ASSESSING CITRUS C CROP C COE OEFFI FFICIENTS FOR OR OPTI TIMIZING W WATER ER US USE A AND ND SUS USTAINING ENVIRONME ONMENT NTAL QUALITY Davie Kadyampakeni, Wije Bandaranayake and Samuel Kwakye UF/IFAS Citrus Research and Education Center, CREC, Lake Alfred, FL E-mail: dkadyampakeni@ufl.edu
CURRENT CITRUS PRODUCTION STATUS Bearing acreage and production of citrus in the US for the past 20 years Florida bearing acreage 1200 Bearing acreage (1000 acres ) has declined from 1000 785,900 acres (70% of 800 national production) 600 in 1998 to about 400 410,700 acres (58% of 200 US production) in 2017 0 representing about 48% decline (USDA, 2018). Crop year Florida California Texas Arizona United States
CURRENT CITRUS PRODUCTION STATUS (2) Citrus production in the US for the past 20 years Florida California Texas Arizona United States Florida production has declined 20000 from 13.6 million tons (76% of 18000 national production) in 1998 to Production (x1000 tons) 16000 about 3.5 million tons (45% of US 14000 production) in 2017 representing 12000 about 74% decline in production 10000 (USDA, 2018). 8000 6000 4000 Bearing acreage and production 2000 losses have been ascribed largely 0 to Huanglongbing (HLB) or citrus greening . Other reasons include hurricanes and urbanization . Crop year
WATER MANAGEMENT STRATEGIES FOR HLB- AFFECTED CITRUS TREES Preventative measures: HLB negative (healthy trees) (Ferrarezi et al. 2017a, 2017b, Schumann et al. 2017) Frequent irrigation (daily or multiple times a day) e.g. Citrus Under Cover Production System Regulated deficit irrigation Ensure Asian citrus psyllid (ACP) exclusion Curative management of HLB positive trees (asymptomatic trees) (Kadyampakeni et al., 2014a,b,c) Daily irrigation plus ACP control Managing pH to optimum levels for nutrient availability Improved nutrition programs via fertigation or use of controlled-release fertilizer (CRF) sources Remediation/Management of HLB affected trees (symptomatic trees) (Hamido et al., 2017a,b; Kadyampakeni and Morgan, 2017) Daily irrigation plus ACP control Managing pH to optimum levels for nutrient availability Fertigation practices and CRF
OBJECTIVES OF THE VARIOUS FIELD AND GREENHOUSE STUDIES • Determining water use patterns of HLB-affected trees at field scale and in greenhouse conditions. • Estimating crop coefficients for HLB-affected and healthy trees under greenhouse conditions. • Evaluating soil moisture thresholds for HLB-affected trees in the greenhouse and field conditions.
HYPOTHESES FOR VARIOUS WATER MANAGEMENT STUDIES • Frequent irrigation management practices would enhance growth, water use and crop resilience to HLB. • Soil moisture availability would be optimal with frequent, but reduced irrigation level, and maintain and/or increase root growth, root water uptake and tree water use.
MATERIALS AND METHODS Water use measurements in field studies and greenhouse studies. Use of sapflow sensors supported by a datalogger, solar panel, and 12-V battery (right and top) Weighing lysimetry for measuring water use (left)
MATERIALS AND METHODS (2) Water monitoring at grove scale and soil moisture measurement at 15, 30 and 60 cm soil depth Water volume Evapotranspiration and root growth measurements measurements between HLB at field scale affected and healthy trees under greenhouse conditions
TREE RESPONSE TO IRRIGATION SCHEDULES • Daily irrigation > Intermediate (irrigating every 1.5 days) > IFAS irrigation (irrigating every two days) scheduling • Daily irrigation could help in managing HLB affected trees and reduce tree water stress • More details: Kadyampakeni and Morgan, 2017. Scientia Horticulturae 224:272-279 Water use of HLB affected trees in south west and central Florida
