Effect of Lycium barbarum L. Root Restriction Cultivation Method on Plant Growth and Soil Bacterial Community Abundance

Abstract

The root restriction of protected cultivation has been widely used to increase productivity and sustainability in modern agriculture. However, there have been few studies of wolfberry (Lycium barbarum) root restriction, and it is cultivated mostly by clean tillage. In this study, we measured the growth of Lycium barbarum and the composition and diversity of the bacterial community and soil properties of L. barbarum under different cultivation methods with root restriction. The results showed that the X60 root-restriction treatment significantly increased the canopy size (east–west), leaf length, leaf width, the number and length of new branches, and the concentrations of chlorophyll and K in L. barbarum. The concentrations of N, P, and K in the root-restriction groups were all higher than those in CK. However, the ratio of N:P was greatest in the CK plants and least in X80, indicating that X80 had a relatively weak effect on the balance of N:P. In addition, root restriction improved fruit quality by increasing soil organic matter and organic carbon and also improved fertilization efficiency to promote plant growth. Moreover, high-throughput sequencing showed that the abundance of soil bacteria under root-restriction cultivation was significantly higher than that in CK. Furthermore, the total abundance of the top 10 bacterial genera was greatest in the X60 treatment. Redundancy analysis showed that total N, total P, total K, and total organic matter were the major soil factors that affected the bacterial community. A comprehensive comparison showed that root-restriction cultivation improved the growth of L. barbarum but reduced the abundance and diversity of the soil bacteria. The X60 treatment yielded the best results on plant growth. Our findings provide an empirical reference for root-restriction cultivation of L. barbarum of an appropriate width.