Alberta Soil Science Workshop Tour, Lethbridge area, July 2013.
Dr. Ross McKenzie introduces why variable rate fertilizer research is needed in Western Canada. Prairie soils are quite variable in undulating topography. Organic matter, pH, even Nitrogen (N) and Phosphorus (P) vary from top of slope, mid-slope and bottom of slopes. In spite of the fertilizer industry's attention to variable rate fertilizer equipment and fertilizer recommendations, those recommendations are not very good and often contradictory. Alberta Agriculture has 5 plots across Alberta covering different soils zones: covering the dark brown soil zone (irrigated and non-irrigated), thin black and black soil zone.
Doon Pauly describes the variability of this specific dryland site (O.M from 3.2% at top and 5.3% at bottom; pH and N and P also vary). Phosphate levels are higher at the bottom of the slope. The crop rotation on the plots was flax, canola and then two years of durum wheat. A full range of fertilizer treatments, for N with and without P and with and without K and with some micronutrients. Their general recommendation for fertilizer application for the rest of the field was 60 units of N on the lower slope, 90 units of N with a low P rate on the midslope and 90 units of N and a high rate of P on the top of the slope. Sampling fields for variable fertilizer applications by dividing the field into 3 areas based on topography top, mid and bottom of slope is their suggestion.
The rates of nitrogen needed for fertilizer are where the advice ranged the most. It was also noted that the land form is significant in determining yield because of moisture content. Dr McKenzie shows the range of soils on the plots looking at soil cores. And he then describes the soil parameters that are measured during the four years of the research. pH is highly variable and likewise organic matter. The phosphorus response on the upper slope was quite strong. And he summarizes the response of the various crops at different slope positions to various nutrients. Canola had a response to sulphur at the upper slope position. Micronutrient responses can't be seen (except for copper).
Rob Dunn talks about conservation tillage and the benefits for this particular southern Alberta field. Doon Pauly describes how soil moisture varies by slope position. P and Zn tend to be low on the top of the slopes. And then he describes the N response at the different positions up the slope.
The speakers were Dr. Ross MacKenzie (now retired), Doon Pauly, both Argonomy Research Scientists, and Rob Dunn, an Agriculture Land Management Specialist, all with Alberta Agriculture and Rural Development, Lethbridge.
