Long-term agricultural land use affects chemical and physical properties of soils from Southwest Saskatchewan

Abstract

Understanding nutrient cycling under different land uses can improve agricultural management practices. In southwestern Saskatchewan, long-term land use as annual cropland, native grassland pasture, tame (planted) crested wheatgrass grasslands, or roadsides altered soil physical and chemical properties based on the intensity and frequency of disturbance, with cropland > roadsides > tame grassland > native grassland. The majority of significant differences were detected at the soil surface (0-7.5 cm); few significant differences below 15 cm suggested that the soils were not significantly different prior to changes in land use. Bulk density was increased in cropland soils compared with native grassland, probably from compaction from farm equipment, and in tame pastures due to their past use as croplands. Croplands also had decreased carbon and organic phosphorus (P) and increased Olsen P compared with grasslands, from crop removal and fertilizer inputs. Roadsides, an important but poorly studied land use in Saskatchewan, had increased clay and Olsen P concentrations compared with native grassland. Roadsides were disturbed during road building and remained disturbed because of runoff from adjacent fields and dust from roads. These results on soil chemical and physical properties, combined with soil microbiology information, will help to improve land management and nutrient use efficiency in soils of this region.

Long-Term Land Use Affects Phosphorus Speciation and the Composition of Phosphorus Cycling Genes in Agricultural Soils

“…At each location, six soil cores (1.9 cm diameter) were collected inside four 1 m 2 quadrats that were situated along a 10 m transect for a total of 24 total soil cores per location. This differs from Cade-Menun et al (2017a) with respect to date, sampling depth and number of study sites. Soil samples were stored in a cooler with ice packs while in the field.…”

“…The four experimental sites [Auvergne Wise Creek (AWC), Val Marie (VM), Masefield (MF1, MF2)], located in southwestern Saskatchewan, have the same soil type (well-drained Orthic Brown Chernozems; Saskatchewan Environment, and Resource Management [SERM], 1997 ) and a known history of more than 50 years in each studied land use type ( Cade-Menun et al, 2017a ). The native grasslands were a mixed grass prairie community, and tame grasslands were crested wheatgrass [ Agropyron cristatum (L.) Gaetern.]…”

“…The fourth land use type in this study was roadside ditches, which serve as buffers between roads and fields. More details of the experimental sites and the broader land use study are available in Cade-Menun et al (2017a) . For the current study, soil samples were collected in July 2013 from the 0 to 30 cm depth from four land use types at four locations ( n = 16).…”

“…Land use change will introduce significant changes in vegetation, which can alter soil biology and nutrient cycling. Vegetation changes will change rooting depth, nutrient and water uptake, soil chemistry and symbioses, such as N fixation or mycorrhizae ( Bainard et al, 2017 ; Cade-Menun et al, 2017a ). Plants and microorganisms are essential drivers of soil P turnover and dynamics.…”

Phosphorus and carbon in soil particle size fractions: A synthesis

“…It has been shown in a study in the UK that arable soils were dominated by orthophosphate, while extensively-grazed grassland soils were dominated by OP compounds (Stutter et al 2015). Further, it was reported that cropland soils in Canada contained decreased OC and OP and increased easily available IP contents compared to grassland soils (Cade-Menun et al 2017). However, the loss of OP relative to OC caused by land-use conversion and the role of minerals for the stabilization of OP is not yet well understood.…”