Natural Grass Cultivation Management Improves Apple Fruit Quality by Regulating Soil Mineral Nitrogen Content and Carbon–Nitrogen Metabolism

Orchard grass cultivation management is an effective measure to safeguard the sustainable development of fruit industry in China. However, details influence natural sod culture on carbon (C)–nitrogen (N) nutrition trees and quality Hanfu apple orchards are lacking. Therefore, a field experiment was conducted, which consisted two treatments: clean tillage (CT) (NG). Results revealed that NG treatment contributed increases soil organic matter (SOM), total N, NH4+-N at depths 0–20 cm 20–40 cm, while NO3−-N concentration under significantly decreased same depth, within range 0–200 profile, compared with CT. also promoted leaf photosynthesis enhanced N sugar metabolism. The results isotope labeling showed obviously elevated 13C accumulation distribution rate fruits, as well 15N whole tree, whereas fruits decreased. Furthermore, increased anthocyanin content. These provide theoretical references for feasibility improve orchards.