Effect of bio-manures on soil quality, cane productivity and soil carbon sequestration under long-term sugarcane (Saccharum officinarum) plant - ratoon system in Indian sub-tropics

Abstract

Multi-ratooning increases productivity and profitability of the sugarcane (Saccharum officinarum L.) production system, however the cane yields decline in subsequent ratoon crops owing to declining soil health. The present field experiment was conducted to assess the long-term effect of bio-manure addition on yield, soil quality and carbon sequestration in sugarcane plant-ratoon system during 2003-2013. It consisted of 10 treatments, viz. farmyard manure (FYM) (10 t/ha), biogas slurry (BS) (10 t/ha), sulphitation press mud cake (SPMC) (10 t/ha), vermi-compost (VC) (10 t/ha) alone and each in combination with Gluconacetobacter diazotrophicus (Gd), control and recommended dose of fertilizers (RDF). The plant and ratoon crops yields with farmyard manure, sulphitation press mud cake (SPMC), biogas slurry and vermi-compost added alone (10 t/ha) or with Gluconacetobacter diazotrophicus (Gd) were at par with RDF till the fourth ratoon crop. However, significant increase in ratoon crop yield with bio manures addition over RDF were recorded from fifth to ninth ratoon crop. Bio manure addition enhanced soil quality through increased SOC, infiltration rate (up to 47.5%), soil aggregates (up to 20.3%), soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) and decreased bulk density (up to 12.1%). The highest increase in SOC (72%), SMBC (413.86%) and SMBN (113.88%) were registered with SPMC + Gd addition. A two fold increase was recorded in average annual rate of soil carbon sequestration (1.05 to 1.97 t/ha/yr) against control (0.49 t/ha/yr). A linear relationship existed between SOC, carbon sequestration rate, cane yield and gross carbon input.

Keywords

• Bio manures
• Long term plant-ratoon system
• Sequestration
• Soil carbon
• Soil quality
• Sugarcane