As a major form of land use, permanent pastures are of great interest as a means for mitigating greenhouse gases. We review the fundamental knowledge of the complex factors that regulate soil organic carbon dynamics in pastures. These insights help us interpret the often highly variable results from regional-specific studies as well as identify best management options for promoting carbon sequestration in pastures.

The vegetation productivity and soil texture in arid desert grasslands in the Hexi Corridor region of north-west China showed a high spatial heterogeneous distribution. We found that vegetation biomass, soil organic carbon (SOC) concentration and storage was significantly and positively related to soil silt+clay or clay content, and soil silt + clay content could explain 42–79% of the variation in SOC density. Soil texture could be an important controlling factor for vegetation productivity and SOC capacity in the study area.

Cultivation of grassland is known to lead to the depletion of organic matter but the effect on soil chemical functions, including cation retention, has not been well documented. We measured cation exchange capacity and exchangeable cations (Ca, Mg, K, Na) eight years after conversion of long-term pasture to arable cropping (crops established using either intensive-, minimum- or no-tillage). Cation concentrations (top 25 cm) declined significantly under cropping, but were unaffected by tillage type.

Water ‘availability’ in sands relies on the water capacity and the unsaturated hydraulic conductivity. To predict ‘availability’ we use the diffusivity in weighting the water capacity prior to integration to obtain the integral water capacity. Interestingly, the diffusivity leads to the employment of the (mis-named) ‘matric flux potential’, which is partly effective (and can be adjusted) when applied from the inflection point of the water-retention curve on semi-log paper.

Si from amorphous silica in soils is assumed to play a major role in Si availability and cycling due to its greater solubility compared to that of crystalline clay minerals. For quantifying Si from amorphous silica in soils of temperate-humid climate, we focused on optimising the alkaline extraction of amorphous silica. Based on the results of the test series with materials of known composition, extracting amorphous silica from these soils using 0.2 m NaOH at room temperature proved to be the most appropriate method.

Road dusts deposited along busy roads commonly contain toxic chemical elements that may be washed by rain into rivers, lakes and bays, causing water pollution that affects fish and other living creatures. Our study in eastern coastal Australia showed that five such elements mainly originating from vehicle brakes, tyres and road-surface abrasion were highly enriched in dust deposits. However, this did not increase the elemental contents in the water sediments in a nearby bay.

Cu-DTPA-HEDTA-EDTA, Cu-EDTA and Cu-lignosulfonate chelates were more effective than other Cu sources at providing triticale in neutral soils with an appropriate level of Cu nutrition. The potentially available Cu present in the soil correlated with Cu uptake by the triticale in a greenhouse experiment. Only the Cu-lignosulfonate fertiliser produced noticeable increases in Cu content in triticale grain without Cu losses due to leaching.

Teak (Tectona grandis L.f.) has been planted in a wide variety of soils, including many with serious fertility problems (e.g. Ultisols and perhaps Oxisols) or with added difficulties due to their physical properties (e.g. Vertisols). A general K deficiency can be observed in the Central American teak plantations, where P deficiency and acidity toxicity are also relatively common problems.

This study evaluated the effects of slurry additions and soil physical properties on preferential flow and nitrate concentrations in two Mediterranean soils of central Chile. Preferential flow, assessed by a dye staining method, showed no evidence of being affected by pig slurry. Instead, tillage and soil physical properties helped to explain the stained patterns. Mediterranean climate triggered a decrease in N mineral forms during the winter season, which coincides with the period of concentrated rainfall.

Changes in chemical, biological and physical characteristics of soils used for the land treatment of dairy factory wastewater, for periods up to 20 years, are reported from treatment areas used by three factories in North Island, New Zealand. The soil condition was compared with equivalent soils under conventional dairy farming and the sustainability of waste disposal to land discussed in relation to loadings.  

Disposal of untreated olive-mill wastewaters (OMW) is a major environmental problem in many Mediterranean countries. Land spreading of untreated OMW on soil had long-term residual effects on soil chemical properties and microbiological parameters, with soil respiration and microbial biomass C being significantly influenced by the changes in soil chemical properties. The early monitoring of soil chemical and microbiological parameters indicates that disposal of OMW on soil is a sustainable management practice.