1 / 17

Screening Deficit Irrigation Strategies Using Crop Growth Simulation

Screening Deficit Irrigation Strategies Using Crop Growth Simulation R. Louis Baumhardt and Scott A. Staggenborg USDA- ARS Conservation and Production Res. Lab. Bushland , TX Kansas State University Plant Science Center, Manhattan, KS. Depth to Water. Depth to Water.

sarah-jacobs
Télécharger la présentation

Screening Deficit Irrigation Strategies Using Crop Growth Simulation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Screening Deficit Irrigation Strategies Using Crop Growth Simulation R. Louis Baumhardt and Scott A. Staggenborg USDA-ARS Conservation and Production Res. Lab. Bushland, TX Kansas State University Plant Science Center, Manhattan, KS

  2. Depth to Water Depth to Water Irrigation Well No. 2 - Bushland, TX Irrigation Well No. 2 - Bushland, TX 0 0 -50 -50 1957-77 1957-77 -100 -100 65 ft Decline 65 ft Decline -150 -150 1977-98 1977-98 21 ft Decline Depth Below Ground - ft -200 21 ft Decline Depth Below Ground - ft -200 -250 -250 Red Bed Red Bed -300 -300 (aquifer bottom) (aquifer bottom) -350 -350 1955 1965 1975 1985 1995 2005 1955 1965 1975 1985 1995 2005 Year Year • Well capacity has declined with the decreasing water table. • The choice is between deficit irrigation or concentrating water to adequately irrigate a portion.

  3. Irrigation-strategy Question: • Will uniformly spreading water resources to deficit irrigate a large area produce more or less crop yield than if that same water resource was concentrated to irrigate a smaller area and averaged with the complementary dryland area? Uniformly Irrigate Variably Irrigate

  4. APPROACH • Use crop growth simulators (SORKAM and GOSSYM) and recorded weather at Bushland from 1958-1999 to calculate sorghum grain and cotton lint yields for several deficit irrigation combinations. • Determine crop growth and yield response to deficit irrigation levels for various planting practices or cultivar maturity.

  5. IRRIGATION PARAMETERS • Irrigation – 7 d application interval and 4 capacity levels: • No – Irrigation = Rain only • Irrigation + Rain = 2.5 mm d-1 (2 gpm/ac) • Irrigation + Rain = 3.75 mm d-1 (3 gpm/ac) • Irrigation + Rain = 5.0 mm d-1 (4 gpm/ac)

  6. OTHER FACTORS • Sorghum: • Cultivar Maturity = Early (15-leaf), Medium (17-leaf), Late (19-leaf) • PlantingDate = 15 May, 5 June, 25 June • Cotton: • Irrigation Duration = 4 and 8 weeks

  7. MODEL VALIDATION 7000 SIMULATED = 390 + 0.95*MEASURED r2 = 0.70 6000 RMSE = 903.5 kg ha -1 5000 4000 Simulated Grain Yield, kg ha-1 3000 2000 1:1 1000 0 0 1000 2000 3000 4000 5000 6000 7000 Measured Grain Yield, kg ha-1

  8. 1:1 Dryland 5.0 mmd-1 2:1 3.75 mmd-1 Dryland UNIFORM 2.5 mmd-1

  9. 1:1 Dryland 5.0 mmd-1 2:1 3.75 mmd-1 Dryland UNIFORM 2.5 mmd-1

  10. SUMMARY • Simulated grain yield increased with increasing irrigation, but simulations also reflect generally better WUE at 3.75 mm d-1 than at 5.0 mm d-1 irrigation levels. • The weighted average grain yield for variable irrigation strategies with a dryland component increased net grain yield from 13% to >20% over uniformly irrigated sorghum.

  11. CONCLUSION • For declining water resources, converting uniform deficit irrigation (water spreading) of a determinate crop like grain sorghum to variable irrigation that concentrates water on smaller areas with a complementary dryland area will increase overall sorghum grain yield.

  12. 4 - Week irrigation 8 - Week irrigation Weighted Percent Weighted Percent Irrigation Irrigation Averag e of Base Average of Base Strategy Capacity Yield Yield Yield Yield Yield Yield ____ ____ ____ ____ mm/d % % kg/ha kg/ha UNIFORM 2.5 390 390 87 450 450 100 2:1 3.75 530 425 94 615 480 106 Dryland 220 220 1:1 5.0 660 440 98 7 20 470 104 Dryland 220 220 1:1 Dryland 5.0mm/d 2:1 3.75mm/d Dryland UNIFORM 2.5 mm/d SIMULATED COTTON YIELD vs IRRIGATION STRATEGIES

  13. CONCLUSION • Cotton yield levels are maintained or increased by converting from uniform deficit irrigation (water spreading) to variable irrigation on part of a field (concentrating water) with a complementary dryland area.

  14. } YEAR = 3 YEAR = 1 } 2.5” 2.0” WHEAT 1.5” O S A N D 1.0” J J J F M FALLOW 0.5” A M 0.0” Rain A M F M J J SORGHUM D J N A O S } FALLOW O S A N YEAR = 2 J D J J F M A M Wheat-Sorghum-Fallow Rotation • Two crops in three years, • Storage of precipitation as soil water, • Stable grain crop yields

  15. 35 11’ N, 102 5’ WElevation = 1170 mGrowing season = 181 d 2500 Pan-Evaporation 2000 Precipitation 1500 WATER DEPTH, mm 1000 500 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MONTH

More Related