No abstract

Oases in arid regions of northwestern China are main sites for agriculture and human settlement. Conservation of these important oasis habitats involves establishing shrub shelterbelts around the oases. We investigated how different types of shrub shelterbelts affect the diversity of ground beetles. We sampled carabid and tenebrionid assemblages with pitfall traps in spring and summer and measured key environmental variables in four habitats of the arid region: planted stands of pure and mixed plantations of two long‐lived shrubs (Haloxylon ammodendron and Tamarix ramosissima) and natural grassland (NG) from which planted systems were converted. Beetle abundance and species richness reduced significantly in the pure plantations but the mixed plantation had similar abundance and higher richness in spring and lower richness in summer relative to NG. We found differences in response between functional groups of beetles. The pure plantations resulted in reduced abundance and richness of herbivores and detritivores and increased predator abundance in spring and reduced predator abundance in summer. The mixed plantation resulted in increased detritivore richness in spring and reduced detritivore richness in summer as well as increased herbivore abundance in spring and reduced herbivore and predator abundance and richness in summer. The beetle community was largely determined by shrub cover and herbaceous plant diversity. We conclude that the pure shrub plantations reduce beetle diversity, whereas the mixed shrub plantation has less adverse effect on beetle diversity. Shrub mixtures can therefore be a practical measure to minimise the negative impacts of shrub shelterbelts on beetles.

To study the effects of different cultivation material formulas on the growth and quality of spp. With the cultivated species strains extracted from wild spp. in Diebu County, Gannan Prefecture as experimental materials, an experiment was designed and the data then obtained was anyalyzed using the single factor variable method. By measuring the pileus length, pileus perimeter, stipe length, stipe perimeter and yield as well as the ash content, total sugar content, crude protein content and crude fiber content of wild spp., the effects of four different cultivation material formulas on the growth and quality of spp. were studied. The result showed that the spp. cultivated using Formula 1, i.e., the formula to which spp. footing soil was added, grew best, and had the highest yield and the best quality; and the qualities of spps cultivated using other formulas decreased in a row. Formula 1 to which spp. footing soil was added had the optimal effect on promoting the growth and quality of spp.

To explore the reason causing low yield, poor quality of , this paper investigated the influence of different remained stem heights on the yield, quality and water consumption of in Gannan plateau area using field single factor randomized block method. Research results showed that which was cut before blooming period in the last ten-day of July with remained stem height of 25 cm had the lowest water consumption, the best underground root traits (including main root length, root diameter, and root dry weight per plant), and the highest yield which was higher that control group by 18.73% (P< .01) Moreover, with remained stem height of 25 cm had the lowest ash content while the highest content, therefore its quality was the best. The water use efficiency (WUE) of with remained stem height of 35 cm at September was the highest (1.12 kg⋅h⋅m⋅mm). However, in terms of biological yield WUE and economic yield WUE, with remained stem height of 15 cm was the highest. Therefore, it can be concluded that remained stem height from 15 to 25 cm is an ideal solution, which can not only save water, but also improve yield and quality of