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Using LandMapper to Monitor Soil Salinity and Mitigate Its Effects on Rice Production at US Gulf Coast

Landmapper - Portable and Scalable EC meterMost of the soils along US Gulf Coast are naturally slightly saline and some are waterlogged during much of the growing season. Naturally, those areas are used for rice production rotated with cattle grazing or hay growing. Soil salinity of those areas varies spatially and temporarily due to drought, hurricane-pushed sea water surges, micro-elevation within fields, variability of salinity levels in irrigation water. Monitoring soil and water salinity with conventional techniques of collecting soil samples by farmer and sending them to outside lab is costly and time-consuming. Such approach fails to provide timely advice to the farmer regarding crop selection pre-planting and mitigation inputs during the growing season. Several rice farms affected by Katrina and Ike hurricanes were monitored in 2006-2011 utilizing field soil EC meter, LandMapper ERM-02, consumer-grade GPS, and other common equipment available to a farmer. On six test fields EC values were recorded with LandMapper directly in the field at 30 locations in less than 45 min.

Cite this presentation:

Golovko, Larisa, and Anatoly Pozdnyakov. “Using LandMapper to Monitor Soil Salinity and Mitigate Its Effects on Rice Production at US Gulf Coast.” In Making Waves: Geophysical Innovations for a Thirsty World. Tucson  AZ: Environmental and Engineering Geophysical Society, 2012. http://www.landviser.net/webfm_send/94.SAGEEP 25 - 2012 - Tucson, AZ

Registered users can download full proceeding paper: 
 

Using LandMapper to Monitor Soil Salinity and Mitigate Its Effects on Rice Production at US Gulf Coast

EC on those fields varied from 5 mS/m to 106 mS/m on surface; and from 19 mS/m to 400 mS/m in deeper layer. Thus, advice on soil salinity levels and possible ways of its mitigation was given to the farmer directly at the field. Pre-planting and within-season advices included selection of salt-tolerant rice hybrids, adjusting fertilizer rates, scheduling additional field flushes and monitoring irrigation water salinity with small, low-cost EC meters. A few farmers have reported higher yields from such closely monitored fields despite worse than optimal salinity levels in soil.

Salinity – persistent problem of irrigated agriculture
Electrical parameters in soils of arid zone
EC/ER:  direct indicator of total soil salinity
 
¨LandMapper® is… Portable and Scalable!
  • 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 ~10 m depth

¨LandMapper® is… Easy and Fast!

  • 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.
Rice is flooded and flushed - salinity problem in non-arid environment!
  • 2005 - hurracaines Katrina and Rita
  • Saline surges wipe out second rice crop at TX and LA shores but this is only start of the problem
    • Storm surge brings in salt water
    • Drought leaves it in place
    • High pumping cost reduces options for flushing soil
 
Salinity levels for greenhouse study: Hybrids can withstand salinity up to 1000 ppm
 
Vermilion Parish Field Plots
  • Planted hybrids along with varietal checks at  the farm.
  • Variable readings 300 – 1700 ppm in test area
  • RiceTec Hybrids seem to have better tolerance to salt damage than varieties in field as well
2008 - Ike – 2 weeks before AGI-CSA-ASA-SSSA Meeting in Houston
RiceTec reassures farmers hit by storm surge
7 years after Rita, 4 year after Ike - TX and LA farmers still having problems
=> Soil Salinity is highly dynamic:
  • Spatial variability
  • Temporal variability
Many samples are needed to characterize a single field.
 
Soil Salinity is influenced by
  • management practices
  • water table depths
  • soil properties
  • evapotranspiration rates
  • rainfalls
  • salinity levels of groundwater
  • hydrogeological conditions
Continuous monitoring needed
 
Soil Sampling frustration:
  • Speed of turn-over - up to a month to get a sample results from a lab
  • Units ???
  • Techniques – results non-comparable between different labs
 
 
Rice salinity management guidelines
  • Good soil EC in top 30 cm < 1.5 dS/m measured in flooded or “mud” conditions
  • EC of irrigation water <1 dS/m – no yield reduction
  • EC of irrigation water 1-3 dS/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
 
Thank You
¨Farmers (James Gentz, Jim White, David Murrel, Mr. Saltzman, Mr. Goulding).
¨RiceTec Inc. (Derrol Grimes, Robert Miller, Mark Spilman)
¨Helena Chemicals (Ronnie Melancor)
¨Russian Visiting Scientists (Alexey Rusakov, Anatoly Pozdnyakov)
new collaboration website just launched  www.LANDVISER.net
 
 

 

Locations

Winnie, TX 29° 49' 12.7956" N, 94° 23' 2.6808" W
SAGEEP 2012 Tucson, AZ 32° 13' 18.2748" N, 110° 55' 35.3244" W

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