Asian Research Journal of Current Science

This study was conducted to investigate the effects of mulching and combinations of different urea levels with rhizobium inoculation on the soil microclimate and nodulation of groundnut (Arachis hypogaea L.) at the Oilseed Crops Research Section, Department of Agricultural Research (DAR), Myanmar, during the post-monsoon seasons from December 2024 to March 2025 and from November 2025 to March 2026. Field experiments were conducted using a split-plot design with three replications. The main-plot factor consisted of rice straw mulch (6 t ha⁻¹) and no mulch, while the sub-plot factor comprised six combinations of urea levels (U) with rhizobium (Rh) inoculation: 100% U without Rh, 100% U with Rh, 75% U with Rh, 50% U with Rh, 25% U with Rh, and 0% U with Rh. Sinpadathar-11 was used as the tested variety. For the main-plot factor, mulching significantly maintained soil moisture and regulated soil temperature. It also significantly enhanced nodulation, including the total number of nodules per plant, effective nodules per plant, and nodule dry weight. For the sub-plot factor, the highest nodulation parameters were recorded with 25% of the recommended urea with Rh, followed by 50% of the recommended urea with Rh, whereas the lowest values were observed with 0% urea with Rh. There was no significant interaction effect between mulching and combinations of different urea levels with Rh. These findings indicate that rice straw mulching is an effective practice for conserving soil moisture and buffering soil temperature in groundnut cultivation. Furthermore, the application of 25% of the recommended urea combined with Rh under rice straw mulching is an effective agronomic practice for enhancing nodulation in groundnut in the study area.