Bottomland afforestation is frequently unsuccessful, partly because of low-quality planting stock and low soil fertility following row cropping. In autumn 1999, two 16.2-ha fields at two conservation areas in central Missouri were seeded to redtop grass or allowed to revegetate from the seedbank. In spring 2004, one of five nitrogen (N) treatments was applied to one row of five-row tree plots planted in 2000 with all combinations of bare-root and root production method (RPM) seedlings of swamp white oak and pin oak. In late July 2006, foliar N averaged 1.83 percent after annual application of 83 g of 20N-10P-10K as slow-release ammonium nitrate, 1.82 percent after annual application of 87 g of 19N-6P-9K as slow-release urea, 1.78 percent after planting two N-fixing false wild indigo seedlings adjacent to each oak sapling, 1.79 percent after planting two buttonbush seedlings, and 1.81 percent when left untreated. Foliar N averaged 1.70 percent for swamp white oak from bare-root planting stock, 1.80 percent for swamp white oak from RPM planting stock, and 1.88 percent for pin oak from RPM planting stock. Foliar N averaged 1.74 percent for oaks growing in cover of weeds and 1.81 percent for oaks planted in redtop at one site; no differences were caused by ground cover at the other site (1.83 percent). Compared with estimated sufficiency ranges, foliar phosphorus, potassium, calcium, magnesium, zinc, boron, and copper were adequate for both species. Foliar N, manganese, and iron were deficient for both species with only foliar sulfur deficient for pin oak. A high soil pH likely limited micronutrient availability, especially manganese, and negated any response to applied N. Soil pH will need to be neutralized and quality planting stock planted for bottomland restoration of hard-mast species on moderately alkaline soils within the lower Missouri River floodplains.
Van Sambeek, Jerry W.; Kabrick, John M.; Dey, Daniel C. 2017. Foliar nutrient responses of oak saplings to nitrogen treatments on alkaline soils within the Missouri River Floodplain. In: Kabrick, John M.; Dey, Daniel C.; Knapp, Benjamin O.; Larsen, David R.; Shifley, Stephen R.; Stelzer, Henry E., eds. Proceedings of the 20th Central Hardwood Forest Conference; 2016 March 28-April 1; Columbia, MO. General Technical Report NRS-P-167. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 58-71.