『Abstract
Phosphorus (P) loss from urban areas has been identified as a
major contributor to declining surface water quality. The objective
of this study was to determine the relationship between extractable
soil P, depth of soil sampling, and dissolved reactive P (DP)
concentration in runoff from turfgrass areas. At each site, runoff
was generated on turfgrass and adjoining areas where turfgrass
cover was removed. Across all six locations and the wide range
of nutrient management schemes, variation of extractable soil
P concentration and saturation ratios of 0-2 cm samples accounted
for 49-59％ (r2 = 0.49-0.59, n = 92) of variation of
DP concentration in runoff from bare soil and soil with turfgrass
cover. Despite a high degree of soil P stratification, changing
sampling depth generally did not improve the relationship between
soil test P and runoff DP concentrations. Across the narrower
range of soil P levels common to lawns in New York (0-50 mg kg-1
Morgan extractable soil P), none of the soil tests or P saturation
levels (for 0-2 cm depth) could accurately predict runoff P concentrations
from soil with turfgrass cover (r2 = 0.02 to 0.23,
n = 72). For bare soil plots, restricting the analysis to the
same range (＜50 mg kg-1 Morgan extractable P) did not
alter the relationship between soil test P and runoff DP concentrations
observed for the entire range (0-658 mg kg-1O of soil-test
P concentrations. These results suggest soil testing will not
be an effective tool to predict runoff from turfgrass areas across
the range of soil P levels common to New York State.
Keywords: Turfgrass; Turf; Runoff; Soil phosphorus; Soil testing』
(Introduction)
1. Materials and methods
1.1. Description of research sites
1.2. Rainfall simulation and runoff
1.3. Soil sampling and analysis
1.4. Statistical analysis
2. Results and discussion
3. Conclusions
References