02284naa a2200181 a 450000100080000000500110000800800410001910000160006024501400007626000090021652017460022565000130197165000170198465000120200165300110201370000180202477300600204212800472025-06-25       1978    bl uuuu     u00u1 u    #d1 aHOOK, J. E.  aNitrate leaching during long term spray irrigation for treatment of secondary sewage effluent on woodland sites.h[electronic resource]  c1978  aTwo waste water‐treated sites at The Pennsylvania State University Wastewater Renovation Project were monitored to measure nitrate and total N in soil water. Both long‐term waste water irrigation and varied irrigation rates were examined. Soil water was sampled by porous cup samplers. The concentration of N at the 120‐cm depth was taken as a measure of N which escaped the root zone and which would leach to the ground water. Recharge volume was calculated from irrigation, rainfall, and potential evapotranspiration. A hardwood forest site located on a well‐drained sandy loam soil was irrigated year round with secondary municipal effluent at a rate of 5 cm/week. In the last 6 of 9 years of effluent treatment 83% of the 4,954 kg N/ha added leached from the site. Nitrate concentration in soil water at the 120‐cm depth was generally &gt 15 mg N/liter. The hardwood forest was also ineffective in keeping nitrate concentration below 10 mg N/liter at the 120‐cm depth when the 5‐cm weekly application was split into two 2.5‐cm irrigations or when it was lowered to 2.5 cm/week year round. An abandoned old field site planted with white spruce ( Picea glauca Moench) and located on a well‐drained clay loam soil was irrigated with effluent at 5 cm/week from Apr. through Nov. each year, beginning in 1963. Nitrate concentration at the 120‐cm depth rarely exceeded 10 mg N/liter and only 36% of the 1,246 kg N/ha applied leached during the 6th through the 9th years of this effluent treatment. In the 10th and 11th years, when the application rate was increased to 7.5 cm/week, nitrate concentration exceeded 10 mg N/liter at the 120‐cm depth, and the amount of N which leached increased to 75% of the amount applied.  aFloresta  aLixiviação  aNitrato  aEsgoto1 aKARDOS, L. T.  tJournal of Environmental Qualitygv. 7, p. 30-34, 1978.