A Simple, Inexpensive, DIY System for Controlling the Height of High Tunnel Sidewall Rollbars Remotely

The Problem

High tunnel growers come to know through trial and error and some hardship that their success depends on managing the temperature and other conditions inside the high tunnel with care. That is, that maximum yield and quality are possible only when conditions inside the tunnel and near the crop are optimal as often as possible. High tunnel growers also come to learn that achieving optimal conditions round-the-clock and day after day is difficult and costly in various ways. For example, it is difficult because crop needs and conditions outside the tunnel can change dramatically and quickly, especially during key points in the crop cycle in spring and fall. Reacting to changes in crop need and other must-dos on the farm can be challenging. Managing temperature and other conditions inside the tunnel usually also requires undesirable investments in time, effort, and money. Of course, conditions inside the tunnel are usually set by controlling the extent to which sidewalls, vents, and/or doors are open, with the height of sidewall rollbars being particularly significant. The trouble is that the position of most sidewall rollbars is set by hand. This requires the grower or another person to stop what they are doing, travel/go to the high tunnel, and reposition the rollbars manually. This commitment and expense are unfortunate enough. However, the fact that it may need to be done multiple times per day for many days in a row for conditions near the crop to remain optimal becomes problematic for many high tunnel growers. They are required to choose between: (a) continually repositioning sidewall rollbar heights (“babysitting” the tunnel) at some direct cost and at the expense of engaging in other activities or (b) setting sidewall rollbar position at a “compromise” height and accepting the consequences of conditions (e.g., temperature, wind) being above- or below-optimal for potentially lengthy periods. In our view, high tunnel growers should not be required to have to make that choice.

Existing and New Solutions

Various companies (e.g., https://www.advancingalternatives.com) agree and offer automated ventilation control systems involving sensors, a control panel, and sidewall motors. We have had a version of the Advancing Alternatives system on a moveable Rimol high tunnel since 2015 and have been very pleased with both (control system, high tunnel). The high tunnel’s sidewall motors, endwall vents, inflation fan, and control panel are all powered by a standard 12-volt battery charged by one medium-size solar panel. It’s an impressive system. However, we are also aware that fully automated approaches to ventilation can cost more than some growers are willing or able to pay and place control of the high tunnel conditions largely in the hands of the control panel, not the grower.

Therefore, we have been working to develop a low cost, DIY way to control sidewall motors remotely that keeps the grower directly in control of sidewall position (e.g., to account for conditions that a fully automated system may not monitor, at least without additional cost).

Alex Herridge will soon complete his undergraduate degree in Computer Science and Engineering at The OSU and his contributions to the effort have turned the idea for this alternative, grower-friendly system into reality. Full plans for the system will be available in a separate publication soon but its key features include:

1. Standard sidewall motors powered by a battery-solar panel combination, as described above;
2. A standard voltage-regulating unit converting 12 volts from the battery to 24 volts needed by the motors (approx. $80.00);
2. A motor controller (available at electronics stores or online for approx. $15.00);
3. An off-the-shelf, WiFi-enabled microcontroller to act as the brains of the system (approx. $5);
4. WiFi already present on the farm property or wireless access with a hotspot or similar ($0 to monthly charge typical of a mobile phone plan); and
5. Code for the motor controller (no charge).

To proceed, motors are attached to sidewall bars and powered and a basic network connection linking the grower’s phone (or other device) and the microcontroller is established. The entire process can be completed in approximately four hours once all materials and WiFi are on site. Thereafter, the sidewall motors can be controlled with one’s mobile phone or other linked device using a simple interface setup for the purpose. Pictures of the preliminary, bare-bones version of the interface we used to raise and lower a sidewall bar on a high tunnel at OARDC on December 13 are given here. The bottom-line of this approach and system is that it will allow growers to raise and lower sidewalls from wherever they have internet access using low cost, off-the-shelf hardware. Watch for additional posts regarding this system at VegNet and other locations and contact me (Matt Kleinhenz; kleinhenz.1@osu.edu; 330.263.3810) if you are interested in learning more about or testing the system on your farm.

(OSU Computer Science and Engineering student with the motor and micro controllers and standard battery charged by a solar panel.)

