PRODUCTIVITY OF INTERMEDIATE WHEATGRASS AS INFLUENCED BY DATE OF INITIAL CUTTING, HEIGHT OF CUTTING, AND N FERTILIZER

Abstract

The interactions of three dates of initial cutting followed by one or two subsequent cuttings, three heights of cutting, and four fertilizer treatments on the dry matter yield, crude protein content, and crude protein yield of intermediate wheatgrass (Agropyron intermedium (Host.) Beauv.) were studied on irrigated land for 2 yr. Cutting on 15 June during the shot blade stage resulted in severe summer killing. Variation in height of cutting and N fertilizer levels resulted in differences in annual yields. On the basis of the 2-yr mean yield, however, these differences were masked by interaction of these factors with years. Crude protein content of the forage at cut 1 decreased with the deferment of the first cut, was not influenced by height of cutting, but increased with increases in N fertilizer. The yield of crude protein increased with increasing levels of N fertilizer and showed significant interactions for year × date of initial cutting × fertilizer and years × date of initial cutting × height of cutting. Split applications of N fertilizer showed no advantage over a single spring application in either year.