Abstract
The coordination between carbon and nitrogen metabolism is central to plant adaptation to water-limited environments. This study investigated how soil management practices modulate the metabolic and physiological performance of Citrus sinensis trees cultivated under semi-arid conditions. Six field treatments combining weed-control netting, subsurface drainage, and zeolite amendment were evaluated for their effects on vegetative growth, yield, and fruit metabolome. Using (1)H-NMR spectroscopy, 23 metabolites in peel and 21 in juice were identified and quantified, revealing that sugars, organic acids, and amino acids were the most responsive compound classes. Multivariate analyses (PCA, PLS-DA) showed distinct metabolic fingerprints associated with each soil management regime. Treatments integrating netting and zeolite (T4) induced a coordinated reprogramming of carbon and nitrogen metabolism, characterized by altered levels of glucose, fructose, citrate, and proline. These changes suggest enhanced osmotic regulation and tricarboxylic acid cycle activity, supporting improved water-use efficiency and physiological stability under semi-arid stress. The results demonstrate that soil management directly influences fruit metabolic homeostasis, linking environmental modulation of root-zone conditions with whole-plant biochemical adjustment. This integrative metabolomic approach provides mechanistic insight into how soil-plant interactions shape the metabolic resilience of citrus under water-limited field environments.