Once a site has been selected for a particular species, soil tests are taken to check the nutrient levels of the soil. Each species has its own nutrient requirements; therefore, nutrients (i.e. lime, nitrogen, phosphates, potassium, gypsum) should be applied to the site. To ensure thorough incorporation, fields are plowed or rototilled. Which type of tillage method used is determined by the previous crop. If no trees, thus no stumps, are in the field, we use a conventional moldboard plow. If stumps exist, a heavy-duty rototiller is used to not only incorporate nutrients, but also to grind the existing stumps.