Optimizing Soil Moisture in Drip-irrigated Soils

When a lot must get done and crop needs for water are high, fine-tuning irrigation is usually an afterthought. Still, consider a few issues when working to get the most from drip-irrigated crops. This is one thought that came to mind when I returned to an article published by Drs. Michael Dukes, Lincoln Zotarelli, and Kelly Morgan of the University of Florida. The article is available at https://journals.ashs.org/horttech/view/journals/horttech/20/1/article-p133.xml?rskey=f046lk. Do not be thrown by the title, there is something for Ohioans and others to gain from the summary. Sections on verifying and optimizing soil moisture distribution in drip-irrigated soils (especially within plastic-covered raised beds) are one example.

Of course, distribution is influenced by soil type, irrigation frequency and duration, loss (ET, drainage), and other factors. Sampling using a soil probe or other approach can reveal unexpected and, possibly, damaging surpluses and deficiencies which is a first step in correcting them. My team and I have experienced this firsthand many times over the years, including this season. Taking 10-15 minutes to pull soil samples has told us we can or cannot afford to delay an irrigation and where it is least or most important relative to crop need, weather, other tasks, etc. Also, the article from the Univ of FL includes pictures depicting desirable and undesirable distributions of soil moisture and effects of under-and over-watering. For example, the team used dye to track the movement of water and fertilizer through and outside the rooting zone. Seeing the pictures helps illustrate what is rarely seen (so must be imagined) but can be seen with a spade or shovel and a little time and care.

The Dukes, Zotarelli, and Morgan article (Use of irrigation technologies for vegetable crops in Florida; HortTechnology 20(1):133-142) is highlighted here. However, there are many other similarly excellent irrigation guides and resources. All contain bits of information we can act on. I am also glad to help resolve irrigation-related questions; just let me know if I can help (kleinhenz.1@osu.edu; 330.263.3810). Regardless of how you proceed, recall that in addition to the sunlight, air, nutrients, and protection crops require, the right amount, timing, location, and quality of water is also very important. As far as nutrients are concerned, recall that fertility experts often say root zone moisture strongly influences whether their levels, etc are optimal.

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