Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem

Nutrient Cycling in Agroecosystems
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Abstract

Even though nitrogen (N) is a key nutrient for successful cranberry production, N cycling in cranberry agroecosystems is not completely understood. Prior research has focused mainly on timing and uptake of ammonium fertilizer, but the objective of our study was to evaluate the potential for additional N contributions from hydrologic inputs (flooding, irrigation, groundwater, and precipitation) and organic matter (OM). Plant biomass, soil, surface and groundwater samples were collected from five cranberry beds (cranberry production fields) on four different farms, representing both upland and lowland systems. Estimated average annual plant uptake (63.3 ?? 22.5 kg N ha-1 year-1) exceeded total average annual fertilizer inputs (39.5 ?? 11.6 kg N ha-1 year-1). Irrigation, precipitation, and floodwater N summed to an average 23 ?? 0.7 kg N ha-1 year-1, which was about 60% of fertilizer N. Leaf and stem litterfall added 5.2 ?? 1.2 and 24.1 ?? 3.0 kg N ha-1 year-1 respectively. The estimated net N mineralization rate from the buried bag technique was 5 ?? 0.2 kg N ha-1 year-1, which was nearly 15% of fertilizer N. Dissolved organic nitrogen represented a significant portion of the total N pool in both surface water and soil samples. Mixed-ion exchange resin core incubations indicated that 80% of total inorganic N from fertilizer, irrigation, precipitation, and mineralization was nitrate, and approximately 70% of recovered inorganic N from groundwater was nitrate. There was a weak but significant negative relationship between extractable soil ammonium concentrations and ericoid mycorrhizal colonization (ERM) rates (r = -0.22, P < 0.045). Growers may benefit from balancing the N inputs from hydrologic sources and OM relative to fertilizer N in order to maximize the benefits of ERM fungi in actively mediating N cycling in cranberry agroecosystems. ?? 2011 Springer Science+Business Media B.V.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem
Series title Nutrient Cycling in Agroecosystems
DOI 10.1007/s10705-011-9442-4
Volume 91
Issue 1
Year Published 2011
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Nutrient Cycling in Agroecosystems
First page 41
Last page 54