Analysis of Four Delineation Methods to Identify Potential Management Zones in a Commercial Potato Field in Eastern Canada

Management zones (MZs) are delineated areas within an agricultural field with relatively homogenous soil properties, and therefore similar crop fertility requirements. Consequently, such MZs can often be used for site-specific management of crop production inputs. This study evaluated the effectiveness of four classification methods for delineating MZs in an 8-ha commercial potato field located in Prince Edward Island, Canada. The apparent electrical conductivity (ECa) at two depths from a commercial Veris sensor were used to delineate MZs using three classification methods without spatial constraints (i.e., fuzzy k-means, ISODATA and hierarchical) and one with spatial constraints (i.e., spatial segmentation method). Soil samples (0.0–0.15 m depth) from 104 sampling points was used to measure soil physical and chemical properties and their spatial variation in the field were used as reference data to evaluate four delineation methods. Significant Pearson correlations between ECa and soil properties were obtained (0.22 < r < 0.85). The variance reduction indicated that two to three MZs were optimal for representing the field’s spatial variability of soil properties. For two MZs, most soil physical and chemical properties differed significantly between MZs for all four delineation methods. For three MZs, there was greater discrimination among MZs for several soil properties for the spatial segmentation-based method compared with other delineation methods. Moreover, consideration of the spatial coordinates of the data improved the delineation of MZs and thereby increased the number of significant differences among MZs for individual soil properties. Therefore, the spatial segmentation method had the greatest efficiency in delineation of MZs from statistical and agronomic perspectives

From aluminium industry waste to soil amendment for cash crops and fertiliser for lowbush blueberry

Rio Tinto's Aluminium division operates smelters in Canada, primarily in the Saguenay–Lac-Saint-Jean region in Quebec, where its entire aluminium production line generates two specific calcium sulphate (CaSO4) by-products. The aqua-catalysed hydrated lime (CHAC) is the by-product of the sulphur scrubber at the coke calciner plant, and the neutralised synthetic anhydrite (SA) is derived from the industrial processes of the chemical transformation of calcium fluoride into aluminium fluoride, which is used in the manufacture of electrolysis bath for aluminium production. Since 2015, several research projects have been developed at the Rio Tinto-Arvida Research and Development Center, in collaboration with local universities, to evaluate the potential of these by-products as a liming agent for various agroecosystems and as a certified calcium-rich fertiliser for lowbush blueberries, our regional flagship. The aim of this paper is to present the research and development programme that has led to the agricultural recycling of these two by-products