The interaction effect of irrigation intervals and the size of the blocks on the dirt surface sclerosis and its impact on the emergence of sunflower seedlings

Abstract

The Study was conducted in plastic basins in alluvial silt clay soil .The aim of this experiment is to investigate the effect of different irrigation intervals and sizes of soil aggregates on the surface crust and , consequently on the sunflower seedling emergence . The experiment included two different sizes of soil aggregation fine aggregates ( < 4 mm in diameter ) and coarse aggregate ( 2 – 3 cm in diameter ) and three irrigation intervals : ( daily water addition , two days interval water addition and three days interval water addition ) up to field capacity moisture equivalent . The results indicated to late of surface crust appearance in coarse aggregate soil ( 2 – 3 ) cm in comparison with fine aggregate soil as a result of the late in irrigation intervals . Increasing the moisture content of soil led to an increase of seedling emergency percentage according to the variance between the soils under study . The results showed that the coarse aggregate soil is characterized with less resistance to penetration force than that in the fine aggregate soil . It can be concluded that daily irrigation is possible to be used until seedling emergency stage completes , Then irrigation can be organized in accordance to the plant needs .