Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2006
Publication Date: 3/1/2007
Citation: Sorensen, R.B., Butts, C.L., Lamb, M.C. 2007. Peanut response to row pattern and seed density when irrigated with subsurface drip irrigation. Peanut Science. 34:27-31. Interpretive Summary: Increasing pod yield while decreasing input costs is of major importance to peanut growers. Past research has shown that planting peanut in twin versus single rows can increase pod yield by as much as 400 lbs/ac and total sound mature kernels (TSMK) by one to two percentage points. In addition to yield and grade increases, the twin-row pattern has shown reductions in the incidence of tomato spotted wilt virus (TSWV). Though the relationship between reduction in TSWV and twin-row patterns is not fully understood, planting in twin-rows has become a standard recommendation to reduce the risk of TSWV incidence. Producers in the Southeast normally plant 6 seed/ft runner-type peanuts in single rows on 3 ft raised beds. This relatively high seeding rate is a hedge against poor germination and emergence in the hope of attaining a recommended stand of approximately 4.0 plants/ft. In addition to better yield, closer spacing and higher population benefits include: a) enhanced weed suppression, b) faster canopy coverage, and c) reduced incidence and severity of tomato spotted wilt virus. The cost of peanut seed is one of the major expenses to the grower. The TSWV Index was validated on non-irrigated and overhead sprinkler irrigation type systems. There has been little peanut yield data collected, especially concerning twin- and single-row patterns, on sites where SDI was used as the primary source of irrigation. Therefore, the objectives of this project were to determine the yield and grade response of peanut when planted in two row patterns (single and twin) at two plant populations (recommended, 1.0R and half recommended, 0.5R) and irrigated with subsurface drip irrigation. Two sites were used in southeast GA, one in Sasser and one in Shellman. Peanut was planted following cotton at both sites and for both years. Peanut was planted in single row and twin rows at the recommended and half the recommended rate. Both sites received the same tillage practices, irrigation scheduling (precipitation dependant), and cultural practices (pest control). This two-year study showed that twin-row planting pattern had 434 lbs/ac higher pod yield compared with single row plant pattern when irrigated using subsurface drip irrigation. The twin-row pattern also had a one percentage point increase in grade value (TSMK) compared with the single row pattern. These yield and grade values for single and twin-row patterns correspond to existing literature values determined when using overhead sprinkler. Yield data from this project imply that SDI could be used to irrigate peanut without reduction of yield or grade. There was no difference in kernel size distribution with row pattern. Twin-row pattern had an $86.20/ac higher market value ($892/ac) compared with the single row pattern ($806/ac). There was no difference in market value for seeding rate. This implies that it may be possible for a grower to plant in a twin-row pattern at half the recommended seeding rate without sacrificing net market returns but may increase the risk of loss of yield due to TSWV.
Technical Abstract: A two year study (2001 and 2002) was conducted at Sasser and Shellman, GA to determine the effects of planting pattern and plant population on the pod yield, market grade, and market value of peanut (Arachis hypogaea L.) when irrigated with subsurface drip irrigation (SDI). Soils were a Tifton loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) and Greenville sandy loam (fine, kaolinitic, thermic Rhodic Kandiudults) with 1% slope. Seeds were planted at recommended (20 seeds/m; 1.0R) and half the recommended rate (10 seeds/m; 0.5R) in a single and twin-row pattern. Plots were irrigated daily to replace estimated daily evapotranspiration (ETa). This study showed that twin-row plant pattern had 488 kg/ha higher pod yield compared with single-row pattern when irrigated using subsurface drip irrigation. The twin-row pattern also had a one percentage point increase in grade value (TSMK) compared with the single-row pattern. There was no difference in kernel size distribution with planting pattern. Twin-row planting had a $213/ha higher market value compared with single-row. There was no difference in yield on market value for seeding rate. This implies that it may be possible for a grower to plant in a twin-row pattern at half the recommended seeding rate without sacrificing net market value but may increase the risk of TSWV yield damage.