Estimation of economic and environmental potentials of variable rate versus uniform N fertilizer application to spring barley on morainic soils in SE Norway

Abstract

Spring barley was grown for 4 years (2001)(2002)(2003)(2004) in field trials at two sites on morainic soil in central SE Norway, with five N level treatments: 0, 60, 90, 120 and 150 kg N ha -1 . Regression analyses showed that a selection of soil properties could explain 95-98% of the spatial yield variation and 47-90% of the yield responses (averaged over years). A strategy with uniform fertilizer application of 120 kg N ha )1 (U N120 ) was compared with two variable-rate (VR) strategies, with a maximum N rate of either 150 kg N ha )1 (VR N150 ) or 180 kg N ha )1 (VR N180 ). These strategies were tested using either Norwegian prices (low price ratio of N fertilizer to yield value; P N /P Y ), or Swedish prices (high P N /P Y ). The VR N180 strategy had the highest potential yield and net revenue (yield value minus N cost) at both sites and under both price regimes. Using this strategy with Norwegian prices would increase the profit of barley cropping as long as at least 40 and 31% of the estimated potential increase in net revenue was realized, respectively. Using Swedish prices, uniform application appeared to be as good as or even better economically than the VR methods, when correcting for extra costs of VR application. The environmental effect of VR compared with uniform application, expressed as N not accounted for, showed contrasting effects when using Norwegian prices, but was clearly favourable using Swedish prices, with up to 20% reduction in the amount of N not accounted for.

Environmental life cycle assessment of cereal and bread production in Norway

“…We hope, however, that more refined methods for estimating such emissions will be available in the near future, so that we may visualize possible positive effects of alternative management methods (e.g. precision agriculture; Korsaeth & Riley, 2006), which may reduce gaseous N-emissions by increasing the utilization of N, irrespective of fertilizer level.…”

Comparison of the variable potassium fertilization on light and heavy soils

“…adjusted to the current content) use of the mineral fertilizers. The variable rate fertilization can significantly reduce the expenses associated with the fuel and fertilizers consumption in the areas with the soluble forms of nutrients being sufficient for the optimal crop production [14][15][16][17]. Another important aspect offered by the VRF technology is an essential reduction of the environmental burden resulting from an extensive use of the mineral fertilizers [18][19][20].…”

Economic and environmental optimization of nitrogen fertilizer recommendations for cereals in Norway

“…This figure would doubtless be lower in grassland and it may in future be reduced by the adoption of precision fertilization (Korsaeth and Riley 2006). Catch cropping with ryegrass has a potential to reduce soil mineral N in autumn after cereals (Breland 1996).…”