Soybean Irrigation Management

Transcription

1 Soybean Irrigation Management Daran Rudnick-Extension Specialist Chuck Burr and Troy Ingram -Nebraska Extension Educators Importance of Irrigation Source: Rudnick and Irmak (2015) 1

2 Periods When Crops are Most Susceptible to Water Stress [a] Pollination period very critical if no prior water stress. Source: Doorenbos and Pruitt (1977) Yields by Irrigation Strategy /build/g1367.htm 2

3 Monsanto Water Utilization Learning Center 2010 Corn Monsanto Water Utilization Learning Center 2010 Soybeans 3

4 Average Soybean Yield and Irrigation Water Use Efficiency for all sites in 2015 Treatment Soybean Yield bu/ac Irrigation inches Irrigation Water Use Efficiency bu/inch Full Irrigation % Irrigation % Early,Full After R Rainfed Average Rainfall 17.1 inches Concepts for Managing Irrigation with Soil Water Sensors 4

5 Soil Water Diagram for Irrigation Scheduling Indirect methods measure a surrogate property and relate it to soil water content or potential. Some Indirect methods Hand Feel Neutron Attenuation Capacitance Time Domain Reflectometry Frequency Domain Reflectometry Electrical Resistance Tensiometers Measure Variable Surrogate Relationship (a.k.a. Conversion) Estimated Soil Water Status 5

6 ETgage (Atmometer) Reference ET Legend: SWP: Soil Water Potential SWC: Soil Water Content Temp: Soil Temperature EC: Bulk Electrical Conductivity Irrometer Tensiometer SWP Campbell Scientific CS616 SWC Irrometer Watermark SWP Acclima True TDR SWC, Temp, & EC Campbell Scientific CS655 SWC, Temp, & EC MPS-2 or MPS-6 5TE EC-5 SWP & Temp SWC, Temp, & EC SWC Decagon Devices Stevens Hydra Probe II SWC, Temp, & EC 6

7 Electrical Resistance Sensors Description: Relatively low cost & easy to use/install Reports tension not water content Requires good soil contact Some issues with high sandy soils at high tensions or swelling clays Minor Temperature effects Tension decreases by 1% for each 1ᵒF increase above 70ᵒF & vice versa Response Time (potential lag) Hysteresis Effects (i.e., wetting and drying curves are not the same) Watermark Gypsum Blocks 7

8 Tensiometers Description: Operational range: 0 to ~85 cb Within irrigation range for sandy soils Not within irrigation range for fine-textured soils Potential limitation on depth of install Reports tension not water content Requires good soil contact Response Time (potential lag) Hysteresis Effects (i.e., wetting and drying curves are not the same) Routine maintenance Capacitance Sensors in Access Tubes Description: Based on dielectric properties of soil Capacitors can often be placed at various depths within access tube Continuous monitoring capabilities Fast response time Susceptible to various factors: soil type and structure, temperature, wetting patterns, soil salinity, air gaps, clay content, among others Proper installation is essential Measurement frequency impacts the sensing volume 8

9 Laboratory evaluation using site specific soils can help identify the accuracy and precision of the sensors. Field evaluation is necessary to determine how well the sensors will perform under dynamic in-season conditions. Laboratory Sensor Comparison 9

10 Convenience Financial Cost Remote Access Sensor Accuracy Product Support Soil Type & Condition How Many are Needed Crop Type and Rooting Depth Integration with Other Sensors Pros vs Cons Select Sensor 10

11 Crop Water App Free App Available for Apple/Android Provides an easy way to estimate soil water status Will estimate water used/water available Log readings over time CropWater Calculate average reading down to 4 feet Water depleted in inches/foot Calculate water depleted in soil profile Also displays total water available 11

12 CropWater IrrigatePump Cost - $3.99 Available in Apple and Android platforms Figure how well your pumping plants on your irrigation wells stack up against the Nebraska Pumping plat Criteria (NPC) Should be a reasonable target for every new pumping plant 12

13 IrrigatePump Results: Click on the Calculate button to figure your performance rating Figures potential savings if you could bring the unit up to NPC standard Also figures payback years MeterCalc Acre inches pumped displayed Inches per acre displayed Total inches pumped during season Tracks annual allocations 13

14 Soywater: - Launched on May1, Irrigation management tool - Developed by UNL & Nebraska Soybean Board Soywater on Cropwatch 14

15 Login page Soywater inputs 15

16 Output table Input rainfall Input irrigation Soil water depletion Predict growth Stages Water use chart 16

17 Watermark sensor calculator Nelson Regulators Function the Same Senninger 17

18 Pressure Regulator Tester Pressure Regulator Tester 18

19 Thank You! acres 19

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