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Maximizing Timothy Forage Yield and Quality by Balanced Nitrogen, Phosphorus, and Sulfur Fertilization

Malhi, Sukhdev Singh, Coulman, Bruce, Schoenau, Jeffrey John
Agronomy journal 2009 v.101 no.5 pp. 1182-1189
Phleum pratense, forage grasses, crop yield, forage quality, fertilizer application, nitrogen fertilizers, phosphorus fertilizers, sulfur fertilizers, fertilizer rates, crude protein, nitrogen, acid detergent fiber, neutral detergent fiber, plant nutrition, mineral content, phosphorus, sulfur, soil fertility, nutrient-nutrient interactions, nitrate nitrogen, Saskatchewan
A 3-yr (2005–2007) field experiment was conducted on a Gray Luvisol (Typic Cryoboralf) loam near Star City, SK, Canada, to determine the influence of single and combined annual applications of N, P, and S fertilizers on timothy (L.) forage dry matter yield (DMY), quality [concentration of crude protein (CP), nitrate N, acid detergent fiber (ADF), neutral detergent fiber (NDF), total P, and total S] and N, P, and S uptake, and residual nitrate N, extractable P, and sulfate-S in soil. The highest DMY and nutrient uptake were obtained when N and S were applied together. Concentration of CP and total P in forage increased with application of N alone, but decreased with the addition of S along with N. Concentrations of nitrate N in forage (< 0.011 g nitrate N kg) were much lower than those considered potentially toxic (>2.26 g nitrate N kg) to livestock. Concentration of ADF and NDF in forage increased with N application. Concentration of total S in forage increased with S application, but decreased with N application. Residual soil nitrate N in 0 to 60 cm depth increased with N application, but decreased when S was applied in combination with N. Residual soil extractable P in 0 to 15 cm depth increased with P fertilizer, but decreased when N and/or S were applied in combination with P. Residual soil sulfate-S increased with S fertilization, but usually decreased when S was applied in combination with N. In conclusion, combined applications of N and S fertilizers produced maximum forage yield and nutrient uptake of timothy, and reduced accumulation of nitrate N in this soil lacking in these nutrients.