Peanut Irrigation Study, 1985, Georgia Coastal Plain

Yield Comparisons:
Study:

Research Objectives:

    1. Determine zones of water extraction with time when peanuts are maintained in well watered (no zone drier than 30 cb) versus rainfed.
    2. Compare irrigation scheduling and replenishment methods for effects on top growth and yield.
      a. Davidson model
      b. Maintaining topsoil vs. subsoil moisture
      c. Simple fixed schedule
    3. Determine top growth and root density at the start of R1, R2, and R4 stages for future model validation.
    4. Monitor meteorological conditions - hourly wet/dry bulb temperatures, wind run at 2m, direct plus diffuse solar radiation, net radiation, and soil temperature under peanut row at 5 and 10 cm (moist canopy) and growth stages.
Treatments:
 1.Well-watered - Apply 2.5 cm of water whenever any depth tensiometer (20-150 cm) exceeds -30 kPa metric suction in two or more replicates.
 2.Shallow replenishment - Add 70% of accumulated pan evaporation every four days after either (1) the start of R2 stage or (2) the 18 to 24 cm zone dries to metric suction greater than 45 kPa. The amount of water or frequency may be increased to maintain a metric suction of less than 30 kPa at 20 cm after irrigation begins.
 3.Deep cycle - Add 90% of depleted water holding capacity of 0 to 60 cm zone after all depths in that zone dry to metric suction exceeding 30 kPa in two or more replicates.
 4.Fixed schedule - Add 4.0 cm of water within one week after start of R2 (after gypsum application) and 14 and 28 days later.
 5.Davidson model 1
 6.Davidson model 2
 7.No irrigation

Basic Crop Management: PLANTED - 02 May 1985 (rows 0.9m apart, placed 4-5 cm deep, seed rate 24 seeds/m); HARVEST - 16 Sep 1985; TILLAGE - Moldboard Plow (30 cm deep plus smoothing and bed shaping), wheel traffic controlled at 1.2 m centers; FERTILIZATION - Typical Extension Recommended Rate; WEED & PEST CONTROL: Typical Extension Recommendations.
Chronological Treatment and Observation Details

Observations and data sets for individual treatments (crop years) follow:
Treatment 1:
  Well-watered
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.98; Individual plots - 6.36, 6.22, 5.45, 5.89 Text File
Treatment 2:
  Shallow 70% evaporation pan
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.80; Individual plots - 6.13, 5.37, 6.23, 5.46 Text File
Treatment 3:
  Deep cycle
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.94; Individual plots - 6.59, 4.93, 5.88, 6.36 Text File
Treatment 4:
  Fixed schedule
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.64; Individual plots - 6.89, 5.62, 4.58, 5.48 Text File
Treatment 5:
 Davidson model 1
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.51; Individual plots - 4.91, 5.70, 6.19, 5.23 Text File
Treatment 6:
 Davidson model 2
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.53; Individual plots - 4.40, 7.50, 5.18, 5.02 Text File
Treatment 7:
  No irrigation
  • Irrigation Dates and Amounts: Text Format;
  • Phenology: Emergence - 10 May 1985; Pollination (R2) - 19 Jun 1985; Maturity - 03 Sep 1980
  • Stand Count:
  • Soil Water Pressure Observations: Tensiometer & Gypsum Block
  • Yield Peanuts, 7% moisture, T/ha: Average - 5.97; Individual plots - 5.51, 5.73, 5.82, 6.82 Text File
For more information on the study and its interpretation contact:
Dr. Jim Hook Professor, Soil and Water Management
Crop and Soil Sciences Department and NESPAL
The University of Georgia, College of Agricultural and Environmental Sciences
P.O. Box 748, Tifton, GA 31793-0748
e-mail: jimhook@tifton.cpes.peachnet.edu

Page developed by James E. Hook, Amanda Richards, and Linsey Forlow.
Last Modified on 29 June 2000.