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Soil Nitrate Nitrogen Dynamics after Biosolids Application in a Tobosagrass Desert Grassland
Author(s) -
JuradoGuerra Pedro,
Wester David B.,
Fish Ernest B.
Publication year - 2006
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/jeq2005.0062
Subject(s) - biosolids , growing season , environmental science , agronomy , mulch , irrigation , dry season , soil water , grassland , nitrate , soil science , ecology , environmental engineering , biology
Dormant‐season application of biosolids increases desert grass production more than growing season application in the first growing season after application. Differential patterns of NO 3 –N (plant available N) release following seasonal biosolids application may explain this response. Experiments were conducted to determine soil nitrate nitrogen dynamics following application of biosolids during two seasons in a tobosagrass [ Hilaria mutica (Buckl.) Benth.] Chihuahuan Desert grassland. Biosolids were applied either in the dormant (early April) or growing (early July) season at 0, 18, or 34 dry Mg ha −1 A polyester–nylon mulch was also applied to serve as a control that approximated the same physical effects on the soil surface as the biosolids but without any chemical effects. Supplemental irrigation was applied to half of the plots. Soil NO 3 –N was measured at two depths (0–5 and 5–15 cm) underneath biosolids (or mulch) and in interspace positions relative to surface location of biosolids (or mulch). Dormant‐season biosolids application significantly increased soil NO 3 –N during the first growing season, and also increased soil NO 3 –N throughout the first growing season compared to growing‐season biosolids application in a year of higher‐than‐average spring precipitation. In a year of lower‐than‐average spring precipitation, season of application did not affect soil NO 3 –N. Soil NO 3 –N was higher at both biosolids rates for both seasons of application than in the control treatment. Biosolids increased soil NO 3 –N compared to the inert mulch. Irrigation did not significantly affect soil NO 3 –N. Soil NO 3 –N was not significantly different underneath biosolids and in interspace positions. Surface soil NO 3 –N was higher during the first year of biosolids application, and subsurface soil NO 3 –N increased during the second year. Results showed that biosolids rate and season of application affected soil NO 3 –N measured during the growing season. Under dry spring–normal summer precipitation conditions, season of application did not affect soil NO 3 –N; in contrast, dormant season application increased soil NO 3 –N more than growing season application under wet spring–dry summer conditions.