Advances in Nutrient Management of Grass Seed Crops

Nutrient management of herbage grass seed crops is just as complex as for other agricultural crops when the aim is to optimise economic net return and minimise environmental impact. The use of economic optimum nitrogen (N) application rate (ECO-N) defined as the N application rate that maximise net return for the seed grower is an easy and applicable method for seed growers. Besides the economic advantages of implementing ECO-N there is an additional positive environmental effect as ECO-N is lower than the N rate that maximises seed yield and a lower N application rate will concomitantly lower the potential risk of N leaching. Another interesting but not yet implemented method for N management in grass seed production is the use of canopy reflectance and calculation of crop index or using data for multivariate data analysis to measure plant N status and predict seed yield. The use of canopy reflectance in combination with critical N dilution curves is very interesting and promising. The practical way of using these methods would be to measure plant N status, compare estimated plant N status with critical N status and intervene by applying more N if necessary. Grass seed production is a biological complex process and focusing on N will only succeed if other nutrients, water and the seed yield potential are not a limiting factor for the final seed yield