Agronomic and Economic Assessment of Variable Rate
Determine the agronomic information required to choose the optimum nutrient rates and assess the economic the benefits of variable rate fertilization.
IPNI-1995-CAN-SK17
30 Mar 1999
1998 Annual Interpretive Summary
Agronomic and Economic Assessment of Variable Rate Fertilization, 1998
Farmers in the Canadian Prairies are interested in variable rate fertilizer application, but don’t know the best way to manage it. The rolling topography typical of the prairies lends itself to variable rate technology because the re-distribution of water results in variable crop yields between upper, mid and lower slope soils. The researchers in this study have developed tools using digitized black and white aerial photos to separate soils into management units based on topography. These management units have been tested with wheat and canola using prescription fertilizer applications for 3 years.
Sub-optimal growing season conditions limited yields in 1998, but small differences in fertilizer response in the various management units occurred. Both canola and wheat had small yield increases in mid and lower slope positions when N rates were increased and canola yields increased in response to adding more P in the lower slope positions. Results have been variable in this study, depending on the growing season, but generally they shown that the wetter, lower slope soils need more N and P than drier soils in upper slope positions. SK-17