Field-Measured Water Uptake of Sudangrass Roots as Affected by Fertilization
1977
Flühler, H. | Ardakani, M. S. | Szuszkiewicz, T. E. | Stolzy, L. H.
Cultural practices could affect the flow of water and solutes toward groundwater. In this field experiment we analyzed the effect of fertilization on water uptake of sudangrass (Sorghum vulgure sudanense, Germain's piper cultivar) and its indirect influence on deep drainage and nitrate leaching. Root water uptake was calculated as sink term in the continuity equation using successive measurements of water content and matric potential profiles in connection with field measured hydraulic conductivity functions. The experiment was conducted in three field plots on Hanford fine sandy loam (coarse-loamy, mixed, thermic, Typic, Xerorthent). Fertilization increased dry matter production and water uptake significantly and reduced deep drainage and nitrate leaching. Water uptake patterns and root length distribution was not correlated. Mainly due to fertilization with nitrate nitrogen, the evapotranspiration approximated the amount of irrigation water applied. These results indicate that optimum water and fertilizer use and minimum groundwater pollution per unit crop production are intimately linked together.
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