好，平茬效果最佳，防护效益随着后期生长将持续增大。

Regeneration of Stumping of Calligonum caput-medusae in Shelterbelt

The shelterbelts going across the hinterland of the Gurbantonggut Desert have played an important role in protecting the irrigation channels against aeolian sand disasters for many years. In order to keeping the sustainability of the effects of Calligonum caput-medusae shelterbelts, three kinds of stumping experiment of Calligonum were carried out. The percentages of the stumping were 50%, 67% and 78% respectively. The results showed that the stumping of C. caput-medusae could promote the absorbing capability of C. caput-medusaeWTBZ] roots to soil moisture, and the plants could grow rapidly and strongly after stumping. The shelterbelts of C. capu-medusae grew rapidly in the stumping years and played an important role in protecting the irrigation channels against aeolian sand disasters and sand fixation. The effective superficial area of assimilation twigs was increased, and as a result the biomass of assimilation twigs and the productivity of C. caput-medusae were also increased. The regeneration of C. caput-medusae was promoted under these three kinds of stumping, especially under the stumping of 78%.