12/30/2021 - By Dr. Tom Reed

Conclusion:

The study compared a conventional grower fertilizer program to a single preplant application of a POLYON® controlled-release fertilizer (CRF) blend at reduced N and P₂O₅ rates. The conventional program consisted of a preplant application (56 lb N, 56 lb P₂O₅, and 56 lb K₂O per ac) and a sidedress application (50 lb Nand 50 lb K₂O per ac) on October 2, 16 days after planting for 106 lb N, 56 lb P₂O₅, and 106 lb K₂O per ac total nutrients applied compared to the single CRF preplant application of 90 lb N, 28 lb P₂O₅, and 107 lb K₂O per ac. Preplant applications were on September 10 with planting on September 16. There were leaching rainfall events in September accumulating 4.3”. On October 1, soil samples were taken to a 6” depth that revealed soil N content was over four times greater in plots with the CRF application than the conventional grower program after the heavy rainfall indicating reduced leaching and environmental impact with the use of POLYON® CRF blend. Commercial use of POLYON® CRF blends have proved beneficial in green bean production by maintaining or increasing yields with the opportunity to reduce applications and total nutrients applied.

Figure 1: Soil analyses for treatments of conventional program (quick release) and Harrell’s POLYON® CRF blend.