Field implementation of “Irrigation on Demand” technique in commercial orchards
The Israeli southern Arava region is characterized by an annual ET0 (class A pan) of ~3200 mm and only ~20 mm of precipitation. In other words, the total amount of rainfall in one year is not much more than the maximum ET0 for a single summer day (15mm). Typical to many other arid regions, the water resources of the southern Arava are limited and of low quality. As the agriculture in this region expands, it consumes more water and fertilizers. To improve the water use efficiency of crops and decrease the drainage, irrigation water should be applied according to the plant demand. In order to achieve this, a cheap and reliable water content sensing system and an irrigation system that can adjust its discharge are required. Using an irrigation regime, that enables to change the time intervals between irrigation pulses, will allow application of water at various discharges in a way that matches the system discharge to the plant water uptake.
Such a system and its concept were successfully implemented in field crops such as green onion, radish, lettuce and corn. The R&D station developed a Tensio-dripper, sensors wrapped in Geo-textile and buried in the soil. The Geo-textile media encourages a massive root growth therein and, therefore, root density in this media is very high and as a result, most of the plant water uptake is from this area. Reading the metric potential in this media yielded better indication of water availability to the plants. This technique supplies water to the crops according to their demand, all this without any user interference during the entire growth season.
At the first stage, a unique buried tension-dripper for tree crops will be developed. During the second stage, the IOD irrigation regime in Pomegranate lysimeters, located at the southern Arava R&D will be studied, as well as in a commercial date palm orchard at Kibbutz Samar. The measured water use efficiency and the commercial yield will be compared, at both sites, to a control plot at which a common irrigation management practice will be applied.
Root texture and root-growth dynamics in trees differ from annual field crops. The challenge in this work is to explore the feasibility of using an automated irrigation system, based on real-time feedback from a cheap and reliable integrated sensing system, in fruit orchards.