Potential of fertilizer segregation during application using spinner disc spreader

Granular blended fertilizers are commonly applied using spinner disc spreaders in the U.S. with recent advances including wider spreads. Today, uniformity of spread is important as growers and custom applicators attempt to implement site-specific management and utilize global navigation satellite systems (GNSS)-based guidance systems which permit equipment to follow the same field traverses over time. However, the variation in physical properties of nitrogen-N, phosphorous-P and potassium-K components of blended fertilizers make it difficult to spread them uniformly, leading to segregation. Segregation negatively impacts precision application. Therefore, an investigation was conducted to understand the potential of fertilizer segregation during application with a spinner disc spreader. A series of standard pan tests were carried out for evaluating nutrient distribution for a blended fertilizer (10–26–26). Treatments included two feed rates (224 and 448 kg ha−1) and three spinner disc speeds (600, 700 and 800 rpm). The results indicated that application of the blended fertilizer resulted in non-uniform spread of the nutrients. Distinct nutrient patterns were generated for the different constituents; “W” shaped for DAP-P2O5 and “M” for Potash-K2O regardless of feed rate and spinner disc speed. An increase in spinner disc speed widened the maximum transverse distance travelled by particles. However, it was not equal in magnitude for DAP (P2O5) and Potash (K2O) highlighting the possibility of segregation. The level of segregation increased with spinner disc speed (p   0.05) as DAP (P2O5) particles travelled farther with increase in speed due to larger mean particle size of 3.2 mm against 3.0 mm for potash (K2O).