Today, unlike the original gantry systems where one set of uncropped pathways received the same amount of traffic, a CTF managed field may have different pathways, some cropped and some uncropped, receiving different levels of traffic depending on the implement working widths, but all in multiples of the narrowest machine working width. CTF can also be viewed and implemented differently in different regions and/or across different farming groups with ‘seasonal CTF’ for example deploying a CTF system after primary cultivation until the end of that season or until the harvesting operation. The essence of CTF is to eliminate soil compaction within the cropped area, improve tractive efficiency on the permanent tracks, and thereby improve crop yield and economic return. Setting a CTF system on a farm is often made over years during which the machines being replaced are chosen, or they are modified, to match the CTF system chosen. Mainly a base working width has to be chosen . Fertilization and crop protection is often made at widths of 2, 3 or 4 times the primary working width. While CTF originally in Australia aimed to have the track width of all equipment the same, today in Europe it is often accepted that this is expensive, inconvenient and not suitable for road transport. Consequently a wider track width for combines is accepted. Besides, wider tyres are deployed to reduce the impact of traffic as all other traffic paths are cropped . Researchers have attempted to assess the economic and environmental benefits of CTF using field experiments. From a case study for a multi-cut grass silage system in Scotland, UK, Hargreaves et al. documented that introducing CTF provides a net economic return derived from increased yields due to a reduction in compaction and sward damage.
Antille et al. provided a review of the effects/implications of CTF systems on overall soil health, crop performance and yield,mobile vertical farm fertilizer and water use efficiency, and greenhouse gas emissions. As early as 1986, energy savings of approximately 50% were reported from CTF use in the Netherlands . In Denmark, Gasso et al. presented the significant potential for CTF to reduce environmental impacts through reduced greenhouse gas emissions in intensively managed arable cropping systems with at least 20% reduction in direct emissions from field operations. Based on a 10 year field experiment from Loess Plateau in China, Bai et al. indicated that CTF increased mean wheat yield by 11.2%. Drawing from a case study on an Australian sugar cane farm, Halpin et al. concluded that a farming system with precision CTF and minimum tillage is more profitable than traditional practice. Using whole farm modelling in Australian dryland agriculture, Kingwell, Fuchsbichler reported that CTF would increase profit by 50% mainly through its beneficial effect on yield and crop quality. Hussein et al. reported 30% increase in sorghum yield due to CTF. Studies from Denmark and the UK showed that CTF enables a considerable reduction in headland area and input use and claimed that the overall benefits would be higher if CTF was integrated with other precision farming techniques . CTF also provides other benefits such as minimizing soil runoff, economizing on input use from reduced overlaps, providing reduced operator stress with auto-steering and reducing soil-emissions . Tullberg documented that by restricting compaction to narrow and permanent wheel tracks, CTF contributes to reducing nitrous oxide emissions which are higher in compacted soils. Tullberg et al. concluded that CTF can bring about 30–50% reduction in soil nitrous oxide and methane emissions. The benefits can potentially be higher when CTF is combined with reduced tillage or no-tillage systems and assisted by precision agriculture technologies . While CTF is considered to provide multifaceted benefits as summarized above, there are also potential drawbacks associated with it. The main drawback is the investment required in suitable width matched machinery and the associated auto-steering technology. Driving patterns must be controlled, which can have implications for field efficiency in service vehicles like grain trailers or slurry tankers which must follow the pathways rather than turning to exit the field by the shortest distance when their load cycle is complete .
CTF is compatible with EU soil protection laws and regulations aimed at preventing soil compaction. While soil is compacted in the permanent track area 70–80% of the farm area is not compacted by field traffic where CTF is deployed . Low soil disturbance minimum tillage or no-till is more easily deployed with CTF as the soil is not subjected to traffic induced compaction. While the permanent tracks will be compacted, negative effects are limited to a small area and are more than compensated for by the lack of random traffic and intensive soil cultivation in the larger field area . While experimental evidence suggests multiple benefits from CTF, its use on commercial farms is limited for various reasons such as the high cost of machinery modification ; the perception that CTF is not for small farms ; and the lack of demonstrated benefits under local conditions. Moreover, CTF demands a change of mindset towards prioritizing soil health, careful route planning and making decisions with a long-term perspective and in a holistic manner. In Europe, soil compaction is already recognized as a threat . However, CTF remains a niche activity. In the literature, the benefits of CTF in terms of yield improvement, soil health, input-use efficiency and environmental benefits are frequently reported. However, literature on the perceptions/views, knowledge and concerns relating to CTF and its adoption, of current, and of potential, CTF using farmers, is lacking. This study intends to fill part of this gap by analyzing data from a survey of farmers, as part of adoption studies in two ICT-AGRI European projects: CTF-OptiMove and PAMCoBA . The primary objective is to assess and understand farmers’ perceptions about CTF and related technologies; what limits them from using the technology and how they think it could be improved. The study also seeks to identify intervention approaches, relevant stakeholders, and their roles for the future development of CTF. The data used in this study is from a cross sectional survey collected from January to April 2018 from 8 European countries using the network of the project participants to secure participants.The survey was a structured questionnaire administered online using the SurveyXact platform . An overview of the survey data is provided in Thomsen et al. . All 263 members of the CTF Europe association which includes farmers, advisors, machinery companies and others with an interest in CTF farming systems, were invited to participate.
