Calcium and potassium fertilization improves productivity and forage quality with implications for soil available potassium in Opuntia ficus-indica under hot arid condition

Background Climate change and increasing aridification have intensified the need for nutrient management strategies that sustain productivity while preserving soil fertility in dryland production systems. Opuntia ficus-indica , a drought-tolerant multipurpose crop, has gained importance in arid regions, yet information on the combined effects of calcium (Ca) and potassium (K) fertilization remains limited. Methods A one-season field experiment was conducted under the hot arid conditions of Kutch, India, using a 4 × 4 factorial randomized block design with four replications. Four Ca (0, 20, 40, and 60 kg ha −1 ) and four K (0, 30, 60, and 90 kg ha −1 ) application rates were evaluated for their effects on plant growth, forage yield and quality, fertilizer-use efficiency, and post-harvest changes in soil available K. Results Calcium and potassium fertilization significantly improved plant growth, cladode production, biomass yield, and forage quality ( P< 0.05 ). The combined application of 40 kg Ca ha −1 and 60 kg K ha −1 produced among the highest fresh and dry biomass yields while increasing crude protein concentration and reducing fiber fractions compared with the unfertilized control. Fertilizer-use efficiency declined with increasing nutrient application rates. Greater forage productivity was associated with larger changes in soil available K after harvest, indicating the need for careful K management in perennial cactus production systems. Conclusion Calcium and potassium fertilization improved productivity and forage quality with implications for post-harvest soil available K. These findings indicate that fertilizer recommendations for O. ficus-indica should integrate forage productivity with fertilizer-use efficiency and post-harvest soil nutrient dynamics to support nutrient management under hot arid conditions.