Change of soil quality based on humic acid with date palm compost incorporation

Purpose The most important factor affecting soil quality is soil humic fraction. Effects of adding carbon in soil humic compoundsin arid environments have only been slightly investigated. The change in soil humic acids’ structures in relation withmanure and palm compost application and the evolution of humic acids’ structures during palm composting have not beensufficiently investigated. The purpose of this study is to evaluate if date palm compost is suitable for the sustainable increaseof soil carbon content with increasing soil humic compounds.Methods Soil was amended with date palm compost and sheep manure, which represented two treatments, in addition to acontrol represented by unamended soil. Soil samples were taken from depth layers of 0–20 cm and 20–40 cm. Physicochemicaland spectroscopic analyses were used to study humic acids extracted from organic amendment and soil.Results The neutral pH and the C/N ratio of 11.9 revealed that the palm/manure compost was mature. Date palm compostapplication on soil showed its effectiveness in improving soil quality. Spectroscopic studies of humic compounds extractedfrom date palm compost and manure, showed the abundance of aromatic structures, confirmed by the low E4/E6 ratio associatedwith an increase in polycondensation and polymerization. Infrared spectroscopy of humic acids extracted from amendedsoil revealed its enrichment with aromatic structures.Conclusions Using date palm compost for a short term suggests that this compost may be useful as an alternative to increasethe soil fertility by increasing the humic acids quantity with enhancing aromaticity degree and functional groups.