Seed Yield of Kentucky Bluegrass as Affected by Post‐Harvest Residue Removal¹

Abstract

Field burning of post‐harvest residue has been an established management practice for economical production of Kentucky bluegrass (Poa pratensis L.) seed. Fields not burned soon after harvest usually have poor seed production in the following year. Residue remaining on fields shades, and thereby restricts tiller growth and subsequent seed yield. To explore the hypothesis, polyethylene shade screens which excluded 30 and 67% of sunlight were placed over September field‐burned ‘Baron’ Kentucky bluegrass plants for 75 and 130 days. Other treatments included mechanical vacuum clipping at 2.5, 7.6, and 15.2 cm levels, field burning of residue and no residue removal. The grass was seeded on Thatuna and Naff silt loam series (fine‐silty, mixed, mesic Xeric Argialbolls and fine‐silty, mixed, mesic Ultic Argixerolls, respectively). Tiller numbers from plants where residue was removed to the 2.5, 7.6, and 15.2 cm levels in 1978‐1979 were comparable to tiller numbers from plants shaded at the 30% level. Tiller numbers for plants shaded at 67% were comparable to tiller numbers where residue was removed at 15.2 cm, or where no residue was removed. Leaf and sheath length were generally inversely related to the level of residue removal. Panicle numbers for shading at 67% in 1979‐1980 were comparable to residue removal at 15.2 cm and no removal of residue. Seed yields from artificially shaded plants in 1978‐1979 were 51 to 55% less than yields from plants where residue was not removed. In 1979‐1980, seed yields from shaded plants at the 67% light exclusion for 130 days were 76% of yields from plants of open‐field burn but did not differ from yields from plants where residue was not removed or mechanically clipped to heights of 7.6 or 15.2 cm. It was concluded that reduced Light penetration into the canopy could change plant growth and reduce seed production potential.

Stubble Management Effects on Three Creeping Red Fescue Cultivars Grown for Seed Production

“…Chilcote et al (1974) reported that fall tiller regrowth of creeping red fescue was shorter when straw and stubble were removed by burning. Similar results have been reported in Kentucky bluegrass (Hickey and Ensign, 1983; Ensign et al, 1983). The regrowth height of fall tillers has been shown to be negatively correlated with flowering and yield potential in Kentucky bluegrass (Chastain et al, 1997).…”

Kentucky Bluegrass Seed and Vegetative Responses to Residue Management and Fall Nitrogen

“…The first seed crop is usually harvested 14 to 15 mo after planting, and is produced without prior post‐harvest residue management. Following harvest of the first and subsequent seed crops, post‐harvest residue must be removed from Kentucky bluegrass fields to maintain future seed yields (Ensign et al, 1978) Where post‐harvest residue remained on grass fields, seed yields declined as much as 80%, compared with seed production with open‐field burning (Canode and Law, 1977)…”

Effect of Harvest Processes on the Nutritive Value of Kentucky Bluegrass Residue from Seed Harvest

“…Idaho and Oregon placed restrictions on when, where, and the amount of acreage that can be burned daily based on meteorological models that predict when the atmospheric wind current will best disperse the smoke away from population centers. Several studies evaluated alternatives to burning, but none were as effective as burning in maintaining productive stands and seed yields (5,7). Removing at least 90% of the post-harvest residue maintained stand productivity (seed yield) in non-burn production systems for the first three years of production, but after three years the non-burning residue removal method yielded less than burning (4,5).…”