(Exterior of the Rimol moveable high tunnel and the solar panel used to charge the battery powering rollbar motors, endwall vents, inflation fan, and control panel.)

(Simple, password-protected interface for controlling sidewall rollbar position. Usable from anywhere the owner has internet access and allowing them to control sidewall rollbar height remotely.)

 

 

 

 

 

Soil Heating Effects on Days to Harvest, Quality, and Regrowth of Three High Tunnel- and Fall-grown Vegetable Crops

Grower interest in fall-to-spring marketing of crops freshly harvested from high tunnels is increasing, along with the number and types of questions they have about the production side of the process. Excellent resources and information are available on major aspects (e.g., crop selection, planting schedules) but growers continue to seek and test cost-effective steps to enhance yield and/or quality. Managing temperatures near the crop so they maximize yield and quality has become a major focus for some. We say “temperatures” because root-zone and above-ground temperatures are often different and influence crop development and composition differently. So, we have been studying the effects of common production materials and strategies used to alter temperatures near the crop for many years. Experiments have included various combinations of row covers (film, fabric) to increase air temperatures (primarily) and soil heating. The most recent experiment was started in September and is described in the five panels below. Please contact us (Matt Kleinhenz; kleinhenz.1@osu.edu; 330.263.3810) if you would like more information, have questions about your production methods, and/or would like to discuss collaborative research that could be completed on your farm.

 

Optimizing Film, Fabric, and Root Zone Heating Combinations in Fall-to-Spring High Tunnel Vegetable Production

An increasing number of growers look to harvest and market vegetables grown in high tunnels fall to spring. Selling freshly harvested material (e.g., leafy, root, and other crops) from roughly October through April appeals to some farmers but it also raises many production-related questions in practice. Many of these questions relate to the use of plastic films, fabric row covers, and supplemental heating (including of the root zone). Questions such as which ones to use, when, for how long, under what conditions, and in what combination are common. The Vegetable Production Systems Lab has completed research in this area for more than fifteen years, cooperating with farmers often and using high tunnels at OARDC in Wooster which range in size, approach (conventional, organic; flat ground, raised beds), and other characteristics. Findings from these experiments have been summarized in publications (including VegNet) and during programs around the Eastern U.S. Our newest experiment was initiated on Sept 23 and includes the 20 wood-framed raised beds shown here, each seeded to either Scarlet Nantes carrot, Outredgeous lettuce, or Ovation greens (Brassica) mix from Johnnys Selected Seeds. This experiment will examine the influence of daily (8 am – 5 pm) root zone heating (accomplished with electric cables placed approx. 7 inches below the soil surface) in combination with vented plastic film row cover on crop development, yield, and quality. Vented plastic film covers all twenty plots (beds) while daily root zone heating occurs in ten of the twenty plots. Root zone heating will be discontinued at six weeks after seeding but the film will remain in place through final harvest in December. These treatments were chosen partly because two findings have been common in previous research. First, crops (e.g., lettuce, Brassica greens, carrot) and varieties have responded very differently to the use of film, fabric, and root zone heating — whether used alone or in various combinations. The same trend appears to be underway given the relative sizes of the crops shown in the pictures below (taken 10/9/21; carrot at top, Ovation Brassica mix in middle, lettuce at bottom). Second, in this experiment, we are very interested in root zone heating as a supplement to the above-ground heating that occurs with film in place and is typically pronounced September to early November and late January through March. Finally, temperature and relative humidity are recorded in each plot every five minutes, allowing us to describe treatment effects on these conditions very reliably. The sensor unit shown in the bottom-most picture below also relays the temperature and relative humidity readings to the “cloud,” allowing us to see the numbers in near real-time. This battery- and solar-powered Hobolink monitoring and reporting system from Onset Computer Corporation has been in place for more than two years and has greatly enhanced the efficiency and effectiveness of our high tunnel ventilation management across the ten tunnels in our program.

 

Grafted Watermelon Plants: Under What Conditions and Practices Does Using Them Offer the Best Return on Investment?

