Forage Yield and Quality of Oat Cultivars with Increasing Rates of Nitrogen Fertilization
- M. Collins ,
- M. A. Brinkman and
- A. A. Salman
Forage yield and several quality parameters of oat (Avena saliva L.) have been addressed in the literature, but the effect of N fertilizer rate on forage yield and quality of oat cultivars, and the possibility of cultivar by N interactions, has received little attention. The objective of this study was to evaluate oat cultivar responses to N fertilization when harvested as forage at heading. Nine adapted oat cultivars ranging from early to late in heading date were grown in four field environments from 1982 to 1984 with five N application rates (0, 28, 56, 84, and 112 kg ha−1). Nitrogen application rates up to 84 or 112 kg ha−1 increased forage yield and increased N concentration in two of three environments. Increasing N application rate increased neutral detergent fiber (NDF) 46 g kg−1 in one environment but decreased it slightly otherwise. In three of four environments, forage yield at heading increased (r2 = 0.66−0.94) linearly with later heading date. Nitrogen concentration generally decreased and NDF, acid detergent fiber, and acid detergent lignin concentrations increased with later heading date. The difference in NDF between the earliest and latest cultivars could affect forage utilization by affecting forage intake. In situations where high quality is important, early maturing oat cultivars might be preferable because they produce higher quality forage. Early harvest would also alleviate competition with an underseeded perennial legume earlier in the season. Application of 84 to 112 kg ha−1 of N produces maximum yields and increases N concentration with generally small effects on fiber concentrations and without increasing lodging.
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