Planting soybean seeds under low soil moisture condition

Abstract

The effects of soil moisture content and seed treatments/coatings on germination/ emergence of Davis soybean seed were determined for two soil types, the silty-clay loam and the sandy loam., In the silty-clay loam soil the most favorable soil moisture ranqe for qermination was 13% to 16% (-7 atm to -1.9atm.)while soil moisture contents in the range 8.5% to 12% (-0.31 atm to -1.4 atm) were most favorable for emergence in the sandy loam. The seed did not absorb sufficient moisture for germination (about 52% - 55%) at moisture contents below about 9% in the silty-clay loam and below about 4.5% in the sandy loam. The high seed moisture contents attained in soil at moisture contents too low for germination resulted in rapid deterioration of the seed and loss of their capacity to germinate and emerge. When seed were planted at soil moisture levels too low for germination for nine days before adequate water for germination was supplied, emergence percentage decreased as soil moisture level was decreased until there was no emergence, then emergence percentage increased as soil moisture content was further decreased to a near "air dry" level. This phenomenon was explained on the basis of seed moisture contents attained at the various  low soil moisture levels. Treating the seed with captan, and linseed oil improved retention capability for emergence during periods in soil too dry for germination.