Methane consumption by soils of dryland rice agriculture: Influence of varieties and N-fertilization

Growth of three rice varieties (Heera, Dhala Heera and Narendra-118) and th eir relationship with methane consumption was investigated under rainfed (d ryland) condition. Overall methane flux rates ranged between -0.58 to 1.25m g m(-2) h(-1) across varieties, treatments, and dates of measurements. Exce pt for two days when soil was saturated, the soil consumed 0.05-0.58 mg CH4 m(-2) h(-1); these rates were inversely related with soil moisture. N-fert ilization reduced consumption rates. Although all plant growth parameters, except for number of tillers, exhibited relationship with methane consumpti on in control plots, only root porosity did so in fertilized plots. Combina tions of plant growth characteristics explained 74-92% variability in seaso nal CH4 consumption in unfertilized plots. It was concluded that methane co nsumption by dryland soils was influenced by rice variety, soil moisture an d nitrogen fertilization. (C)1998 Elsevier Science Ltd. All rights reserved .