Using Aerial Imageryto Aid Site-Specific

Management of Fields

report to the Potash and Phosphate Institute

Jennifer Wells and Craig Kvien for the

Precision Agriculture TeamUniversity of Georgia -- NESPAL

February 2002

Using aerial imagery to aid in selecting fields for variable rate

management of inputs

“Good”, “medium”, and “poor” growth areas within each peanut field were selected

• Deep core soil samples and divided into A and B horizons

• Soil texture, organic matter content, pH, calcium, potassium, magnesium, manganese, phosphorus, and zinc measured

• Cation exchange capacity estimated

Variability in Surface Texture

Field: B-06

Poor GrowthYield: 2257 lbs/A

Medium GrowthYield: 3610 lbs/A

Good GrowthYield: 4013 lbs/A

83%sand 11%clay 66%sand 27%clay69%sand 19%clay

Variability in Subsoil Texture

Field: B-06

Poor GrowthYield: 2257 lbs/A

Medium GrowthYield: 3610 lbs/A

Good GrowthYield: 4013 lbs/A

82%sand14%clay 52%sand 42%clay78%sand 17%clay

Variability in Organic Matter

Field: B-06

Poor GrowthYield: 2257 lbs/A

Medium GrowthYield: 3610 lbs/A

Good GrowthYield: 4013 lbs/A

1.1% 2.7%3.8%

Variability in Phosphorus in Surface Horizon

Field: Thaggard7

Poor GrowthYield: 3177 lbs/A

Medium GrowthYield: 3866 lbs/A

Good GrowthYield: 4716 lbs/A

221 lbs P/A118 lbs P/A

278 lbs P/A

Variability in Phosphorus in Subsoil

Field: Groover

Poor Growth 2

Medium Growth

Good Growth8 lbs P/A

Yield: 4554 lbs/A

33 lbs P/AYield: 4063 lbs/A

5 lbs P/AYield: 4383 lbs/A

Poor Growth 121 lbs P/AYield: 3021 lbs/A

Variability in Potassium in Surface Horizon

Field: Butler

Poor GrowthYield: 3844 lbs/AMedium Growth

Yield: 4985 lbs/A Good GrowthYield: 3524 lbs/A

72 lbs K/A 185 lbs K/A56 lbs K/A

Variability in Potassium in Subsoil

Field: Thaggard8

Poor GrowthYield: 2155 lbs/A

Medium GrowthYield: 4579 lbs/A

Good GrowthYield: 4606 lbs/A

116 lbs K/A 40 lbs K/A138 lbs K/A

Variability in Calcium in Surface

Field: Groover

Poor Growth 2Yield: 4063 lbs/A

Medium GrowthYield: 4383 lbs/A

Good GrowthYield: 4554 lbs/A1088 lbs Ca/A

267 lbs Ca/A

800 lbs Ca/A

Poor Growth 1Yield: 3021 lbs/A

392 lbs Ca/A

Variability in Calcium in Subsoil

Field: Butler

Poor Growth2Yield: 3844 lbs/AMedium Growth

Yield: 4985 lbs/A Good GrowthYield: 3524 lbs/A

294 lbs Ca/A624 lbs Ca/A180 lbs Ca/A

Poor Growth1Yield: 3987 lbs/A

162 lbs Ca/A

Variability in CEC in Surface

Field: Groover

Poor Growth 2Yield: 4063 lbs/A

Medium GrowthYield: 4383 lbs/A

Good GrowthYield: 4554 lbs/A4.0 meq/100g

1.1 meq/100g

2.9 meq/100g

Poor Growth 1Yield: 3021 lbs/A

1.6 meq/100g

Variability in pH at Surface

Field: Crossroads

Medium GrowthYield: 4110 lbs/A

Good GrowthYield: 3979 lbs/A

pH 5.9pH 6.0

Poor GrowthYield: 2492 lbs/A

pH 6.8

Variability in pH in Subsoil

Field: Thaggard7

Poor GrowthYield: 3177 lbs/A

Medium GrowthYield: 3866 lbs/A

Good GrowthYield: 4716 lbs/A

pH 5.0pH 5.5

pH 5.0

• We found large differences in soil properties among the sixteen fields.

• The reasons for differences varied both within and between fields, and no single reason was common among all of the fields.

• Site-specific agriculture embraces the concept of variability within a field, thus it is no surprise that the reasons for variability between fields also varied.

• This brief report contains a small sub-set of data now being analyzed as part of Jennifer Wells’ MS thesis project. For more information:

• Craig Kvien (ckvien@tifton.cpes.peachnet.edu)

• Jennifer Wells (jsanders@tifton.cpes.peachnet.edu).