Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 102 - Soil, Plant, Water, Nutrient Relationships | 999 - Citrus, general/other | 1060 - Biology (whole systems) | 50% |
| 111 - Conservation and Efficient Use of Water | 999 - Citrus, general/other | 1060 - Biology (whole systems) | 50% |
Agricultural operations traditionally use large quantities of water and fertilizer in order to maximize plant growth, product quality, and profits. Irrigation is typically based on microjets in citrus groves, and frequency relies on a pre-determined schedule or visual evaluation of plant water status. These approaches lead to over-watering, which causes leaching and runoff. The release of water and nutrients results in surface and groundwater contamination and may contribute to environmental degradation.Precise irrigation management provide a less-limiting environment to roots while minimizing over irrigation and leaching of nutrients. Drip irrigation and sensor-based irrigation can be used to minimize or eliminate leaching by precisely regulating the amount of water applied compared to microjets, applying water more constantly and slowly. This concept can improve tree growth in the presence of huanglongbing (HLB) or citrus greening due to the reduced root system, and help optimize water and nutrient use. Higher tree density can also increase water use efficiency, resulting in higher fruit yield per area under high HLB pressure.Our hypothesis is that drip irrigation and sensor-based soil moisture monitoring or weather-based irrigation monitoring will provide an accurate tool to apply water based on plant demand. That address research project objectives 1 (Develop robust and appropriately-scaled methods of irrigation scheduling using one or more soil-, plant- or weather-based approaches) and 2 (Develop microirrigation designs and management practices that can be appropriately scaled to site-specific characteristics and end-user capabilities).The project goal is to determine the efficiency of irrigation methods on 'Ray Ruby' grapefruit and 'Valencia' production under different irrigation systems, fertilization methods and tree density. Specific objectives are related to study 1) Grapefruit production using different irrigation systems and plant density under open hydroponics, 2) Round orange production using different dry granular fertilizer blends, irrigation systems and plant density, and 3) Evaluate the water and nutrient use efficiency and plant growth. Soil moisture sensors will be installed to make irrigation decisions.
Objective 1 (Grapefruit production using different irrigation systems and plant density under open hydroponics)We are testing 'Ray Ruby' grapefruit (for fresh fruit) on a combination of rootstocks {'Sour orange' [C. aurantium] and 'US897' [Cleopatra (C. reticulata) × Flying Dragon (Poncirus trifoliata)]}, tree spacing {standard [3.8 × 7 m, 358 trees/ha] and high density staggered [(2.74 × 1.5 × 0.9 m) × 6.1 m, 953 trees/ha) (HDS)]}, fertilization [16N-2.2P-8.3K dry granular and 15N-2.6P-22.4K water-soluble fertilizer (WSF)], and irrigation systems (3.8 LPH drip and 40.5 LPH micro jet), arranged on five treatments: T1) 'Sour Orange' + standard spacing + dry granular fertilizer + micro jet, T2) 'US897' + HDS + WSF + drip, T3) 'Sour Orange' + HDS + WSF + drip, T4) 'Sour Orange' + HDS + WSF + micro jet, and T5) 'US897' + HDS + WSF + micro jet. The experimental design is a completely randomized with five replications. Trees were planted in Sept/2013 (total 2,769 trees/3.23 ha).Objective 2 (Round orange production using different dry granular fertilizer blends, irrigation systems and plant density)We are testing 'Valencia' round oranges (for juice processing) on a combination of fertilizer blends {"Orange": Harrell's Grower Standard 16-3-20 + IFAS minor recommendation and "Yellow": Harrell's Improved NPK 12-3-9 (50% coated muriate of potash [potassium chloride] + 50% soluble potassium sulfate, coated calcium nitrate) + 2.5-3x micros using Tiger-Sul Fe, Mn, Zn and B}, and three tree spacing {"Blue": Standard tree spacing (12' 6" × 23' 6", 144.5 trees/acre, 189 trees total [8 plots]) + dry granular fertilizer + micro jet irrigation (microsprinkler 50 green nozzle size, 16.7 GPH @ 20 psi) (Bowsmith, Exeter, CA); "Green": High Density staggered ([9' × 5' × 3'] × 20', 385.5 trees /acre, 512 trees total [8 plots]) + fertigation + micro jet irrigation (microsprinkler 50 green nozzle size, 16.7 GPH @ 20 psi) (Bowsmith, Exeter, CA); and "Red": High Density staggered ([9' × 5' × 3'] × 20', 385.5 trees /acre, 511 trees total [8 plots]) + fertigation + drip irrigation (Emitterline 0.58 GPH @ 10 psi, 12 inch spacing) (Jain Irrigation, Fresno, CA). The experimental design is a completely randomized with four replications. Trees were planted in Sept/2013 (total 1,212 trees/1.3 ha).Objective 3 (Evaluate the water and nutrient use efficiency and plant growth)The technology may provide proven water savings and reductions in production costs (due to reduced fertilizer losses and fuel costs associated with irrigation use) and possible yield improvements.
