Water Works: Deficit Irrigation in Processing Tomatoes

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In today’s Water Works, brought to you by AquiMax, research looking at deficit irrigation in the production of processing tomatoes has produced some interesting results.  Because of the nature of what processing tomatoes are used for, tonnage is not necessarily the most accurate metric for crop success.  University of California researchers have discovered an approach using deficit irrigation that can help produce the desired characteristics.Deficit Irrigation

“The issue will be, of course, that individual fields will vary somewhat in this mostly because of the various textures of soils from clays to sands,” said Professor Emeritus in the Department of Plant Sciences at UC Davis Tim Hartz, “so you need to address your management based on your soil type.”

Since the biggest use of processing tomatoes is to make tomato paste and other concentrated material, the goal in production is to maximize the amount of tomato solids in the fruit, with the least amount of water content as possible.  Finding the appropriate balance in an irrigation strategy to produce fruit with a low amount of water content, but still a healthy and vibrant crop is a critical component of employing deficit irrigation techniques.

Hartz noted that finetuning will be required for each individual grower, but they have found a solid baseline to start from. “In general, using about 50 percent of what we call ETA or actual evapotranspiration, what the crop would transpire if it had enough water, adding half of that amount over the fruit ripening period appears to be a reasonable place to start the process,” Hartz said.

Some of the things to consider when contemplating this type of approach are what time of year it is, as well as the amount of moisture that may already be in the soil.  By reducing the amount of water being applied to the crop it can help reduce some of the costs of groundwater pumping as well as cutting some of the costs related to transport.


Listen to the report below.