Precision control of water-fertilizer for industrial strawberry production: A closed-loop framework balancing dynamic growth indicators and economic-environmental

Industrial strawberry production faces critical trade-offs between yield stability, resource costs, and environmental compliance. To resolve this, we established a closed-loop decision framework integrating stage-specific growth dynamics with precision resource allocation. Over two growing seasons, a quadratic orthogonal rotation design was employed, which set the substrate water content (W) at five specific levels of 52–58%, 61–67%, 71–77%, 81–87%, and 89–95%; nitrogen (N) at 112.23, 135.20, 169.43, 203.23, and 226.20 kg·ha −1 ; and potassium (K) at 117.87, 142.13, 177.67, 213.20, and 237.46 kg·ha −1 . This design was employed to quantify stage-specific responses of 10 growth and photosynthetic indicators across seedling (S), flowering (F), and harvesting (H) stages. Results revealed dynamic growth-driven interactions: The responses of strawberry growth and photosynthetic indicators to the combined application of W, N, and K varied with stages. The effect of W on the dry matter (LD) of leaves in the S stage was the most significant, while in the H stage, the effect of K on LD was the most significant, and the effect of W on net photosynthesis rate (Pn) and chlorophyll (Chl) was the most significant. The pathway analysis revealed that LD S (0.465) regulated LD H (0.471) by influencing Chl F (0.772), thereby affecting yield. The overall difference combination method was introduced by integrating three single evaluation models, and a comprehensive score (C) was generated. The comprehensive strawberry score showed an open downward parabolic response to W, N, and K. In response surface analysis, the optimal interval shifted toward higher N and K levels as W increased. During model validation, the mean relative error (MRE) between theoretical and experimental values was 0.60%. The optimal combination of water and fertilizer was determined by balancing economic profit, resource efficiency and environmental protection, with irrigation of 77.2∼86.3%, N application of 182.0 ∼ 218.8 kg‧ha −1 , and K application of 187.2 ∼ 224.9 kg‧ha −1 , which can achieve comprehensive optimization of high yield, high efficiency, low consumption, and low pollution through water and fertilizer application, providing core support for sustainable agricultural production. • Framework optimizes water-fertilizer management using growth stage dynamics. • Deficit irrigation (77%-86%) with balanced N-K maximizes yield, reduces resource use. • Reduces costs 26.83%, boosts productivity of fertilizer 51.04% vs conventional. • Model achieves 0.60% error, enables sustainable strawberry supply chains.