Global attention to food and water security is increasingly being informed by Digital Soil Mapping (DSM), a science that uses complex modelling and statistical techniques. DSM was used to map the suitability of various crops in Tasmania; however, an important consideration was soil drainage, which generally requires expensive field measurements to inform DSM, but was beyond the available budget. This paper demonstrates expert field estimates can be applied instead to DSM to produce cheaper, but effective soil drainage suitability mapping.

In amending sodic soils, calcium is commonly applied as gypsum and, less frequently, as lime. A site where gypsum, lime and combinations of the two had been applied 12 years earlier was used to assess rehabilitation strategies as alternatives to gypsum alone. Residual amendments in the soil were not detected after 12 years and a marked improvement in soil health was observed where lime had been applied alone at 5 t ha^–1, suggesting that lime had acted as a vehicle for increased function of the soil and plant system.

Soil potassium levels are a critical issue for agriculture in terms of potential crop deficiency, as well as for viticulture from excess potassium through adding wastewater. An investigation of soil potassium variables and potassium plant uptake enabled the risk of potassium deficiency and the effect of adding potassium on potassium plant uptake efficiency to be determined. Future soil potassium problems should evaluate non-exchangeable soil potassium and use the content of illite and clay to predict soil potassium variable status.

The apicuns are a unique hyper-saline ecosystem that play important ecological and social roles in the tropical estuarine zone. Despite their ecological importance, these ecosystems have been highly impacted by anthropogenic activities. This has prompted a search for basic information about this ecosystem, including soil formation and pedogenetic processes that occur there. Knowledge about the formation of apicum soils is crucial for environmental studies focused on conservation and sustainable management of these ecosystems.

It has been suggested that biochar develop negative charge with ageing in soils. In this study, we investigated the effect of aged biochar on surface charge characteristics and adsorption behaviour of cadmium and arsenate. We did not observe any change in the cation exchange capacity of aged biochars. However, Cd adsorption increased in the presence of aged biochars, whereas the adsorption arsenate varied with soil type. Our results suggest that aged biochar may be suitable for the remediation of contaminated soils.

Soil charcoal is an important carbon sink because of its refractory nature and thereby plays an important role on the sequestering of atmospheric CO₂. Potassium -dichromate and -permanganate are used for the quantitative determination of charcoal and the easily assimilable soil organic matter (respectively), although the molecular composition of permanganate- and dichromate-oxidation resistant organic matter has not yet been determined. Dichromate effectively concentrates charcoal but also an aliphatic fraction, whilst permanganate oxidized microbial biomass. Theses findings improve the charcoal detection in soils, crucial to elucidate its role on geobiochemical cycles.

Carbonates are important constituents of many semi-arid soils in which they play a particular role in organic C storage and physical quality. However, little is known about the mechanisms by which carbonates are involved in the formation of structure in calcareous soils. We postulate that dissolution and precipitation cycles of carbonates create a particular soil fabric that can explain their role in aggregates stabilization. These structural particularities can give calcareous soils a different capacity for protecting organic matter, resisting erosion and storing and conducting water.

Potential shortages of phosphorous (P) that will limit food production are at the forefront of scientific debate. Efficient use of soil organic P can help address these shortages. Therefore, the present study developed a quick, easy method that can be used to evaluate a plant’s ability to access soil organic P. Because cropping systems are the future of sustainable agriculture, these results will be valuable in designing cropping systems that should make maximum benefit of soil organic P resources.

Genetically modified crops, which express genes from other organisms, continue to be a subject of concern, particularly with regard to impacts on the wider environment. We looked at the soil microbiology associated with roots of a range of genetically modified and conventional cotton plants and found that differences in the cultivar grown, more so than the genetic modification, resulted in changes in this biology. The work implies that varietal differences cause changes in plant-associated soil biology to a greater level than current commercial gene insertion events involving Bt and herbicide resistance.