Crop desiccation little or no advantage in doing so. Glyphosate was found in 5–15% of cereal crop samples tested in the UK between 2000 and 2004, although never exceeding the Maximum Residue Level of 20 mg/kg. A survey of British wheat in 2006–8 found average levels of 0.05–0.22 mg/kg with maximum levels of 1.2 mg/kg. In July 2013 Austria banned the use of pre-harvest glyphosate citing the precautionary principle. In April 2015 an oat buyer in Western Canada announced that it was refusing oats in which pre-harvest glyphosate had been used. Crop desiccation Pre-harvest crop desiccation (also siccation) refers to the application
Cover crop recycle soil nitrogen already present. The catch crops take up surplus nitrogen remaining from fertilization of the previous crop, preventing it from being lost through leaching (Morgan et al. 1942), or gaseous denitrification or volatilization (Thorup-Kristensen et al. 2003). Catch crops are typically fast-growing annual cereal species adapted to scavenge available nitrogen efficiently from the soil (Ditsch and Alley 1991). The nitrogen tied up in catch crop biomass is released back into the soil once the catch crop is incorporated as a green manure or otherwise begins to decompose. An example of green manure use comes from Nigeria, where the