SOIL MOISTURE DISTRIBUTION AT 3 DEPTHS Arcadia 0.12 Volumetric water content (m 3 m -3 ) IFAS Keeping water in the top 0-30 cm improved Intermediate 0.10 Daily 0.08 water use for HLB affected trees. Greater 0.06 moisture content beyond the root zone (at 0.04 0.02 45 cm) in Immokalee (bottom) could be due 0.00 Avon Park Volumetric water content (m 3 m -3 ) 0.12 to capillary rise since the soils have a high IFAS Intermediate Daily 0.10 water table and in Avon Park (middle) 0.08 0.06 could be due to deep percolation because 0.04 0.02 those soils are well drained. 0.00 Immokalee Volumetric water content (m 3 m -3 ) 0.12 More details: Hamido et al. 2017a. IFAS Intermediate Daily 0.10 HortScience 52(6):916-921. 0.08 0.06 0.04 0.02 0.00 0-15 15-30 30-45 Soil depth (cm)
SOIL MOISTURE DISTRIBUTION USING DRIP AND MICROSPRINKLER IRRIGATION SYSTEMS CMP -Conventional 30 30 microsprinkler irrigation CMP CMP MOHS 25 25 MOHS MOHS -Microprinkler DOHS-C35 Water content (%) DOHS-C35 open hydroponic system Water content (%) 20 20 with daily irrigation and weekly fertigaton. 15 15 DOHS-C35 -Drip open 10 10 hydroponic system with daily irrigation and 5 5 fertigation 0 0 Soil moisture at 10 cm 188 192 196 200 204 208 234 236 238 240 242 244 246 248 Julian day depth was close to or Julian day slightly above field July 2010 Aug-Sept 2011 capacity in the range of 7 and 15%. Kadyampakeni et al. 2014a, b. Soil Science Society of America Journal 78:645–654; 78:1351–1361
MEASURING WATER CONTENT IN THE SOIL AND APPLIED WATER VOLUMES Water monitoring at grove scale and soil moisture distribution at 15, 30 and 60 cm soil depth ~217,238 gal/acre since Feb 2018
CROP COEFFIENTS FOR HLB VS NON-HLB AFFECTED TREES • Patterns of crop coefficients (K c ) 1.5 Crop coefficient (Kc) similar for HLB affected and non- Crop Coefficient (Kc) for HLB affected trees 1 affected trees in southwest Florida • Non-affected tree K c similar to under greenhouse 0.5 Hamlin Hamlin - HLB Valencia those found to field trees prior to conditions Valencia - HLB IFAS 0 greening Dec-13 Feb-14 Apr-14 Jun-14 Aug-14 Oct-14 Dec-14 Date • Infected trees consistently with More details: Hamido 1.2 lower K c et al. 2017b. 1.0 Crop Coefficient (Kc) HortTechnology 0.8 • K c 35.2% and 20.8% lower for HLB- 27(5):659-665 0.6 affected trees in 2014 and 2015, 0.4 Hamlin Hamlin - HLB Valencia respectively. 0.2 Valencia - HLB IFAS 0.0 Dec-14 Feb-15 Apr-15 May-15 Jul-15 Sep-15 Oct-15 Dec-15 Date
Month -year ET o ET c (mm d -1 ) ET c diff. (%) ‡ 22 to 35% greater water Hamlin-Non HLB Hamlin-HLB (mm d -1 ) Jan-Jun-14 3.57 2.97 2.23 23.73 use for Non-HLB Jul-Dec-14 4.42 4.16 2.63 34.82 Jan-Jun-2015 3.38 4.08 2.83 29.82 affected trees Jun-Oct-15 3.73 4.94 3.18 35.20 Inter-season and annual Overall Average 3.79 4.00a** 2.69b** 30.75 variability in water use Valencia-Non HLB Valencia-HLB Jan-Jun-14 3.57 2.83 2.22 22.28 Comparable water use Jul-Dec-14 4.42 3.97 2.83 28.85 Jan-Jun-2015 3.38 3.85 2.69 30.98 between varieties Jun-Oct-15 3.73 4.79 3.56 26.42 Overall Average 3.79 3.82a** 2.80b** 26.99**
SUMMARY • Daily irrigation is critical for maintaining tree production and performance. • Optimal irrigation scheduling along with monitoring water use is important for high irrigation efficiency, greater water use efficiency and minimizing leaching losses. • Soil moisture content at or close to field capacity is possible with modified water application methods on Florida’s sandy soils • Trees affected by HLB appear to use about 22 to 35% less water than healthy trees. These results, if confirmed at field scale, will result in modified crop coefficients for HLB-affected citrus leading to water savings.
ACKNOWLEDGEMENTS • Collaborators: • UF/IFAS CREC: Dr. Arnold Schumann, Dr. Evan Johnson, Dr. Tripti Vashisth • UF/IFAS SWFREC: Dr. Kelly Morgan, Dr. Said Hamido. • SWSD Gainesville: Dr. Peter Nkedi-Kizza, Dr. Gabriel Landry-Maltais • My Program Team: Dr. Wije Bandaranayake, William Ratnasiri, Alex Hernandez, • Graduate students: Samuel Kwakye, Qudus Uthman and Eduardo Esteves • Sponsors: UF/IFAS Citrus Initiative, SWFWMD, USDA-NIFA
QUESTIONS/COMMENTS? E-mail: dkadyampakeni@ufl.edu Tel. 863-956-8843 Facebook and Twitter: Water and Nutrient Management Lab @ CREC
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