Tile drainage in Massachusetts cranberry production: Implementation and best management practices

Tile drainage in Massachusetts cranberry production: Implementation and best management practices

Summary

Along with cranberry grower project advisors at existing and new tile drainage installations, the project scientists and graduate student spent 2014 intensively studying the functioning of cranberry drain tiles. Three grower surveys (each with over 100 respondents) have confirmed that the 20-foot horizontal spacing is the most common in Massachusetts cranberry farms, accommodating existing buried sprinkler irrigation pipes. Field experimentation has confirmed that this spacing (compared to 15- or 30-foot) is associated with good plant growth and the greatest crop yield. Ideal depth to the top of the drain pipe has become our current focus. We have established a depth study on a renovated bog and will add another as a retrofit in spring 2015.  Because tile drains so effectively mitigate soil saturation, there is concern that over-irrigation will be an issue, potentially promoting off-site nutrient movement. In order to quantify these relationships and develop BMPs, the project team has intensively studied hydrology, nutrient movement, and irrigation parameters (soil moisture, irrigation scheduling) on a 5-acre section on the farm of one of the grower-advisors to the project and on another partner’s bog where controlled release materials were implemented. Field days in 2015 will be held at the depth experiment sites and at the intensive study site.  Financial barriers to implementation are real but commitment to the use of tile drainage remains strong.

Objectives/Performance Targets

Fifteen growers install tile drains on a total of 140 acres (1% of MA acreage) with five incorporating project-developed BMPs for installation, maintenance, and irrigation supplementation, resulting in increased yield of 20 barrels/acre (~$850/acre), reduction of sprinkler irrigation cycles (quantified energy and water savings), and the elimination of at least one pesticide application per year.

Accomplishments/Milestones

Milestones:

• Five growers sign on as early adopter participants/project advisors; one provides the site with varied horizontal spacing (experiment 1).

A five-grower team of project advisors has been established. One has provided a site for in-depth study (grad student project) of nutrient and water movement in drains established at a site with tiles installed 20 ft apart and 18 in deep). This site has been monitored since mid-2013. Another of the project advisors has provided the site for a tile depth study under renovation conditions. The tiles there were installed in very early spring of 2014 and the vines replanted soon thereafter. A second depth study site will be established by early spring of 2015. The horizontal spacing study (exp. 1) has been completed. Based on grower surveys (see next section), horizontal spacing at 20 feet appears to have become the industry standard and is supported by exp. 1 results.

• 300 growers learn about project including data collection requirements of those that participate and receive a survey regarding current drainage practices and challenges.
• 200 return survey, 150 are interested in additional education, 30 are interested in establishing drainage for project evaluation.

At a meeting held on Jan. 16, 2013 (attendance = 290), attendees were shown a PowerPoint presentation describing the project and were provided with a handout with further details (see 2013 report). Growers were surveyed about management practices, including drainage, in January 2012 (n=171). In January 2013, they were surveyed specifically about tile drainage (n=118). In January 2014, the meeting survey again included a section regarding drainage (n=115). A summary of the questions and responses is attached in the next section.

• Five growers install tile drains with guidance from the project team and advisors. They begin to keep records of management activities using the template provided by the team.

The largest grower on the project team is planning a twenty-year project of adding 100 new acres – these will include tile drains. The planning for this installation has included consultation with the project scientists.

• At the end of the first year, growers and team members have produced a first draft of the BMP and have selected the site and horizontal spacings for Experiment 2.

BMP topics have been selected, the draft will be worked on into early 2015 following an additional meeting of the project scientist-grower team in January.

• Early adopters evaluate practices on their farms and host on-farm workshops. The team conducts and evaluates experiment 2 and meets individually with early adopters to confirm participation and record keeping.

The depth experiment was established in early 2014 and data collection was accomplished through the summer.

• Interim information is disseminated at winter meetings (300 growers) and brief surveys are conducted at the meetings to verify progress towards performance target.

