Physicochemical properties of 50 New Zealand pasture soils: a starting point for assessing and managing soil microbial resources

Abstract

New Zealand's pastoral agriculture faces challenges associated with increasing on-farm productivity, while minimizing the environmental footprint of farming. Soil microorganisms mediate a wide range of processes that affect plant production and also have environmental consequences. However, there has been little attempt to manage these in a farming system context. This is primarily because of difficulties in determining what microbiological resources are present in soils, how they link with soil processes and function, and how variation in soil types, climate or farm management practices influence microbial function. We sampled 50 pasture soils from across 11 of New Zealand's major soil groups, 10 geographical zones and under different grazing systems (high input dairy units to dry-stock grazing). The environmental and physicochemical properties of the soils were characterized and DNA extracted. The concentrations of elements primarily associated with fertilizer use (phosphorus, nitrogen and sulphur) were all significantly (P B 0.05) higher in dairy-based systems, yet soil carbon was unchanged. The concentration of many properties varied between the soil types, reflecting a combination of their pedogenesis and predominant land use. The amount of DNA in soils was closely related to anaerobically mineralizable nitrogen (P B 0.001), a measure of soil organic matter content, but did not vary with grazing system intensity. The extensive data set for each soil, coupled with DNA originating from the same samples, provides a unique opportunity for a number of ancillary studies to map biological resources in pastures and assess how these are regulated by edaphic and environmental properties.

Detection of Invertebrate Suppressive Soils, and Identification of a Possible Biological Control Agent for Meloidogyne Nematodes Using High Resolution Rhizosphere Microbial Community Analysis

“…There was a wide range of pH and macronutrient levels across the soils used in this study ( Table 1 ), with broad agreement between levels measured here and those by Wakelin et al (2013) from the same soils, with the exception of pH in soil 9. The northernmost soils (1 and 2) had the greatest CEC values while soil 5 was notable for a high level of Mg and soil 8 for low total N.…”

“…Soil samples were collected from 10 sites previously characterized by Wakelin et al (2013) that represented a wide range of geographical locations and soil characteristics, primarily pH and nitrogen levels ( Figure 1 ). In addition, half the sites were on brown soil type and half on recent soils, while four sites were dairy farms and six were sheep and beef farms.…”

Cost of root disease on white clover growth in New Zealand dairy pastures

“…Soil physicochemical properties were determined at Hill Laboratories Ltd. (Christchurch), using well characterised methods (e.g. as described in Wakelin et al 2013).…”

“…Alleviation of soil biological constraints (i.e. reduction of pathogens or supply of beneficial symbionts) is identified as a key path towards achieving this goal (Wakelin et al 2013). …”

Analysis of soil eDNA functional genes: potential to increase profitability and sustainability of pastoral agriculture

“…For simplicity, relationships between the functional gene data and farm management were compared only for dairy vs 'other' grazing systems (see later definition) in this work. A comprehensive set of soil physicochemical properties and long-term environmental conditions from the sites (Wakelin et al 2013b) enables the assessment of the soil ecological genomics against a set of appropriate metadata, and these can be used in future studies to assess, for example, influences of intensification more precisely. Overall, the two sets enable changes in functional soil biology to be interpreted alongside soil, climatic and farm-management influences.…”