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Abstract: Tillage might be unnecessary for crop production, but no practical mechanised system can avoid field traffic, usually by wheels. Wheels can cause soil damage, but this can be limited to a small proportion of field area by restricting all heavy wheels to permanent traffic lanes. Widespread adoption of controlled traffic in Australia, and permanent raised beds in Mexico has demonstrated the effectiveness and practicability of Controlled Traffic Farming (CTF) systems in very different cropping environments. This paper considers the system impact of wheel traffic on productivity and sustainability of mechanised cropping, citing comparisons between CTF and conventional “random traffic” cropping systems where possible. Evidence of the extent and effects of wheeling on soil structure is summarised in terms of hydrology and crop performance. Soil erosion and broader environmental effects are considered briefly. Tillage and traffic effects on greenhouse gas emissions from cropping are discussed, including emissions from fuel, herbicide and fertiliser inputs. Soil emissions are considered in some detail, citing evidence from soil compaction studies, and where emissions have been monitored from wheeled and non-wheeled soil. Outcomes have been encapsulated in a spreadsheet comparison of emissions from cropping systems using tillage with random traffic, no-till with random traffic and CTF no-till. Using data from extensive grain production systems in Australia this indicates that CTF could provide a major reduction in cropping emissions. CTF can improve productivity, and all measures of sustainability; it also overcomes some important constraints to the adoption of conservation agriculture. As precise guidance becomes progressively cheaper, machine system width compatibility remains the only major impediment to a significant improvement in food security and the environmental footprint of cropping. Width compatibility is simple in principle, but complex in practice, and will occur only with the active engagement of the farm machinery industry. The paper urges ISTRO to join with regional farmer CTF groups to draw attention to this issue and provide a forum for the development of compatibility standards. [Copyright &y& Elsevier]

Abstract: Precision farming relies on diverse sensor techniques to collect site-specific information at field scale. To comprehend and interpret miscellaneous information referring to each specific soil, crop and weather conditions, different case studies are needed. This paper presents two case studies. A horizontal dielectric penetrometer, an EM38 (Geonics Ltd., Canada) and a yield sensor (RDS Technology Ltd., UK) were used. Several parameters, volumetric soil water content (VSWC), penetration resistance (PR), apparent electrical conductivity (ECa) and crop yield, were investigated. A case study (20ha, Warleberg Farm, Kiel, Germany; crops: rapeseed (Brassica napus L.) in 2007/2008, winter wheat (Triticum aestivum L.) in 2008/2009) indicated that VSWC maps at a depth of 20cm conformed to both ECa maps and yield maps over two years. Another case (7.7ha, Dikopshof Experimental Farm, Bonn, Germany; crops: winter wheat (T. aestivum L.) in 2007/2008, winter barley (Hordeum vulgare L.) in 2008/2009) had similar results except a yield map of 2009. For soil strength distribution at the depth of 20cm, a PR map at Warleberg Farm generally agreed to other maps (VSWC, ECa and yield), whereas the PR map from Dikopshof Experimental Farm only partly agreed to those. In brevity, this study concludes: (i) an assessment for the availability of the horizontal dielectric penetrometer applied at field scale; (ii) ECa pattern measured by EM38 can be viewed as a fingerprint within a field for predicting the distribution of soil water content and crop yield; (iii) PR pattern on top layer is relatively difficult to interpret than ECa pattern. [Copyright &y& Elsevier]

Despite the fact that soil erosion by water causes considerable on-site and off-site problems, farmers in Europe are reluctant to adopt prevention and control measures when such measures require additional labour and material inputs. This paper documents the impact of multiple sowing of small grains on concentrated flow erosion rates and grain production for a winter triticale field (X Triticosecale Wittmack ex. A. Camus) in the Belgian loess belt. Multiple sowing refers to drilling more than once in zones of concentrated flow erosion in order to increase the total root mass in this zone. Multiple sowing strongly altered the morphology of erosion channels and reduced soil loss significantly. Statistical analysis confirmed that differences in channel dimensions could be explained by the seedling density. Doubling the root mass in the topsoil by multiple sowing, resulted on average in a reduction of soil loss by 42% for the whole growing season. For the winter period, soil loss reduction, mainly attributed to the triticale roots, amounted even to 53%, showing the tremendous impact of seedling roots on soil erosion by concentrated overland flow in the early stages of vegetation growth. Furthermore, total grain yield in the multiple drilled zones was not significantly smaller compared to the conventionally drilled parts of the field. Grain size of cereals was slightly smaller. The results of this case study indicate that double sowing in concentrated overland flow zones may be a viable soil erosion control technique. [Copyright &y& Elsevier]