Leaching losses from Kenyan maize cropland receiving different rates of nitrogen fertilizer
Russo, Tess A.
Tully, Katherine L.
MetadataShow full item record
Meeting food security requirements in sub-Saharan Africa (SSA) will require increasing fertilizer use to improve crop yields, however excess fertilization can cause environmental and public health problems in surface and groundwater. Determining the threshold of reasonable fertilizer application in SSA requires an understanding of flow dynamics and nutrient transport in under-studied, tropical soils experiencing seasonal rainfall. We estimated leaching flux in Yala, Kenya on a maize field that received from 0 to 200 kg ha−1 of nitrogen (N) fertilizer. Soil pore water concentration measurements during two growing seasons were coupled with results from a numerical fluid flow model to calculate the daily flux of nitrate-nitrogen (NO3−-N). Modeled NO3−-N losses to below 200 cm for 1 year ranged from 40 kg N ha−1 year−1 in the 75 kg N ha−1 year−1 treatment to 81 kg N ha−1 year−1 in the 200 kg N ha−1 treatment. The highest soil pore water NO3−-N concentrations and NO3−-N leaching fluxes occurred on the highest N application plots, however there was a poor correlation between N application rate and NO3−-N leaching for the remaining N application rates. The drought in the second study year resulted in higher pore water NO3−-N concentrations, while NO3−-N leaching was disproportionately smaller than the decrease in precipitation. The lack of a strong correlation between NO3−-N leaching and N application rate, and a large decrease in flux between 120 and 200 cm suggest processes that influence NO3−-N retention in soils below 200 cm will ultimately control NO3−-N leaching at the watershed scale.
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nutrient Cycling in Agroecosystems 108 (2017): 195–209, doi:10.1007/s10705-017-9852-z.
The following license files are associated with this item:
Showing items related by title, author, creator and subject.
Tian, Hanqin; Lu, Chaoqun; Melillo, Jerry M.; Ren, Wei; Huang, Yao; Xu, Xiaofeng; Liu, Mingliang; Zhang, Chi; Chen, Guangsheng; Pan, Shufen; Liu, Jiyuan; Reilly, John M. (IOP Publishing, 2012-10-31)Chemical nitrogen (N) fertilizer has long been used to help meet the increasing food demands in China, the top N fertilizer consumer in the world. Growing concerns have been raised on the impacts of N fertilizer uses on ...
Plant nitrogen dynamics in fertilized and natural New England salt marshes : a paired 15N tracer study Drake, Deanne C.; Peterson, Bruce J.; Deegan, Linda A.; Harris, Lora A.; Miller, E. E.; Warren, R. Scott (Inter-Research, 2008-02-07)We examined the effects of increased nutrient availability on nitrogen (N) dynamics in dominant New England salt marsh plants (tall and stunted Spartina alterniflora and S. patens) using paired large-scale nutrient and ...
Nitrogen dynamics in arctic tundra soils of varying age : differential responses to fertilization and warming Yano, Yuriko; Shaver, Gaius R.; Rastetter, Edward B.; Giblin, Anne E.; Laundre, James A. (2013-03)In the northern foothills of the Brooks Range, Alaska, a series of glacial retreats has created a landscape that varies widely in time since deglaciation (= soil age), from ~10k years to more than 2M years. Productivity ...