Water injection into the seed zone as an aid to emergence of dryland cereals

Graduation date: 1979An adequate stand at the optimum time is an important factor\ud affecting potential yield and soil erosion control. However, obtaining\ud adequate stands of fall planted winter wheat in the dryland areas of the\ud Pacific Northwest is often complicated by marginal seed zone soil\ud moisture. The purpose of this laboratory study was to assess the value\ud of adding water to the seed zone at planting (water injection) and to\ud determine what rates of water were required to insure quick and uniform\ud emergence under sub-optimal soil moisture conditions. Adding\ud water to the seed zone increased the percent stand and/or the emergence\ud rate over those treatments not receiving water at each of the five levels\ud of moisture tension (-5, -8, -11, -15, -20 bars) at 13°C and 18oC mean\ud seed zone soil temperatures. Among those treatments not receiving\ud water the percent stand and the emergence rate decreased with each\ud unit increase in moisture tension, until at -20 bars there was no\ud emergence. The effective range of water injection was between -5 and\ud -20 bars. However, the practical range appears to be between -5 and\ud -14 bars. A graph was constructed to illustrate the minimum amount\ud of water required to obtain 80% stand, 3 days after initial emergence\ud for those parameters of soil temperature and soil moisture tension\ud studied. From these data it appears that water injection has the potential\ud to enhance stand establishment under sub-optimal soil moisture\ud conditions. Field trials are needed to substantiate laboratory findings