THE ECONOMICS, ENERGY USE EFFICIENCY, AND GREENHOUSE GAS EMISSIONS OF HIGH AND LOW INPUTS USED IN AGRICULTURE: A WHEAT-PEA ROTATION STUDY

In recent years, alternative farming practices have received considerable attention to reduce use of fossil fuels, enhance efficiency of nitrogen fertilizer, improve pest managements, and adopt conservation tillage practices. The objective of this study was to determine energy efficient cropping systems and management methods, which provide economic benefits, lower fossil fuel consumption, and reduce emissions of greenhouse gases. Data collected during a 5-year study were used to examine the economic, energy and GHG performance of a wheat and pea rotation with variable rates of fertilizer and herbicide in a high- and low-disturbance seeding-system. We also compared actual measurement of N2O with the estimates of soil nitrous oxide emission based on IPCC approach to examine if the differences between these two figures are significant. Results suggest that lower application of fertilizer under the low-disturbance seeding-system provides better yields, net benefits, and net carbon fixed than the high-disturbance system for both crops. Environmental-economic indicators revealed that, overall, lesser use of fertilizer (50 % to 75 % of recommended rates) with the low-disturbance seeding-system was preferable. Results also indicated that N2O emission computed from IPCC was significantly higher than actual soil N2O emission measured in the sites. 1