Although many problems regarding pecan production result from pest or disease pressure, the crop may also be adversely affected by nutritional imbalances, nutrient deficiencies, or environmentally induced disorders. These are some of the more difficult problems to diagnose. Some nutrients may be more available than others on certain soil types and under certain soil conditions. Additionally, complex interactions often occur between nutrients, which influence uptake by the pecan tree. Pecans can also be quite sensitive to environmental conditions, which stress the tree, limiting its growth and productivity.