Grazing Winter Wheat: II. Height Effects on Response to Production System

Abstract

AbstractCurrent wheat (Triticum aestivum L.) cultivars are shorter and have more lodging resistance than previous cultivars. Thus, the reduction in height and lodging caused by grazing may be less desirable now than previously. The objective of this research was to compare the growth and yield response to grazing of hard red winter wheat cultivars that vary in height and other traits. Siouxland, a tall cultivar, Vona, a semidwarf, and Q588, a short hybrid, were grown 2 yr in irrigated grain and grazed production systems. In 1986, Siouxland yielded the same in grain and grazed systems and was insensitive to grazing termination date except that severe grazing after 15 March reduced yield 20%. In contrast, Vona and Q588 yielded less in all grazed systems than in the grain system and were more sensitive to grazing termination date than Siouxland because they had lower leaf area and headed earlier. Grazing until 29 March reduced yield of Vona and Q588 two to five times more than Siouxland. In 1987, grazing increased yield of Siouxland and Vona by 41 and 23%, respectively, while reducing yield of Q588 by 8% in a lodging‐prone environment (330 mm spring irrigation) because Siouxland and Vona lodged without grazing and Q588 did not. With 130 mm spring irrigation, lodging was less and all cultivars responded similiarly to grazing. In conclusion, grazing is more likely to reduce the yield of a lodging‐resistant short cultivar with high yield potential than a tall cultivar that is susceptible to lodging.