Calcium Carbide–Based Formulations Cause Slow Release of Acetylene and Ethylene in Soil and Nitrification Inhibition

Abstract

Nitrification inhibition (NI) of applied fertilizer nitrogen (N) is a suitable approach to improve N-use efficiency. Formulated calcium carbide (CaC₂), a slow-release origin of acetylene, is a potent nitrification inhibitor; however, its efficacy in relation to different formulations has not been thoroughly investigated. In this study, seven CaC₂ formulations viz. encapsulated; coated with beeswax, paraffin wax or paint, and matrix-I (21% CaC₂, 58% polyethylene and 21% plaster of paris), matrix-II (42% CaC₂, 48% polyethylene and 10% plaster of paris) and matrix-III (61% CaC₂, 34% polyethylene and 5% paraffin oil) were incubated with soil and their effectiveness in acetylene and ethylene release and NI potential were compared up to 91 days. In CaC₂ treatments, acetylene flux was decreased, whereas that of ethylene first increased and then decreased with time. During all the time intervals after day 7 of incubation, fluxes of acetylene and ethylene and NI were significantly greater with matrix I, followed by matrix II, paint-coated, and wax-coated CaC₂. No acetylene release was noted with encapsulated or matrix III formulations after day 35 of incubation. Among other CaC₂ formulations, matrix I, matrix II, and paint-coated CaC₂ were better precursors of acetylene and ethylene, and nitrification inhibitors in the soil.

Keywords:

• Acetylene
• calcium carbide formulations
• ethylene
• nitrification inhibition