Getting by with Less Water in Trees & Vines UNIVERSITY of - PowerPoint PPT Presentation

Getting by with Less Water in Trees & Vines UNIVERSITY of CALIFORNIA COOPERATIVE EXTENSION Blake Sanden -- Irrigation & Agronomy Farm Advisor Kern County Drougth Preparedness Workshop DWR-CIT Fresno Dec. 17, 2013

3 foot push or slide hammer probe ($150-$250)

Hand-powered twist augers ($150 - $300)

Tensiometer The first “at a glance” in-situ soil moisture sensor ($60-$90, depending on length)

A device using low levels of radiation, the neutron probe, was developed in the 1960’s for checking soil moisture. Used mostly by researchers and irrigation consultants, it is often the standard check for the accuracy of other instruments. Largest sample “volume” to estimate moisture.

Watermark blocks estimate soil moisture tension (matric poten- tial) using electrical resistance and require no maintenance (~$30). However, a separate meter or logger ($200+) is needed to read the device.

Dozens of new soil moisture sensors and logger combinations have come on the market in the last 10 years

Real-time data transmission and analysis over the internet can be convenient and sometimes fustrating and confusing at the same time.

Field loggers that simply record data have to be downloaded but are much cheaper than web-based systems (Loggers used in Kern County irrigation projects)

Where do I monitor in these large-scale fields?

Where do I monitor?

How many sensors are enough? What type is best for which crop?

Soil Moisture Monitoring in Citrus

Installing Watermark blocks and a Hanson AM400 logger in citrus Fine silty soil and a good shot of water down the hole improves contact with soil pores. Good capillary movement of water is what makes these sensors work.

Loggers used in Kern County irrigation projects

Understanding mid-season soil moisture trends in citrus using Watermark Blocks Microsprinkler Irrigation (Page 10) 6/8 6/22 7/6 7/20 8/3 8/17 8/31 9/14 (a) 0 Deficit irrigation and -10 Soil Moisture Tension (cb) slow loss of moisture -20 -30 "0 cb" rdng & sharp 36 hr set & -40 dropoff Perfect recharge to indicate recharge to 30" with slight saturation & -50 30" with no 15" leaching leaching Uphill side of hose. leaching 30" Densest planted -60 10 year old trees (10x20'), 12 gph Fanjet, 24 hr sets part of block.

Soil Moisture Changes in Citrus Under Different Set Pressures (b) 6/8 6/22 7/6 7/20 8/3 8/17 8/31 9/14 0 Soil Moisture Tension (cb) -10 -20 Set 1-- Good hose pressure. Drainage at the 15" depth takes Loamier ground than set 2. about 3 days before normal -30 Possible deep Possibly too wet, but trees crop water use commences. percolation look great and grower used -40 below 30". less water than previous year. 15" Foliage on tree skirt also -50 30" reduced throw of water. -60 Mature Trees (15x20'), 12 gph Fanjet, 24 hr sets (Page 10) (c) 6/8 6/22 7/6 7/20 8/3 8/17 8/31 9/14 0 Soil Moisture Tension (cb) -10 -20 -30 -40 Set 2 -- Lower pressure than set 1 -50 and sandier ground. 15" No leaching past 30" 30" -60 but refill adequate. Mature trees (15x20'), 12 gph Fanjet, 24 hr sets Same row as set 1.

3/11 3/25 4/8 4/22 5/6 5/20 6/3 6/17 7/1 7/15 7/29 8/12 8/26 9/9 9/23 10/7 10/21 11/4 11/18 0 -25 Soil Moisture Tension (cb) -50 -75 Drip Irrigation -100 with excessive frequency -125 18" Citrus, Row 8 Near "T" and duration in a -150 36" Delano Loam with Coarse Sand 60" -175 loam/clay loam soil -200 3/11 3/25 4/8 4/22 5/6 5/20 6/3 6/17 7/1 7/15 7/29 8/12 8/26 9/9 9/23 10/7 10/21 11/4 11/18 0 -25 Soil Moisture Tension (cb) -50 -75 18" -100 Citrus, Row 9 Hose End 36" Delano Loam with Coarse Sand -125 60" -150 -175 -200

4/3 4/17 5/1 5/15 5/29 6/12 6/26 7/10 7/24 8/7 8/21 9/4 9/18 10/2 10/16 10/30 0 -20 Soil Moisture Tension (cb) -40 -60 -80 -100 -120 CONTROL -140 15" Estimate 30" -160 2004 - Flood Almonds 41 inches 48" -180 Kimberlina Sandy Loam infiltration -200 4/3 4/17 5/1 5/15 5/29 6/12 6/26 7/10 7/24 8/7 8/21 9/4 9/18 10/2 10/16 10/30 0 -20 Soil Moisture Tension (cb) -40 -60 15" -80 30" Sensors @ 18, 36 and 60" GYPSUM -100 48" depths, middle of drive. Poor Estimate -120 infiltration due to tractor wheel (Sensors moved near edge compaction. Profile slowly 44 inches -140 of berm.) drying out. -160 infiltration -180 2004 Watermark Readings -- Flood Almonds, 19th Leaf, Kimberlina Sandy Loam -200

But what does soil moisture “tension” tell us about the actual amount of water depletion? • How big is the cup (soil AWHC)? • How thirsty is the crop (ET)? • How often/much do you fill the cup?

