ASABE Technical Library - Abstract

Abstract. Wheat is the second most irrigated crop in Kansas but the area under irrigated wheat is declining. This reduction is due to wheat being less profitable under irrigation compared to other crops like corn. However, with declining irrigation capacity there is a need to extend the irrigation season over both warm and cool growing seasons. Rotating winter wheat with summer crops also provides agronomic benefits such as weed, pest, and disease control. Winter wheat is the most adopted cool-season crop in the Central Great Plains. Thus, there is an urgent need to increase water productivity of wheat under limited irrigation to enhance profitability and sustainability of limited irrigation cropping systems. A study was conducted to evaluate wheat yield, protein and test weight response to limited irrigation in southwest Kansas. Preliminary results from 2014 indicate that the effect of irrigation capacity on wheat yield, protein content, and test weight was significant (p-value<0.0001). There was no significant difference between treatments that received a fluxapyroxad and pyraclostrobin based fungicide at Feekes 6 and those that did not (p-value>0.2). The effect of interactions between irrigation capacity and fungicide application on yield was also not significant (p-value>0.2). Protein content increased with decrease in irrigation while test weight was highest at high water level. Under full irrigation, wheat crop water use (ETc) was 533 mm. Wheat responded linearly to irrigation with irrigation water use efficiency ranging from 0.94 to 1.22 kg m^-3. Wheat yield versus ETc production function also had linear relationship with an ETc threshold of 152 mm and water productivity of 0.00923 Mg ha-mm^-1. These results indicate irrigation affects wheat yields and that applying a fluxapyroxad and pyraclostrobin based fungicide at Feekes 6 had no significant effect on yield compared to the control. More research is needed to quantify the effect of fluxapyroxad and pyraclostrobin based fungicides applied at Feekes 6 on wheat yield and water use efficiency.