Publication date: 1 January 2017
Source:Geoderma, Volume 285
Author(s): Peter M. Kopittke, Ram C. Dalal, Neal W. Menzies
Demand for agricultural products is increasing, but there remains considerable uncertainty regarding many of the impacts of long-term cropping systems on soil properties. Using six soils from low input cropping systems of subtropical Australia, the effects of long-term cultivation (≤Triticum aestivum ) also remained constant over time. However, concentrations of DTPA-extractable Cu, Zn, and Mn often (but not always) decreased significantly over time, with Cu decreasing 21%, Zn by 34%, and Mn by 46% (when averaged across soils where significant differences were found). In some soils, these decreases in DTPA-extractable micronutrients also resulted in concomitant decreases in grain tissue concentrations. These decreases in DTPA-extractable Cu, Zn, and Mn concentrations do not result only from the export of nutrients in grain tissues, but also, from an increase in soil pH caused by a cultivation-induced mixing of alkaline subsoil into the surface soil. The data presented here demonstrate the potential impact of long-term cropping on nutrient availability, and in particular, the need to consider changes in nutrient availability and its potential impact on plant and human nutrition.
Source:Geoderma, Volume 285
Author(s): Peter M. Kopittke, Ram C. Dalal, Neal W. Menzies