It was great to attend the 2022 Mid-Atlantic Fruit and Vegetable Convention in February. It gave me a chance to catch up with old friends, Extension/research colleagues and growers. I especially wanted to gather information on drip irrigation for this column. I know that growers understand why timely irrigations are important, but let me state the obvious: of all foods, vegetables provide the most water, often being over 90% water by weight. Vegetables high in water include lettuce, celery, bok choy, radish, cucumber, zucchini, watercress, tomatoes, bell peppers and asparagus. As I’ve said over the years, somewhat tongue in cheek, growers are just marketing water in different shaped and colored packages.
I always enjoy catching up with Bill Wolfram, district sales manager, drip irrigation sales in the Northeast and Eastern Canada, for the Toro Company. Bill is a wealth of information and experience on drip irrigation and has assisted me and my colleagues over the years by providing the drip irrigation supplies that enabled us to do our research and Extension work. I always said that it was the unique partnership between land grant university personnel, growers and industry folks like Bill that moved any technology forward into the mainstream.
It was 1980 when I began working on drip irrigation at North Carolina State University along with the late Dr. Doug Sanders and Dennis Adams (my technician at the time). In addition, I was fortunate to begin a valuable collaboration with Eddie Denny and Clarence Lemons of Hendrix and Dail Inc. out of the Oxford, NC, demonstrating and promoting the entire plasticulture system.
We promoted plasticulture as a system that encompassed individual components such as plastic mulches, drip irrigation, fertigation, weed control measures, transplanting machinery, direct seeding technology, season extension technology (row covers, low tunnels and high tunnels) and recovery of the used plastics and utilization of the energy trapped in the used plastics. Drip irrigation continues to evolve and become even more widespread in the U.S.
Bill and I always have great discussions on the latest innovations in drip irrigation, water measurements under plastic mulch and what the best instruments are for measuring moisture and ensuring crops are getting enough moisture but not wasting water. I’ve always pushed Bill and others to provide me with real time visuals of water moving through the soil under the plastic-covered beds. My friend Dr. George Hochmuth, Professor Emeritus, University of Florida, an irrigation/fertigation expert, always admonishes me that you have to be a good irrigator first to be a good fertigator. Since most of the action under the raised plastic mulch bed occurs no deeper than 12 to 15 inches, I believe we’re moving toward having the technology that will be displayed on a computer screen or phone showing the movement of water and the fertilizer under the bed.
I believe that water will get even more valuable in the future, and we need to make every drop count. Many times, we reduce our yields by overwatering.
Irrigation needs for plants can vary, not just by the day, month or season, but by the minute. Changes in environmental conditions can have a dramatic impact on plants, particularly in the zone where the roots are most active in obtaining water (eight- to 12-inch depth).
Plants are highly sensitive, dynamic organisms which have evolved to compete for limited resources both above and below the ground. Plants are constantly assessing their circumstances and adapting in response to environmental cues. Under- and over-watering produces telling responses in plants’ root activity. The inability to realize a crop’s needs with a precise application of water puts a fundamental constraint on plant growth and ultimately impacts crop yield and quality. Studies have shown that the absolute best source of actionable information for effective water and nutrient application is present and accessible in the plant itself. So along with field capacity, extensive environmental monitoring of the crop environment needs to be conducted.
I’m a person who began his career in drip irrigation using a screwdriver that had the head filed to a sharp point, which I then inserted into drip tape and a layflat hose, making a hole into which I inserted a piece of quarter-inch diameter feeder tube cut on both ends at an angle. I felt more like a vascular surgeon doing bypass surgery than an irrigation man. We have come a long way, and I expect us to advance even further in the future.
As new technology, instrumentation and analytics become available, our ability to ascertain the needs of a crop plant will become even more precise and will increase dramatically the effectiveness of our irrigation/fertilizer applications, saving more water in the future.
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