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Nitrogen Removal and Nitrate Leaching for Two Perennial, Sod‐Based Forage Systems Receiving Dairy Effluent
Author(s) -
Woodard Kenneth R.,
French Edwin C.,
Sweat Lewin A.,
Graetz Donald A.,
Sollenberger Lynn E.,
Macoon Bisoondat,
Portier Kenneth M.,
Rymph Stuart J.,
Wade Brett L.,
Prine Gordon M.,
Van Horn Harold H.
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.9960
Subject(s) - perennial plant , agronomy , leaching (pedology) , cynodon dactylon , effluent , forage , nitrate , environmental science , cynodon , cropping system , chemistry , zoology , biology , soil water , crop , environmental engineering , ecology , soil science
In northern Florida, year‐round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N NO − 3 –N concentration below the rooting zone for two perennial, sod‐based, triple‐cropping systems over four 12‐mo cycles (1996–2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzipsamment). Effluent N rates were 500, 690, and 910 kg ha −1 per cycle. Differences in N removal between a corn ( Zea mays L.)–bermudagrass ( Cynodon spp.)–rye ( Secale cereale L.) system (CBR) and corn–perennial peanut ( Arachis glabrata Benth.)–rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125–170 kg ha −1 ) and rye (62–90 kg ha −1 ) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha −1 ), with the bermudagrass removing an average of 191 kg N ha −1 In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO − 3 –N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long‐term prevention of NO − 3 –N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates ≥ 500 kg ha −1 yr −1 have the potential to negatively affect ground water quality.