OPTIMIZING IN-SITU SOIL SALINITY MAPPING WITH LANDMAPPER
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The document details research presented by Larisa Golovko on geophysical methods applied to agricultural practices, specifically concerning soil salinity and irrigation effectiveness. It discusses various techniques for measuring electrical conductivity and resistivity in soils, their impact on crop yield, and the spatial as well as temporal variability of salinity. The findings highlight the relationship between irrigation water salinity and rice crop performance, emphasizing management practices for optimizing soil conditions.
OPTIMIZING IN-SITU SOIL SALINITY MAPPING WITH LANDMAPPER
- 1. Larisa Golovko, PhD Landviser LLC and RiceTec Inc, Houston, TX Presented at Agricultural Geophysics and Material Properties. Symposium on the Application of Geophysics to Engineering and Environmental Problems 2015: pp. 1-11. https://doi.org/10.4133/SAGEEP.28-001
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- 4. 4 10 Ohm m =1 dS/m = 1 mS/cm = 1 mmho/cm = 640 ppm = 640 mg/L= 0.64 g/L=0.064%.
- 6. AEMP-14, from KB Electrometry (Russia) Quick EM method of EC mapping down to 10 m, 14 frequencies. Other EM Equipment by Dualem, Geonics, GF Instruments, etc.
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- 8. Fits in shirt pocket Runs all season from standard 9V battery Measures EC/ER in irrigation water, saturated soil paste as well as in the field soils from 2 cm to ~20 m depth 8
- 9. No calibration – EC output calibrated once for each probe size. No GPS integration – no wait for satellite fix Push one button – get EC value in 4 seconds! Stores 1000 EC values – can be merged with concurrently taken GPS data to produce quick maps. 9
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- 15. Planted hybrids along with varietal checks at the farm. Variable readings 300 – 1700 ppm in test area
- 16. 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 EP1122 EP1122 CLXL8 CLXL8 CL161 CL161 CL131 CL131 XP730 XP730 XP729 XP729 Rice yield, lb/acre Soil salinity at planting, ppm Soil salinity at harvest, ppm
- 17. No salt 294 ppm 0.5 gm/kg 378 ppm 1.0 gm/kg 302 ppm 1.5 gm/kg 581 ppm 2.0 gm/kg 721 ppm 2.3 gm/kg 1043 ppm LA soil (check) 1570 ppm
- 24. Storm surge brings in salt water Drought leaves it in place High pumping cost reduces options for flushing soil
- 26. Spatial variability Temporal variability Many samples are needed to characterize a single field.
- 27. management practices water table depths soil properties evapotranspiration rates rainfalls salinity levels of groundwater hydrogeological conditions
- 28. Speed of turn-over Units Techniques – results non- comparable between different labs 1000 umho/cm = 1 dS/m = 10 Ohm m = 1/ 640 ppm = 0.64 g/L = 0.064% = 45.7 grains per gallon
- 30. y = 0.1225x + 2.7372 R² = 0.5156 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 FieldERin1',Ohmm TAMU Soil Extract conductivity, Ohm m Resistivity of soil solution vs in-situ values
- 31. • 910 acres research farm • 426 points ER measured at 1’ and 2’ depth • 2 days, 2 LandMappers, 3 people, AT vehicle (mule)
- 32. More dense measurements in problem fields Cross-scanning other fields Collecting samples from areas of very low/high resistivity
- 33. Top: bad, deep: non-salty Top: bad, deep: salty
- 36. Good soil EC in top 30 cm < 1.5 dS/m (ER > 6 Ohm m) measured in flooded or “mud” conditions EC of irrigation water <1 dS/m (ER > 10 Ohm m) – no yield reduction EC of irrigation water 1-3 dS/m (ER=3-10 Ohm m) – yield reduction up to 50% On marginally salty soils/water: delay permanent flood - use several flushing with fresh water instead, reduce N fertilizer, apply some gypsum on sodic soil pre-season, consider switching to other crops or rice hybrids 36
- 38. USA Farmers (James Gentz, Jim White, David Murrel, Mr. Saltzman, Mr. Goulding). RiceTec Inc. (Derrol Grimes, Robert Miller, Mark Spilman, Jose Plaza, Jaime Suarez) & Helena Chemicals (Ronnie Melancor) Russian Visiting Scientists (Alexey Rusakov, Anatoly Pozdnyakov) Indonesian STEM Oil and Gas University, Cepu, Central Java) www.landviser.net