
%0 Journal Article
%A Turpin, J. E. 
%A Thompson, J. P. 
%A Waring, S. A. 
%A MacKenzie, J. 
%T Nitrate and chloride leaching in Vertosols for different tillage and stubble practices in fallow&#8211;grain cropping
%J Soil Research
%D 1998/01/13
%V 36
%N 1
%P 31-44
%K nitrate, chloride, leaching, fallow management, tillage, stubble.
%R https://doi.org/10.1071/S97037
%U https://www.publish.csiro.au/paper/S97037 
%X Research conducted in the mid 1980s on a &#8216;long-term fallow management trial&#8217;, located on a black Vertosol at the Hermitage Research Station, indicated that leaching may have been the cause of low concentrations of nitrate-N within the root-zone of zero-tillage stubble-retained treatments. The &#8216;fallow management trial&#8217; has 12 management treatments: a factorial combination of zero or conventional tillage&#215;stubble retention or burning&#215;3 nitrogen fertiliser rates (0, 23, and 69 kg N/ha). To test the leaching hypothesis, all trial treatments were analysed for nitrate and chloride concentrations to a depth of 5&#183;4 m in order to assess the relative rates of drainage, solute movement, and nitrate leaching between treatments. Similar analyses were conducted on 2 cultivated sites and 2 permanently grassed sites on-farm, also on black Vertosols, to compare solute movement rates under the continuous winter cereal rotation (trial site) with a winter&#8211;summer cropping regime and permanent pasture. Results from the Hermitage trial site showed zero tillage with stubble retention had a chloride concentration peak 2 m deeper down the profile (4&#183;5 m) than all other management treatments, indicating that drainage rates were greatest in zero tillage&#8211;stubble retained treatments. Nitrate profiles, however, showed that movement of nitrate-N to below the root-zone was greatest under zero tillage with stubble burning with 69 kg N/ha applied (Z-B 69N), followed by zero tillage with stubble retention and 69 kg N/ha. The large nitrate loss from the root-zone of Z-B 69N (about 30% of applied fertiliser) was considered to be a result of high concentrations of nitrate-N in the top 1&#183;5 m associated with stubble burning and fertilisation. The on-farm cultivated sites had very little nitrate-N throughout the whole profile, suggesting that either the use of summer as well as winter crops reduced residual or &#8216;spared&#8217; nitrate-N (through control of root-lesion nematodes) and/or mineralisation rates were lower on these sites. 
