Actinomycete inoculant improves the growth and yield of rainfed lowland and upland rice under field conditions

Abstract

This study aimed to assess the effectiveness of actinomycete inoculant in enhancing the growth and yield of rainfed lowland and upland rice across wet and dry seasons in real field conditions. This field assessment took place at four sites, comprising two rainfed lowland and two rainfed upland ecosystems, over two cropping seasons (dry and wet seasons). The experiments involved testing both soil-based and carbonized rice hull (CRH) inoculants. Actinomycetes were found to be effectively carried by CRH and soil, and evidence from field studies in rainfed lowland and upland conditions showed that the actinomycete inoculant significantly improved rice production even under stressful environmental conditions. Regarding plant height, root depth, and tiller number, the inoculated treatments outperformed both the control and the full fertilization rates. Rice yield significantly increased with the application of actinomycete inoculum in both lowland and upland experiments. Inoculation alone led to substantial improvements, with yield increases of up to 48% in Lowland Site 1, 50% in Lowland Site 2, 78% in Upland Site 1, and 43% in Upland Site 2. Similarly, growth was enhanced by inoculation alone, reaching up to 50% in Lowland Site 1, 75% in Lowland Site 2, 24% in Upland Site 1, and 26% in Upland Site 2. When added to the full rate of fertilization, the inoculant significantly boosted yield by up to 16% in Lowland Site 1, 82% in Upland Site 1, and 40% in Upland Site 2. Additionally, growth substantially improved with inoculation in conjunction with the full rate of fertilization, reaching as much as 50% in lowland site 1, and 24% in upland site 1. Actinomycete inoculant proves to be a valuable alternative and addition to agricultural fertilizer management, as it was found to significantly increase growth and yield even in adverse weather conditions.