The water-use of fruit tree orchards: Project Update

Transcription

1 : Project Update Mark Gush CSIR Nicky Taylor Univ. Pretoria Sebinasi Dzikiti CSIR Teunis Vahrmeijer CRI / UP John Annandale Univ. Pretoria Gerhard Backeberg - WRC

2 Introduction Water-use of fruit tree orchards - WRC Project K5/177 The challenge Agriculture uses ±6% of surface water in South Africa 9% of fruit production is dependent on irrigation Increasing water stress & competition: How to use less water without reducing fruit quality and yield? Traditional soil moisture methods are indirect & less accurate (percolation / evaporation) The research and development Measurement of transpiration and total evaporation of fruit trees and orchards using new instrumentation and techniques Long-term monitoring across wide-ranging sites for priority fruit tree species Development of water-use models & crop factors for optimum irrigation scheduling in fruit tree orchards CSIR 212 Slide 2

3 Methods The approach Project duration April 27 to March 214 (7 years) Reviewed international knowledge on the water use of fruit trees Ranked & selected the most important fruit tree species in SA Selected min of 4 fruit tree species incorporating sub-tropical & deciduous species in winter and summer rainfall areas (pome, stone, citrus and nut varieties) - TOR Measured unstressed water use & additional variables for up to 2-years in the field at each site Testing the most appropriate crop water use model(s) for the selected fruit tree species. Deriving monthly Crop Coefficients (K cb & K c ) for each species Disseminating information to IAPs (ongoing) CSIR 212 Slide 3

4 Species selection Listed main fruit tree species grown in South Africa (excluding grapes and berries) Distinguished Deciduous Pome Fruit Stone Fruit Apples Pears Peaches Plums Nectarines Apricots Almonds between sub- Cherries tropical and Pecans deciduous species Banana & papaya excluded by Nuts Hazelnut s Walnuts Pistachio s definition (not Citrus woody) Fruit Tree Species Subtropical Avocados Litchis Mangos Macadamias CSIR 212 Slide 4 Guavas

5 Priority Ranking Ranking and selection Based on economic importance, production, hectarage & knowledge gaps Geographic distribution (rainfall seasonality) & species category (deciduous vs. sub-tropical) considered throughout - TOR Preference for farms with best management practice Selected widest possible range of priority fruit tree species within constraints of project pome, stone, citrus and nut species CSIR 212 Slide 5

6 Study Sites Rustenburg Cullinan White River Malelane Citrusdal Ceres / Wolseley CSIR 212 Slide 6

7 Methods Measurements Full suite of climatic variables using Automatic Weather Stations (AWS) Reference ET o Sap flow / transpiration (Heat Pulse Velocity technique) 2-yrs of continuous hourly measurements Total orchard evaporation (Eddy Covariance technique) seasonal Irrigation applications (Timing and amounts) and soil water variation - continuous Structural (e.g. dimensions), physiological (e.g. xylem anatomy) and phenological (e.g. timing of bud-burst, flowering, fruiting and leaf area) characteristics and changes of the various fruit tree species over time Regular site visits to check systems, change batteries, download data, and record structural, physiological and phenological changes in the trees CSIR 212 Slide 7

8 Modelling Modelling Aim: to predict water use of orchards in South Africa using an existing model, or to develop a new robust model, with minimal and easily accessible input requirements Field measurements used to calibrate & verify simulations of annual T & ET (and E s ) Various models being tested(e.g. FAO56, SWB, Samani, Allen & Pereira, Dual-source transpiration & soil evaporation with Jarvis stomatal conductance sub-model) 2 Peak summer sap flow / transpiration rates Transpiration ET Heat Pulse Velocity (cm/hr) 1 Soil evaporation Tree 1, Probe 7 Leafless winter periods (no sap flow / transpiration) -1 CSIR 212 Slide 8

9 Modelling Modelling Daily values of T and ET from measurements and modelling Used to derive basal (K cb ) and full (K c ) crop coefficients for FAO56 type application 1 Eto - FAO56 Reference Evapotranspiration Mar-9 16-May-8 16-Jun-8 17-Jul-8 17-Aug-8 17-Sep-8 18-Oct-8 18-Nov-8 19-Dec-8 19-Jan-9 19-Feb-9 Reference Evapotranspiration (mm) 22-Apr-9 23-May-9 23-Jun-9 Date CSIR 212 Slide Reference Evapotranspiration (mm) 16-May-8 16-Jun-8 17-Jul-8 17-Aug-8 17-Sep-8 18-Oct-8 18-Nov-8 19-Dec-8 19-Jan-9 19-Feb-9 22-Mar-9 22-Apr-9 23-May-9 23-Jun-9 Eto - FAO56 Reference Evapotranspiration.9 Date.1 Kcb Cripps Pink apples - Ceres Kc Cripps Pink apples - Ceres Reference ETo Modelled ET Measured T Measured ET Kc & Kcb - 'Cripps' Pink apples - Ceres Transpiration (T) and Evapotranspiration (ET) -mm

