Evapotranspiration = The combination of Water that is consumed by a crop (and transpired as vapor from crop stomata) and surface evaporation.

Transcription

1 Irrigation Assessment Tools: SmAcIA (Small Acreage Irrigation Audit) CCAA Pueblo: Nov 2010 Water Resources Team: Denis Reich and Perry Cabot, PhD. Overview Irrigation Water Management Basics Why a Small Acreage Irrigation Audit? Small Acreage Irrigation Audit Algorithm Tools for furrow and side-roll irrigation Pilot Program: Grand Valley 2010 Future Programming 1

2 IWM Basics: : Water Pathways We irrigate primarily in response to these two water pathways IWM Basics: : Definitions Evapotranspiration = The combination of Water that is consumed by a crop (and transpired as vapor from crop stomata) and surface evaporation. Irrigation Field requirement or application = amount of water to be applied to a field or bed that meets crop needs. The amount accounts for system inefficiency and current soil moisture conditions. Efficiency = the amount of water consumed by the crop and lost to evaporation i.e. Evapotranspiration, as compared to the amount of water applied. ET Applied 2

3 IWM Basics: : Definitions Saturation = the point at which no more water can be added to the field or bed. Field or Bed Capacity = the maximum amount of water a field or bed can hold under gravity. Wilting Point = The point at which water is too scarce for a crop to effectively transpire. IWM Basics: : Irrigation Saturation Capacity 50% 0% 3

4 IWM Basics: : Irrigation Saturation! Runoff, Ponding, and Deep Percolation Capacity Irrigation 50% 0% IWM Basics: : Irrigation Saturation Capacity Molecular Forces hold water against gravity: no runoff or perc 50% 0% 4

5 IWM Basics: : Irrigation Irrigation Timing and amount determined by cumulative ET and soil type Saturation ET Determined by crop type (and health) and daily weather conditions Capacity Irrigation Wilting ET 50% 0% IWM Basics: : Irrigation Saturation Capacity Capacity ½ Air 50% Wilting Poor IWM Crop Optimum Good IWM Wilting ½ Wa ater 0% 50% 5

6 -Water-Crop Dynamics rather than crop appearance. Watering Timing and Amounts are best driven by root zone soil moisture Why A Small Acreage Audit? Commercial family farm acreage is shrinking (~5% drop *) Small farms, especially small acreage land parcels are growing (now ~1/4 total acreage of family farms *): Primary source of income is off-farm Most operators are new to irrigation Typical enterprise includes horses and/or perennial grass based crop *NASS Colorado 6

7 SmAcIA Algorithm No Irrigation water advanced? (Furrow) Yes Distribution Uniformity? DU No Poor Potential problem with IWM Poor Seasonal irrigation practices: typical interval and set length throughout h t season Good Field Efficiency? Is furrow / sprinkler flow sufficient or excessive? Poor Good IWM OK or better Good Seasonal Efficiency? Annual field and crop maintenance practices Crop?? Irrigation Assessment Tools 7

8 Mesa County Pilot ~$5,000 from CSU Extension in 2009: Auditor (Magflow meter) Advertising Mileage Fall 2009: Developed audit protocol (furrow and side-roll) in cooperation with: Western Colorado Research Centers (Fruita and Orchard Mesa), US Bureau of Reclamation (Rham Dan Khalsa), Urban Landscape Audits (Curt Swift, Ardith Blessinger), Don Lancaster (local side-roll irrigator). Mesa County Pilot Outline: Book 1-2 hour visit with auditor during next irrigation Visit includes: Furrow / sprinkler snapshot (%DU) moisture measurement / root zone examination Discussion of set and interval management Free soil and water test Examination of problem areas Pond / Landscape issues Report within 2 weeks of visit (soil/water tests usually take < 1 week) Follow up call at end of audit period 8

9 Mesa County Pilot Spring 2009: Began Advertising with Grand Junction Sentinel: Excellent Response: About 50 phone calls over 2 months. Some looking for landscape audits, with others there were scheduling conflicts. 14 audits completed: 164 acres (average of ~12 acres). All furrow pasture/hay 2 audits in Delta Co. DU = Distribution Uniformity Average (lower ½ of furrow catch can flows) volumes) Average (all furrow catch can flows) volumes) Furrow Snapshot: 9

10 DU = Distribution Uniformity Average (lower ½ of catch can volumes) Average (all catch can volumes) Side-roll Snapshot: Outside Test can placement (opposite side of lateral to Inside test) Diesel Engine for moves EIW ½ sprinkler throw Catch Cans Inside Test can placement Snapshot Efficiency 10

11 Seasonal Efficiency Loma Workshop

12 Audit Examples Important to note: Calculations were only part of the visit. Establishing a relationship with the irrigator was probably more important: Irrigator A: Good Irrigator Irrigator B: Decent Irrigator Audit Examples Irrigators C & D: Well that s just makin a mess! 12

13 Next Steps Colorado Basin Roundtable WSRA funds ~$15,000 Mesa Conservation District as Fiscal Agent. For 2011 Irrigation Season. Program set to expand: To employ and train full-time auditor. Pay for an auditor to be perform audits and follow up for 30 hours per week. Program duration: when water first becomes available until July 4 th weekend. Matching Funds: Grand River Mosquito Control District $7,000 Grand Valley Water Users Association $500 Grand Valley Irrigation Company $500 Questions? Denis.Reich@Colostate.edu, Perry.Cabot@Colostate.edu 13