I i I i Irrigation and Salinity Irrigation and Salinity ti ti d - PowerPoint PPT Presentation

I i I i Irrigation and Salinity Irrigation and Salinity ti ti d S li it d S li it Management In a Dry Year(s) Management In a Dry Year(s) Management In a Dry Year(s) Management In a Dry Year(s) Terry Prichard Terry Prichard Terry Prichard Terry Prichard UC Davis UC Davis Dept Land Air and Water Resources Dept Land Air and Water Resources Dept Land, Air, and Water Resources Dept Land, Air, and Water Resources

Stretching Water Supplies Stretching Water Supplies Stretching Water Supplies Stretching Water Supplies  Application Efficiency Application Efficiency  System Design/ Uniformity System Design/ Uniformity  Runoff Collection and Reuse Runoff Collection and Reuse  Reduce Evaporation Reduce Evaporation p  Targeted Application / micro irrigation / buried drip Targeted Application / micro irrigation / buried drip  Proper Irrigation Scheduling  Proper Irrigation Scheduling Proper Irrigation Scheduling Proper Irrigation Scheduling  Reduce Transpiration Reduce Transpiration- - water stress water stress

Evaluate and upgrade irrigation systems Evaluate and upgrade irrigation systems Evaluate and upgrade irrigation systems Evaluate and upgrade irrigation systems improve distribution uniformity improve distribution uniformity Pressure variation Pressure variation Nozzle size uniformity

Surface Irrigation Surface Irrigation  Runoff Runoff  All soils All soils All soils All soils  Deep percolation Deep percolation  Sandy soils S S Sandy soils d d il il

Eli Eli Eliminate or minimize cover crops or weeds Eliminate or minimize cover crops or weeds i i t t i i i i i i d d which can compete for water use which can compete for water use

Reduce Water Use Reduce Water Use-- Reduce Water Use Reduce Water Use -- Transpiration Transpiration Transpiration Transpiration  Use ET estimates and reduce by a fraction  Use ET estimates and reduce by a fraction Use ET estimates and reduce by a fraction Use ET estimates and reduce by a fraction of full water use of full water use  Use Stem water potential measurements Use Stem water potential measurements with thresholds for a particular stage of with thresholds for a particular stage of with thresholds for a particular stage of with thresholds for a particular stage of development development  Measure soil moisture and apply at a Measure soil moisture and apply at a threshold value threshold value threshold value threshold value

Water Use Water Use Climate Climate Evapotranspiration Reference Evapotranspiration Reference (ET ) (ET ) (ETo) (ETo) Sun Interception Sun Interception (Kc) (Kc) Size of Canopy Size of Canopy Size of Canopy Size of Canopy Time of season Time of season (canopy Expansion) (canopy Expansion) Spacing Spacing Plant Controls Plant Controls Stomata Stomata Available Moisture

Calculate Full Potential Water Use Calculate Full Potential Water Use Calculate Full Potential Water Use Calculate Full Potential Water Use  ETo x Kc = Full Potential Water Use  ETo x Kc = Full Potential Water Use ETo x Kc = Full Potential Water Use ETo x Kc = Full Potential Water Use  Use weekly summed data Use weekly summed data

Mature Almond Water Use Mature Almond Water Use Manteca Normal California, inches Manteca Normal California, inches Historical Historical Date ETo Kc ETc March 16-31 0.54 1.25 2.32 April 1-15 0.60 1.52 2.54 April 16-30 0.66 1.90 2.88 May 1-15 0.73 2.39 3.27 May 16-31 0.79 2.88 3.65 June 1-15 0.84 3.19 3.80 13 14 13.14 March 16 - June 15th March 16 - June 15th

Mature Almond Water Use Mature Almond Water Use Manteca Normal California inches Manteca Normal California inches Manteca Normal, California, inches Manteca Normal, California, inches Historical Date Date ETo ETo Kc Kc ETc ETc June 16-30 3.98 0.86 3.42 July 1-15 4.08 0.93 3.80 July 16-31 3.94 0.94 3.70 August 1-15 3.65 0.94 3.43 August 16-31 August 16 31 3.49 3.49 0.94 0.94 3.28 3.28 September 1-15 2.88 0.94 2.71 September 16-30 2.38 0.91 2.16 O t b October 1-15 1 15 1 96 1.96 0 85 0.85 1 67 1.67 October 16-31 1.56 0.79 1.23 November 1-15 0.7 0.76 1.08 June 16 – Nov 15 26.17

