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The condition or quality of soils determines its ability to deliver a range of functions that support ecosystem services, human health and wellbeing. The increasing policy imperative to implement successful soil monitoring programmes has resulted in the demand for reliable soil quality indicators (SQIs) for physical, biological and chemical soil properties. The selection of these indicators needs to ensure that they are sensitive and responsive to pressure and change e.g. they change across space and time in relation to natural perturbations and land management practices. Using a logical sieve approach based on key policy-related soil functions, this research assessed whether physical soil properties can be used to indicate the quality of British soils in terms of its capacity to deliver ecosystem goods and services. The resultant prioritised list of physical SQIs were tested for robustness, spatial and temporal variability and expected rate of change using statistical analysis and modelling. Six SQIs were prioritised; packing density, soil water retention characteristics, aggregate stability, rate of erosion, depth of soil and soil sealing. These all have direct relevance to current and likely future soil and environmental policy and are appropriate for implementation in soil monitoring programs. [ABSTRACT FROM AUTHOR]

A series of preferential flow experiments were conducted to investigate the temporal and spatial variability in a large block (5.4 by 3.4 by 1.2 m) of undisturbed soil (Dystric Eutrocrept) situated in midDevon, UK. Chloride and nitrate tracers were applied using rainfall sprinklers and the soil water was sampled continuously using 54 ceramic suction samplers installed throughout the block. Two main types of breakthrough curve occurred, a rapid response with a high peak concentration and a slower response with a lower peak concentration. Analysis of the spatial patterns of these characteristics confirmed the importance of the horizontal and vertical heterogeneity of flow. Peak concentration and time to peak concentration were related to depth in one quadrant but no relationship was found when the entire block was considered. Preferential flow paths occurred at intensities above 2 mm h[sup -1] and were less important for intensities of 1 mm h[sup -1]. A delayed leaching experiment was conducted in which a nitrate tracer remained in the soil for l0 d before leaching commenced. The pattern of response to the 5-mm h[sup -1] rainfall application was similar to the earlier experiments. Analysis of the shape of the breakthrough curves and time to peak suggested that nitrate movement was minimal in the wet soil during the intervening period. The spatial variability, noted even at this limited block scale, suggests that simplified approaches to understanding water and chemical transport are unable adequately to describe field behavior. [ABSTRACT FROM AUTHOR]

There are significant gaps in our understanding of how to sustainably manage agricultural soils to preserve soil biodiversity. Here we evaluate and quantify the effects of agricultural management and location on soil microbiology using nine field trials that have consistently applied different soil management practices in the United Kingdom using DNA barcode sequence data. We tested the basic hypothesis that various agricultural management interventions have a significant and greater effect on soil bacterial and fungal diversity than geographic location. The analyses of soil microbial DNA sequence data to date has lacked standardisation which prevents meaningful comparisons across sites and studies. Therefore, to analyse these data and crucially compare and quantify the size of any effects on soil bacterial and fungal biodiversity between sites, we developed and employed a post-sequencing DNA-barcode biodiversity standard analysis method (DNA-BSAM). The DNA-BSAM comprises a series of standardised bioinformatic steps for processing sequences but more importantly defines a standardised set of ecological indices and statistical tests. Use of the DNA-BSAM reveals the hypothesis was not strongly supported, and this was primarily because: 1) there was a large variance in the effects of various management interventions at different sites, and 2) location had an equivalent or greater effect size than most management interventions for most metrics. Some dispersed sites imposed the same organic amendments interventions but showed different responses, and this combined with observations of strong differences in soil microbiomes by location tentatively suggests that any effect of management may be contingent on location. This means it could be unreliable to more widely extrapolate the findings from trials performed only at one location. The widespread use of a standard approach will allow meaningful cross-comparisons between soil microbiome studies and thus a substantial evidence-base of the effects of land-use on soil microbiology to accumulate and inform soil management decisions. • Development of a post-sequencing DNA-barcode biodiversity standard analysis method. • Soil microbiology at nine different field trials was compared. • Interaction between location and management better defines soil microbiology. • Extrapolating findings from trials at one location to others is possibly unreliable. [ABSTRACT FROM AUTHOR]