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Agricultural soils are important sources of greenhouse gases (GHGs). Soil properties and environmental factors have complex interactions which influence the dynamics of these GHG fluxes. Four arable and five grassland soils which represent the range of soil textures and climatic conditions of the main agricultural areas in the UK were incubated at two different moisture contents (50 or 80% water holding capacity) and with or without inorganic fertiliser application (70 kg N ha−1 ammonium nitrate) over 22 days. Emissions of N2O, CO2 and CH4 were measured twice per week by headspace gas sampling, and cumulative fluxes were calculated. Multiple regression modelling was carried out to determine which factors (soil mineral N, organic carbon and total nitrogen contents, C:N ratios, clay contents and pH) that best explained the variation in GHG fluxes. Clay, mineral N and soil C contents were found to be the most important explanatory variables controlling GHG fluxes in this study. However, none of the measured variables explained a significant amount of variation in CO2 fluxes from the arable soils. The results were generally consistent with previously published work. However, N2O emissions from the two Scottish soils were substantially more sensitive to inorganic N fertiliser application at 80% water holding capacity than the other soils, with the N2O emissions being up to 107 times higher than the other studied soils. [ABSTRACT FROM AUTHOR]

The need for sustainable intensification of agricultural production has ushered in a growing awareness of soil health and a requirement to identify with some certainty how changes to land management will affect soil. From an agricultural perspective, the active management of soil health needs to balance the production of a healthy and profitable crop with environmental protection and improvement. However, the extreme spatial and temporal heterogeneity of soils, and the complexity of biological, physical and chemical interactions therein, makes predicting management effects on soil health challenging. Although the general principles underlying effects on soil health are well understood, they still need interpretation in a local context and the inclusion of site‐specific details. Approaches from landscape ecology provide a potential framework to integrate consideration of the structural (pools, patterns), dynamic and functional (processes, flows) aspects of the soil system. These approaches allow the crucial transition from a "descriptive and general" understanding toward a "detailed and site‐specific" prediction to be made. Using this conceptual framework, we have taken knowledge of the effects of fixed site factors (soil type and climatic zone), cropping systems and farm management practices on a range of soil physical, chemical and biological parameters for UK lowland agricultural systems, and have developed a predictive framework that shows semi‐quantitatively the effects of typical management choices on soil health and crop yield. [ABSTRACT FROM AUTHOR]