C-Probe 12in 24 in 36 in 48 in 60 in 75.0 Irr = 1.4 in 70.0 65.0 60.0 55.0 55 0 Moisture 50.0 45.0 40.0 35.0 30 0 30.0 25.0 6/13 6/20 6/27 7/4 7/11

C-Probe 12in 24 in 36 in 48 in 60 in Sum 275.0 Irr = 1.4 in 225.0 175.0 175 0 Moisture 125.0 125.0 75.0 25.0 6/13 6/13 6/20 6/20 6/27 6/27 7/4 7/4 7/11 7/11

Tree Water Stress Tree Water Stress  Measured as midday Measured as midday stem stem water potential water potential  Using a pressure chamber Using a pressure chamber • aka pressure bomb aka pressure bomb

Lower scaffold limb Lower scaffold limb Fully expanded leaf Bag for 15 minutes min

pressure chamber Measure it in a Measure it in a

Plant pressure chambers Plant pressure chambers are available from: are available from: PMS Instruments in Albany, Oregon PMS Instruments in Albany, Oregon (http://pmsinstrument.com/) (http://pmsinstrument.com/) Soil Moisture Equipment Corp.in Santa Soil Moisture Equipment Corp.in Santa Barbara California Barbara California Barbara, California Barbara, California (http://www.soilmoisture.com/) (http://www.soilmoisture.com/)

Almond Deficit Strategies Almond Deficit Strategies Almond Deficit Strategies Almond Deficit Strategies  Moderate 30% savings Moderate 30% savings g  little effect on yield little effect on yield  Severe 50% savings  Se ere 50% sa ings Severe 50% savings Se ere 50% sa ings  Reduced yield due to smaller kernel size Reduced yield due to smaller kernel size– – current year current year  Reduced yield in subsequent year due to reduced nut Reduced yield in subsequent year due to reduced nut y y q q y y number and kernel size number and kernel size  Staying alive  Staying alive Staying alive 12 inches water Staying alive -- --12 inches water 12 inches water 12 inches water  No concern for yield current or subsequent year No concern for yield current or subsequent year- - • tree survives tree survives

Moderate Deficit Strategy Moderate Deficit Strategy 30% 30% 30% savings 30% savings i i  Full Irrigation  Full Irrigation Full Irrigation Full Irrigation  Leafout to Mid June Leafout to Mid June  Deficit Irrigation Deficit Irrigation  Mid June to harvest 50% of full irrigation Mid June to harvest 50% of full irrigation % % f f f f Or Or  -20 to 20 to - -22 bar threshold before irrigation 22 bar threshold before irrigation

Moderate Deficit Strategy Moderate Deficit Strategy 30% 30% 30% savings 30% savings i i  Deficit Irrigation Deficit Irrigation  Constant reduction of applied water in relation to ET Constant reduction of applied water in relation to ET • 70% of full requirement 70% of full requirement Calculate full crop water use Calculate full crop water use-- -- then apply irrigation then apply irrigation at 70% at 70% This method can be influenced by the amount of stored soil 0% 0% This method can be influenced by the amount of stored soil moisture and should be accounted for in the applied water moisture and should be accounted for in the applied water

More Severe Deficit Strategy More Severe Deficit Strategy 50 50 - 0 60% S -60% Savings 60% S 60% Savings i i  Deficit Irrigation  Deficit Irrigation Deficit Irrigation Deficit Irrigation  Leafout through mid June Leafout through mid June -12 to 12 to 12 to 14 bars mid 12 to - -14 bars mid 14 bars mid day stem water potential 14 bars mid-day stem water potential day stem water potential day stem water potential  Deficit Irrigation D fi it I i D fi it I i Deficit Irrigation ti ti th to harvest June 15 th  June 15 to harvest -20 to 20 to - -25 bars w/ 1 inch applied at hull split 25 bars w/ 1 inch applied at hull split

Keeping the Trees Alive Keeping the Trees Alive Keeping the Trees Alive Keeping the Trees Alive  This method does not consider growth or yield  This method does not consider growth or yield This method does not consider growth or yield This method does not consider growth or yield– just just just just survival survival  estimated 12 inches applied water depending on stored soil estimated 12 inches applied water depending on stored soil moisture moisture moisture moisture  Deficit Irrigation Deficit Irrigation  Leafout through May Leafout through May -16 bars mid 16 bars mid- -day stem water potential before application day stem water potential before application  Deficit Irrigation Deficit Irrigation  June to harvest June to harvest -25 bars before application 25 bars before application 25 bars before application 25 bars before application Until water supply is depleted Until water supply is depleted