Submitted to: Proceedings of Ciclo de Conferencios Internationale de Nogalero a Nogalero
Publication Type: Proceedings
Publication Acceptance Date: 2/28/2006
Publication Date: 3/30/2006
Citation: Wood, B.W. 2006. Mineral nutrition of pecan with emphasis on nitrogen. Proceedings of Ciclo de Conferencios Internationale de Nogalero a Nogalero. p. 11-21. Interpretive Summary: Efficient usage of nitrogen fertilizers applied to orchards is a major biological and economic problem for pecan farmers. This communication reviews basic principles that can be used by farmers to design improved nitrogen management strategies. The roles of sunlight, and that of sulfur, nickel, and boron nutrition are emphasized. This information makes it possible for farmers to minimize nitrogen usage in orchards while still improving nutmeat production.
Technical Abstract: Pecan mineral nutrition has been studied for nearly a century; yet, there remains much mystery about pecan’s true need for nutritive non-metals and metals. It is important to recall that pecan evolved in a relatively high organic flood-plain soil and is therefore well adapted to such habitats. These natural habitat soils are typically rich in all required nutrient elements. It is often overlooked that most commercial pecan orchards are in low organic mineral soils possessing physical, chemical, and biological characteristics that are relatively alien compared to most flood-plain soils, thus being much different than those of which the tree has adapted over millions of years. It then becomes problematic when orchard managers expect trees to produce high nutmeat yields in an “alien” soil environment to which they are not necessarily well adapted with regards to certain aspects of mineral nutrition. It is noteworthy that there are multitudes of subtleties associated with the interaction of pecan with alien soil environments that influence the tree’s ability to optimize crop yields, especially those cultivated on high pH water-limited mineral soils. The discussion herein is largely limited to nitrogen (N) nutrition, as N is typically both the most expensive fertilizer needed and is often the most limiting to orchard yield. It is likely that many commercial producers of pecan apply excessive N to orchards. The “rule of thumb” commonly adopted by most commercial farmers is 8-10 pounds of elemental N per expected 100 pounds of in-shell nuts. It is possible that this “rule of thumb” could be revised to 4-6 pounds of elemental N per expected 100 pounds of nuts if N management strategies were optimized. With the rising cost of nitrogen fertilizers, such a reduction in N usage without a yield loss makes a considerable difference in orchard profitability. This communication provides a brief overview regarding N management and certain other elements affecting the tree’s ability to use N.