A lot of research is focused on answering that two-part question for watermelon and other crops (e.g., cucumber, cantaloupe, tomato, pepper). Full answers will emerge as growers and researchers share and integrate their experiences then evolve as circumstances change. Currently, most agree that using grafted plants is most beneficial when a resistant rootstock is selected to help offset the effects of a significant soilborne disease (e.g., Fusarium, Verticillium), regardless of crop. However, rootstocks with additional traits are being tested under other troublesome conditions (e.g., salinity, heat, cold, drought, flood). Growers are encouraged to listen as peers and research-extension and industry personnel share new information on the performance of grafted plants under various conditions. Information will be specific to crop, setting (field, high tunnel), system (conventional, organic), market, farm size, and other key variables.

Soil and other production conditions are not the only factors that influence the value of grafted plants to growers. Practices used to grow the plants are also important. Plant and row spacings (plant populations), irrigation and fertility programs, and planting and harvesting dates may also affect growers’ experiences with grafted plants.

Industry-research/extension partnerships can help fast-track arriving at answers to where and how grafted plants should be grown for growers to benefit most. We work with plots at OSU and on farms to understand the impacts of in-row spacing, fertility programs, and more on watermelon fruit yield and quality. Grafted and standard (ungrafted) plants are included in each experiment. Results from a multi-year study in Wooster through 2020 are summarized in a short video at https://go.osu.edu/vegeprosystemslab. Overall, fruit number and total weight have been significantly greater in grafted plots and at an in-row spacing of five versus four feet (between-row spacing of six feet in all cases). The results suggest growers can reduce plant populations but increase yield meaningfully – i.e., reduce plant costs while increasing income potential. Importantly, evidence of Fusarium in this experiment has been absent or minimal in all previous years. As explained and shown in the panels below, Fusarium is affecting the experiment significantly in 2021. Standard (ungrafted) Fascination and Sweet Dawn plants are very weak or dead while grafted versions of both (Carnivor, Pelops as rootstocks) remain healthy and vigorous. Harvest will begin soon and fruit yield data will be available by season’s end. Please contact me if you would like more information on this experiment or grafting.

Optimizing Vegetable Fertilizer Programs

Recent farm visits, questions from growers, and observations of research plots have me thinking about nitrogen and other fertilizer programs for vegetable crops grown in open fields and high tunnels for fresh and processing markets. What are optimal ranges for each production situation, which factors influence optimal rates most significantly, and what steps can growers and others take to identify optimal rates for each farm and planting?

Ranges currently recognized as optimal are published in numerous guides, handbooks, and other resources. The Midwest Vegetable Production Guide for Commercial Growers, Southeast Vegetable Production Handbook, Mid-Atlantic Commercial Vegetable Production Recommendations, New England Vegetable Management Guide, and references available from Cornell (e.g., https://cropandpestguides.cce.cornell.edu/) and other universities are helpful in Ohio and the region. The publications provide operating fertilizer application targets and tips on how to reach them. Targets in the publications are the best available benchmarks. However, it is best to think of them as not fixed in stone and as needing to be validated for individual cropping situations. On-farm validation (adjustment by trial and error) using published, research-based and other reliable benchmarks as starting points saves time, money, and headache.

Indeed, since production conditions change continuously and research-based recommendations require years to develop, evaluating fertilizer programs (material, rate, timing, placement) often is good practice. Like effective crop protection programs, fertilizer ones are not static, they need to be updated as weather patterns, varieties, rotations, fertilizer materials and their costs, and other factors change. Observe crops now and through the remainder of the season and ask if you are convinced their fertilizer programs are optimal. If you aren’t convinced, consider experimenting carefully.

Experiments are most effective when they account for factors that tend to influence their outcomes most significantly and consistently. To refresh my memory on these factors, especially nitrogen application rate effects on watermelon and other Cucurbit crops, I looked at extension resources referenced above and reports from research completed in the U.S. and other countries. I was also very pleased to hear from Ohio growers on the same topic.

