Cotton production in the desert southwest is commonly characterized by high input production practices that usually result in high yields. Among the inputs that are involved in this intensive production scenario include first and foremost water. Other inputs include pest control, fertilizer nitrogen (N), and plant growth regulators. Since cotton is very responsive to crop inputs, such as water and fertilizer N, management of these inputs is critical to achieve not only maximum agronomic but also economic yield. As the US cotton industry moves towards a more open and free market with less government support, efficient management of these inputs becomes increasingly important. Producers need to be very critical of what is put into the crop and have a relatively good assurance that a specific input is actually having a positive effect on the crop.