Reduced Irrigation Amounts on Durum Wheat and Barley Production in Northwest North Dakota.

Water for irrigation is limited, resulting in a critical need to improve water use efficiency. We investigated using reduced irrigation amounts on durum wheat and barley in northwestern North Dakota for six years. Four different water amounts were tested. The greatest amount applied to each crop was determined by using the “checkbook” method to maintain the soil water content at field capacity. The other irrigation amounts were 67%, 33%, and 0% of this amount. We evaluated crop performance by measuring grain yield, protein, and test weight. The effect of reduced irrigation on crop performance varied from year to year due to differences in seasonal rain amounts and air temperatures. Durum was affected more by reduced irrigation than was barley. Of the three measured characteristics, reduced irrigation influenced yield the most and test weight the least. Reducing irrigation by one-third reduced durum yields in two of six years but did not reduce barley yields. Grain protein of both crops increased one year but were unaffected the other five years. Grain test weight of both crops was not affected. Reducing irrigation by two-thirds reduce durum yield four of six years and reduced barley yield three of six years. Grain protein of wheat was increased three years and unaffected three years; barley protein was increased only one year and unaffected the other years. Grain test weight of durum was reduced two years; barley test weight was reduced one year. Not irrigating had a significant effect on both crops: durum yield was reduced all six years; barley yield was reduced five years. Durum protein was increased five years, barley protein was increased three years. Test weight of both crops was reduced three years. Our findings suggest that reducing irrigation by as much as one-third will not significantly reduce the yield and quality of barley or the quality of durum, however, durum yield may be significantly reduced some years.