Profile layering, root zone permeability, and slope affect on soil water content during putting green drainage

Abstract

Laterally uniform soil water content should aid in turf management on high sand content putting greens. This study examined soil profile layering, root zone permeability, and slope effects on soil water content within experimental putting green root zones. Either a one-tier (subgrade underlying root zone) or two-tier (gravel underlying root zone) putting green soil profile was used, with each containing root zones having either 530 mm h-1 (higher permeability, HP) or 320 mm h-1 (lower permeability, LP) water permeability of the freshly prepared root zone. The 1.2- by 7.3-m greens were adjusted to slopes of 0, 2, and 4% and simulated rain was applied at either 45 or 112 mm h-1 for 3 h. Soil water contents at five lateral locations and three depths within each green were monitored during rainfall and for 48 h after rain stopped. In the early drainage period (1 to 9 h), the two-tier greens had smaller water contents that were more uniform laterally and with root zone depth. The one-tier greens showed effects of drainpipe spacing with greater water contents midway between the drainage elements. Expected greater water contents were observed for the LP than the HP root zones. Later in the drainage period (27 to 45 h), increased green slope contributed to upslope drying of all root zones with larger lateral water content gradients occurring in the LP and one-tier systems. The presence of a gravel layer beneath the root zone yielded reduced and more uniform water contents than in its absence. Slope-induced lateral water movement was apparent, however, in all greens.