Enzyme-aware soil fertility prediction using dual optimization with improved SCSO

Soil enzyme activity is a key determinant of crop productivity, as it regulates nutrient cycling, organic matter decomposition, and nitrogen transformation. The existing Machine Learning (ML) and Deep Learning (DL) approaches for soil fertility assessment often underutilize biochemical indicators owing to noise, missing data, and complex feature interactions. These models treat Feature Selection (FS) and Hyperparameter Tuning (HPT) as separate process. This limits the overall model performance. Conventional Sand Cat Swarm Optimization (SCO) method suffers from rigid exploration-exploitation transitions and premature convergence. To overcome these limitations, an Improved Sand Cat Swarm Optimization (Improved SCSO) based framework is implemented in this work. The proposed work sequentially performs FS and HPT within a unified optimization process and includes a stochastic escape-from-worst update mechanism. Cosine-modulated search behavior is incorporated in the model to enhance exploration. Exploitation and convergence stability are improved by Time-adaptive best-solution inheritance strategy. Enzyme-related soil attributes were explicitly incorporated into the optimization process, enabling the selection of biologically meaningful features. A correlation-based filtering step was applied to remove redundant features and improve the prediction consistency. The optimized feature subset was evaluated using multiple ML, DL and Hybrid models have also been assessed to understand the predictive performance of proposed framework. The model was evaluated using stratified k-fold cross-validation with Accuracy, Precision, Recall, and F1-score. The experimental results show that the proposed framework consistently outperforms traditional SCO-based methods. Gradient Boost (GB) achieved the highest accuracy of 98.48%, followed by hybrid models such as Decision Tree (DT) + Random Forest (RF) (98.38%) and GB + RF (98.28%) respectively. In addition, a dynamic crop mapping strategy was developed to estimate crop suitability based on predicted fertility levels and enzyme activity, thereby improving its practical application. Overall, the proposed framework improves prediction accuracy and interpretability, providing an effective solution for soil fertility assessment and data-driven crop recommendation.