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ARS Home » Research » Publications at this Location » Publication #72613
Title: BUDGETS OF NON-NITROGEN NUTRIENTS IN A HIGH FERTILITY PASTURE SYSTEM

Author
item Owens, Lloyd
item VAN KEUREN, ROBERT - OSU-OARDC
item Edwards, William

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Concern about the impacts of agricultural management on the environment is increasing. Much of the research so far has dealt primarily with nitrogen and phosphorus in row crops. Some attention has been given to the influence of nitrogen fertilization of pastures on water quality. However, few studies have been conducted concerning other nutrients in relation to pasture management. In a multi-year study on a high fertility pasture system near Coshocton, Ohio, it was found that concentrations of non-nitrogen nutrients in both surface and subsurface flow were strongly influenced by the amounts of lime and non-nitrogen fertilizers applied. Concentrations and movement of non-nitrogen nutrients from a pasture system were little influenced by a variation in the cattle management or by a change in nitrogen source from fertilizer to legumes. Therefore, losses of non-nitrogen nutrients from pastures can be regulated by the rates of application of lime and non-nitrogen fertilizer. The results of this research can be used by producers to change the nitrogen management of their pastures, thus lowering the potential contamination by non-nitrogen nutrients of surface or subsurface water.

Technical Abstract: Concentrations and transport of non-nitrogen nutrients in surface runoff and subsurface flow were determined under a high fertility pasture system during a multi-year study. Rotationally grazed grass pastures received 224 kg N/ha annually as NH4NO3 for 5 yrs and had a legume interseeded into the grasses to be the N source during the following 8 yrs. Part of the pastures were grazed during the summer only. Other pastures were used in the winter months with cattle eating fall regrowth and the hay made on that area during the summer. Topsoil pH of 6.5 - 7.0 and available P and K levels of 56 and 336 kg/ha, respectively, were maintained. Concentrations of P, K, Na, Ca, Mg, Cl, and TOC were measured in surface runoff collected from small watersheds with automated samplers and in water from springs draining each area. Nutrient concentrations in both surface and subsurface water were strongly influenced by the amounts of fertilizer and lime applied. The majority of P and K were transported via surface runoff. Th concentrations and transport of P and K were greater during the 8 yrs because of increased rates of application of these fertilizers. Nutrient levels in subsurface flow did not vary greatly on a monthly basis but there were some increases during the span of the study. Concentrations of K and Na changed very little; Mg increased slightly; and Ca and Cl had large increases during the 13 yrs. Increased rates of KCl application during the 8 yrs was a primary cause for the increased Cl levels in the shallow groundwater. Concentrations and transport of non-nitrogen nutrients from a pasture system were little influenced by the summer vs winter management of this study or the N source change from fertilizer to legumes. Application of P and K fertilizers and lime was the major factor of influence.