About half of the watermelon fields in our area are not equipped with supplemental irrigation. Watermelon production in these fields is therefore dependent exclusively on rainfall. In fields where supplemental irrigation is available, drip irrigation under black plastic mulch is the most commonly used system. Overhead irrigation through central pivot is also used in some fields. Irrigation management is complex in our area because of significant but unpredictable rainfalls during the watermelon production season. Supplemental irrigation is profitable because it avoids water stress during periods of drought, thereby increasing and stabilizing yields. However, there is always a question whether supplemental irrigation is required for watermelon production in our region; if so, how much water should be applied; if not, what would be the consequence if there was an extended drought period. I do not have a straightforward answer to all the questions. But here are a few facts that I[Read More…]
3 articles tagged "Irrigation".
We recently received several calls reporting blossom end rot of tomatoes (Figure 1). Although blossom end rot is caused by deficient supply of calcium to the developing fruit. The occurrence of this physiological disorder often relates to inconsistent supply of water. As a general rule, vegetables require 1-1.5 acre-inches of water per week. Since there is no rain in high tunnels, all the required water should be applied through irrigation. How does one determine if enough water has been applied to vegetables? This article provides some ideas. The first information needed is the irrigated area. For example, tomatoes are growing in a 30 × 96 high tunnel with 6 beds that are about 4 feet wide. Then the irrigated area is about 2,304 square feet (6 × 4 × 96 = 2,304). An acre has 43,560 square feet. So the irrigated area is roughly 2,304 / 43,560 = 0.05 acre.[Read More…]
I have recently received calls from growers who use surface water to irrigate produce crops. Their concern was that the results of their current water tests were very different from their last tests and that levels of indicator organisms appeared to have increased dramatically. Ponds and lakes that are used for irrigation can be very dynamic. Research has shown that levels of indicator organisms can change dramatically in a very short time. Because surface water is open to the environment and unprotected, changes in temperature and weather can affect ponds and lakes. During the spring and autumn seasons, ponds and lakes undergo inversions, stirring up sediments that have settled on the bottom of the pond. Rainfall can also cause bottom sediments to be stirred up. Bottom sediments may contain any number of materials. Soil particles from runoff are one of the primary components. Decaying bits of plant and animal debris may also be found in bottom[Read More…]