Peanut Irrigation Study, 1988, Georgia Coastal Plain

Yield Comparisons:
Study:

Research Objectives:

    1. Compare irrigation scheduling techniques for their ability to meet peanut water needs - yield effects and water use efficiency.
    2. Compare model predictions of soil water with measured soil water.
    3. Compare changes in pod zone moisture and temperature during dewatering of the root zone.
    4. Measure changes in water content by depth following infiltration of irrigated water. To determine "recoverable" water.
    5. Measure in-situ hydraulic conductivity with the Guelph permeameter, and ponded infiltration with the saturated and unsaturated infiltrometer.
Treatments:
 1.Control - Any tensiometers in the 20-90 cm depth trigger irrigation at 30 cb. Irrigation deep enough to refill to dry zones.
 2.PNUTGRO model - trigger when 50% depleted in the upper 2 layers (approx 40 cm); refill entire zone.
 3.Tensiometer at 20-30 cm triggering irrigation at 30 cb; subsoil moisture ignored. Irrigation replaced only into the upper 30 cm.
 4.Tensiometer at 60-90 cm trigger irrigation at 30 cb; topsoil moisture ignored. Irrigation replaced to the 75 cm depth.
 5.PNUTGRO model - trigger when the entire 20 to 90 cm zone has dewatered 50%,; refill entire zone.
 6.Irrigate twice with 5 cm water; once at 50 DAP, once at 64 DAP, adjusted later if SWC is greater than 50% full due to rain.
 7.No irrigation

Basic Crop Management: PLANTED - 04 May 1988 (rows 0.9m apart, seed placed 5 cm deep and 5-7.5 cm apart); HARVEST - 27 Sep 1988; 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:
 Control - Tensiometer at 30 cb - vary at 20-90 cm depths
 Treatment 2:
  PNUTGRO model - 50% depletion to 40 cm 100% refill
 Treatment 3:
  Tensiometer at 30 cb - shallow at 20-30 cm depths
 Treatment 4:
  Tensiometer at 30 cb - deep at 60-90 cm depths
 Treatment 5:
  PNUTGRO model - 50% depletion to 90 cm 100% refill
 Treatment 6:
  Fixed schedule
 Treatment 7:
  No irrigation
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.