The tile function evaluation study of graduate student Nick Alverson was presented in poster format to the 2014 grower meeting (attendance 262) along with a PowerPoint presentation by Casey Kennedy of that study and the tile depth work [presentation attached]. Dr. Kennedy also presented project results [presentation attached] at the winter meeting of the Cape Cod Cranberry Growers Association in March 2014 (attendance approx. 250). A survey was conducted at the 2014 January meeting and another is planned for January 2015.

• 10 new adopters have installed drainage and are evaluating the practice (using the provided template) by Year 3 (at least half have installed and manage their drains based on developed BMPs – these are in draft form during Year 2 and finalized in Year 3). The team meets with adopters during the season to evaluate progress and confirm recordkeeping.

Individual installations and evaluations have been delayed due to depressed economics in the cranberry industry. Therefore, we anticipate that completion of all project objectives and targets will require an additional year beyond our original schedule. During 2015, the scientist/grower planning team will identify recent installations and interview growers regarding outcomes to help to supplement the information gathered from new installations. As part of that effort, three on farm workshops will be held in spring 2015.

Discussion:
Grower surveys in 2012, 2013, and 2014 show that, consistently, larger acreage growers were more likely to have tile drains on at least some of their acres and are most likely to install additional drains [survey summary attached]. The barrier for smaller growers appears to be primarily financial, with the majority of growers viewing tile drainage as an advantageous practice. Based on a comparison of the 2013 and 2014 surveys, drain tile installation is continuing to be accomplished. This was confirmed in an interview with a grower (not part of the project team) who has provided custom retrofit installation services to other growers in addition to installing tiles on his own farm. This grower will provide the installation services for the second depth installation study, a retrofit (into an existing bed) application. He met with three of the project scientists in the fall of 2014 at his farm where he discussed his experiences and showed his tile installations. He noted that on one of the retrofitted beds, he put the tiles into the subgrade and was not satisfied with the result. To compensate, he added surface ditches. It was only after those additions that the bed began to increase in yield, approaching that on beds that had been retrofitted with shallower drains.

Survey responses continue to confirm the information provided by the team of 5 early adopters (see 2012 report): most Massachusetts growers are installing drains at a depth of 6-12 inches (to the top of the pipe), owing to a relatively shallow peat layer and a paucity of accessible sand (at least by comparison to farms in Wisconsin and the Quebec Province of Canada), and the 20-foot horizontal spacing is the most common. That horizontal spacing accommodates working around existing sprinkler pipe spacings, especially important in retrofits. We are focusing on retrofit applications for several reasons – they can be used to drain isolated wet areas of beds (identified as a primary motivation for growers to use tile drains) and they can be done as spot or partial installations, saving money.

In the spring of 2014 (delayed by one year due to grower financial constraints), a tile depth experiment was established on the farm of one of the project participants. The bed in question was to be renovated and replanted. After re-leveling the subgrade, ‘keyhole’ trenches were dug into the subgrade at every 20 feet, corresponding to the future location of the tiles [photo 1]. The keyholes were filled with sand, the tiles placed on top of the keyhole and then a layer of sand was distributed across the bed [photo 2] and vines were planted. Tiles were placed in groups of 5 at two depths, 4-6 inches from the surface and 8-10 inches from the surface. These groupings were replicated three times for each depth. These depths were chosen based on grower surveys of their common practice regarding tile depth – the common depths were distributed between 6 and 12 inches. We chose the shallowest and mid-range depths for this location. A second depth experiment will be established in a retro-fit situation (existing bog, not under renovation) in early 2015 and will target the mid-range depth (8″) and the lower depth (12″). By late summer, vines were established [photo 3] and data were collected regarding cranberry plant and weed densities, cranberry photosynthetic activity, yield, fruit rot, and soil moisture.

Neither cranberry plant nor weed density in September was significantly affected by tile depth [table – weed survey]. However, the deeper tiled areas showed greater carbon assimilation and yield and less fruit rot [graphic – fruit] compared to the areas with shallow tile. An evaluation of soil moisture (tension readings – more negative are drier) following a rain event was consistent with the yield results – the soil at 4 and 8 inches from the surface, drained more rapidly in the areas with the deeper tiles installed [graphic – tension]. This site will host a spring on-farm workshop.

