## INTRODUCTION

#### Biophysical factors

The design and installation of sub-surface drainage is heavily influenced by existing biophysical features. As noted, eight of the drainage contractors/experts interviewed believed that topography or slope of the land strongly influences the motivation of drainage contractors/experts to promote the installation of CTD, and for producers to adopt it (within a CTD retrofitting context). One drainage contractor pointed out: ‘If you have excessive grades, to control that water table is very, very difficult. We do have some low-grade fields where you have a hundred acres which is very flat, those are ideal situations obviously, but there are fields that just won't allow you to use it … and a lot of farms, [the grade] changes so much.’ In the South Nation River basin, it was estimated very roughly ∼50% of the total land base or ∼80% of cropland would be suitable (from a topographic perspective) for CTD without excessively customized water level control associated with topographically complex terrain (Que et al. 2015). Topographic constraints regarding this BMP are understood by drainage contractor/experts intuitively. Thus, this may be one reason why topographic impediments to CTD adoption in a region largely suitable for the practice from a topographic perspective was highlighted as a primary disincentive by contractors.

Additional biophysical factors that were raised by both drainage contractor/experts and producers were related to climate in the region and soil properties (the latter only a concern raised by drainage contractors/experts). Three of the drainage contractors and two of the producers interviewed stated that the climate in the last few years (prior to interview) has been too wet to warrant any interest in using CTD to retain water. These perceptions suggest that some producers and drainage contractors are influenced by recent, short-term conditions (perhaps revolving around spring and/or fall time periods when field trafficking predominates), although specificity of the issue was not explored in depth herein.

#### Innovation and management factors

The main factors that influenced drainage contractor preference of control structures were: simplicity, flexible control, durability/robustness, functionality, and capacity to easily retrofit. Drainage Contractor 1, when describing the control structures, states: ‘I like the [stopgate system] because it has a good reputation. It has a good structure, didn't leak, was simple to use, and durable.’ This suggests that contractors seek to understand producers' experiences with drainage technologies in order to promote control structures to other clients. It remains unclear to what extent drainage contractors and producers compare different CTD technologies and their appropriateness for farming operations. Interestingly, most producers and a few drainage contractors interviewed were familiar with either the float or the slot stopgate systems, but not both.

Of the 10 producers interviewed, two had specific issues with their float systems and both were no longer using them due to them malfunctioning. CTD structures with stopgates were viewed by several producers as easy to manage. In this region, most producers adjust their systems once during the spring and once during the fall.

Increased labor managing the structures was the top disincentive to adoption identified among both drainage contractors/experts and producers collectively. Labor to operate CTD systems was a key factor in cost–benefit analyses of CTD, as discussed in Nistor & Lowenberg-DeBoer (2007). Increasing the number of structures (accounting for drainage on multiple fields) was seen as critically increasing workloads. Producers looking at installation of CTD on a large scale would want it to fit into their existing operations with minimal time commitments. While each individual control structure was perceived to take less than 5–10 minutes (depending on the system) to adjust, the additional time constraints of getting to each control structure, particularly in poor weather conditions, was emphasized by producers (even under the two stopgate adjustments per year approach). Automation was perceived as beneficial to manage drainage for large operations to minimize labor requirements, but only a few producers and drainage contractors/experts identified this as a positive incentive given expense and maintenance requirements. One producer suggested that even sparing a short amount of time to operate a structure is perceived as a disincentive, particularly during busy periods that coincide with additional management of fields. Nistor & Lowenberg-DeBoer (2007) indicated that adoption of CTD could decrease as available labor becomes more limited. Yet some drainage contractors/experts who support CTD suggested its management is not too demanding.

