As technology advances for applicators, it is assumed that the control and distribution of material should improve. A study was conducted to evaluate if real-time spinner disc control improves the distribution of poultry litter. A typical litter spreader equipped with an electronically adjustable hydraulic flow control (proportional) valve was used to test closed loop spinner-disc control and compare these results to a traditional manual valve, open-loop setup. Three application rates of 2242, 4483, 6725 kg/ha (1, 2, and 3 ton/acre, respectively) were selected. The litter was collected with using standard pans based on ASABE Standard S341.3 but modified to assess pattern uniformity using a two-dimension pan matrix. Analyses included assessing the variability and consistency of distribution patterns and spinner speeds. The single-pass distribution patterns produced by the manual valve were more symmetrical between the rates tested but demonstrated more variability than those of the proportional valve. Overlap patterns were also generated along with summary statistics to assess spread uniformity. The proportional valve patterns generated CV's of 28.1%, 16.0%, and 13.4%, from low to high rates, respectively while the manual valve produced CV's of 28.7%, 31.7%, and 29.5%, from low to high rates, respectively. The proportional valve maintained more consistent spinner speeds than the manual valve. Results indicated that closed-loop spinner control to maintain the desired speed provided improved distribution of poultry litter over the range of application rates tested. Armstrong, S., J. Iqbal, P. Owens, and D. Smith. 2006. Spatial Variability of Nutrient in Soils Following Long-Term Poultry Litter Applications. Purdue University. Site Specific Management Center Newsletter.