In addition to our renovation site of 6 and 10″ depths, we will install a second depth study of 8 and 12″ depths as a retrofit in 2015. In that study, we intend to do both partial (not the entire length of the bed) and full bed length installations on adjacent beds. This will allow focus on the two primary applications that we have identified for cranberry tile drains – draining localized wet spots and lowering the perched water table. Shallow installations appear to function well in draining wet spots or in sites where deeper installations would be placed in the subgrade with susceptibility to clogging. This site will host a spring on-farm workshop.

Nick Alverson, the project graduate student, along with Casey Kennedy and Peter Jeranyama, is intensively studying an installation at a grower-advisors farm with 18-inch/20-foot spacing to quantify drainage functionality (hydrology), interaction with soil moisture, and potential for mobilization/discharge of nutrients. Because the tile drains mitigate soil saturation, there is concern that growers might over-irrigate, enhancing the potential for offsite discharge of nutrients. This site will host a spring on-farm workshop.

In 2013, on the farm of another grower-advisor we looked at nutrient (nitrogen and phosphorus) mobilization from the soil to the tile drains, comparing controlled-release and standard soluble fertilizer sources. In general, little phosphorus was found in the drainage water from any of the fertilizer treatments. Nitrogen (N) was found in tile drains, with differences in concentration among the fertilizers. Of the four controlled release fertilizers examined, two had less N in the tile drains compared to soluble fertilizer. Thus, there is potential to select materials with less potential for off-site movement of N. The movement of soluble N in tile drainage led us to ask the question – “will increased N along drains result in an environment that favors weed competition?” We will attempt to answer this question by surveying weeds along tiles vs. between tiles at several sites in 2015.

A group of 46 Massachusetts growers, handlers, and researchers came together at the Cranberry Station on December 1 to discuss the 2014 growing season and upcoming challenges for 2015. Most of the project growers were present. At the gathering, one of our project participants reported on a newly renovated bed that had severe fruit rot in 2013. This bed has tile drains installed. In 2014, the grower added the use of tensiometers to his management and had almost no fruit rot. He did note, however, that from 2013 to 2014, the plant canopy had filled in significantly, perhaps reducing heat stress on the fruit and thus decreasing susceptibility to rot. This points out the importance of including irrigation management as part of the BMP guidance for tile drainage use and for continued study of disease incidence with and without tile drains.

Also discussed at the gathering was the large rain event in July 2014. From July 4-5, 5.89 inches of rain was recorded in East Wareham, accounting for all but 3 inches of the total for the month. Growers reported 7+ inches for that storm with one receiving 8 inches in a 6-hour period. As a result, many experienced flooding conditions on their bogs, some coinciding with full bloom. At those locations, even the short inundation reduced crop significantly. The increasing frequency of these large rain events points out the need to continue to improve our ability to rapidly drain cranberry beds.

• Presentation at 2014 Cranberry Station grower meeting
• Photo 3
• Table – Weed Survey
• Figure – Fruit
• Photo 2
• Presentation at Cape Cod Cranberry Growers March 2014 Meeting
• Survey Summary
• Photo 1
• Figure – tension

Impacts and Contributions/Outcomes

The topic of tile drainage continues to be of great interest to MA cranberry growers. The very active frost season in the 2013 spring and the record rainfalls in June 2013 and July 2014 point to the need to be able to drain away excess moisture in the cranberry beds. Experimental components have been established on partner farms and are completed or under continuing evaluation. While project participation has begun slowly primarily due to financial constraints, we have seen steady implementation and know of additional installations planned for 2015. The planned on-farm workshops in spring 2015 should help to stimulate interest in greater participation. The core group of project farmer-advisors remain well engaged and committed to the use of tile drains and to sharing information with fellow growers. One is planning a 100-acre expansion project, including the use of tiles. We have begun to find other growers who are sharing experiences and who will also be important in helping to craft the BMP recommendations for tile use. While our progress has been delayed due to current industry economic conditions, we remain confident that we will reach our target goals.

Collaborators: