%0 Journal Article %T Field-scale validation of an automated soil nitrate extraction and measurement system %A Sibley, Kevin %A Astatkie, Tessema %A Brewster, Gordon %A Struik, Paul %A Adsett, John %A Pruski, Kris %J Precision Agriculture %V 10 %N 2 %P 162-174 %@ 1385-2256 %D 2008-09-19 %I Springer US %~ DeepDyve