Current knowledge in enhancing moisture content for sandy soil through application of pristine rice husk biochar and polyvinyl alcohol (PVA): Can coupling biochar and PVA do better?

By: Gift Gladson Moyo, Zhiquan Hu,

Abstract

Biochar and super-absorbent polymers such as polyvinyl alcohol (PVA) possess numerous unique properties that are increasingly used in soil amendment applications. A number of studies and reviews done on singular utilization of rice husks biochar and PVA have proven effectiveness of these carbonaceous materials. Subsequently, a combined application of rice husks biochar and PVA or utilization of biochar/PVA composites could be a promising direction to enhance moisture content of soils in arid regions. In most recent research work on utilization of biochar and PVA, the intersection have been on improvement of other properties of soils but little on enhancement of moisture content of sandy desert soils. Moreover, to the authors’ knowledge, there has been no compilation of the independent data from individual studies to explicitly expose the unique properties, and the processes of biochar and PVA preparation intended to improve soil properties for growth of plants in arid places. Besides that, effectiveness of coupling biochar and PVA as a potential sandy soil ameliorating technology is currently unknown. Therefore, a review of recent articles was done to enhance our understanding of the essence of the processes involved; provide insight about future research directions; and contribute to the development of theoretical framework for soil amendment using biochar and PVA. In this case, properties of rice husks biochar and PVA; effects of pyrolysis temperature on hydrological and chemical properties of rice husks biochar; and their deficits and advantages are discussed. Applications of PVA in singular or combined forms in various fields; and preparation of biochar-PVA composites are also highlighted. Finally, the model for mechanisms responsible for enhancement of water and PVA retention in soil is exposed. Based on this work, coupling biochar with PVA would be super singular use of biochar and PVA in improving water content of soil in arid environment.