10 Results Species-specific volumes of water-use Daily, monthly, seasonal and annual totals(l/tree & mm) Species-specific seasonal variation in water-use Links between phenology and water-use Apple 8_9 Apple 9_1 Delta Valencia Bahianinha Navel Rustenburg Navel Nectarine Macadamia day -1 ) Apple 8_9 Apple 9_1 Delta Valencia Bahianinha Navel Rustenburg Navel Pecan 9_1 Pecan 1_11 Nectarine Macadamia Jul 15-Jul 29-Jul 12-Aug 26-Aug 9-Sep 23-Sep 7-Oct 21-Oct 4-Nov 18-Nov 2-Dec 16-Dec 3-Dec 13-Jan 27-Jan 1-Feb 24-Feb 1-Mar 24-Mar 7-Apr 21-Apr 5-May 19-May 2-Jun 16-Jun 3-Jun Daily Transpiration (L tree Jul 15-Jul 29-Jul 12-Aug 26-Aug 9-Sep 23-Sep 7-Oct 21-Oct 4-Nov 18-Nov 2-Dec 16-Dec 3-Dec 13-Jan 27-Jan 1-Feb 24-Feb 1-Mar 24-Mar 7-Apr 21-Apr 5-May 19-May 2-Jun 16-Jun 3-Jun Daily Evapotranspiration (mm day -1 ) CSIR 212 Slide 1

11 Kc Cripps Pink apples - Ceres Kc 'Alpine' Nectarines - Wolseley K c & Kcb - 'Cripps' Pink apples - Ceres Kcb Cripps Pink apples - Ceres K c & Kcb - 'Alpine' Nectarines - Wolseley Kcb 'Alpine' Nectarines - Wolseley Kc & Kcb 'Beaumont' Macadamia Nuts - Plaston Kc 'Beaumont' Macs - Plaston Kcb 'Beaumont' Macs - Plaston Total Evap poration (mm annum -1 ) This Project Green Book SAPWAT2 SAPWAT3 K c & Kcb 'Choctaw' Pecan Nuts- Cullinan Kc 'Choctaw' Pecans - Cullinan Kcb 'Choctaw' Pecans - Cullinan Sep Oct Nov Dec Jan Feb Mar Apr May 2 K c & Kcb 'Rustenburg' Navel Oranges - Citrusdal Kc 'Rustenburg' Navels - Citrusdal Kcb 'Rustenburg' Navels - Citrusdal Apple Nectarine Pecan Delta Valencia K c & Kcb 'Baihaininha' Navel Oranges - Groblersdal Kc 'Baihaininha' Navels - Groblersdal 1.2 Kcb 'Baihaininha' Navels - Groblersdal CSIR 212 Slide 11. Bahianinha Navel Rustenburg Navel Macadamia K c & Kcb - 'Delta' Valencia Oranges - Groblersdal Kc 'Delta' Valencias - Groblersdal Kcb 'Delta' Valencias - Groblersdal

12 Conclusions Outcomes Improved fruit tree water-use knowledge, crop factors & models Transpiration (mm) Irrigation (mm) due to <1% IE Uptake Workshops, farmer info days & publications Potential Impact Improved on-farm water management and irrigation scheduling Increased water-use efficiency through distinction between beneficial (T) & non-beneficial (ET-T) water-use Informed water allocation calculations (m³/ha) Water footprint / Virtual water / Sustainable farming assessments Way Forward Requirement for comprehensive AWS network (for Et o ) Ongoing liaison with DAFF, DWA, Irrig. Boards, Grower Assoc. s Explore possibility to broaden measurements to extra species CSIR 212 Slide 12

13 Acknowledgements Funding - Water Research Commission & Dept. Agric. Forestry & Fisheries Project Team and students: Seb Dzikiti & Vivek Naiken (CSIR) Nicky Taylor, John Annandale & Teunis Vahrmeijer (Univ. Pta / CRI) Alistair Clulow, Caren Jarmain, Michael Mengistu, Colin Everson Nadia Ibraimo, Walter Mahohoma, Solomon Gezehei, Eunice Avenant, Hestia Pienaar Farmers & Farm Managers: Louis Reynolds, Arno Marais, Danie du Plessis, Leon de Kock, Albert Baumeester, Jaco Burger, Hendrik Schoeman, Deon de Kok, Corli Thank you!