2012 Annual Report
1a.Objectives (from AD-416):
Objective 1. Develop crop water requirements and irrigation strategies for perennial horticultural crops using remotely sensed data.
Objective 2: Develop sustainable water management strategies for perennial horticultural crops with limited and impaired water supplies.
Objective 3: Develop sustainable agricultural water reuse systems to protect soil/environmental health of drainage impacted soils when using poor quality water.
1b.Approach (from AD-416):
Using weighing lysimeters and precision water and nutrient application through micro irrigation systems to assess water, nutrient, crop yield and quality, and deep percolation relationships for annual crops and perennial horticultural crops. Use field studies to develop sustainable cropping systems in areas with restricted drainage discharge, and to determine the impact of management practices on soil salinity, groundwater and drain water quality and quantity, and crop yield. Determine, through greenhouse and field studies, the ability of crop species to tolerate and accumulate selenium, boron, and other constituents found in arid saline soils and shallow groundwater. Field studies to determine water requirements and deficit irrigation strategies will be used to determine the sustainable production of biofuel crops.
Progress was made on characterizing and controlling irrigation systems using remotely sensed data. Extra infrared sensors were installed for the peach water stress study. All sensors were re-calibrated prior to deployment. Soil water content and plant water potential data collection started after irrigation treatments started following peach harvest in late May. For the pomegranate study, a Tetracam camera and a radiometer system were acquired and a mount was built for simultaneous measurement of canopy size and spectral properties. Plans were developed for the irrigation and variety trial for the sugarcane water stress study, supplies purchased, plans were made to travel to Hawaii to install the sensors, the eddy covariance tower, and start the experiment. A project with ARS researchers from Beltsville to remotely determine peach water use is operational. Second year deficit irrigation trials are in place on both early and late season table grapes, raisin grapes, and wine grapes. In the second year of the study, initial data analysis from the early season table grapes demonstrated treatment effects from the first year impacted yield and quality. Instrumentation installed in each irrigation trial enables remotely sensed measurement of soil water. The fertilization and irrigation treatments on the pomegranate trials were initiated this year following two years of uniform application of fertilizer and water to ensure uniform plant establishment. Analysis of pomegranate grown in pot studies using poor quality water for irrigation has demonstrated an increase in vitamin C and phenolic content in the fruit. Substantial progress was made on developing sustainable systems to protect soil environmental health when using poor quality water. A field trial was established to grow 100 acres of mustard on poor quality soil using only rainfall. Uptake and volatilization measurements were made to determine the amount of selenium removed from the Se-laden soil to a depth of 1m. Up to fifteen percent of the Se net losses were accounted for in plant material and by volatilization, approximately 30% was assumed lost by leaching due to rainfall. Seed yield was approximately 2 tons/acre. Seed processed for oils with an on-site oil press produced up to 160 gallons of biodiesel 100 per acre. After transesterification, biodiesel 20 fuel was produced and is being used by diesel equipment on Red Rock Ranch. Residual seed meal is being used for Se biofumigation field trials to reduce root knot nematode infestation in carrots and weeds in broccoli, and spinach grown on transitional organic land. Multi-year field trials are in progress on growing over 1000 salt and boron tolerant poplar trees in poor quality soil with shallow ground waters contaminated with high salinity, boron, and selenium. Trees will be cut annually and the biomass used for energy generation. Field trials were expanded with salt and boron tolerant clones of Opuntia (cactus) on severely drainage impacted soils at Red Rock Ranch. Fruit and cladodes (flattened green stems) are sampled annually and analyzed for the different species of selenium, and micro and macronutrients.
Plants for poor quality water use. Reductions in water supplies have reduced production in irrigated agriculture in the western U.S. ARS researchers at Parlier, CA identified plant species, e.g., mustard, poplar-tree clones, opuntia cactus, adapted to high saline drainage or ground waters. These plants can be used for producing new bio-based products and have economic value for the grower, e.g., biofuel, Se-enriched feed and fruit products, and biofumigants. These findings improve our ability to develop a sustainable and agronomic-based system on drainage-impacted soils for drainage water reuse or use of poor quality waters. This reduces the growers need for high quality water in the western U.S.