CTF Europe member farmers generally operate larger farm sizes than average in their countries. In the Netherlands, the survey was distributed to 63 farmers, 3 were from the list in CTF Europe and the rest were members of a farmers’ association in the Hoeksche Waard district who cooperated in earlier projects on in-field traffic. Compared to other regions in the Netherlands, HW member farmers are considered more advanced and early adopters. In Belgium, the survey was distributed to approximately 2200 farmers using the sprayer inspection customer database for Flanders, administered by the Research Institute for Agriculture, Fisheries and Food . In Ireland, the survey was distributed to 140 farmers with active email addresses from the total membership of 200 of the Irish Tillage and Land Use Society . ILTUS members tend to be the larger growers in the country with between 100 and 800 ha per farm. A total of 103 valid survey responses were received and used in this study. The survey data included demographic attributes of the respondents , farm size, machinery ownership, tillage type, concern about soil damage due to heavy machinery and remedial measures, mode of farm ownership, perception/expectation about longterm benefits from using Precision Farming & GNSS and, use of CTF practices. Survey participants who considered themselves as ‘CTF-users’ were asked technical, experience and expectation related questions relating to their use of CTF. The survey questionnaire contained an introduction section giving background information about soil compaction and CTF. The conceptual definition of CTF provided in the introduction section was: “Controlled Traffic Farmingis a production and management system that requires the repeated use of the same wheel track for every operation, and for all vehicles and implements to have a particular span corresponding to the base wheel track”. In this study, ’CTF user’ denotes farmers’ own perception of their CTF use as responded to the question “Do you use CTF” . Two issues must be considered when analyzing the survey data. Firstly, the low response rate may introduce a selection bias, i.e., those farmers with prior experience with CTF technology and early adopters of mechanization technologies may have participated at a higher rate than those operating small farms and/or not considering CTF. Secondly, there is heterogeneity in sampling across countries in the survey. Members of CTF Europe already have awareness of and are interested in CTF.
The respondents from Ireland were members of a soil and tillage association that had participated in previous workshop events concerning soil compaction prevention, though not specifically CTF. However, the sample from Belgium is quite different because the criterion was owning a sprayer and only included the Flanders region with relatively small farm sizes. The study used a descriptive approach to present farmers’ perceptions, experiences, expectations, challenges and needs regarding CTF. Numerical data was summarized using percentages, cross-tabulations, vertical farming racks and histograms. Responses to open-ended questions were summarized and explained under thematic headings. Where it was considered useful, data was disaggregated by country and/or CTFuse category. Owing to the small sample size and sampling heterogeneity across the countries surveyed, the use of statistical analysis methods was limited. To assess the presence of statistically significant differences in mean farm size between CTF-user and non-user groups, a T-test was performed. 3. Results 3.1. Sample distribution, farm size and production type by country The distribution of survey respondents, farm size and production type is presented by country in Table 1. Most of the respondents were from Belgium, Ireland, the UK and the Netherlands. In terms of proportion of CTF-users, the UK sample ranks first followed by Ireland and Belgium . Because of their very small representation, samples from Germany, France, Canada and Sweden are grouped together as ’Others’. In Table 1 summary statistics for total farm size and the percentage of farm area where CTF is applied is presented . There is a wide difference in farm size across countries. Categorizing farm area into large , medium and small shows that nearly 86% of respondents from Belgium operate small farms in contrast to none for the UK sample. The majority of the respondents from Ireland and the Netherlands lie in the medium farm size category. Farm sizes are larger for the Danish and UK sample with 75% and 65% respectively greater than 500 ha. The percentage of farm area under CTF operations also differs across countries. The sample from Belgium is the lowest both in terms of farm size and the proportion under CTF practice. The UK sample features the highest values both in farm size and percentage area under CTF and this data is also from 14 CTF user farms, which is a much larger sample than from the other countries. As shown in Table 2, there appears to be considerable difference in the type of crop/animal production respondents are involved in . For the aggregate sample, 82% of respondents said to produce one or more cereal crops, 40% onion, 37% perennial crops and 31% beet with the least proportion involved in pig production. Note that a respondent could engage in more than one type of crop and/ or animal production. Cereal production is the most common for the sampled farmers with the vast majority reported to have produced one or more cereal crops . In UK and Ireland, all sampled farmers produce cereal crops. Pig production is the least common with only 50%, 16% and 6% of the samples from Denmark, Belgium and UK respectively involved in it.