Managing soil potassium through green manuring with gliricidia for improving cotton yield and quality of shrink-swell soils of Central India

Abstract

Soil potassium (K) content in the swell-shrink soils of Central India has been decreasing in recent decades due to higher inputs of N and P fertilizers concomitant with lower or no inputs of K fertilizers. Therefore, nutrient management to mitigate the negative K budget is urgently required. Therefore, we aimed to exploit the abundance of K in gliricidia (Gliricidia sepium) to substitute the fertilizer K requirement to improve soil quality and sustain cotton productivity. Results indicated a significant (p < 0.05) improvement in soil physical properties and organic carbon under treatment 100% NP + 10 kg K (inorganic) + 20 kg K (gliricidia) (T₄). The same treatment had 18.2 and 11.4, 36.22 and 4.7, and 17.8 and 9% higher content of available N, P, and K compared to the control and 100% RDF, respectively. Available micronutrients and biological properties were significantly higher under treatment T₄ and 100% NP + 15 kg K (inorganic) + 15 kg K (gliricidia) (T₃). Hydraulic conductivity, organic carbon, and microbial biomass carbon were identified as key SQ indicators for the experimental soil. The treatments T₃ and T₄ had about 105 and 122% more seed cotton yield compared to the control and 17 and 27% more than 100% RDF treatment (T₂). We conclude that gliricidia can be efficiently utilized in the nutrient management packages to partially substitute the fertilizer K requirement of rainfed cotton. This will further address the K depletion and nutrient imbalances and help to restore the soil K in shrink-swell soils of Central India.

Keywords:

• Gliricidia sepium
• nutrient management
• rainfed cotton productivity
• soil properties

Acknowledgment

The authors thank the Indian Council of Agricultural Research (ICAR) and Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad for providing the financial and technical assistance to carry out this work under All India Coordinated Research Project for Dryland Agriculture at Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra, India.

Disclosure Statement

The authors declare that they have no conflict of interest.