Soil physical conditions in a New York orchard after eight years under different groundcover management systems

An experiment was conducted near Ithaca, New York, to compare orchard soil and groundcover management systems (GMSs) in a silty clay loam soil (mixed, mesic, Glosaquic Hapludalf). Three replications of four GMS treatments wer e randomly assigned to 12 plots and maintained since 1992 in 2 m-wide strip s within tree rows: (1) Sod: Red fescue (Festuca rubra) turfgrass mowed biw eekly; (2) Post-HBS: Post-emergence applications of glyphosate herbicide in May and July annually; (3) Pre-HBS: Pre-emergence applications of paraquat , diuron and norflurazon herbicides each May; and (4) Mulch: A 15-cm depth layer of shredded hardwood bark mulch, renewed triennially. After eight yea rs of continuous treatments, we compared soil physical conditions and hydra ulic properties in these GMSs. Bulk density was lower and soil porosity gre ater under Mulch than other GMSs. Infiltration was more rapid under Mulch t han other GMSs, and under Post-HBS than Sod. Saturated hydraulic conductivi ty ranged from 6 x 10(-4) m(.)s(-1)under Sod to 12 x 10(-4) m(.)s(-1) under Mulch plots, and was equivalent in Sod and Pre-HBS, lower in Sod than Post -HBS or Mulch treatments, higher in Post-HBS than Pre-HBS, and higher in Mu lch than all other GMSs. Volumetric soil water content at field capacity ra nged from 0.47 under Mulch to 0.40 under Sod, and was not significantly dif ferent among GMSs between 0.99 and 39.22 kPa of pressure. GMS treatments an d related management practices at this orchard had substantially different long-term effects on soil physical conditions. Compaction and reduced infil tration in Sod compared with other GMSs were attributed to tractor wheel tr affic during mowing. Mulch treatments improved soil conditions relative to other GMSs. Greater infiltration rates and hydraulic conductivity under Pos t-HBS compared with Pre-HBS suggest relative advantages of post-emergence h erbicides.