Welcome to Acta Prataculturae Sinica ! Today is Share:

Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (1): 63-74.DOI: 10.11686/cyxb2022009

Previous Articles     Next Articles

Effects of a cover crop on deep soil water and root characteristics in a dryland apple orchard on the Loess Plateau

Wei-jie LI(), Li WANG, Jing-yong MA, Zi-kui WANG()   

  1. College of Pastoral Agriculture Science and Technology,State Key Laboratory of Grassland Agro-Ecosystem,Lanzhou University,Lanzhou 730020,China
  • Received:2022-01-06 Revised:2022-03-03 Online:2023-01-20 Published:2022-11-07
  • Contact: Zi-kui WANG


To clarify the interaction between soil water content and root distribution and provide information for orchard cover crop management in the Loess Plateau, the distribution of apple tree root systems and deep soil moisture contents in the presence or absence of a cover crop were investigated. The experiment was conducted in the apple orchard of Qingyang National Field Station of Grassland Agroecosystems. Two planting patterns were set up, namely, orchard with cover crop (Dactylis glomerata, planted in 2014) and orchard with clean tillage, with annual crop farmland as control. Soil moisture and fine root length density in 0-500 cm soil layer were measured at four locations in the tree rows and between the tree rows for two consecutive years in summer and the effects of cover crop on soil moisture deficit and fine root length density were determined. Soil moisture levels in 0-300 cm soil horizon of orchard with clean tillage decreased by 6.7%-8.3% (P<0.01) compared to the control farmland, while soil moisture in 300-500 cm soil layer was not significantly changed (P>0.05); soil moisture levels in the whole profile of 0-500 cm of the cover crop treatment were on average 11.5%-12.3% lower than those of the clean tillage treatment. The water deficit in the 0-500 cm soil horizon of the control farmland was 163.9-172.1 mm after 6-7 years of cover crop planting, which was 3.2-4.2 times of that in the clean tillage orchard. In addition, the fine root length density of apple tree roots in the 0-100 cm soil layer was higher than that in deeper layers, and averaged 0.187 cm·cm-3 in density. Cover crop promoted root length density in the 0-100 cm soil layer. The soil moisture content in the various soil horizons from 0-500 cm decreased with increase in fine root length density and the correlation coefficient was increased by the presence of a cover crop, and was higher in the dry season.In summary, long-term cover crop planting in apple orchards in the dryland area on the Loess Plateau promoted the growth of apple tree roots, reduced deep soil moisture and aggravated deep soil drying, which would have a negative effect on the production of apple trees and water cycling in the local agricultural ecosystem. Cover crop management in apple orchard should be reviewed to ensure sustainable water use.

Key words: Loess Plateau dryland, tree-grass system, soil water deficit, fine root length density, deep soil desiccation