Enhancing plant and soil health through organic amendments in a humid environment
Ram L. Ray, K. M. Kularathna, Richard W. Griffin, N. S. Abeysingha, Selamawit Woldesenbet, Almoutaz Elhassan, Ripendra Awal, Ali Fares
Abstract
Root distribution and soil characteristics significantly influence plant growth. Understanding the distribution of roots is essential for optimizing crop growth, soil health, and irrigation management. This research aimed to study the effects of type and rate of organic amendments (OA) on selected soil properties, root density, and distribution of roots in collard greens ( Brassica oleracea var. viridis ). A field experiment was conducted at Prairie View A&M University research farm in two seasons (October 2017 to April 2019). Three OA types, chicken manure (CM), dairy manure (DM), & milorganite (MG), were applied as treatments, including a control, to nine randomly selected plots (Total 9*3=27+9 controls = 36 plots). One week before planting, these treatments were applied at three different rates as 168, 336, and 672 N-Kg/ha. Soil samples were collected from two depths (0-15 and 16-30 cm) to analyze the soil characteristics and quantify the root density and distribution of roots at the end of the growing season. Results showed that DM significantly increased total soil organic carbon (TOC) across all application rates and seasons. Bulk density in the surface layer decreased with OA application after 1.5 years. MG had the lowest root density and distribution of roots, possibly due to its slower nutrient release dynamics. The study determined that CM exhibited superior performance among the tested OA, resulting in enhanced root density and improved root distribution patterns, even at lower application rates (5.6 Mg/ha). These findings support the sustainable soil management practices by selecting appropriate soil amendments and application rates.