Skip to main content
ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #103007
Title: EARLY SEASON NITROGEN FOR GRASS-CLOVER PASTURES IN THE NORTHEASTERN USA

Author
item Stout, William
item Weaver, Stefan

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2000
Publication Date: 10/20/2001
Citation: Stout, W.L., Weaver, S.R. 2004. Early season nitrogen for grass-clover pastures in the northeastern usa. Agronomy Journal. 93(5):1000-1005.

Interpretive Summary: To maintain farm profitability, a growing number of dairy farmers in the Northeast USA are using pastures to provide the bulk of the feed during grazing season. However, grass/clover pastures that rely on biologically fixed N are often N deficient in the spring. To overcome this period of N deficiency, researchers in the United Kingdom and New Zealand have developed programs of early season N applications to grass/clover pastures Because the benefit of such N applications is greatest when temperature is low, it should also benefit grass/clover swards in the colder climate of the Northeast USA. We measured the effect of early season N fertilization on an orchardgrass/white clover pasture. With an application 40 pounds per acre on nitrogen, we were able to increase early season yields on the orchardgrass/white clover pasture by about 20%, without reducing the amount of clover in the pasture. It is important for the sustained production of the grass/clover pasture sward and the nutrition of the grazing animal to maintain the clover portion of the pasture sward. This research gives farmers a management option that can help them extend the grazing season earlier into the spring.

Technical Abstract: To maintain farm profitability, a growing number of dairy farmers in the northeast USA are using pastures to provide the bulk of the feed during grazing season. However, grass-legume pastures that rely on biologically fixed N, are often N deficient in the spring. To overcome this period of N deficiency, researchers in the temperate maritime climates of the UK and NZ Zhave developed programs of early season N applications to grass/clover pastures. Because the benefit of such N applications is greatest when temperature is low, it should also benefit grass/clover swards in the temperate continental climate of the northeast USA. The effect of early season N fertilization (0, 22.4, 44.8, and 89.6 kg ha-1) was measured on an orchardgrass/white clover sward managed to three sward heights (15, 22.5, and 30 cm). Increasing N fertilization and target sward harvest height (TSHH) generally increased the grass harvest and reduced the clover harvest from the sward. However, by the end of the growing season, the clover harvest from the fertilized treatments was identical to that from the unfertilized treatments. Early season dry matter (DM) yields on mixed grass/clover pasture could be increased by about 20%, with an application of about 45 kg N ha-1. Also, maintaining a 15-cm TSHH would maximize the clover fraction in the sward.