Objective  Reasonable fertilization and surface mulching are necessary measures for high yield and quality of Castanea mollissima (Chinese chestnut) in arid areas. This study proposed an optimized soil management model of interrow mulching and combined application of organic and inorganic fertilizers based on the local actual situation in Qianxi County, Hebei Province of northern China, and verified the effect to provide a theoretical basis for its improvement and promotion.

  Method  This experiment took the 8-year-old Chinese chestnut variety Castanea mollissima ‘Yanshanzaofeng’ as the research object, adopted a split-plot design, and the main treatments were inter-row grass covering (GC) and clearing (CT), the secondary treatments were 4 fertilization treatments, single application of inorganic fertilizer (F), single application of organic fertilizer (M), combined application of organic fertilizer and inorganic fertilizer (F + M) and no fertilization (CK). In 2019 and 2020, the effects of grass mulching-fertilization mode on leaf function and fruit yield and quality of Chinese chestnut were studied for two consecutive years. Finally, the principal component analysis (PCA) method was used to comprehensively evaluate the 28 indicators of each treatment, and the best soil management mode was selected.

  Result  The length and roughness of shoots, leaf area, dry quality of louver, thickness of louver and mineral element content of leaf increased to different degrees in each fertilization treatment, and the GC(F + M) treatment was significantly higher than that of other treatments. The chlorophyll content, photosynthetic rate and water use efficiency of leaves could be improved by surface covering grass and different fertilization treatments. The most obvious increment was GC(F + M) treatment, which was 6.00%, 20.13% and 44.87% higher than GC(CK), respectively. The combined application of organic and inorganic fertilizer (F + M) was better than single fertilization in improving fruit setting rate, fruit yield rate, single grain quality and single plant yield of Chinese chestnut. Among them, The single grain quality of GC(F + M) and CT(F + M) treatments could reach 10.32 and 9.92 g, respectively, which were 26.01% and 21.12% higher than that of CT(CK). The yield per plant increased by 4.95% to 45.21% under different grass mulching-fertilization modes, and the content of starch and soluble sugar in GC(F + M) increased by 13.04% and 36.57%, respectively compared with CT(CK). The result of principal component analysis showed that GC (F + M) treatment had the highest comprehensive score, the second treatment was GC(F) treatment, the third was CT(F + M) and the fourth was CT(F) treatment. It showed that combined application of organic and inorganic fertilizers was more beneficial to the growth and development of Chinese chestnut branches, as well as the improvement of photosynthetic performance and fruit yield and quality than single application of inorganic fertilizer.

  Conclusion  In the cultivation of Chinese chestnut in arid area of Qianxi County, the mulch-organic and inorganic fertilizer combined application model is the most suitable soil management method for improving quality and increasing yield of Chinese chestnut in this area.