Abstract: Establishment of vegetation for sand stabilization is a widely used technique in restoration of desertified land, and little research has been conducted into the effects of different planting patterns on restoration outcomes. In particular, few studies have examined different planting patterns for composite grass-sand barriers for restoration in alpine-cold desert regions. In this study, typical alpine sub-humid sandy land in the northwest of Sichuan was planted in 2014 in three patterns (row planted, band planted, or scatter planted) with a mixture of three grasses: Avena sativa, Elymus nutans and Festuca sinensis. Data were collected in August 2014 on the growth of A. sativa, and again in August, 2017 to check plant community, coverage, biodiversity and collect soil samples. Soil water content, bulk density, pH value, organic carbon, total nitrogen, total phosphate, ammonia nitrogen, nitrate nitrogen and available phosphate were determined by standard laboratory techniques. Results showed that band and scatter planting patterns had significant positive effects on restoration of sub-humid sandy land. The annual species A. sativa had disappeared from the ecosystem by 2017, and the two perennial grasses grown well. The band and scatter planting patterns showed significantly superior plant coverage, biodiversity and ecosystem development, together with decreased soil bulk density, but increased soil water content, organic carbon, total nitrogen, total phosphate and other benefits. For sub-humid alpine sandy land restoration using grass mixtures, we suggest soil bulk density, organic carbon and total nitrogen are useful indexes of soil improvement. Also we recommend use of grass mixtures in band or scatter planting patterns as a suitable technique for restoration of desertified alpine land, to both restore vegetation cover above ground, and improve soil properties below ground.

Key words: grasses, vegetation community, sub-humid, soil property