Soil test calibration is a continuous process required to maintain up to date recommendations of fertilizers for different crops. Average crop yields are increasing yearly basis due to use of best management practices and the development of new varieties. NC State University is maintaining three long-term trials to check if phosphorus and potassium fertilizer recommendations based on soil testing are still adequate. The three long-term trials testing rates of phosphorus and potassium fertilizers are located at Tidewater Research Station (TRS), Peanut Belt Research Station (PBRS), and Piedmont Research Station (PRS). In one location, also poultry litter and levels of pH has been studied. These trials were initiated in 1966 (TRS), 1982 (PBRS), and 1985 (PRS), and they have been tested every year with row-crops, generally with a soybean-corn rotation. These trials are extremely important for checking if our recommendations are adequate or if increases in the fertilizer rates due to increasing yields are needed. This proposal had support from Corn Growers Association in 2021/2022, with a budget of $4,412 for supplies (travel, seeds, fertilizers, chemicals) and services (soil and plant tissue analysis); a graduate student was also funded. Starting in the next season, we will no longer have a graduate student working on this project, and thus field activities will be conducted by the research technician of our group. In this proposal, we are requesting $11,700 to cover two months of salary and wages for our technician.