Data from: Soil chemical variation along a four-decade time-series of reclaimed water amendments in northern Idaho forests

Application of municipal reclaimed water to forests for water reclamation
is a pragmatic approach that provides water and nutrients to soil and
lowers the liability of reclaimed water disposal, yet little is known
about the long-term impacts of reclaimed water amendment on forest soil
chemical properties. We hypothesized that reclaimed water constituents
will increase plant nutrient availability in soil with the magnitude of
response depending on the facility establishment date. We collected
samples from three mineral soil depth layers to 75 cm from treated and
control plots at five water reuse facilities that represent a four-decade
time series. Depth explained most of the observed variation. Several plant
nutrients increased in soil at the different sites in response to
reclaimed water treatments, including N, Ca, Fe, S, and B concentration as
well as B content, while P was not significantly affected. Increases in
cation concentrations positively correlated with pH and salinity. The
treatment response was significantly greater at all facilities for total
N, B, and Na. However, the treatment response only occurred at
long-established facilities for NO3-N and Ca concentrations and for Fe and
S content. The outcomes of this study are useful for guiding future
management of soil at forest water reclamation facilities and for limiting
the risk of downstream environmental impacts.