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JECAM | Joint Experiment for Crop Assessment and Monitoring

USA - Tifton, GA. - Little River Watershed

Project Overview

Goals of the site in terms of:

Mapping Resolution:


Project Reports

Implementation Plans

Crop identification and acreage estimation:

The site is the Little River Experimental Watershed (LREW). The LREW comprises 334 square kilometres of agriculture and riparian forest land in the headwaters of the Suwannee River Basin in southwestern Georgia, USA. Based on the 2011 National Land Cover Database (NLCD) datalayer, agricultural land cover in the LREW consists of cultivated crops (~12,600 ha, 37%) and pasture (~3200 ha, 9%). Cropping systems in the region consist largely of a cotton-peanut-maize rotational system, with smaller acreages devoted to soya and specialty crops (e.g. vegetables, fruits). The remaining non-agricultural land is predominantly forest or forested wetlands (~13,000 ha, 39%). Developed, herbaceous, emergent wetlands and open water together make up the remaining proportion (~15%). Operational activities in crop identification and acreage estimation are ongoing. Annual surveys of summer crop cover are conducted over 20% of the watershed area, and have been collected since 1997. Acreage estimations for crops in the watershed can be derived from USDA Cropland Data Layer (CDL) datasets that have been produced since 2008. The in-house “windshield survey” serves as an independent accuracy assessment of the CDL, and also provides information on finer scale, that is sometimes missed in the 30m pixel resolution CDL data.

Residue and Tillage mapping:

In the past we have been involved in a project to evaluate winter cover cropping patterns. Our lab developed methods to detect winter cover residue using remotely sensed imagery.

Soil moisture:

We have a network of nearly 30 soil moisture sensors to “assess regional soil moisture conditions in the rooting zone” throughout the watershed. This has recently be supplemented by additional soil moisture sensors for 2017 SMAP validation efforts.

Crop biophysical variables:

At a few farms we take yield and biomass measurements at various stages during the growing season. We measure across a spatially distributed grid, so our measurements include measures of variability. At these locations we also fly a UAV with a 5-band multispectral sensor at regular intervals throughout the growing season.

Site Description


Little River Watershed
Site Extent   Centroid: 31.61138, -83.65947
Top left: 31.75, -83.772 Bottom Right: 31.478, -83.772

Centroid Latitude 31.61138 Longitude -83.65947
Site Extent Top Left 31.755348 Top Right -83.772482
  Top Left 31.755348 Top Right -83.519949
  Bottom Left 31.478142 Bottom Right -83.772482
  Bottom Left 31.478142 Bottom Right -83.519949


Typical Field Size (Area): mean: 7 ha; min: 0.24 ha; max: 47 ha

Crop Types:  cotton, peanut, maize, soybean, speciality crops

Typical Crop Rotation: cotton/peanut/maize (irrigated); cotton/peanut (non-irrigated)

Crop Calendar: February/March: winter cover kill, and soil bed prep, plant maize; May: plant peanuts and cotton; August: harvest ma

Climate Zone: USDA Zone 9; subtropical

Soil Texture: “Soils are well-drained, brownish, and loamy, o

Specific Project Objectives & Deliverables

 Mapping Agricultural Areas

  1.  Land Cover :  Resolution (minimum mapping unit):  30m    Mapping Frequency: 5 years
  2.  Cropped Land :   Resolution(minimum mapping unit):  10m    Mapping Frequency: 2x per year 
  3. Pasture/Rangeland :   Resolution(minimum mapping unit):    NA    Mapping Frequency:    NA

 Estimating Crop Areas:  

  1. Statistical Units: acres and hectares: N/A

Crop Growing Conditions Over the Growing Season

  1. Soil moisture, precipitation, temperature, evapotranspiration

Estimation of Biophysical Variables

  1.  Biomass, yield, vegetation indices. Starting in 2017 some limited LAI and fAPAR

Phenological Events 

  1. Stage / Timing : n/a
  2. Stress : n/a

Integration of the EO-Derived Information Into Crop/Agro-Met Models : n/a
Forecasting Agricultural Variables from Crop/Agro-Met Models : n/a
Using near real time data

  1. Using climate scenarios : n/a





In Situ Observations

  1. Parameter: crop cover
    Data Collection Protocol:

    'windshield' survey

    Frequency: 1-2 times per year
  2. Parameter: soil moisture
    Data Collection Protocol:

    SMAPVEX17 protocol and ongoing measurements

    Frequency: continual measurements
  3. Parameter: stream flow and water quality
    Data Collection Protocol:

    See Bosch et 2001. "Precipitation , soil moisture , and climate database, Little River WatershedM Georgia United States"

  4. Parameter: climate: precipitation and temperature
    Data Collection Protocol:

    See Bosch et al. 2001. “Precipitation, soil moisture, and climate database, Little River Experimental Watershed, Georgia, United States”

  5. Parameter: above ground biomass
    Data Collection Protocol:

    manually collected

    Frequency: 2 times per year

EO Data Requirements

Approximate Start Date of Acquisition:
Approximate End Date of Acquisition:
Spatial Resolution:
Temporal Frequency:
Latency of Data Delivery:
Wavelengths Required:
Across Swath:
Along Track:

SAR Data Requirements

Approximate Start Date of Acquisition:
Approximate End Date of Acquisition:
Spatial Resolution:
Temporal Frequency:
Latency of Data Delivery:
Wavelengths Required:
Incidence Angle Restrictions:
Across Track:
Along Track:


Little River Watershed

Latitude: 31.61138
Longitude: -83.65947

Site Extent
Top left
Latitude: 31.75
Longitude: -83.65947
Bottom Right
Latitude: 31.478
Longitude: -83.772

Optical Sensors

Imaging Mode: OLI and TIRS
Spatial Resolution: 30m
Acquisition Frequency: minimum , 4 times per growing season
Pre-Processing Level: L1

JECAM | Joint Experiment for Crop Assessment and Monitoring | Group on Earth Observation

©2013 Joint Experiment for Crop Assessment and Monitoring © HER MAJESTY THE QUEEN IN RIGHT OF CANADA SA MAJESTE LA REINE DU CHEF DU CANADA (2012)