Cactus Pear [Opuntia ficus-indica (L.) Mill.] Under Different Agronomic Practices Affects Soil Microbial Activity, Carbon Management Indices and Soil Quality

The cactus pear (Opuntia ficus-indica) has garnered attention for its potential to enhance sustainability in semi-arid regions. The aim of this study was to examine the impact of various agronomic practices, including planting time, irrigation, and farmyard manure (FYM) application, on soil microbial communities, enzymatic activity, carbon management indices, and soil quality in cactus pear (Opuntia ficus-indica) cultivation under the semi-arid climate of India. The study was conducted from 2016 to 2023 in Jhansi, India, assessing four planting periods (February, April, July, and October) and two agronomic management strategies (with or without fertilizer and irrigation). Various parameters, including microbial populations, enzymatic activity, nutrient availability, organic carbon content, carbon fractions, and soil quality indices, were evaluated. The results indicated that planting in July, combined with FYM (2 kg plant−1) and irrigation, significantly improved microbial populations (~18–44%), enzymatic activity (~2–33%), carbon indices (~32%), and nutrient availability (~0.75–4.75%) compared to the control. This combination of practices also enhanced organic carbon content in the soil. The treatments involving FYM and irrigation outperformed the controls in all parameters, showing improvements in organic carbon levels, carbon fractions, carbon management index, and the overall soil quality index. The study concludes that optimal agronomic practices, particularly planting in July with the application of FYM (2 kg plant−1) and irrigation, are key to improving the sustainability and ecological health of cactus pear cultivation in semi-arid regions. These practices not only enhance soil quality and microbial activity but also contribute to climate change mitigation through improved carbon management.