ARS | Publication request: Nitrogen fertilization for new plantings of hybrid hazelnuts in the Upper Midwest of the United States of America

Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2011
Publication Date: July 1, 2011
Citation: Braun, L.C., Gillman, J.H., Hoover, E.E., Russelle, M.P. 2011. Nitrogen fertilization for new plantings of hybrid hazelnuts in the Upper Midwest of the United States of America. Canadian Journal of Plant Science. 91(4):773-782.

Interpretive Summary: Numerous perennial crops are being considered for use as biomass feedstocks. Those that provide additional income streams for producers are of particular interest. Hybrid hazelnut is one such species that can be grown as hedgerows in other crops, such as alfalfa. Hybrid hazelnut is a new crop, is still in the early stages of variety development, and there are no reports about its nitrogen requirements for establishment. Nitrogen fertilizer often is the largest input of energy in agriculture and can be the source of significant contamination of water and the atmosphere. In earlier research, we found that uptake of nitrogen fertilizer was low compared to other woody crops and most herbaceous crops, regardless of the timing of fertilizer application. In this report, we show that avoiding fertilizer nitrogen for the first year after transplanting improves plant survival. Nitrogen needs continue to be low while the plants are juvenile. We also developed a leaf tissue test that can be used by hazelnut growers to determine whether the plants require fertilizer. This information should reduce the cost and improve the success of hybrid hazelnut establishment and reduce risk of profit loss and environmental damage from excess fertilizer nitrogen applied in later years.

Technical Abstract: Seed-propagated hybrids of Corylus avellana and C. americana are a potential crop for the Upper Midwest. Current N recommendations for hazelnuts are based on research on clonally propagated C. avellana in Oregon and may not be applicable in the Upper Midwest due to differing soils, climate, and plant genetics. We established three field plots in 2003 to test N fertilization rates on new plantings, with rates up to 33 g N/plant as ammonium nitrate applied annually in the spring, starting 2 wk after transplanting. We observed a strong negative linear effect of N rate on plant survival. In the second year we added trials on same-aged plants that had not previously been fertilized and found no N effect on survival. We concluded that waiting 1 yr after transplanting before fertilizing increases plant survival, but even then N requirements during establishment years are very low for hybrid hazelnuts. Standard leaf N concentrations for C. avellana in Oregon are roughly applicable to hybrid hazelnuts, except that the threshold between deficiency and sufficiency should be raised slightly to 1.9% N. The current threshold between deficient and sufficient, 2.2%, should be regarded as a target, rather than as a threshold to be exceeded.