Soybean Response to Furrow Irrigation Initiation.

ABSTRACT

A three year study on two soils in southeast Arkansas investigated irrigation initiation delays of 0 to 17 days for three soybean maturity groups (MG) on plant growth and yield.  In 2008, a 5 day delay significantly reduced yield of a MG 4 on a Sharkey silty clay.  In 2009, yields of a MG 3 on a silt loam soil were lower at a 17 day delay, but not for delays of 5 and 10 days.  There were no treatment effects for the MG 5 cultivar on the silt loam soil in 2009 or 2010.  Yields of the MG 5 on the silty clay were lower for 10 and 15 day delays compared to 0 days in 2009.   Irrigation delays reduced yields for the MG3 in the silt loam soil in 2010, but not for MG's 4 and 5.  Yields for a MG 5 were reduced on the silty clay soil in 2010 by a five day irrigation initiation delay.  To summarize, a five day delay in irrigation initiation reduced yields in 2 of 9 MG-soil-site years.  A 15 day delay reduced yields in six of nine MG-soil-years.  Yields of the MG 3 were effected the most by delays in irrigation initiation.  A 15 day delay reduced yields in all years on the silty clay soil.  Treatment effects on soil-water tension, plant heights, and canopy coverage during flowering and pod fill were also observed.