Target Audience
The target audience for this work are the scientific community, local farmers and other players in the citrus industry, such as processors and crop advisors.
Changes / Problems
Nothing Reported
Training & Professional Development
The Citrus Horticulture Laboratory team visited the CREC CUPS once in 2019, hosted several tours for growers and visitors. The masters student attended a special course in root biology sponsored by the project.
Dissemination Streams
The Ferrarezi Lab organized the 2019 Florida Citrus Show to bring new information to more than 800 local growers. We prepared publications for citrus trade journals (Citrus Industry Magazine) and the UF/IFAS Citrus Production Guide. Abstracts were also presented in scientific conferences.
Next Reporting Steps
Nothing Reported
Target Audience
The target audience for this work are the scientific community, local farmers and other players in the citrus industry, such as processors and crop advisors.
Changes / Problems
Nothing Reported
Training & Professional Development
The Citrus Horticulture Laboratory team visited the CREC CUPS once in 2019, hosted several tours for growers and visitors. The masters student attended a special course in root biology sponsored by the project.
Dissemination Streams
The Ferrarezi Lab organized the 2019 Florida Citrus Show to bring new information to more than 800 local growers. We prepared publications for citrus trade journals (Citrus Industry Magazine) and the UF/IFAS Citrus Production Guide. Abstracts were also presented in scientific conferences.
Next Reporting Steps
The project has ended. <br><br>
<br>What was accomplished under these goals? Objective 1 "Grapefruit production using different irrigation systems and plant density under open hydroponics" Precise irrigation and fertigation management provide a less-limiting environment to roots while minimizing over irrigation and leaching of nutrients. This concept can improve tree growth in the presence of HLB and help optimize water and nutrient use. Higher tree density can increase fruit yield per area under high HLB pressure. We conducted a study to evaluated the efficiency of open hydroponics on 'Ray Ruby' grapefruit production under different irrigation systems and tree density. We tested a combination of rootstocks (Sour orange and US897), tree spacing [standard and high density staggered (HDS)], fertilization (dry granular and fertigation), and irrigation systems (drip and microjet). Objective 1 "Evaluation of water and nutrient use efficiency" Irrigation systems are designed to maximize crop productivity and optimize uniform water application. The amount of water applied is usually determined by empirical methods, which are based on timers instead of the actual crop requirements. Several technologies have recently been developed looking for alternative methods to improve water management efficiency based on weather and soil sensing methods. One of the most relevant advances are the capacitance sensors, offering a great potential to estimate soil volumetric water content (VWC) and electrical conductivity. We conducted a laboratory study to evaluate the accuracy of data collected from several commercial capacitance sensors and establish a calibration equation for different soil types. Tested treatments were five sandy soils (Pineda, Riviera, Astatula, Candler and Immokalee) divided in two depths (0-30 and 30-60 cm) representing the majority of Florida soils used for citrus production. Objective 2 "Round orange production using different dry granular fertilizer blends, irrigation systems and plant density" Sweet oranges (Citrus sinensis) are impacted by huanglongbing (HLB), a disease associated with Candidatus Liberibacter asiaticus. The disease is threatening the citrus industry, with devastating effects on fruit production. Higher plant density can increase fruit yield per area under high HLB pressure, maximizing income and extending grove survival until a definite cure is found. This study evaluated the effect of tree planting density, fertilizer type and irrigation systems on fruit yield and quality. 'Valencia' orange on 'Kuharske' citrange (C. sinensis × Poncirus trifoliata) trees were planted in Sept/2013 (2,995 trees in 1.61 ha). We tested three treatments: standard tree spacing (3.8×7 m, 357 trees/ha) + dry granular fertilizer + microsprinkler irrigation (one emitter per tree; microsprinkler 50 green nozzle, 16.7 GPH at 20 psi) (Bowsmith, Exeter, CA), high density staggered ([2.7×1.5×0.9 m]×6.1 m, 953 trees/ha) + fertigation + microsprinkler irrigation (one emitter per two trees), and high density staggered + fertigation + drip irrigation (two lines per row; Emitterline 0.58 GPH at 10 psi, 12-inch spacing) (Jain Irrigation), in a complete randomized block design with eight replications. <br><br><b>Publications</b><br>
Target Audience
The target audience for this work are the scientific community, local farmers and other players in the citrus industry, such as processors and crop advisors.
