Effects of tillage systems and planting methods on water use efficiency, carbon dioxide emission from soil and wheat yield

Water scarcity challenge and the high rate of population growth means food production needs to be increased, therefore using proper management practices which can improve water use efficiency (WUE), increase grain yield and reduce carbon dioxide emission from soil, seem to be necessary. In this research, effects of tillage systems and planting methods on water use efficiency, carbon dioxide emission from soil and wheat yield was studied at Agricultural Science and Natural Resources University of Khuzestan located in North of Ahwaz county in 2018-19. The study was conducted using a split complete randomized block design with 3 replications. Tillage at two levels including conventional tillage system (moldboard plow followed by offset disc) and minimum tillage system (combination tillage implement) as main factor and planting methods including flat and raised bed planting methods considered as sub factor. The results indicated that tillage systems and planting methods had a significant effect on water use efficiency at 5% and 1% levels, respectively. The results, also, showed that interaction of tillage systems and planting methods had a significant effect on water use efficiency at 5% level. The results related to yield showed that planting methods had significant effect on wheat yield, while effect of tillage systems and their interaction on wheat yield was not statistically significant. Minimum tillage significantly reduced carbon dioxide emission from soil compared to conventional tillage at 5% level. Although conventional tillage had a lower soil cone index at the beginning of wheat cropping season compared to minimum tillage, over time, soil cone index was approximately the same for both tillage levels. Considering the interaction effect, minimum tillage-raised bed planting treatment with a grain yield of 5426 kg/ha, water use efficiency of 1.13 kg/m3 and carbon dioxide emission of 13.33 kg. ha-1.day-1 was suggested as the best system for the studied region.