IMPROVIEMENT OF NUTRIENT DEPLETED SOILS WITH BIOCHAR FOR INTENSIVE AGRICULTURAL SYSTEMS IN RORAIMA.

Soils as a system is complex and diverse. It provides a broad range of services from food
supply, to carbon storage, greenhouse gas regulations, flood mitigations and other pertinent
ecosystem services. Intensive agriculture, rapid human population growth, increased
consumption and varied consumer consumption preferences globally, has placed
unprecedented pressure on soils which is a finite resource. Unsustainable agricultural
intensification of production exacerbates soil degradation. The major forms of soil
degradation include, loss of organic matter and the release of greenhouse gases, compaction
and erosion, over and under-application of fertilizers, pollution, contamination,
acidification, salinization, and loss of bio- diversity. Continuous cropping has depleted soils
nutrients in various farming systems in Roraima. The objective was to evaluate the status of
pH, soil carbon and nitrogen content in selected soils of Roraima and proffer solutions of
biochar as an amendment. The biochar used for this study are RHB - rice husk, SDB - wood
sawdust others are BSDRH - wood sawdust plus rice husks and BSDSM - wood sawdust plus
cattle manure. These biochar formulations had as common component, fish waste, rock
powder, and wood sawdust with a proportion of 60% of the vegetable residues used for each
outlined biochar type. The residues combinations were subjected to slow pyrolysis in an
earthen oven with oxygen limitation. After the biochar synthesis process, a sample of each
biochar was submitted for Near infraRed Spectroscopy (NIR) analyses, Thermogravimetric analyzes (TGA), Scanning Electron Microscopy (SEM) analyses, and Energy Dispersive X-ray Spectroscopy (EDS) analysis. The biochar, BSDRH showed the highest levels of nitrogen and organic
carbon. NIR analysis also showed a linear relationship between absorbance and organic
carbon content. The pH of neutral obtained for the BSDSM and 6.9 for RHB biochar
respectively, shows promise for correcting acidic soils.