Effect of leaching greens on soil chemistry

July 9, 2007

A research study on the effects of leaching was recently conducted with the cooperation of superintendent Mike Hathaway, CGCS (a PACE advisory board member) and assistant Nathan Radwick at The Bridges at Rancho Santa Fe. The full report has been posted onto the PACE Super Journal website, and the results are summarized below.

Summary: To quantify the benefits as well as any hazards of leaching, soil chemical analyses were performed on G2 bentgrass greens that had been leached by applying 5.5 inches of water over a period of 22 hours. A parallel set of analyses were performed on greens that had not been leached. Significant benefits, as well as some lesser, but potential risks were observed, including:

• Leaching reduced salinity by 37% using saturated paste extraction (SPE) methods or 26% using 1:2 soil to water electrical conductivity evaluations (which were converted to saturated paste equivalents).
• Sodium parts per million was reduced by 30% using SPE and to 33% when evaluated using Mehlich III (M3) extraction.
• Sulfur was reduced by 46% using SPE and by 40% when evaluated using M3 extraction.
• Chloride was reduced by 50% using SPE and by 52% when evaluated using M3 extraction
• Although all of the reductions listed above are beneficial, there was also a significant loss of potassium detected in the leached samples. This indicates that applications of supplemental potassium may be needed following heavy leaching in order to replenish levels to the guideline level of 110 ppm or above (as determined by Mehlich III extraction).

Full print version of report (24Kb)

Principal investigators: Mike Hathaway, CGCS and Nathan Radwick (The Bridges at Rancho Santa Fe)

Cooperators: Larry Stowell and Wendy Gelernter (PACE Turfgrass Research Institute)