Soil properties in northern temperate pastures do not vary with management practices and are independent of rangeland health

Abstract

Studies examining the influence of disturbance and management history on pasture soils across a large sampling area are uncommon. We report on the soil properties found in 102 northern temperate pastures sampled in central Alberta, Canada, and relate these attributes to ongoing pasture management practices compiled from producer surveys and aboveground measures of rangeland health (RH). Tame pastures, typically seeded to introduced forages, were associated with higher soil fertility (total carbon, nitrogen, and organic matter) than semi-native grasslands, which were associated with coarse-textured soils. Soil properties remained independent of most grazing and pasture management practices, including the grazing systems, class of livestock, fertilization, and stocking rate. However, manure application, often combined with harrowing, was associated with improved soil fertility and increased electrical conductivity (salinity). Soils with a fire history reported by land managers, largely in the Boreal natural region, were characterized by a greater soil C:N ratio. Soil surface properties (litter cover, litter depth, and bare soil) were responsive to grazing management, with growing season and year-round grazing associated with a thinner litter layer having less cover, and bare ground twice as high under continuous grazing compared with pastures rotationally grazed. Further, variation in soil surface cover was associated with contrasting RH classes (healthy, healthy with problems, and unhealthy), whereas soil attributes remained unrelated to RH. This study demonstrates that soils within these northern temperate grasslands are relatively insensitive to many pasture management practices, and highlights that existing RH assessments may provide limited insight into differences in mineral soil properties.

Northern temperate pastures exhibit divergent plant community responses to management and disturbance legacies identified through a producer survey

“…sand, % silt) were measured. Procedures and specific responses are summarized elsewhere (Pyle et al, 2019).…”

“…Modified-tame pastures were more likely to be semi-native and non-cultivated due to their biophysical limitations (e.g., sandy soil) that limited annual cropping (Pyle et al, 2019); however, their condition as native grassland was nevertheless altered by ongoing F I G U R E 1 Three-dimensional NMDS ordination of pasture plant community composition (stress = 0.17). Centroids of management factors (bolded, blue) are displayed at p < 0.025, treatment is indicated as follows: "+" = occurred, "−" = did not occur,"?"…”

“…Aydin and Uzun (2005) found that legume biomass decreased 88% over three years with fertilization, similar to our finding of a four-fold reduction in legume cover with fertilization. Fertilization of temperate pasture improves forage biomass (Bork et al, 2007) and increases both litter cover (Pyle et al, 2019) and rangeland health scores, which can suppress niche space for ruderal plants (Facelli & Pickett, 1991), explaining the reduction in ruderals. We were limited in our interpretation of fertilization effects as our survey did not determine the frequency, rate, or composition of nutrients added.…”

“…In previous publications, we reported on the management actions and disturbances occurring across northern temperate pastures in Alberta, Canada, including their relationship with rangeland health (Pyle et al, 2018) and underlying soil conditions (Pyle et al, 2019).…”

Effects of grazing management on spatio-temporal heterogeneity of soil carbon and greenhouse gas emissions of grasslands and rangelands: Monitoring, assessment and scaling-up

“…Knudsen et al (2019) showed that changes of soil carbon and biodiversity could significantly affect life cycle assessment of dairy production in Western Europe. Sustainable grassland management is critically important for meeting global food demand, mitigating emissions, and protecting soil and water resources (Robertson and Swinton, 2005).…”