Sandy soils hold little water, organic matter or nutrients and are often severely water repellent. These represent significant challenges for grain growers, especially in low rainfall environments like south-eastern Australia. However, there remain significant opportunities for improving crop productivity here. Water repellency can be readily identified and managed to greatly improve crop establishment. Problems of reduced root growth and crop water uptake may require more radical interventions but are likely to be essential in this environment.

Soil limitations constrain plantation tree performance in savanna soils worldwide. We measured the effect on plant growth of phosphorus (P), nitrogen (N), potassium, sulfur (S) and trace element fertilisation in glasshouse factorial experiments – growth was usually greatest for N + P + S treatments and was highly sensitive to soil pH. Establishing productive plantations or agriculture on savanna soils will require detailed knowledge of soil properties, careful attention to soil pH and balanced fertiliser applications to avoid perverse outcomes.

Maintaining soil organic carbon (SOC) and total soil nitrogen (STN) is essential for sustaining soil health. No-tillage combined with stubble retention and nitrogen fertiliser was more successful at maintaining SOC and STN in a wheat-cropped Vertisol relative to conventional tillage practices with stubble burning and no fertilisation over 47 years, although SOC and STN still declined over time. Therefore, these farm management practices can sustain better soil health for grain production in semi-arid regions.

The amount of hot water extractable organic matter in soil is considered a good general indicator of soil health and biological activity. Literature evidence suggests that microbial biomass is a primary source of the carbon and nitrogen extracted in hot water. Our results demonstrate that organic matter desorbed from mineral surfaces may be an important contributor to hot water extractable carbon and nitrogen, and factors that affect the adsorption–desorption process may significantly influence organic matter extractability in hot water.

A grassland set-aside (GLSA) is a field taken out of crop production and seeded with a mix of grasses and legumes to improve soil quality. Just two seasons of GLSA improved soil structure, but not the soil organic carbon pools. Identifying soil quality indicators that quickly respond to soil conservation practices such as GLSA is of importance for farmers and other professionals who provide guidance on how to best implement conservation practices to improve and maintain soil quality.

Studies on litter decomposition are still scarce in some Cerrado ecosystems such as palm swamps. This study had an objective to compare the decomposition of litter in environments of palm swamp (veredas) composed by Organosols, and in the cerrado sensu stricto, composed by Quartzeneic Neosols. The results allowed a better understanding of the decomposition process in two of the Cerrado ecosystems and the correlations between physical and chemical attributes and soil microorganisms.

Humic acids are principal compounds of soil life and function, and soil management has a dramatic effect on humic acids in soil. Long-term tillage reduced humic acids in organic matter and humification degree while non-cultivated soil with natural vegetation maintained greater levels of organic matter and humification degree. Combination of tillage with long-term application of olive mill wastewater increased humification degree, promoted organic matter stabilisation in soils and enhanced sustainability of agroecosystems.

Under future climate change scenarios the availability of nitrogen (N) might change, thereby changing the soil N cycling in agro-ecosystems. The present research work addresses an important topic of effect of the changing climate on soil N pools as well as its relation to growth of rice crop. Better N management will alleviate faster depletion of soil N in future.

Acidification is an important aspect of soil degradation and one of the main challenges for agricultural production in (sub)tropical areas. Palygorskite is a clay mineral with alkaline properties, making it a promising agent to amend acidic soil. The ameliorative effects of palygorskite on acidic soil and its corresponding mechanism were studied and the results pave the way for efficient amendment of acidic soils and so contribute to food shortage mitigation in developing countries in (sub)tropical regions.