Submitted to: Transactions of the ASABE
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/22/2008
Publication Date: 8/1/2008
Citation: Rowland, D., Leffler, J., Sorensen, R.B., Dorner, J.W., Lamb, M.C. 2008. Testing the Efficacy of Deuterium Application for Tracing Water Uptake in Peanuts. Transactions of the ASABE 51:455-461. Interpretive Summary: A new method of measuring water uptake patterns in peanut was tested. The method involved applying labeled water (deuterium) to the crop and testing the levels of the labeled water in stems and soils after application. The water uptake in two irrigation systems, a crop watered with overhead irrigation and one watered with subsurface drip irrigation, were tested to see if the patterns of uptake differed. Two cultivars of peanut were also tested. Water entered and dispersed through the soil differently between overhead and subsurface drip irrigation but it had no effect on subsequent crop water uptake. There were no statistical differences between peanut cultivars, but numerically the results indicated that the cultivar Georgia Green used more surface water than Andru II. It appears that peanut is able to utilize water applied either through irrigation or rainfall for a period of 48 to 72 hours. This study demonstrated that the use of deuterium was successful in a peanut production setting for determining water uptake patterns in the crop.
Technical Abstract: ability to determine how long a crop utilizes a given amount of water either from an applied irrigation or a precipitation event would have great potential in improving irrigation decision systems. This would be true particularly for peanut growers since over 50% of all U.S. peanut production is irrigated and has the potential to increase yields by 19% over dryland production. However, technical methodologies available to accomplish this measurement are almost entirely unavailable and untested. We attempted to quantify water movement through soil and peanut plants in two soil types in southwest Georgia: Tifton sandy loam and Greenville clay loam. During the active growth phase (~ 80 days after planting), deuterium labeled water was applied to peanuts growing in both soils simulating a typical irrigation or rainfall event experienced by peanut plants. Soil at four depths and stem tissue was collected after the deuterium was applied. The first experiment in Greenville soil was conducted over a 24 hour period in order to determine how much of a rainfall or irrigation event was utilized in a fully charged soil profile. The second experiment in Tifton soil was conducted over a four-day period starting with a relatively dry soil profile in order to determine how long a peanut plant could utilize an irrigation or rainfall event over a time period that would be typical between irrigation applications in this region. Differences in soil water infiltration between overhead irrigation and subsurface drip irrigation were observed, but it had no effect on subsequent peanut water uptake patterns. While no statistically significant differences in overall water uptake patterns occurred between the two peanut varieties, there was evidence of greater surface water uptake by Georgia Green over Andru II. The duration of water uptake after a simulated irrigation or precipitation event appears to be between 48 and 72 hours for peanut plants. In conclusion, this study demonstrated the utility of applying deuterium labeled water in order to follow soil infiltration and plant water uptake patterns in a peanut agricultural system.