University of Vermont

Soil Nutrient and Manure Research at The University of Vermont Yield And Quality Of Cool Season Grass As Affected By Semi-Solid Manure And Fertilizer N Applications

Sid Bosworth, Bill Jokela and Jeff

Duration: 1992 - 1995

The application of dairy manure on cool season grasses is a common practice in Vermont, yet little is known concerning the utilization of manure nutrients in this situation. A three year trial was conducted on a dairy farm in Bakersfield, VT to evaluate the impact of semi-solid dairy manure plus fertilizer N on the yield, forage quality, and mineral uptake of a mixed grass sward as well as changes in soil test phosphorus (P) and potassium (K). The study site was a 25 year old stand of mixed grass species predominantly orchardgrass. Manure treatments consisted of a control (no manure) and semi-solid dairy manure as a single application after first cut (1X, 8 - 11 tons/acre/yr) or three applications per year (3X, 28 - 32 tons/acre/yr). Nitrogen (N) treatments consisted of ammonium nitrate at rates of 0, 45, 90, and 135 lb N/a in 1992 and 0, 60, 120, and 180 lb N/a in 1993, split evenly in 3 applications (early spring, after 1st cut, and after 2nd cut).

Yield was increased by both manure and N treatments and percent crude protein was increased by manure and N in 5 out of six cuttings. Our results suggest that a grass farmer could optimize returns over costs by combining manure applications and supplemental N. From this combination, the manure provides some N and all the P and K needs depending on the manure rate and P and K needs of the crop. Since much of the N in surface applied manure is lost due to volatilization, the fertilizer N on grass is important to optimize yields. In this study, the 3X manure application supplemented with 90 to 120 lb of N/acre/year gave the best return over treatment costs; however, this resulted in very high P loading, whereas the 1X manure treatment with 120 lbs of supplemental N gave only slightly lower returns and resulted in a balance of P applied to P removed from the crop.

See Optimizing Manure and Nitrogen Fertilizer Applied to Grass Hay Crops for more detail

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Last modified May 26 2004 12:55 PM

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