Effects of Irrigation Method and Tillage Regime on Peanut (Arachis hypogaea L.) Reproductive Processes

Abstract

The ability of peanut gynophores to peg through cover crop residue in reduced tillage systems is a primary concern of many growers and may be hindering adoption of the practice in peanut production. The interaction between tillage and irrigation could also play a major role in final yield. Experiments were conducted during 2004 and 2005 to determine what effects tillage (conventional tillage – CT and strip tillage – ST) and irrigation method (overhead – OH and subsurface drip – SDI) had on peanut reproductive processes and if climatic conditions were correlated with the formation of reproductive structures. Counts of flowers, pegs, and pods were conducted on two time scales: every 3–4 days for six weeks during peak flowering and peg production; and season long starting at 30 days after planting and continuing until harvest. In 2004, flowers were permanently tagged and the percent and time elapsed for peg production was measured. Overall, few differences in peanut reproduction between tillage treatments were found in either 2004 or 2005. The primary difference in reproduction was a greater production of flowers in ST than CT plants in 2004, but there were no subsequent differences in pod production due to the tillage system in that same year. The peak flowering time period in 2004 for both tillage and irrigation treatments was between 19 and 23 June, while in 2005, flower production peaked around 6 July. Maximum peg and pod counts in the OH and SDI irrigation treatments in both tillage treatments occurred between 4 July and 6 July 2005. There was a significant interaction for pod production between tillage and irrigation method in 2005 and showed, on average, the SDI-CT treatment produced 2.4 pods per plant in comparison to 1.5 pods per plant in the SDI-ST treatment, indicating that the use of the two management systems together be avoided. Limited effects of climatic conditions on formation of flowers, pegs and pods were found across all tillage and irrigation treatments in both years.