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Fertilizer Nutrient Losses from Rangeland Watersheds in Central Oklahoma
Author(s) -
Olness Alan,
Rhoades E. D.,
Smith S. J.,
Menzel R. G.
Publication year - 1980
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/jeq1980.00472425000900010019x
Subject(s) - surface runoff , fertilizer , nutrient , watershed , environmental science , rangeland , phosphorus , forage , agronomy , vegetation (pathology) , grassland , human fertilization , hydrology (agriculture) , nitrogen , zoology , grazing , chemistry , biology , ecology , agroforestry , geology , medicine , geotechnical engineering , organic chemistry , pathology , machine learning , computer science
Four native grassland watersheds were monitored for nitrogen and phosphorus nutrient losses in surface runoff. The watersheds, paired in surface hydrology and grazing management, were 8 to 11 ha in area with 3% slopes. One watershed of each pair was fertilized with 85 kg N/ha (as NH 4 + ‐N) and 75 kg P/ha surface broadcast. Ten 3.66 by 5.49 m (20 m 2 ) areas within each watershed were covered with plastic sheets during fertilization to provide unfertilized check plots. Fertilizer losses in surface runoff over the first year were 5% or less of the amounts applied. Soluble NH 4 + ‐N concentrations in surface runoff increased significantly only during the first month after fertilizer application. Soluble P concentrations increased sharply after fertilization and remained relatively high even after 12 mo. Forage yields were increased 50 to 100% on fertilized areas. Increases in nutrient uptake of fertilized vegetation the first year equaled 17 to 25.5 kg/ha and 7.5 to 11 kg/ha of the added N and P, respectively.