#### Knowledge and learning factors

Three drainage contractors indicated that guidelines and standards for installation and management of CTD are lacking (a point not raised by producers); at least within the framework of the region of their business. Past studies found that there were few specific guidelines regarding CTD in the literature (Pitts et al. 2004), but more recently, some prescription/guideline specific documentation exists regarding installation, management, and maintenance that could be drawn upon (e.g., American Society of Agricultural & Biological Engineers (ASABE) 1990; USDA 2001, 2008, 2010). However, this underscores a lack of Canadian-derived (even regionally contextualized) guidelines, as identified, by some contractors (as a disincentive to promote the practice); since most existing materials of this sort were sourced from the United States where climatic conditions in particular are different. There was mutual agreement that developing the capacity to retrofit CTD to existing tile drained systems would be an incentive. As one drainage contractor indicated, retrofitting would be less of a concern if retrofit prescriptions were well documented and disseminated. Retrofits were perceived by one drainage contractor to be prohibitively expensive, in part due to additional design and installation requirements he felt were necessary for optimal drainage network design (something he felt would be important to consider). This kind of retrofitting must be placed in context, since producers that would significantly alter their field drainage networks could do so in a way that optimizes CTD benefits (Frankenberger et al. 2006); but, the expense of such efforts would be seen for many in the study herein, to be prohibitive. Retrofits in a more conventional sense rely on placing water flow control structures on outlets of existing tile networks irrespective of network disposition (e.g. Sunohara et al. 2014, 2015). Clearly, perceptions regarding retrofitting need to be contextualized properly, so that potential adopters do not think they need to reinstall or reconfigure an existing tile drainage network significantly, at great expense, for the purpose of operationalizing CTD; hence, knowledge translation and transfer regarding these aspects would appear to be important (e.g., guideline support). Design and installing a tile drainage network that optimizes the effects of CTD and sub-irrigation would enhance benefits for cropping systems, but considerations on prospective engineering design/install were not raised en masse by producers or drainage contractors/experts. The lack of specific standards for CTD installation and operation in Canada (and the issue of local context) appears to constitute one barrier to promotion of the practice by drainage contractors/experts. None of the producers interviewed discussed any informational materials or resources that they were exposed to from government agencies or drainage contractors.

Many drainage contractors/experts explained that they rely on scientific publications to glean insights on CTD pros and cons. One of the drainage contractors obtained his primary knowledge at drainage conventions where researchers presented their findings. Drainage contractors/experts (5/11), unlike producers (0/10), touched upon the issue of perceived and existing gaps in research, the need for locally contextualized data on benefits (both producers and drainage contractors felt an issue), and data on the environmental impacts on deeper groundwater. One drainage contractor stated that localized research was necessary for promoting CTD among his client base. Interestingly, two of the drainage contractors interviewed had no knowledge of benefits or issues associated with CTD. For example, some of the drainage contractors could not identify studies or resources providing information on CTD, notwithstanding scientific studies published nearly two decades ago with regional and supra-regional context on CTD benefits and approach (e.g., Drury et al. 1996; Lalonde et al. 1996; LICO http://www.drainage.org/). Also, for many contractors, demand for tile drainage installation as a primary revenue maker may have muted the impetus to take-up and disseminate new information on drainage water management science and technologies to producers. In the past few years in the region there has been a very high demand for installing drainage systems.

Attention must also be paid to the perceived validity and legitimacy of research/extension material among those making the decisions about CTD adoption (one of the highest ranking collective producer and drainage contractor/expert concerns). Some producers and contractors remain skeptical of research findings. One drainage contractor stated that when evaluating the research, the specific interests of whoever conducts the research are important to consider. There is some perception that some researchers are biased or unduly influenced by stakeholders. That is, institutions are viewed differently by producers and drainage contractors depending on their affiliation, history, and mandate. The concerns over perceived lack of extension services that would help support or bring to light credible research, is very noteworthy here considering it was raised as the second most important overall disincentive for CTD adoption by producers and drainage contractors/experts (mainly contractor viewpoint) alike.

The plethora of factors governing variable CTD effects in fields (Cicek et al. 2010; Kross et al. 2015) and variable seasonal-commodity on-farm benefits (Skaggs et al. 2012), perhaps contribute to uncertainty, or reduced confidence in the technology. Controlled tile drainage equates in many ways to a passive form of irrigation (water trapping), and in that way both environmental and agronomic responses will vary depending on weather, cropping practice, and antecedent soil conditions. Yet, on the longer-term average there are modest yield boosts that are well documented, notwithstanding immediate environmental benefits associated with CTD. Drainage contractors/experts, who are in an excellent position to promote CTD, may seek to prioritize promotion of drainage practices that demonstrate more immediate and consistent cost–benefits to producers.

#### Institutional factors

Many producers are interested in achieving public good benefits, but several of those interviewed believed that there should be funding available to help support the installation and, perhaps more importantly, implementation of some of the practices that improve environmental quality beyond the farm. However, some cost-share programs were/are available to farmers to support CTD; such as the Canada-Ontario Farm Stewardship Programs (COFSP) (http://ofa.on.ca/issues/fact-sheet/canada-ontario-environmental-farm-plan) and South Nation Conservation Clean Water Program (http://www.nation.on.ca/water/grant-programs/clean-water-program), for example. No producer interviewed indicated they had applied to these programs.

