Premium
Solute Movement in Uncropped Ridge‐Tilled Soil under Natural Rainfall
Author(s) -
Jaynes Dan B.,
Swan J. B.
Publication year - 1999
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1999.03615995006300020002x
Subject(s) - tracer , ridge , precipitation , geology , soil horizon , hydrology (agriculture) , leaching (pedology) , tillage , soil science , environmental science , soil water , geotechnical engineering , geography , paleontology , ecology , physics , biology , meteorology , nuclear physics
Point injection of N fertilizers within the ridge of ridge‐tilled soils has shown promise in reducing nitrate leaching in short‐term rainfall simulation studies, but it has not been studied under natural rainfall throughout the growing season. At two uncropped locations, we measured the leaching of tracers injected into different ridge positions in established ridge‐tilled plots that were leached by natural rainfall. A point injector was used to inject conservative anionic tracers 100 mm below the soil surface every 38.1 mm along ridge‐top, ridge‐shoulder, and furrow positions. Movement of tracers was measured four times after tracer application by triplicate soil sampling with a 38.1‐mm‐diam. soil probe to a maximum depth of 1.22 m. Sample collection spanned a period of 102 d with 282 mm of cumulative precipitation after tracer application at the Boone site and 97 d with 314 mm of precipitation at the Treynor site. Mass recoveries of furrow‐applied tracer was significantly lower ( P = 0.05) than ridge‐applied tracer on the last two sampling dates at both sites. There was no consistent difference in mass recoveries between tracers applied at ridge top compared with shoulder positions. Furrow‐applied tracer had lower concentrations in the soil profile than tracers applied to ridge‐top and shoulder positions after 40 d and 76 to 129 mm of precipitation. Tracer movement was essentially vertical below the ridges, with ≥96% of the recovered ridge‐applied tracer found below the ridges. Lateral spreading was more pronounced under the furrows, with ≥49% of the recovered furrow‐placed tracer found below the furrows. Fertilizer injection within the ridge shows promise for reducing leaching and potentially increasing nutrient availability to plants.