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Fresh versus Field-Cured Grass Quality, Mineral, and Nitrate Concentration at Different Nitrogen Rates
- Singer, Jeremy W.
- Crop science 2002 v.42 no.5 pp. 1656
- Dactylis glomerata, Bromus inermis, mineral content, nitrogen content, nitrogen, nutrient availability, nitrate nitrogen, crude protein, application rate, dietary fiber, ammonium nitrate, New Jersey
- Determining the extent of change in fresh versus field-cured grass hay quality, mineral, and NO-N concentrations under rain-free conditions provides valuable information to hay producers. The objectives of this research were to evaluate the effect of fresh vs. field-cured forage on crude protein (CP), neutral detergent fiber (NDF), total digestible nutrients (TDN), P, K, Ca, and NO-N concentrations of orchardgrass (L.), smooth bromegrass (Leyss.), and timothy (L.), and to determine if interactions with N rate exist. At the low N rate in 1999 and 2000, orchardgrass CP in fresh and field-cured forage, NDF, and TDN concentrations were different. Orchardgrass P and K concentrations were lower in field-cured compared with fresh forage, but differences were inconsistent across N rates. In contrast, smooth bromegrass K (23 vs. 27 g kg) and Ca (4.3 vs. 6.2 g kg) concentrations were greater in field-cured compared with fresh forage in 1999 across N rates. Tissue NO-N concentration was greater in field-cured orchardgrass at all N rates and at the low N rate in smooth bromegrass in 1999. Interactions between N rate and fresh vs. field-cured smooth bromegrass were detected for all variables in 1999 and orchardgrass K concentration in 2000. These results demonstrate that changes in grass quality, mineral, and tissue NO-N concentrations occur under rain-free field curing conditions. Consequently, forage scientists conducting research on grass hay quality indices and mineral content should sample subsequent to field-curing to provide accurate results.