That input pointed to the following seven factors as most likely to shape optimal fertilizer, especially nitrogen, application rates for individual farms, soils, crops, and plantings.
1. Soil type and condition. Sandy, loam, or clayey? Organic matter level? Have a prominent plow layer or other condition affecting drainage, etc? Fertilizer programs must be calibrated to soil type and condition since they influence many facets of nutrient availability at any one time.
2. Fertilizer application approach. For example, will fertigation be used? Fertilizer application approaches influence which materials are used, when and where they are applied, and their likely efficiency.
3. Precipitation and irrigation. Soil moisture management is a very large percentage of nutrient management. Are the irrigation and fertilizer programs in sync? Is rainfall cooperating? Can the program be adjusted for weather?
4. Variety(ies). Shifting market expectations (e.g., large to personal-size melon) may have implications for the fertilizer program. Similarly, the program may also need to be adjusted to maximize gains from using grafted planting stock because rootstocks may differ in, for example, their abilities to obtain nutrients and water.
5. Cultural practices. Production on plastic-covered raised beds versus the flat. Standard versus strip- or reduced tillage approach. Row and plant spacings (plant populations). These and other factors are consistently mentioned as factors shaping the four R’s (material, rate, timing, placement) of all fertilizer programs. The fertilizer program may need to be tweaked if any of these factors are changed.
6. Crop growth stage. Especially important for fruiting vegetables, including Cucurbit and Solanaceous crops. Nitrogen and other macro- and micronutrient levels influence many aspects of crop biology directly impacting (fruit) yield and quality from seeding/transplanting to harvest. Metering nutrient availability by crop stage is a proven, essential tactic in soilless greenhouse production. The same level of control is impossible in soil-based field or high tunnel production; however, a realistic application of the principle can be beneficial in both systems.
7. Nutrient credits. There is often little need to apply what is already there. Basing planned applications on current, reliable soil test data is a cornerstone of successful, efficient, cost-effective fertilizer programs.

Finally, setting optimistic but realistic yields goals, especially for non-vegetable rotation crops, if any, is also beneficial. Realistic yield goals help avoid significantly under- or over-applying fertilizer, regardless of crop. Avoiding such deficiencies and excesses enhances the overall return on investments in the current and subsequent crops.

Syncing the Amount of Water Available to Crops with Their Need for It

Vegetable growers work to ensure their crops have the water they need, but only the amount they need, from crop initiation through harvest. It’s a big, complex job requiring attention to water supply and demand, including soils and crops, and much preparation because the time to verify that drainage and irrigation capacities are adequate is before they are needed.

Indeed, when rainfall is excessive, the combined abilities of the soil and drainage system to accommodate the load is key, along with the crop’s ability to withstand flooding. Mapping fields soon after a “flooding rain” or lengthy irrigation cycle can identify where drainage improvements may be essential. Such improvements often result from combinations of “plumbing” (e.g., tiling), soil management and additives, and rethinking (lengthening and diversifying) crop rotations. If water is entering the high tunnel from outside it, grading the site may be necessary.

Irrigation is applied when there is clear evidence soil moisture is below crop need. Verifying the irrigation system is up to the task and knowing when to turn the system on and off are three critical tasks and decisions.

Whether overhead or drip, each irrigation system can deliver a specific amount of water in a fixed amount of time. However, using flow meters and periodically checking the condition of the system helps verify the flow rate to the crop is truly equal to the system’s calculated capacity. Leaks and blockages interfere with delivering the desired amount of water throughout the field or planting.

Knowing when and for how long to run the irrigation system requires clear and reliable reads on both the crop’s need for water and its availability from the soil. Years of farming experience and a strong understanding of soil conditions and irrigation systems are obvious assets in making those assessments. However, off-the-shelf technology (e.g., soil probes, tensiometers, gypsum blocks, flow meters) and decision aids (e.g., crop evapotranspiration calculators, irrigation charts in production guides) complement experience and reduce the irrigation learning curve. Irrigate to meet crop need and avoid under- or overshooting it significantly as often as possible.

Another point about crop water needs which affect the timing and/or amount of irrigation: they vary meaningfully with multiple crop-based, abiotic, and grower-based factors.

Two related ones may be critical at this point in the season many have experienced to date. First, alternating dry-wet periods have made it difficult for some to maintain soil moisture at levels consistently equal to crop need. For example, some have asked how much to credit rainfall under a variety of circumstances, including when plastic-covered raised beds are used. Moisture sensors under the plastic would be useful in making that determination. Second, soil conditions and irrigation practices can shape root systems which, in turn, influences the crop’s ability to take-up water. Overall, excess soil moisture, including because irrigation has been excessive, can result in shallow root systems. Shallow root systems limit plant access to water, making the crop more prone to displaying symptoms of low water stress although moisture levels deeper in the soil profile may be adequate. Wilting or other symptoms trigger irrigation, continuing the cycle. So, while it is never clear beforehand if the season will be dry, wet, or just right, the best practice is to irrigate according to crop need from the start and to rigorously cross-check assessments of crop need against the best-available information.

