Poultry litter can be a beneficial organic fertilizer when managed properly. A greenhouse and a field study were started in the spring and summer of 2005, respectively. The purpose of these studies was to determine the effects of poultry litter amendments on soil and plant quality during vegetable soybean production. Composted poultry litter (CPL with an N-P-K equal to 2-4-1 on a dry weight basis) or a formulated poultry litter (FPL with an N-P-K equal to 5-5-4 or 22-4-2 on a dry weight basis) was incorporated into a high-P soil (230 kg P ha^-1). Visual evaluation of plant growth and analyses for soil physical, chemical, and biological properties and processes were performed at time 0 and at vegetative and reproductive stages of plant growth. Results for the greenhouse study indicated that the high-N FPL (22-4-2) was most detrimental to soil and plant health.  Inorganic N, dissolved organic C, and soil pH increased markedly while enzyme activities, seed germination, and plant growth were inhibited. Effects of CPL were less evident on soil properties and plant growth. In the field study, seed germination and plant biomass appeared to be more closely related to soybean variety than poultry litter application. In contrast, some soil properties were affected by poultry litter type. Microbial biomass C increased initially in soil receiving FPL as compared to control soil, but levels decreased thereafter. Inorganic N also increased in soil receiving FPL, but concentrations continued to remain higher than the control while plants were in the vegetative stage. Additionally, compared to the control, alkaline phosphatase activities increased in soil receiving FPL, but they also increased in soil receiving CPL. Further site-specific research is needed before making recommendations on the use of poultry litter as a fertilizer in high-P soil.