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Nitrogen Availability and Uptake from Field Soils Five Years after Addition of Sewage Sludge
Author(s) -
Harding S. A.,
Clapp C. E.,
Larson W. E.
Publication year - 1985
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/jeq1985.00472425001400010019x
Subject(s) - sewage sludge , loam , chemistry , anaerobic exercise , zoology , activated sludge , agronomy , nitrogen , mineralization (soil science) , soil water , sewage , sewage treatment , environmental science , biology , environmental engineering , ecology , physiology , organic chemistry
Nitrogen availability and uptake from sewage sludge were studied in a field experiment during 1979 on a Hubbard sandy loam soil (Entic Haploboroll). Treatments of anaerobically digested (low, 6370; medium, 12 770; and high, 25 200 kg N ha −1 ), aerobically digested (12 540 kg N ha −1 ) and waste‐activated (24 500 kg N ha −1 ) sludge were applied between 1972 and 1974. By 1975, 50% more total N remained in plots receiving anaerobic sludge than in plots receiving equivalent N rates of waste‐activated or aerobic sludge. By 1979, only 12% of the 1975 level of potentially mineralizable N (N 0 ) remained in the waste‐activated sludge plots, followed by anaerobic sludge (3, 11, and 9% in the low, medium, and high levels, respectively) and aerobic sludge (2%). In 1979, N uptake by maize ( Zea mays L.) ranged from 67 kg N ha −1 to 184 kg N ha −1 on sludge‐treated plots and was 158 kg N ha −1 on fertilized controls [250 kg N ha −1 as (NH 4 ) 2 SO 4 ; 0 sludge]. Due to early depletion of N 0 in aerobic sludge and slow current rate of mineralization of N 0 in waste‐activated sludge, N uptake in 1979 from those sludge treatments was 51 and 58%, respectively, as high as from equivalent N application rates of anaerobic sludge. Maize grain and fodder yields reflected the uptake differences. In the 0‐ to 15‐cm soil depth, mineral N at planting time ranged from 23 kg N ha −1 in aerobic and low anaerobic treatment plots to 31 kg N ha −1 in medium and high anaerobic treatment plots. Multiple regression analysis indicated the effect of residual mineral N at planting time was more important than N mineralized during the season for both amount and efficiency of N uptake. Low residual NO 3 − ‐N in the 0‐ to 15‐cm depth limited maize uptake of N mineralized during the season and of previously mineralized N present below the 45‐cm depth. The relative influence of residual mineral N on N uptake changed after sludge application. Therefore, combined N indexes and decay series should be used when estimating long‐term N supplying power of high sludge applications.