Partnerships, Teamwork, and Persistence Bring New Potato Varieties

Hundreds of new, promising, numbered (unnamed) potato genotypes are evaluated at research station and farm sites each year. Ohio State is one of many institutions involved. In 2021, we are evaluating more than 100 numbered selections from four breeding programs against seven standard industry varieties. The same evaluation techniques we use can be employed by individual vegetable farms.

High-performing varieties are just one of the core raw materials for vegetable production, which also relies on water, mined or manufactured inputs and equipment, and the know-how to use all of them. Whether formal or informal, variety evaluation is essential for individual growers and the vegetable industry. Since now is when differences among varieties of individual crops begin to show themselves on farms and research stations, it’s a good time to discuss traits and processes used to evaluate varieties.

When we evaluate genotypes of potato being considered for naming and release as varieties, we score plant maturity and record total and marketable yield and more than ten tuber characteristics for each entry (e.g., tuber size and shape, skin color and texture, flesh color, eye depth, incidence of internal defects, and specific gravity and chip color). Collaborators in other states evaluate the same genotypes for pest and disease resistance, crop tolerance to heat stress, storage effects on tuber quality, and tuber cooking quality and sensory properties. So, like for other vegetables, developing potato varieties requires teamwork.

Background on the Variety Development Process

Experimental genotypes originate in public-sector breeding programs based at universities and the USDA. In fact, although varieties developed by private companies (e.g., major processors) contribute significantly, the U.S. potato industry (especially the fresh/tablestock and chip sectors) has long relied on varieties developed in the public sector. Public-sector varieties are developed by large teams led by universities, USDA, and/or state industry associations or organizations and account for most of the available varieties, acreage, and value of production.

Whether public or private, variety development teams include breeders/geneticists, agronomists/horticulturalists, plant pathologists, entomologists, food scientists, farmers, processors, and people with expertise in related areas.

Potato varieties are named, released, and made available for commercial use only after years of comprehensive, widespread testing, beginning with just a few plants and concluding at farm scale. Once released, varieties support processing (i.e., chip, fry), fresh market/tablestock, and/or breeding programs. The varieties ‘Atlantic’ (released in 1976), ‘Dark Red Norland’ (1957), ‘Katahdin’ (1932), ‘Kennebec’ (1948), ‘Red LaSoda’ (1953), ‘Superior’ (1962), and ‘Yukon Gold’ (1981) are just a few examples of public-sector varieties that have been planted to many thousands of acres over decades of production. Varieties like these set the bar for and/or are found in the “family trees” of newer, increasingly popular varieties.

Still, markets, production conditions, and industry factors change continuously. Therefore, variety development must be ongoing and once-popular varieties are eventually displaced by new, more farmer-, processor-, and consumer-friendly ones. The process is designed to enhance industry success and consumer satisfaction.

Evaluation is nearly continuous since sites are located throughout the U.S. and the process begins before planting and ends long after harvest. Groups based in the East, Midwest/Upper Midwest, West and Pacific Northwest, and South often coordinate the work. Ohio State and Ohio farmers and processors have participated annually for more than fifty years. We emphasize the evaluation of genotypes originating in eight breeding programs and with potential value in fresh and chip markets and have contributed to the release of multiple varieties used in Ohio and elsewhere.

Sharing Results

Data from our 2021 trials will be summarized in a report available at https://u.osu.edu/vegprolab/technical-reports/ with data from 2020 and previous years available at https://neproject.medius.re/trials/potato/ne1731 and https://neproject.medius.re/. Later, we will join team members from Maine, New York, Pennsylvania, North Carolina, Virginia, Florida, and USDA and industry partners to discuss evaluation outcomes and begin selecting new entries and others to be evaluated again or dropped from the program. With information reflecting variety or experimental selection performance in the field and on the plate, the breeder and team have key information when making the thumb-up/thumb-down decision on each entry.

