Mineral Nutrition and Plant Energy Metabolism: A Hypothesis-Driven Review of Nutrient Function, Potential Energetic Leverage, and Crop Productivity

Mineral nutrition is evaluated through nutrient supply, deficiency, tissue concentration, and yield response. These indicators help establish sufficiency but do not fully describe the metabolic costs or spatial and temporal constraints involved in correcting a nutrient-dependent limitation. This hypothesis-driven narrative review examines acquisition, assimilation, homeostasis, and respiration alongside photochemical energy conversion, ATP-dependent metabolism, carbon allocation, and crop productivity. It distinguishes basal fertilization from corrective functional mineral nutrition, which targets limitations arising from stress or disrupted acquisition and transport despite apparently adequate background supply. Three provisional, potentially overlapping profiles organize documented mechanisms and proposed energy–carbon connections: Group I (Ca, Fe, K, Mg, Mn, and P), Group II (Cl, Cu, N, S, and Zn), and Group III (B, Mo, and Ni). Their boundaries remain unvalidated and imply no fertilizer priority. Nitrogen is assigned provisionally to Group II because crop responses to additional N vary with nutritional status and sink demand. Correcting N limitation can substantially improve photosynthesis and harvested yield; beyond sufficiency, additional N may increase the costs of assimilation, protein turnover, and maintenance with limited productive benefit. The review distinguishes evidence for functional recovery, harvested yield, and measured energetic efficiency. Current evidence does not permit quantitative comparison of net energetic efficiency across all fourteen nutrients. Mineral correction and biostimulation may complement one another when they address different components of an active limitation.