Using cultivated organic soil depth to form soil conservation management zones

Abstract

Cultivated Organic soils in Montreal's southwest plain are the most productive soils in the province of Quebec. After their initial drainage to enable farming, Organic soils are susceptible to many forms of degradation and soil loss. In this study, we characterized the physical, chemical, and pedological properties of 114 sites from five peatlands to form soil conservation management zones. We attempted to use the maximum peat thickness (MPT) as a soil degradation proxy. The MPT can be defined as the thickness of the layer of peat until coprogenous or mineral materials are reached. The latter are undesired growing media and are not considered in MPT calculation. A series of multivariate analysis of variance indicated that MPT was moderately related to soil degradation (optimal model's Pillai's trace = 0.495). Three soil degradation groups were defined, separated by two MPT thresholds: 60 and 100 cm. When looking at 17 different depth-property combinations, shallower sites (MPT < 60 cm) showed signs of soil degradation significantly higher than sites with an MPT above 60 cm. The second threshold was proposed for practical purposes. Then, these thresholds were used to separate the study area into spatially distinct management zones. Important spatial contrasts were found. This supports the theory that precision agriculture techniques are needed to target fields to optimize soil conservation interventions. The relationship between the MPT and soil degradation should be further explored to account for other degradation factors, and to better identify degraded soils and soils at risk.

Vegetable Response to Added Nitrogen and Phosphorus Using Machine Learning Decryption and the N/P Ratio

“…Peat thickness less than 60 cm shows signs of soil degradation [38]. Soil thickness and quality may vary widely [39]. Peat thickness and the presence of the humus illuviation layer could be documented in future studies.…”

“…On the other hand, crops can be affected locally by other phenomena such as wind erosion, excess water, splash and rill erosion, surface sealing, and pest attacks. Precision agriculture could delineate soil management zones to account for limiting factors [39,40].…”

Mapping the maximum peat thickness of cultivated organic soils in the southwest plain of Montreal

“…Moreover, the accuracy was not sufficient to predict at which depth tile drainage could be installed or if soil conservation MPT thresholds for management are reached (for details, see Deragon et al, 2022).…”

Improving a regional peat thickness map using soil apparent electrical conductivity measurements at the field-scale

“…Recently, peat thickness maps were proposed as a tool for monitoring soil degradation and for defining management zones (13,14). This approach also considered the presence of another organic layer, sometimes found between peaty and mineral layers: the gyttja or limnic layer.…”

“…This gelatinous material has been described in many soil classification systems (15)(16)(17)(18)(19) but is seldom mapped at a regional-scale (20,21). In an agricultural context, this layer can pose management problems to the farmer due to its high salinity, imperviousness, and reduced drainage capacity when found close to the surface (3,13). When growing crops, such as leafy vegetables, potatoes, carrots, and onions, the issues caused by limnic layers may be problematic, and sometimes not cultivable, and hence, there is a need to better its spatial distribution.…”