Using Controlled Release Fertilizer to Increase Nitrogen-Use Efficiency for Overhead Irrigated Snap Bean (Phaseolus vulgaris L.) Production in Florida.

Different from other legume crops, snap bean requires a great amount of nitrogen (N) because it is weak in the fixation of gaseous nitrogen from the air. The objective of this field trial was to explore the potential of controlled release fertilizer (CRF) in improving snap bean’s nitrogen-use efficiency (NUE). Snap bean (cv. ‘Caprice’) trial was conducted on a commercial snap bean farm in southwest Florida in the spring growing season in 2014. The randomized complete block design was employed with four replications. There were seven N treatments: 45, 90, and 135 kg/ha N as ammonium nitrate (AN) only, 45, 90, and 135 kg/ha N as 20% AN and 80% CRF, and 90 kg/ha as CRF only with a paralleled control without N application. The results showed that the NUE was 92.8, 53.7 and 10.4 kg/kg for the first, second, and third 45 kg/ha AN N, respectively. The mixture of 20% AN and 80% CRF increased NUE by 71.5, 9.6, and 37.1 kg/kg compared with the corresponding AN-only treatments. The 90 kg/ha N as CRF-only treatment had 31.2 and 21.6 kg/kg greater NUE than the other two treatments of 90 kg/ha N as AN-only and 20AN-80 CRF mixture. The data indicate that CRF can significantly increase NUE and may become a BMP tool for commercial snap bean production.