About Us | Help Videos | Contact Us | Subscriptions
 

Abstract

 

This article in AJ

  1. Vol. 94 No. 4, p. 840-850
     
    Received: June 6, 2001


    * Corresponding author(s): hdk3@psu.edu
 View
 Download
 Alerts
 Permissions
Request Permissions
 Share

doi:10.2134/agronj2002.8400

Species Contribution to Seasonal Productivity of a Mixed Pasture under Two Sward Grazing Height Regimes

  1. Maria Carlassare and
  2. Heather D. Karsten *
  1. Dep. of Crop and Soil Sci., 116 ASI Bldg., The Pennsylvania State Univ., University Park, PA 16802

Abstract

Mixed pastures often include tall and short plant species that respond differently to grazing intensity. We evaluated the effect of two rotational grazing height regimes on species productivity and availability to animals. We compared tall and short grazing height regimes within current recommendations in a Pennsylvania pasture dominated by orchardgrass (Dactylis glomerata L.) and Kentucky bluegrass (Poa pratensis L.) and grazed by cow–calf (Bos taurus) pairs. Orchardgrass height defined grazing regimes. Tall pastures were grazed from 27 cm down to 7 cm and short pastures from 20 to 5 cm from April 1998 to May 2000. Before each grazing period, herbage was sampled at grazing regime residual heights of 7 or 5 cm (herbage harvested) and at ground level (herbage mass). Species harvest index (HI) was calculated as the ratio of herbage harvested over live herbage mass to compare herbage availability among species and grazing regimes. In tall vs. short pastures, there was 50% more herbage harvested at each grazing event and 23% more total herbage harvested over the 2.3-yr experiment. Higher production was mainly due to orchardgrass (51% more herbage harvested in tall vs. short pastures) and tall legumes. Herbage harvested decreased during dry, warm periods independent of season, with bluegrass decreasing most. Orchardgrass HI was highest, quackgrass (Elytrigia repens L.) and bluegrass HIs were intermediate, and white clover (Trifolium repens L.) HI was lowest. Small differences in grazing height recommendations had significant effects. Tall grazing heights increased productivity and favored tall-growing species that had higher harvest indices.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2002. American Society of AgronomyPublished in Agron. J.94:840–850.