Open AccessNitrogen Availability in Pecan Orchard Soil: Implications for Pecan Fertilizer Management
Author(s) -
M. Lenny Wells
Publication year - 2011
Publication title -
hortscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.518
H-Index - 90
eISSN - 2327-9834
pISSN - 0018-5345
DOI - 10.21273/hortsci.46.9.1294
Subject(s) - orchard , fertilizer , agronomy , growing season , poultry litter , cover crop , litter , environmental science , ammonium nitrate , biology , nutrient , chemistry , ecology , organic chemistry
Nitrogen (N) fertilizer application to plants at rates not adjusted for the N contribution from soil N availability may result in overapplication of fertilizer. Further understanding of proper timing of N applications based on soil N dynamics and plant demand can be valuable information for the efficient use of fertilizer N. The present study measures soil N dynamics in a pecan orchard under various N fertilizer regimes on a southeastern U.S. Coastal Plain soil. The following treatments were evaluated: 1) crimson clover ( Trifolium incarnatum L.); 2) poultry litter; 3) crimson clover + poultry litter; 4) ammonium nitrate (NH 4 NO 3 ); and 5) untreated control. Crimson clover provided from 20 to 75 kg·ha −1 N over the course of the two growing seasons; however, most of the available N from crimson clover became available late in the growing season. As a result, supplemental N may be required in spring where crimson clover is used as an orchard cover crop. Poultry litter, with and without clover, provided available N consistently throughout the growing season with more N becoming available later in the season than earlier. This suggests that poultry litter applications for pecan should be timed before budbreak. Under optimum environmental conditions, N from NH 4 NO 3 is most available within the first 30 days of application. Thus, it appears that synthetic fertilizer applications using NH 4 NO 3 as the N source should be targeted at or 2 to 3 weeks after pecan budbreak.