%0 Journal Article
%T Comparison of bromide and nitrate transport in the Bainsvlei soil of South Africa under natural rainfall
%A Ketema Tilahun
%A Joseph F Botha
%A Alan TP Bennie
%J Water SA
%D 2004
%I Water Research Commission
%X Bromide is commonly used to simulate the movement of nitrate fertilisers through the soil profile. However, there exists no comparative evaluation of the leaching properties of Br- and NO3-_N under local soil and rainfall conditions at Bloemfontein. The purpose of this work was to conduct a field experiment to evaluate the leaching behaviour of Br- in comparison with NO3-_N on the Bainsvlei soil of South Africa under natural rainfall conditions. For this purpose, KBr- and KNO3 solutions were applied to a 2.45 x 2.45 m2 plot at rates of 13.5 g Br.m-2 and 20 g N.m-2 respectively. The subsequent movement of the solutes through the soil was investigated through studies of the water and mass balances, determined from soil samples taken from a 1600 mm deep soil profile during the period October 2000 to May 2001, the rainy season in Bloemfontein. The results were also analysed with the one-dimensional convective dispersive equation and stream tube models. Two important results were derived from the study: Br- can be used with confidence as a substitute for and NO3-_N in studies of the movement of the latter through soils, and it is more economical and environmentally friendly to distribute the application of nitrate over the growing season of a crop, instead of applying it as a batch at the time of planting. Water SA Vol.30(1): 9-16
%U http://www.ajol.info/index.php/wsa/article/view/5020