|BELESKY, DAVID - West Virginia University|
|GODWIN, HARRY - Retired ARS Employee|
Submitted to: International Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2015
Publication Date: 2/20/2015
Publication URL: http://handle.nal.usda.gov/10113/61415
Citation: Halvorson, J.J., Belesky, D.P., Godwin, H.W. 2015. Seedling performance associated with live or herbicide treated tall fescue. International Journal of Agronomy. DOI:10.1155/2015/841213.
Interpretive Summary: Tall fescue is an important forage grass that typically grows in association with a fungus thought to be advantageous to the plants but which may negatively impact livestock, affect soil conditions, and inhibit the establishment of legumes. We compared seedling performance of three legumes and three cultivars of tall fescue with different fungal associations, grown in soil from living and killed fescue sods. Contrary to our expectations legume seedling root growth proved less successful in killed than live fescue soil especially for small-seeded white clover. We also found seasonal patterns of seedling growth with evidence for inhibition of seedlings in killed soil most strongly expressed in soil collected after the growing season compared to spring. These patterns suggest establishing legumes or fescue cultivars is not improved by first killing the existing fescue sod, seedling performance can exhibit significant inter-seasonal variation, related only to soil conditions. If the results from the microcosm work can be verified under field conditions, avoiding the use of herbicides complies with and facilitates organic agricultural practice and reduces expenses and environmental concerns in conventional production systems.
Technical Abstract: Tall fescue is an important forage grass which can host systemic fungal endophytes. The association of host grass and endophyte is known to influence herbivore behavior and host plant competition for resources. Establishing legumes into existing tall fescue sods is a desirable means to acquire nitrogen and enhance the nutritive value of forage for livestock production. Competition from existing tall fescue typically must be controlled to ensure interseeding success. We used a soil-on-agar method to determine if soil from intact, living (L), or an herbicide killed (K) tall fescue sward influenced germination and seedling growth of three cultivars of tall fescue (E+, MaxQ, and E-) or legumes (alfalfa, red clover, and white clover). After 30 days, seedlings were larger and present in greater numbers when grown in L soil rather than K soil. Root growth of legumes (especially white clover) and tall fescue (especially MaxQ) were not as vigorous in K soil as L soil. While shoot biomass was similar for all cultivars of tall fescue in L soil, MaxQ produced less herbage when grown in K soil. Our data suggest establishing legumes or fescue cultivars may not be improved by first killing the existing fescue sod and seedling performance can exhibit significant interseasonal variation, related only to soil conditions.