A device using low levels of radiation, the neutron probe, was developed in the 1960’s for checking soil moisture. Used mostly by researchers and irrigation consultants, it is often the standard check for the accuracy of other instruments. Largest sample “volume” to estimate moisture.

Electronics, data loggers and multi-stage sensors can increase the cost rapidly up to $5,000 to $10,000. The need for this degree of sophistication is debatable.

Separate Layer Graph Day-night stepping indicates root activity at 10, 20, 30 cm 4-inch dries out Rains 4 hrs. 6 hrs. Rain No root activity at 20 & 36-inch levels (no stepping)

Equipment for checking soil moisture • Most Common Method

Does High Tech Irrigation & Research Guarantee Profit & Sustainability? 51 st CA Irrigation Institute “Embracing Innovation: the Next Generation” February 4-5, 2013 Blake Sanden – Irrigation Advisor, Kern County http://cekern.ucdavis.edu/Irrigation_Management/

What are grower “sense” abilities regarding high-tech inputs for ag? 1. Farmers are the most common sense people around. 2. Farmers will adopt practices that make money, but … 3. They tend to only use practices that they feel they understand and can sensibly /practically incorporate into their ranch operation. 4. Information on “soil moisture sensor” technology is confusing and overabundant: >50,000 Google hits in 2003 and >1,000,000 hits in 2013. 5. Performance of many soil moisture and other field sensors has often been inconsistent.

The “science” on adoption is lacking! 5. Irrigation academics and engineers don’t like to study people! Out of 274 presentations and posters combined at the 1996 and 2000 big quadrennial irrigation meetings of the ASAE only 8 presentations dealt with technology transfer and adoption. 6. ULTIMATE ECONOMIC PRINCIPAL: if it makes money it will be done!

… and this much monitoring technology?

PureSense Comprehensive Soil Moisture &Irrigation Summary for Almonds Web-based reporting?

Lerdo Highway Do I need aerial / satelite imagery … California Aqueduct Location of Belridge Oilfield salinity trial

NDVI and % cover from 4 … and color digital aerial imagery spectral captured at a 1 foot pixel resolution 8/14/12 analysis for (differences are statistically optimal significant) 0.7 irrigation? EC 0.5 EC 3.2 0.6 EC 5.2 0.5 NDVI, % Cover 0.4 0.3 0.2 0.1 0.0 % Cover All Plot NDVI Canopy NDVI

CIMIS – CA Irrigation Management Information Service The whole Central Valley covers Zones 12 to 16: for an “normal year” ETo of 53.3 to 62.5 in/yr, with most area @ 53 to 58 inches.

David A. Goldhamer, Elias Fereres California Agriculture May-June 2001 pp32-37 Nothing like a locker box full of electronics to “simplify” irrigation!

Does all this stuff guarantee profit and “sustainability”? YES (maybe?) … NO … DEPENDS …

ANSWERS / DISCLAIMERS: 1. For ALL crop settings/fields? Definitely NO! 2. Do we have “silver bullet” criteria that will tell me what technology will guarantee profitability for given field conditions? NO! 3. Are there guidelines to know what technology is helpful for what areas/problems? YES! 4. Is there a “high - tech” ag consultant out there who can “get it right” every time? Only GOD! 5. I am not God, nor is any irrigation company or even the Regional Water Quality Control Board!

And what the heck is “sustainability” anyway? • Long term profit? (Absolutely!) • No degradation of groundwater, no leaching? • Increasing soil organic matter & “CO2 sequestration”? • Use less water, chemicals, be “greener”?

ELECTRON MICROGRAPH OF STOMATA ON THE UNDERSIDE OF A LEAF. Reduced water, deficit irrigation, causes less turgor pressure in the plant, reduces the size of stomatal openings; thus decreasing the uptake of carbon dioxide and reducing vegetative growth.

What’s the promise of “high tech” irrigation? KNOWLEDGE: a way to look into and quantify the crop rootzone & plant nutrient/water status, which leads to…  Increased efficiency  Increased yield  Decreased inputs (maybe)  Increased profit – the universal goal!

TO MEASURE IS TO KNOW