Methane consumption potential of soybean-wheat, maize-wheat and maize-gram cropping systems under conventional and no-tillage agriculture in a tropical vertisol
Bharati Kollah, Mahendra Bakoriya, Garima Dubey, Rakesh Parmar, J. Somasundaram, A. O. Shirale, S. C. Gupta, A. K. Patra, Santosh Ranjan Mohanty
Abstract
Abstract Methane (CH 4 ) consumption in agricultural soil is imperative for the mitigation of climate change. However, the effect of tillage and cropping systems on CH 4 consumption is less studied. Experiments were carried out in Madhya Pradesh, India with soybean-wheat (SW), maize-wheat (MW) and maize-gram (MG) cropping systems under conventional tillage (CT) and no-tillage (NT). Soybean/maize was cultivated during the kharif season (July–October) and wheat/chickpea in the rabi season (October–March) for 9 years consecutively. Soil samples were collected during vegetative growth stages of soybean and maize from different cropping systems. Methane consumption, the abundance of methanotrophs as particulate methane monooxygenase ( pmoA ) gene copies, soil and crop parameters were estimated. Methane consumption rate was higher in NT and upper soil layer (0–5 cm) than CT and 5–15 cm depth. Methane consumption rate k ranged from 0.35 to 0.56 μg CH 4 consumed/g soil/d in the order of MW>SW>MG in 0–5 cm. The abundance of pmoA gene copies ranged from 43 × 10 4 /g soil to 13 × 10 4 /g soil and was highest in MW-NT and lowest in MG-CT. Available nitrogen, phosphorus and potassium were higher in 0–5 cm than in 5–15 cm depth. Soil and plant parameters and abundance of pmoA genes correlated significantly and positively with CH 4 consumption rate. No-tillage stimulated CH 4 consumption compared to CT irrespective of cropping system and CH 4 consumption potential was highest in MW and lowest in MG. However, the magnitude of the positive effect of NT towards CH 4 consumption was higher in SW and MG than MW.