A literature review was conducted to collate best practice techniques for soil compaction management within cotton-farming systems in Australia. Universally negative effects of traffic-induced soil compaction on the whole-farm system and the wider environment include: (i) increased gap between attainable and potential yields, (ii) increased costs of energy and labour, (iii) reduced fertiliser-use efficiency, (iv) reduced water use efficiency (irrigation and rainfall), (v) increased tillage intensity. Knowledge gaps that merit research priority, and research strategies, are suggested. These include: (i) identifying wider impacts on farm economics to guide decision-making and development of decision support systems that capture the effects of compaction on fertiliser, water, and energy use efficiency; (ii) predicting risks at the field or subfield scale and implementing precision management of traffic compaction; (iii) canopy management at terminal stages of the crop cycle to manipulate soil-moisture deficits before crop harvest, thereby optimising trafficability for harvesting equipment; (iv) the role of controlled traffic farming (CTF) in mitigating greenhouse gas emissions and loss of soil organic carbon, and in enhancing fertiliser and water-use efficiencies; (v) recent developments in tyre technology, such as low ground-pressure tyres, require investigation to assess their cost-effectiveness compared with other available options; and (vi) catchment-scale modelling incorporating changes in arable land-use, such as increased area under CTF coupled with no- or minimum-tillage, and variable rate technology is suggested. Such modelling should assess the potential of CTF and allied technologies to reduce sediment and nutrient losses, and improve water quality in intensively managed arable catchments. Resources must be efficiently managed within increasingly sophisticated farming systems to enable long-term economic viability of cotton production. Agronomic and environmental performance of cotton farming systems could be improved with a few changes, and possibly, at a reasonable cost. Key to managing soil compaction appears to be encouraging increased adoption of CTF. This process may benefit from financial support to growers, such as agri-environmental stewardships, and it would be assisted by product customisation from machinery manufacturers.

This paper determines the influence of lime and gypsum on the rehabilitation of a degraded sodic soil in a semi-arid environment 12 years after application. The aim was to assess rehabilitation strategies for sodic soils as alternatives to the application of gypsum alone. An experimental site was used where lime and gypsum combinations (L0G0, lime 0 t ha–1 and gypsum 0 t ha–1; L0G1, L0G2.5, L0G5, L1G0, L2.5G0, L5G0, L1G1, L2.5G1) had been applied 12 years prior, in 1994. An earlier study had reported on the effects after 3 years of the chemical ameliorants and tillage on a range of soil physical and chemical properties at the site. The current study, sampled in 2006, assessed the effects after 12 years of lime and gypsum on soil chemistry, stability, hydraulics, vegetative growth and soil respiration. Calcium, primarily from lime, was observed to have a major effect on soil health. Significant effects on soil chemistry were limited to increases in exchangeable calcium and decreases in exchangeable magnesium, although aggregate stability in water and hydraulic conductivity were significantly improved where L5G0 was applied. Vegetation patch width, total nitrogen and carbon, and soil respiration were significantly improved where lime had been added at 2.5 or 5 t ha–1. As no lime could be detected in the soil 12 years after application, it was deduced that lime had acted as a catalyst for increased functionality in soil and vegetation interactions. This increased soil functionality resulted in an increased rate of lime dissolution in the soil.

Soil Security is an emerging sustainability science concept with global application for guiding integrated approaches to land management, while balancing ecosystem services, environmental, social, cultural, and economic imperatives. This discussion paper sets the scene for an Australian Soil Security framework as an example of how it might be developed for any country, defining the key issues and justification for Soil Security, as well as detailing implementation requirements and benefits; two examples of beneficial outcomes are provided in terms of facilitating decommoditization of agricultural products and the impact of urban encroachment on productive land. We highlight research gaps, where new knowledge will contribute to well-rounded approaches that reflect differing stakeholder perspectives. We also provide key nomenclature associated with a potential Soil Security framework so that future discussions may use a common language. Through this work we invite scientific and policy discourse with the aim of developing more informed responses to the myriad of competing demands placed on our soil systems.