Aqueous Synthetic Polymer Spraying Application for Mulching of Surface Soil for Revegetation of Critically Degraded Ex-Borrow Pit Area

Abstract

Very low soil fertility status due to borrow pit exploitation was exposed at lower soil horizon layers. Soil among the sites was classified as critical soil type. The soil layer was at C-horizon, so that was classified as not “soil” in the agricultural term, but it was more grouped as still unweathered parent mater for processing in the soil formation. Suffering on surface vegetation biodiversity was found and revegetation action was an alternative method to restore the degraded soil. Legume cover crops were selected for ameliorating pioneer plants to improve soil and vegetation biodiversity step by step towards the effective regreening of environmental health and safety. An aqueous synthetic polymer was applied to spray the soil surface after planting the legume cover crops, whereas, after the water evaporation of the solution, a degradable thin film at the soil surface was left as a mulch for controlling the water evaporation from the soil surface for a long time for a few months. The mulch kept the soil moisture higher for the growth of the legume cover crops. Field application was succeeded in 2010-2011 at an ex-borrow pit area in Jambi. Additional topsoil, fertilizer, compost, and lime were mixed as supporting growth media. Mucuna bracteata was planted before the application of the aqueous synthetic polymers spraying. Aqueous synthetic polymer spraying application for mulching of surface soil was able to reclaim the critically degraded ex-borrow pit area for the start step, whereas the vegetation covering rate of the site increased from initially less than 1% to more than 90% after 10 months application.