Determination of leaf fertilization in lentils using digital agriculture techniques

This study aimed to evaluate the effects of different foliar fertilizer applications on yield, nitrogen uptake, chlorophyll content (SPAD values), and morphological parameters of lentil (Lens culinaris) under the semi-arid conditions of Southeastern Anatolia, Turkey. The experiment was conducted during the 2021–2022 growing season in a randomized complete block design with three replications. Foliar fertilizers (Flo, Mac, Flo+Mac, Zn, K, Zn+K) were applied at the onset of flowering, and chlorophyll contents were monitored using a portable SPAD-502 chlorophyll meter. This sensor-based measurement approach represents an integrated application of digital agriculture techniques to monitor plant nutrition status in real-time. The results showed that foliar applications improved grain yield across all treatments, with Zn application significantly increasing yield by 55% compared to the control (p < 0.05). While biomass production did not significantly differ among treatments, a strong positive correlation (R² = 0.87) was observed between grain yield and harvest index. Notably, Zn application also enhanced total grain nitrogen uptake. SPAD values, reflecting photosynthetic activity and chlorophyll density, increased significantly until day 21 in all treatments and remained highest under the Flo+Mac application throughout the growing period. This suggests a prolonged vegetative activity and more efficient assimilate partitioning toward grain in certain treatments. In conclusion, time- and stage-specific foliar fertilization supported by sensor-based digital monitoring can enhance yield and nitrogen use efficiency in lentil production. The study provides valuable insights into the role of digitally assisted nutrient management for sustainable agricultural intensification and demonstrates its applicability for broader adoption by local farmers.