Short‐term soil carbon mineralization on golf course sand‐based putting green and its effect on creeping bentgrass nitrogen uptake

Abstract

AbstractA rapid soil test for accurately estimating nitrogen (N) supply from soil organic matter would help turfgrass managers develop N fertilization programs. In this study, we tested the feasibility of using a quick test, mineralizable carbon (min‐C), to predict turfgrass growth and N uptake from sand‐based putting green soils. A 2‐year field experiment was conducted in Verona, WI, on four sand‐based research golf greens planted with creeping bentgrass. Nitrogen fertilizer was applied at 0, 10, and 20 kg ha−1 every 2 weeks as liquid urea during the growing seasons. Soil samples were collected at 0–5 cm and 5–10 cm and tested for min‐C by measuring the flush of CO2 following the rewetting dried soil, where the soil was rewetted at 50% water‐filled pore space and incubated at 25°C for 24 h. Min‐C was greater at the shallower soil depth, and unaffected by N rates that were applied. On‐site air temperature, soil moisture content, and estimated soil temperature were negatively related with min‐C, where r2 = 0.26–0.60 for air temperature, r2 = 0.32–0.71 for soil moisture content, and r2 = 0.16–0.53 for estimated soil temperature, indicating the test is quite sensitive to environmental conditions at the time of sampling. Furthermore, min‐C had weak positive to no relationship with creeping bentgrass growth rate (r2 = 0–0.17) and N uptake (r2 = 0–0.23) on sand‐based putting green, suggesting the test does not hold promise as a method for improving fertilizer decisions to these systems.