Mineral Nutrition in Apple (Malus domestica): Physiological Regulation, Rootstock Effects, and the Transition Toward Precision Nutrient Management—A Review

Apple (Malus domestica Borkh.) mineral nutrition reflects interactions among soil nutrient availability, rootstock traits, rhizosphere processes, internal transport and remobilization, water supply, and fruit demand. This review examined research trends and synthesized physiological and agronomic evidence using an audited corpus of 847 Scopus-indexed publications from 1995 to 2025. Bibliometric analyses quantified publication patterns and keyword co-occurrence, while qualitative synthesis examined nutrient acquisition, allocation, and management across experimental settings. Publication activity increased markedly, with 62.3% of included publications appearing during 2016–2025. The keyword network comprised 60 terms, 869 links, and five thematic clusters; nitrogen, yield, and fruit quality were among the most frequent concepts. The literature increasingly connected individual nutrient responses with rootstock-mediated acquisition, soil–rhizosphere interactions, fertigation, fruit mineral allocation, molecular regulation, and precision monitoring. Across these themes, the synthesis highlights that nutrient availability alone does not determine tree nutritional status or fruit mineral composition; physiological transport, phenology, rootstock characteristics, and water availability also matter. Interpretation is constrained by heterogeneous study designs and the absence of formal risk-of-bias appraisal. Future research should integrate multi-season orchard experiments, cultivar- and rootstock-specific diagnostic approaches, and independently validated sensing methods to support site-specific nutrient management and assessment of environmental outcomes.