Mulching effects on soil microbial, physicochemical properties and performance of cowpea on coastal plain sand

Abstract

The presence of residue mulches in farm has been known to effectively save the soil surface, prevent soil erosion on slopes, helps reduce soil moisture loss through evaporation, and insulates soil, protect roots from extreme temperatures, improve soil biology, aeration, aggregation of soil particles and reduce drainage over time, improve soil fertility as certain mulch types decompose, inhibits certain plant diseases, reduces the likelihood of tree damage from “weed whackers” or the dreaded “lawn mower blight”, give planting beds a uniform and provide favorable preservation of ecological stability. This experiment was conducted in the Teaching and Research Farm of Akwa Ibom State University, Obio Akpa Campus to assess the effect of sawdust, pulverized palm bunch and Calopogonium mucunoides leaves mulches effects on soil microbial, physicochemical properties and performance of white dwarf cowpea (Vigna unguiculata) on coastal plain sand of Southern Nigeria. Results showed that soil mulched with Calopogonium mucunoides leaves recorded the highest in the following parameters measured: pH of 6.45, organic carbon (5.16%), nitrogen (2.26%), ECEC of 11.35 cmol, available phosphorus of 323 mg kg^-1, base saturation (91.11%), 100% seed emergence and leaf area. The highest moisture content of 35% was obtained in the sawdust mulched soil. The highest peas moisture content (5.63%), crude fiber (3.91), lipid (4.71), total ash (4.82) and carbohydrates (61.88%) were obtained in the soil mulched with Calopogonium mucunoides while highest bacterial counts of 37×10⁵ cfu g^-1 soil and the fungi counts (51×10³ cfu g^-1 soil). The studied soil contained more than 70% sand. The soil is described as sandy loam which gives rise to Typic Paludult, characteristics of soil derived from Coastal Plain Sand.