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
Crop rotation crop rotation comes from the interrelationship of nitrogen fixing-crops with nitrogen demanding crops. Legumes, like alfalfa and clover, collect available nitrogen from the soil in nodules on their root structure. When the plant is harvested, the biomass of uncollected roots breaks down, making the stored nitrogen available to future crops. Legumes are also a valued green manure: a crop that collects nutrients and fixes them at soil depths accessible to future crops. In addition, legumes have heavy tap roots that burrow deep into the ground, lifting soil for better tilth and absorption of water. Cereal and grasses are frequent cover