Irrigated cotton acreage in Georgia increased from near 150,000 in 1990 to over 600,000 acres in 2000. At the same time,agricultural stewardship of water resources has been scrutinized due to four consecutive years of below average rainfall. Auniquely designed irrigation research farm was designed by the USDA/ARS National Peanut Research Lab (NPRL) to studythe economic effects of limiting irrigation on cotton, peanut, corn, and other commodities. Statistically significant differences(α = .05) were found between irrigated and non-irrigated yields for all varieties in the first two years. Significant differencesamong irrigation treatments varied between years. Average D&PL 458 yields for year one and two were 1110lbs/ac, 968 lbs/ac, and 855 lbs/ac for the full, 2/3, and 1/3 irrigation treatments respectively. Average dryland yield was 401lbs/ac. Subsurface drip irrigation performed numerically though not statistically better than overhead sprinkler in year onebut was statistically worse than sprinkler irrigation in year two. Assuming price plus LDP equals $0.55/lb, per acre net returnsabove variable cost and land using D&PL 458 under sprinkler irrigation were $14.57, $-47.01, $-109.30, and $-159.82for full, 2/3, 1/3, and dryland treatments respectively. Marginal revenue minus marginal cost at the full irrigation level equals$-6.25. While results are encouraging, conclusions should not be drawn from the first two years of data, as rotational differencesmay be evident in later years.
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