Nitrogen fertilization effects on recovery of bush beans from flooding

Nitrogen loss can be a serious problem to vegetable growers in flood-prone areas. In south Florida, waterlogged soil can cause plant N stress through nitrate leaching, denitrification, and reduced N uptake and assimilation. The Comprehensive Everglades Restoration Project will increase water flow into Everglades National Park, resulting in frequent flooding on adjacent agricultural lands. A greenhouse study was conducted to determine effects of nitrogen application method on recovery from flood damage in bush beans (Phaseolus vulgaris L.). There were three fertilizer treatments: 1) normal: N applied preplant, applied at flowering; 2) liquid: daily liquid applications with irrigation water; and 3) foliar: normal fertility treatment plus two foliar spray treatments applied after flooding. Plants were flooded to 1 cm above the soil surface for 2 or 4 days, drained, and allowed to continue to grow under normal greenhouse conditions. At harvest, plants receiving the liquid treatment had a greater pod fresh weight (FW) than those receiving normal and foliar fertility treatments. From planting through recovery from flooding (day 45), the liquid fertility treatment tended to maintain chlorophyll levels either equal to or greater than those of the foliar and normal treatments. Plants receiving liquid fertilizer tended to have a net photosynthetic rate higher than the other fertility methods and recovered faster, and to higher photosynthetic levels, after flooding. Plants flooded for 2 days and receiving the liquid treatment appeared to have a denser root system and a larger leaf area than the other treatment. These plants probably resisted flood damage longer and were better able to recover from injury, and this likely resulted in higher pod FW than the other treatments. Daily liquid fertility treatments (fertigation) may be an acceptable strategy to mitigate certain effects of flood damage to beans.