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Kith, Michael [EHD] <br /> From: Ron Crites <RCrites@BrwnCald.com> <br /> Sent: Monday, July 6, 2020 1:05 PM <br /> To: Kith, Michael [EHD]; harold.leverenz@gmail.com <br /> Subject: RE: Fescue Grass for Nitrogen Uptake <br /> CAUTION:This email is originated from outside of the organization. Do not click links or open attachments unless you recognize the <br /> sender and know the content is safe. <br /> Hi Michael. <br /> The concept of reducing nitrogen impacts to groundwater by crop uptake of nitrogen is a sound one. It is the basis for <br /> slow rate land treatment of wastewater. <br /> I have not seen it used too much for subsurface dispersal of septic tank effluent for several reasons. First, the nitrogen <br /> forms that are plant-available are ammonium and nitrate. Septic tank effluent nitrogen is predominantly in the organic <br /> nitrogen form and some ammonia. If there is adequate time hold-up time in the root zone, ammonia and nitrate will <br /> form and can be taken up by the roots of the plants. <br /> The second issue is the depth at which the septic tank effluent is released into the soil. If you have standard trenches <br /> with 2 to 3 ft of soil cover,the plant roots won't reach the nitrogen for a long time.This can be overcome somewhat by <br /> the shallow depth that is being proposed. <br /> Finally,the crop uptake of fescue is seasonal and ranges from 130 to 290 Ib/acre-year.The size of the dispersal system <br /> must be large enough to effectively reduce the applied nitrogen by those rates. If a family of 3 generates 32 Ib/yr of <br /> nitrogen,the proposed system of 30 ft by 25 ft would be able to uptake about 10 percent of the annual nitrogen load or <br /> about 3.4 Ib/yr(based on 200 Ib/acre nitrogen uptake by fescue). <br /> Ron <br /> Ronald Crites, PE* <br /> Natural Systems Service Leader <br /> Brown and Caldwell I Davis,CA <br /> 202 Cousteau Place,Suite 175 1 Davis, CA 95618 <br /> RCrites .brwncald.com <br /> T 530.204.5204 1 C 530.750.9711 <br /> Licensed in CA, HI,OR <br /> BrownAm • <br /> Caldwell <br /> Get water industry news delivered to your desktop,free,from BCWaterNews.com Sign up now! <br /> From: Kith, Michael [EHD] <m kith @sjgov.org> <br /> Sent:Thursday,July 02, 2020 1:35 PM <br /> To: harold.leverenz@gmail.com; Ron Crites<RCrites@BrwnCald.com> <br /> Subject: Fescue Grass for Nitrogen Uptake <br /> 1 <br />