Changes / Problems
Soil moisture sensors installed on Florida sandy soils malfunctioned/did not provide accurate results.
Training & Professional Development
Nothing Reported
Dissemination Streams
Nothing Reported
Next Reporting Steps
Project endsin 2019 <br><br>
<br>What was accomplished under these goals? Objective 1 "Grapefruit production using different irrigation systems and plant density under open hydroponics" Precise irrigation and fertigation management provide a less-limiting environment to roots while minimizing over irrigation and leaching of nutrients. This concept can improve tree growth in the presence of HLB and help optimize water and nutrient use. Higher tree density can increase fruit yield per area under high HLB pressure. We conducted a study to evaluated the efficiency of open hydroponics on 'Ray Ruby' grapefruit production under different irrigation systems and tree density. We tested a combination of rootstocks (Sour orange and US897), tree spacing [standard and high density staggered (HDS)], fertilization (dry granular and fertigation), and irrigation systems (drip and microjet). Objective 2 "Round orange production using different dry granular fertilizer blends, irrigation systems and plant density" Sweet oranges (Citrus sinensis) are impacted by huanglongbing (HLB), a disease associated with Candidatus Liberibacter asiaticus. The disease is threatening the citrus industry, with devastating effects on fruit production. Higher plant density can increase fruit yield per area under high HLB pressure, maximizing income and extending grove survival until a definite cure is found. This study evaluated the effect of tree planting density, fertilizer type and and irrigation systems on fruit yield and quality. 'Valencia' orange on 'Kuharske' citrange (C. sinensis × Poncirus trifoliata) trees were planted in Sept/2013 (2,995 trees in 1.61 ha). We tested three treatments: standard tree spacing (3.8×7 m, 357 trees/ha) + dry granular fertilizer + microsprinkler irrigation (one emitter per tree; microsprinkler 50 green nozzle, 16.7 GPH at 20 psi) (Bowsmith, Exeter, CA), high density staggered ([2.7×1.5×0.9 m]×6.1 m, 953 trees/ha) + fertigation + microsprinkler irrigation (one emitter per two trees), and high density staggered + fertigation + drip irrigation (two lines per row; Emitterline 0.58 GPH at 10 psi, 12-inch spacing) (Jain Irrigation), in a complete randomized block design with eight replications. Objective 3 "Evaluation of water and nutrient use efficiency" Irrigation systems are designed to maximize crop productivity and optimize uniform water application. The amount of water applied is usually determined by empirical methods, which are based on timers instead of the actual crop requirements. Several technologies have recently been developed looking for alternative methods to improve water management efficiency based on weather and soil sensing methods. One of the most relevant advances are the capacitance sensors, offering a great potential to estimate soil volumetric water content (VWC) and electrical conductivity. We conducted a laboratory study to evaluate the accuracy of data collected from several commercial capacitance sensors and establish a calibration equation for different soil types. Tested treatments were five sandy soils (Pineda, Riviera, Astatula, Candler and Immokalee) divided in two depths (0-30 and 30-60 cm) representing the majority of Florida soils used for citrus production. <br><br><b>Publications</b><br>