Tillage and mulching practices in cassava (Manihot esculenta Crantz): Influence on soil carbon mineralization, enzyme activity and glomalin content

Abstract

A study was undertaken in laterite soils (Ultisols) in 2017 to find out the effects of continuous adoptionof different tillage and mulching practices on carbon and nitrogen mineralization. Soil physico-chemicalproperties and biological parameters viz., soil enzyme (as an indicator of soil biological activity) andglomalin content (as an indicator of soil carbon sequestration) were estimated to find the relationshipswith the mineralization rate. Surface soil samples (0-0.15 m) from five treatments involving four tillageand mulching treatments each with three replications and a control were taken for the study. Resultsshowed that maximum water holding capacity (WHC) of 41.3% was found in soils under conventionaltillage with sheet mulching (T1) as compared to 37.7% in control (T5) with optimum BD (1.41 Mgm-3) and porosity (46%). No significant differences in soil pH were observed among tillage practices.The soil organic carbon registered a maximum value under T5 (1.37%). A significant increase ofcarbon mineralization was noted in T1 (137.7 mg CO2 100 g-1 soil) followed by minimum tillage withmulching (T3). The maximum mineralization of nitrogen, dehydrogenase activity, total glomalin (TG)and easily extractable glomalin (EEG) were recorded with control (T5). Results indicated that adoptionof conventional tillage with porous ground cover sheet mulching practices increased soil carbonmineralization activity to an extent of 18.2, 19.3 and 28.6% over minimum tillage with mulching at 24h, 48 h and 7 days, respectively. Among the soil properties, conventional tillage practices increased thesoil bulk density insignificantly and the water holding capacity to an extent of 15.6% over minimumtillage.