DRAINAGE CHARACTERISTICS OF A SOUTHERN PIEDMONT SOIL FOLLOWING SIX YEARS OF CONVENTIONALLY TILLED OR NO–TILL CROPPING SYSTEMS

Abstract

Sitespecific soil water movement research is needed in order to fully understand chemical movement intosubsurface water bodies. Water flow paths depend on soil, climate, topography, and management practices. In this study, weevaluated drainage and drainage hydrographs over a 12month period from a Southern Piedmont Cecil sandy loam followinga combined six years of corn/rye and cotton/rye cropping system under notill or conventionally tilled treatments. Notillexhibited significantly higher mean and peak drainage rates, drainage in the rising and recession limbs of hydrographs aswell as total drainage, and total drainage time, compared to conventional tillage treatments (P < 0.05). The recession timeconstant of the hydrographs, an index of the structural macropore development in the soil above the water table, wassignificantly less in the notill than conventional tillage, which indicated that notill had less tortuous water flow paths.Notill, therefore, enhanced water movement into deeper profiles in a Cecil sandy loam. Additional longerperiod data wouldbe useful to further evaluate temporal, environmental, and management factors that affect drainage under notill. A studyof the implications of more drainage in notill for nutrient and chemical losses in these systems is pending.