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Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/24/2014 Publication Date: 6/26/2014 Citation: Sorensen, R.B., Butts, C.L. 2014. Peanut Response to Crop Rotation, Drip Tube Lateral Spacing, and Irrigation Rates with Deep Subsurface Drip Irrigation. Peanut Science. 41:1-9. Interpretive Summary: Peanut production covers just over 322,000 ha in the tri-state area of Alabama, Florida, and Georgia with only 28% of these acres being irrigated. Only about 10% of the total irrigated hectares in Georgia were irrigated using drip, trickle or micro-sprinkler while Florida, on the other hand, has over 220,000 ha using some type of drip or trickle irrigation. Economic simulations showed that subsurface drip irrigation (SSDI) would be more profitable for small areas (<30 ha) because of its lower investment per unit land area and lower pumping costs compared to fixed or towable center-pivot systems. These SSDI systems are adaptable to various field sizes and shapes making them an important economic consideration, especially in the southeast. This economic advantage is further evident when considering the option to design a SSDI system to effectively cover an irregularly shaped field that would not be totally covered with a sprinkler type system. With proper SSDI designs these systems can provide sufficient water to different field areas according to the area, soils, and crop species. With increasing concern for water conservation in the tri-state region (Alabama, Georgia, and Florida), the use of SSDI due to the greater irrigation efficiency of these systems, may be of great interest to individual growers, water and environmental conservancy agencies, and policy making agencies. There is little long term peanut yield response data with SSDI in the southeast to make management recommendations. Therefore, the objectives of this research were to determine the long-term yield response of peanut to: 1) three irrigation rates, 2) two lateral spacings, and 3) five crop rotations using SSDI over a 10-year period. A SSDI system was installed in 1998 on a Tifton loamy sand with five crop rotations, two drip tube lateral spacings, and three irrigation levels. Crop rotations ranged from continuous peanut (Arachis hypogeae L) to four years between peanut. The five crop rotations included continuous peanut (PPP), cotton-peanut (CP), corn-peanut (MP), cotton-corn-peanut (CMP), and a cotton-corn-corn-peanut (CMMP) (see Table 1). Laterals were installed underneath each crop row (0.91-m) and alternate row middles (1.83-m). Crops were irrigated daily at 100, 75 and 50% of estimated crop water use. Irrigation water was applied daily based on replacement of estimated crop water use for peanut. The only peanut cultivar used, “Georgia Green” was planted between 01 to 12 May (depending on weather conditions) with a vacuum type planter (Monosem, ATI., Inc., Lenexa, KS) at about 20 seeds m-1 on a 0.91-m row spacing. Harvest dates were based on the optimum crop maturity determined by the hull scrape method. Yield rows were dug with a 2-row inverter and harvested with a 2-row combine. Sample weights were recorded and subsequently divided such that a 4 to 7-kg sub-sample was collected from each plot sample. Rainfall amounts can be quite large with long periods of drought between rainfall events. Thus, irrigation timing and amount is greatly affected by rainfall timing and amount. Two out of ten years showed lower yields at the 50% irrigation treatment. There were no yield difference between the 75 and 100% irrigation treatment. Therefore, irrigating at 75% of estimated ETa would imply a 25% saving of water without compromising crop yield. There was little yield increase when using narrow lateral spacing. Therefore, it is recommended that on these soils and in this environmental location, laterals be spaced in alternate row middles for maximum yield and possible economic return. Over this 10-year period, the alternate year rotation of corn-peanut tended to have higher peanut yield compared with the alternate year rotation of cotton-peanut. When a situation occurs to shorten the time period between peanut to an alternate year rotation, the grower should choose th Technical Abstract: Long term crop yield with various crop rotations irrigated with subsurface drip irrigation (SSDI) is not known for US southeast. A SSDI system was installed in 1998 on a Tifton loamy sand (Fine-loamy, kaolinitic, thermic Plinthic Kandiudults) with five crop rotations, two drip tube lateral spacings, and three irrigation levels. Crop rotations ranged from continuous peanut (Arachis hypogeae L) to four years between peanut. Laterals were installed underneath each crop row (0.91-m) and alternate row middles (1.83-m). Crops were irrigated daily at 100, 75 and 50% of estimated crop water use. Laterals spaced at 1.83-m had the same yield as laterals spaced at 0.91-m in nine out of ten years. Over the 10-year research period, the 50, 75, and 100% irrigation treatments averaged 3263, 3468, and 3497 kg ha-1, respectively. The 50% irrigation treatment showed lower yields compared with 100% irrigated treatment two out of ten years. There was no yield difference between the 75 and 100% irrigation treatments implying 25% water savings without compromising peanut yield. Crop rotation affected peanut yield seven out of eight years. Continuous peanut had lower yield across all years. Increased time between peanut crops increased peanut yield. Irrigation treatment had no effect on total sound mature kernels (TSMK). Lateral spacing affected TSMK two out of ten years. Crop rotation affected TSMK 90% of the time. Continuous peanut rotation had the lowest TSMK. Higher TSMK occurred as time between peanut crops increased. There was no clear evidence of any crop rotation affecting kernel size distribution. |
