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Water‐soluble NO 3 ‐Nitrogen, PO 4 ‐Phosphorus, and Total Salt Balances on a Large Irrigation Tract
Author(s) -
Carter D. L.,
Bondurant J. A.,
Robbins C. W.
Publication year - 1971
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/sssaj1971.03615995003500020042x
Subject(s) - loam , drainage , hydrology (agriculture) , environmental science , soil water , irrigation , fertilizer , phosphorus , calcareous , agronomy , geology , chemistry , soil science , ecology , paleontology , geotechnical engineering , organic chemistry , biology
Return flow from a 82,030‐ha (202,700‐acre) tract of calcareous silt loam soils irrigated with water diverted from the Snake River in southern Idaho increased the downstream total soluble salt and NO 3 ‐N loads, but decreased the downstream PO 4 ‐P load. Under the existing water management practice, 50% of the total input water returned to the Snake River as subsurface drainage. Net total soluble salt output was 2.4 metric tons/ha (1.0 English ton/acre) and, on the average, was considerably greater than necessary to maintain a salt balance. Net NO 3 ‐N output was 33 kg/ha (30 lb/acre). Only about 30% as much PO 4 ‐P left the tract via drainage water as entered the tract in irrigation water. As water passed through the soil, PO 4 ‐P was removed by chemical reactions in the soil, thus decreasing the concentration in the subsurface drainage water and decreasing the downstream PO 4 ‐P load. Applied P fertilizer was not leached into the drainage water.