IMPROVING POMEGRANATE FERTIGATION AND NITROGEN USE EFFICIENCY WITH DRIP IRRIGATION SYSTEM
Water Management Research
2011 Annual Report
1a.Objectives (from AD-416)
Determine real time seasonal nitrogen requirements to improve FUE of young and maturing pomegranates using drip and subsurface drip irrigation. Determine required level of nitrogen to maintain N levels in maturing pomegranates. Determine effect of N fertilization on macronutrient concentrations.
1b.Approach (from AD-416)
The project will use a complete randomized design of 2 irrigation treatments and 3 fertilization treatments with 5 replications. The water requirement will be determined by weighing lysimeter and the fertilization will be determined by tissue sampling in years 2 and 3 of the project. This is a field project on 2 acres.
This agreement supports Objective 1 of the parent project. The pomegranate trees were manually irrigated twice weekly using a water tank throughout the summer because the irrigation system was under construction. The acid and fertilizer tanks were installed during the winter. The control system has been prepared and was installed during the winter. The irrigation was terminated in September to harden off the plants for winter. Trunk diameters were measured in November. Soil sampling was conducted to establish a baseline for the initial nitrate nitrogen content of the soil and analysis has been completed. Average water use on the lysimeter tree was approximately 0.025 inches per day (.6 mm/day) with a cumulative water use in the lysimeter over the season of approximately 4.5 inches (114 mm) of water. Trunk circumference results show no significant difference on plots with the main effects of irrigation systems. However, there is some difference due to blocking. This means that the trees are uniform throughout the field so there will not be differences in the treatments prior to beginning the fertilization. The installation of the instrumentation was completed in Spring 2011, and automated operation based on measured water loss by the lysimeter was begun. The fertilization treatments will be uniform across all treatments and plots in 2011. This is to insure uniform development of the trees. Differential fertilization will begin in the next growing season.