Defoliation Effects on Production and Nutritive Value of Four Irrigated Cool‐Season Perennial Grasses

Abstract

Irrigated cool‐season perennial grasses are becoming an important complementary forage source in the Central Plains. A study was conducted to evaluate effects of clipping stubble height on dry matter (DM) production, growth rate, tiller density, and nutrient content of smooth bromegrass (Bromus inermis Leyss.) orchardgrass (Dactylis glomerata L.), creeping foxtail (Alopecurus arundinaceus Poir.), and meadow bromegrass (Bromus riparius Rhem.) under irrigated conditions on a Cozad silt loam soil (fine‐silty, mixed, mesic Typic Haplustoll). Clipping treatments (35‐cm canopy height cut to 7‐, 14‐, and 21‐cm stubble heights) were applied to monoculture plots of these species for two growing seasons in a randomized complete block design. Stubble height effects on total DM production varied by species (P < 0.05). For orchardgrass and meadow bromegrass, DM production was similar at the 14‐ and 21‐cm stubble heights (22.22 Mg ha−1), but significantly greater than production at the 7‐cm stubble height (14.03 Mg ha−1). In contrast, DM production of smooth bromegrass and creeping foxtail was significantly greater at each successively higher stubble height. End‐of‐season tiller density of the 7‐cm stubble height treatment was about 50% of the tiller density of the 14‐cm and 21‐cm stubble height treatments. Stubble height effects on nutritive value varied by species and clipping period. Stubble height did not affect crude protein (CP) content of creeping foxtail, but CP was lower at the 7‐cm height for the other species. Defoliation strategies that maintain adequate residual herbage will optimize production of nutrient dense forage and maintain tiller density.

Persistence and productivity of orchardgrass and orchardgrass/alfalfa mixtures as affected by cutting height

“…Cutting to 5 cm resulted in the highest yields in this system for both pure orchardgrass and the orchardgrass/alfalfa mixture over 3 years. It is clear that harvesting to a low cutting height will remove a greater proportion of aerial biomass and this has been shown in several experiments with orchardgrass where yields were greater at lower cutting heights (Brink et al., ; Mitchell, ; Raese & Decker, ; Sprague & Garber, ; Volesky & Anderson, ). Low cutting heights, however, remove a greater proportion of photosynthetic leaf area and non‐structural carbohydrates (Ward and Blaser, ).…”

“…Persistence of perennial grasses is defined as the ability of each tiller to produce on offspring annually such that members of the population replace themselves (Edwards & Chapman, ). Many studies use either tiller density (Raese & Decker, ; Volesky & Anderson, ) or per cent ground cover (Brink et al., ; Smith, Jaques, & Balasko, ) to determine the effects of various treatments on the persistence of swards. It is also known, however, that tiller density alone is not always related to the yield of swards (Davies, ).…”

Aboveground Net Primary Productivity and Cover of Vegetation Exposed to Various Disturbances in Arid Argentina

“…Volesky et al (2010) reported that warm-season grasses usually have less total annual production because they do not actively grow during as much of the growing season as do coolseason grasses in Nebraska. These authors also considered that warm-season grasses cannot be made to grow at all during early spring and fall when soil and air temperatures are cool.…”

Defoliation frequency effects on winter forage production and nutritive value of different entries of Agropyron cristatum (L.) Gaertn

“…Comparisons among studies can be difficult because of the differences in species, intensity and frequency of defoliation. Furthermore, responses are likely to change across climates, soil types, soil water and soil fertility conditions (Volesky and Anderson, 2007). For these reasons defoliation recommendations in general are difficult.…”