1a.Objectives (from AD-416)
Overall objective is to optimize water-nitrogen interactions to improve fertilizer use effieiency (FUE) of young and maturing pomegranate.
Specific objectives include:
a. Determine the real time seasonal nitrogen requirements (N) of DI and SDI irrigated maturing pomegranate that improve FUE without yield reduction.
b. Determine the effectiveness of three nitrogen injection rates with DI and SDI on maintaining adequate N levels in maturing pomegranates.
c. Determine the effect of real time seasonal nitrogen injections (N) with DI and SDI irrigated maturing pomegranate on N leaching losses.
d. Develop fertigation management tools that will allow growing to achieve objective "a" and present these results to interested parties.
e. Determine if concentrations of macronutrients (P,K,Ca, Mg) and micronutrients (Zn, Cu, Mn,Fe B and Se) and eventually healthy bioactive compounds in soil, peel, and fruit are influenced by precise irrigation/fertigation management with DI and SDI.
1b.Approach (from AD-416)
Field and laboratory studies will be conducted. The field study will be conducted on a 3.5 field site on the Kearney Agricultural Center that contains a weighing lysimeter. The experimental design is a randomized complete block design with 2 irrigation types and 3 levels of N application with 5 replications. The irrigation systems are surface drip irrigation (DI) and subsurface drip irrigation (SDI) the 3 nitrogen treatments are 70% of adequate, 100% of adequate and 130% of adequate determined using biweekly petiole analysis. The system will be controlled using the weighing lysimeter. Proportional injection of fertilizers will be used to meet the N objectives. Tree and fruit responses will be determined with canopy measurements, pruned plant biomass and bimonthly plant tissue analysis. In the third year flowers, fruit yields, and quality will be measured and statistically analysed.
This grant agreement supports objective one of the parent project. The collaborator has been the on-site manager of the project. He supervised the installation of the fertigation system and installed the data acquisition system used to monitor and control the operation of the project. The goal for this year of the project was to get all systems installed and running and ensure uniform growth of trees prior to initiating differential fertilizer treatments in the next year of the project. The yearly goals were met. The lead scientist visits the site regularly to confirm operation and resolve issues related to the construction and operation of the system.