Still, for all crops, the performance of each variety (or experimental genotype) hinges on how it is managed, the know-how allowing growers to get the most from each variety. Planting and harvest dates, plant populations (spacings), irrigation and fertility programs, etc. influence variety performance and, therefore, whether a grower will select the variety again. So far, potato genotype evaluations at Ohio State have been completed without irrigation and this approach has clearly affected tuber yield and quality. We are rethinking this approach and look forward to speaking with vegetable and potato growers about their use of irrigation.

Recognize and Mitigate Crop Heat Stress

Recent conditions in some areas (soaked soil, fog- and dew-filled mornings, high daytime humidity) can give a different impression about the season so far than weather data at https://www.oardc.ohio-state.edu/weather1/ and various forecasts. Temperature, rainfall, and other data are collected around the clock at OSU vegetable (and other) research sites in Fremont, Celeryville, Wooster, and Piketon and have been for decades. So far in 2021, these four locations have accumulated less precipitation and more growing degree days (GDD) than their historical averages. Also, climate and weather authorities reported on June 11 that the Upper Midwest, including Ohio, is set to experience hot, droughty conditions. Most agree that a dry year is less problematic than a wet one — provided irrigation is possible. However, it can be difficult for vegetable growers to escape the unwanted effects of excessively high temperatures. A way to separate potentially minor, moderate, and severe heat stress, example effects of moderate-severe heat stress, and main strategies for mitigating heat stress during production are summarized below.

Five Major Factors Influencing Whether Heat Stress is Minor, Moderate, or Severe

  1. Crop and variety (sensitivity 1). All crops and varieties have a range of temperature in which they perform best. A crop’s genetic past (i.e., heritage/Center of Origin) and level of improvement through breeding matter. Individual crops and varieties are thought or proven to be relatively heat tolerant or intolerant.
  2. Timing (sensitivity 2). When high temperatures occur in the crop cycle is key. Crop plants can tolerate high temperatures more reliably at some stages than others. Even relatively tolerant varieties can be impacted by temporary spikes in temperature at the “wrong” time.
  3. Intensity. The extent to which actual temperatures exceed the crop’s and variety’s optimal range is important … 5 degrees? 15 degrees?
  4. Duration. The length of time the temperature was consistently above optimal. Short periods of intense stress can be problematic although the effects of prolonged moderate stress typically accumulate.
  5. Mitigation: were steps taken to lessen the stress?

Combinations of these five factors represent common scenarios. For example, for vegetables for which pollination is required, excessively high temperatures lasting only hours can disrupt pollination or trigger flower or fruit drop or interruptions in normal developmental patterns. The result can be loss of a “set” (dip in production) and/or malformed or misshapen units to be harvested (e.g., pods, fruits, roots, stems, leaves, tubers). Longer periods of above-optimal temperatures can speed (e.g., bolting) or delay (e.g., prolonged vegetative state) maturity depending on the crop and when they occur in the crop cycle. Heat stress is also implicated as a contributing factor in fruit ripening and physiological disorders (e.g., blossom-end rot). Above-optimal temperatures can also trigger changes in the chemical composition of plant tissues, possibly affecting the color and/or taste of marketable units. Similarly, prevailing temperatures can influence a crop’s tolerance to typical inputs and protectants.

Irrigation and shading are among the most common strategies for mitigating the effects of excessively high temperatures in field and high tunnel vegetable production. Irrigation is essential for the obvious reason that evapotranspiration is the crop’s primary means of cooling itself. A warm period or season calls for the best irrigation (scheduling) practices, not just pouring water on because, as we know, excessive irrigation (soil moisture) disrupts water uptake, compounding the heat stress problem. Circumstances allow some growers to shade the crop (e.g., in high tunnels) as they attempt to reduce the temperature around it.

At this time, 2021 has not earned the label as a “hot or heat stress” year. Let’s hope that remains true even as we remain aware of factors contributing to heat stress and ways of addressing it. In addition to proper irrigation, shading (if possible), and careful application of inputs and protectants, consider tracking variety performance closely to aid in variety selection going forward.

What are You and Others You Hear from Willing to Pay for New Farming Technology?

