Intercropping orchards with cover crops is an important practice for achieving sustainable soil management. However, little research has addressed the development of a soil quality index (SQI) to evaluate cover crop effects on orchard soil quality. The aim of this study was to ascertain whether cover cropping improves soil quality and fruit yield of Goji (Lycium barbarum L.) while reducing or replacing organic fertilizer application. The main treatments were the traditional management of L. barbarum as a monocrop (M) and intercropping Goji with radish (Raphanus sativus L.) as an annual cover crop (I). Within the main treatments, different levels of organic fertilizer were applied at 0 kg·plant−1 (M0), 2 kg·plant−1 (M1), and 4 kg·plant−1 (M2). After six years of planting, we analyzed the changes in soil quality caused by cover cropping with different organic fertilizer levels based on the SQI method. Goji yields were used for validation of the SQI derived from a minimum data set of soil quality indicators. In contrast with traditional monocropping, cover cropping increased soil total nitrogen, available nitrogen, and available phosphorus contents (by 78.60%, 30.30%, and 138.08%, respectively). There were also increased microbial biomass carbon and nitrogen contents (by 79.01% and 184.01%, respectively), enhanced urease and sucrase activities (by 41.02% and 56.81%, respectively), and reduced bulk density (by 1.92%) in the soil as a result of cover cropping. Compared with IM0 treatment, soil microbial biomass carbon and nitrogen contents considerably increased under IM1 treatment, whereas soil available nitrogen and potassium contents as well as electrical conductivity increased under IM2 treatment. The SQI, which varied among treatments in the order IM1 > IM2 > MM2 > MM1 > IM0 > MM0, was positively correlated with Goji yield. From the soil quality and Goji yield perspective, cover cropping with a medium level of organic fertilizer is the optimal soil management practice for the L. barbarum planting system in arid areas of Ningxia, Northwest China.

The effect of cutouts positions and shapes on deformation behaviors and energy absorption of automobile thin-walled structures is researched by quasi-static axial compression, using MTS machine and digital image correlation method. The accuracy of finite element modeling is verified by axial compression test. The relationship between variation characteristics of different time and sections and deformation of the sample is analyzed. The results show that the number of surface deformation concentrated areas is affected by position of circular cutouts. Peak load of sample could be effectively reduced by slotted-shaped cutouts. The energy absorption of slotted-shaped cutouts with different aspect ratios and directions is different, horizontally-long-slotted cutouts is increased by 5.13 %. The position of deformation concentration region is affected by compression halfwavelength. Deformation concentration region of sample less than half-wavelength is below cutouts. By digital image correlation method, strain of horizontallylong-slotted cutouts is more concentrated. Peak load is effectively reduced. The results of finite element analysis show that when the thin-walled structure is bulking, the section of sample is deformed from top to bottom. The initial area of crosssection at center of cutouts is linear with peak load. These achievements may serve as guideline for enhancing compression performance of thin-walled structures.