Three producers interviewed believe that monies designated for programs such as these are overhead heavy, thereby reducing funding to farmers. Several others felt that the ‘paperwork’ required to apply to such programs outweighed the benefits. Overall, cost-share for CTD has not been utilized significantly by farmers in the region (personal communication with South Nation Conservation 2012).

Research by McCallum (2003) examining producer BMP adoption in Southwest Ontario found that current subsidy levels were insufficient to promote voluntary adoption. In the case of CTD, appropriate subsidy levels are partially dependent on expected economic benefits. For example, Nistor & Lowenberg-DeBoer (2007) modeled the profitability of CTD in the Mid-Western United States and found that if ‘yield advantage due to controlled drainage is below 2.3% (4.5% without subsidy), controlled drainage drops out of the solution and is more profitable to choose free flowing whole farm field drainage’.

#### Marketing by drainage contractors and organizations

The many disincentives identified in Figure 2 contribute to the lukewarm, if not non-existent marketing of the practice by contractors in particular. One drainage contractor suggested that there is a lack of awareness of the many incentives on the part of producers and a lack of promotion on the part of contractors although he believed that CTD is applicable to many farming systems in the area and in more southern portions of the province. Additionally, he suggested that there is no ‘buzz’ about CTD currently; drainage contractors and producers are not talking about the practice and its production and environmental benefits. Finally, he mentions that contractors largely do not contact their clients to determine how well an installation has worked out. There is an absence of evaluation and re-design of marketing approaches, in general, in the region of study.

Other drainage contractors noted that the trade-off between generating revenues and marketing a product must be considered. Although CTD potentially generates a moderate return, drainage contractors do not want to be liable for a technology that fails (or is perceived to fail) to produce in practice, or is of such risk to cropping outputs if managed improperly. Fear of being unable to guarantee a consistently positive high impact on crop performance, for example, reduces emphasis on marketing and promotion of CTD by contractors. There is little desire to promote a practice for which the contractor is uncertain of the benefits and local applicability, at a minimum.

#### Extension support

Many producers and drainage contractors/experts indicated that extension support for CTD was lukewarm. This could translate as an adoption impediment given how valued extension organizations are in terms of providing information to producers on drainage practices and BMPs overall. Vanclay & Lawrence (1994) suggest much extension work can be top-down and may not be as sensitive as it can be to producers' needs and experiences. Whether or not this is the case here is uncertain. However, many interviewees pointed to the need for industry, producer organizations, government (provincial and federal), and suppliers to become more involved in extension and knowledge/technology transfer. Some interviewees suggested that branches of the federal and provincial government and producer associations could play a key role in moving CTD extension forward through existing programs and resources. Others suggest that suppliers should better market their product to drainage contractors and producers, which via diffusion of technology transfer by industry, could help boost confidence in the practice at the producer and contractor level in much the same way formal extension services would endeavor (Table 1).

## CONCLUSIONS

This exploratory study has attempted to identify the range of incentives and disincentives influencing producer adoption of CTD in an area in eastern Ontario, Canada where the potential for use of CTD, from a physiographical standpoint, is relatively high. Interviews with both producers who have adopted the practice and drainage contractors/experts (primarily composed of drainage contractors), indicated a suite of incentives and barriers they felt influenced producer adoption of CTD. The relative importance of the incentives and disincentives identified varied somewhat among the target groups, but there were some commonalities: increased farm labor and lack of extension services to support CTD use were viewed as the most important disincentives for adoption as indicated by both producers and drainage contractors/experts rankings together. However, drainage contractor/experts highlighted more succinctly than producers, costs of structure/install on multiple farm fields as an impediment to producer adoption. Adoption motivators that were common to producers and drainage contractors/experts revolved around agronomic benefits. Environmental benefits, however, appeared to have more bearing for producer adopters than contractors/experts. In this context, there was the indication that some financial incentives (likely beyond on-farm benefits due to yield boosts from CTD alone) would need to be provided to producers to impart greater uptake. Unlike some BMPs that require an effective one-time investment/implementation, CTD requires pulse seasonal labor to manage, and this would occur over the lifespan of the practice. Thus, one-time financial incentives to pay for structures and install might not tip the bucket for producer adoption, and perhaps longer-term financial incentive solutions need to be explored, such as labor resources paid by multiple stakeholders to manage CTD systems on multiple farms. Considering potential watershed-scale benefits of CTD (Que et al. 2015; Sunohara et al. 2015), BMP implementation within nutrient trading or stewardship programs for example, could help financially support such initiatives.

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