Technology surrounds us and is often defined as: “the application of scientific knowledge for practical purposes, especially in industry” and “machinery and equipment developed from the application of scientific knowledge.” Whether by definition or experience, it’s clear that vegetable production requires a lot of technology. Hybrid varieties and clean lots of true-to-type seed, seed coatings and treatments, the many crop inputs (e.g., fertilizers, protectants), small and large pieces of machinery and equipment … the list is long and growing. Each technology growers rely on has its own characteristics and pros and cons of use. Therefore, it’s important to be clear on what you are willing to pay for a technology and what others (e.g., advisors, educators) say about it. Helping develop and people to use new technology effectively is a big part of my job. In recent years, I have tested and advised people on high tunnel, grafting, microbe-containing crop biostimulant, and other technologies. So, what growers like and dislike about these and other technologies and are willing to pay for them is important to me, too. Growers and others provide key information, sometimes in scientific reports. A report describing peoples’ perspectives on biodegradable mulch (BDM) caught my attention recently. It is useful in two ways. First, it includes important information on BDM, an emerging technology. Second, it can help guide similar evaluations of other technologies and, perhaps, products.

The report was published by a team of investigators led by Kuan-Ju Chen (University of Guam) and including partners at Washington State University, Colorado State University, and Massey University (New Zealand). The report is available at https://doi.org/10.21273/HORTTECH04518-20 or from Dr. Chen or me by request.

The team’s specific objective was to assess peoples’ willingness to pay (WTP) for BDM characteristics. More broadly, they wanted to understand how ‘green’ technologies affect agricultural production when they are introduced into the market. Using input from farmers, educators, advisors, and others, the team assessed the WTP for adopting BDMs and peoples’ rankings of the relative importance of different BDM characteristics. The input indicated that study participants were willing to pay a statistically significant premium for healthy soil and a lower fraction of plastic residue left in the field after harvest. The data also indicated that farmers and others ranked the attributes of BDMs differently. In this case, attributes included cost, soil health, plastic residue, and consumer premium.

People interested in BDM may wish to examine the report closely or contact me, the authors, or BDM experts about it. People considering investments in a technology (new or old) or advising people on one may wish to review the report as an example of how willingness to pay assessments are completed.

Irrigation Water Quality Testing

The active irrigation season is underway, so let’s pause briefly to review why irrigation water quality testing is important, the value of proper sampling, and what to look for in test results.

Links to seven resources on the topic follow this brief summary. Reviewing those and similar resources is a good idea.

To summarize, irrigation water can:
1. Have a mineral or chemical composition that damages soil, irrigation plumbing and equipment, or crops directly. That same composition may also lower the effectiveness or complicate the use of other inputs such as fertilizers of crop protectants.
2. Contain plant pathogens.

Of course, using the same water source to wash produce and/or fill spray tanks can raise additional unwanted possibilities.

Regardless, the bottom-line is that irrigation water quality affects growers directly and indirectly and in the short- to long-term.

Testing the chemical and particulate (nonliving) composition or characteristics of water used for irrigation is relatively straightforward when major recommendations are followed. Keep the “garbage in-garbage out” principle in mind and collect, handle, and submit your water samples carefully. Also, be mindful that special steps are required for sampling surface (pond, stream/river) versus well water. Consult your testing service for specific guidance, if needed. Testing for plant and/or human pathogens is also important and consulting a plant pathologist and/or human health and food safety specialist is recommended. As you know, Drs. Sally Miller, Melanie Ivey-Lewis, and Sanja Ilic with The OSU are experts in these areas.

Test results of the chemical characteristics will often include the levels of: pH, total alkalinity, hardness, electrical conductivity, total dissolved solids, and multiple elements. The importance of and acceptable ranges for each are outlined in resources linked below and other publications.

Soil and plant testing are common – consider testing irrigation water, too!

Related Resources

https://extension.psu.edu/interpreting-irrigation-water-tests

https://njaes.rutgers.edu/FS793/

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-4630/L-323–2013.pdf

https://cfgrower.com/testing-irrigation-water-for-pathogens/

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1160&context=anr_reports (focused on nursery and greenhouse crop management but also a good reference for vegetable growers)

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs144p2_033068.pdf

Knott’s Handbook for Vegetable Growers (https://www.amazon.com/Knotts-Handbook-Vegetable-Growers-Maynard/dp/047173828X) also has five pages of handy reference tables on irrigation water quality, including regarding crop tolerance to various characteristics of irrigation water. Contact me for more information, if needed.