Watering with Soil Moisture Sensors - Baseline Systems

©2011, Baseline Irrigation SolutionsooExtremely coarse sand may only hold 0.5 inches of water per foot.Even though plant roots can easily penetrate sand, a plant that is geneticallyprogrammed to have 4-6 inch roots will not have a 12-inch effective root depth nomatter how good you are at irrigating.o If your soil holds 0.5 inches of water per foot and the plant’s effective root depth is 6inches, the plant available water immediately following an irrigation cycle is only 0.25inches.oo• Avoiding dry spotsoooPeak water usage for the plant may be as high as 0.41 inches per day depending onlocation; therefore, you might need to water more than once per day to keep the soilmoisture level above the permanent wilting point.Use the lower threshold watering strategy.• Set your threshold 1-2 points below field capacity.• Set multiple run times for each day trying to avoid the hottest time of the day.• Set run times based on application rates and desired watering depth.• For example, a spray zone applies 1.5 inches per hour, and the waterholding capacity of the soil is 0.5 inches per foot. Filling the soil from drywould take 6 minutes. However, you are not going to start wateringwhen the soil is completely dry, so you need to decrease the run time tosomething like 4-5 minutes depending on distribution uniformity of thezone.Because coarse sand does not allow much horizontal movement of water, distributionuniformity issues are more noticeable in sand.In order to avoid dry spots, you will have to water based on the lowest application ratewithin the zone.The poorer your uniformity, the more water you will be wasting in the average andabove average areas within the zone.Watering with Soil Moisture Sensors22 | P age