The Influence of Form and Rate on the Efficacy of Matrix-Based Fertilizers to Reduce Nutrient Leaching

James A Entry,R E Sojka

doi:10.1155/2009/374540

Abstract

We tested the efficacy of matrix-based fertilizers (MBFs) to reduce , , and total phosphorus (TP) leaching compared to Osmocote 14-14-14, a commercial slow release fertilizer (SRF) in greenhouse column studies. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF4) and more tightly bound compounds (MBF5) with and/or and with high ionic exchange compounds starch, chitosan, and lignin. When N and P are released, the chemicals containing these nutrients in the MBF bind N and P to an and/or starch- chitosan- lignin matrix. SRF leachate contained a greater amount of , , DRP, and TP than leachate from MBF4 and MBF5 regardless of whether fertilizers were pellets, banded or broadcast, or fertilizer rate. St Augustine grass growing in soils receiving MBF4 and MBF5 had decreased shoot biomass by 49% to 56% and decreased total biomass by 33% to 46% respectively as grass receiving SRF. Although further greenhouse and field testing are necessary, results of this initial investigation are promising and with further development, testing, and rate calibration should be competitive with commercial fertilizers in environmentally sensitive markets.

Highlights

Transport of N and P from agricultural soils to surface waters has been linked to eutrophication in fresh water and estuaries [1,2,3]
Statistical comparisons of NO3, NH4, dissolved reactive phosphate (DRP), total phosphorus (TP), shoot, root, and total plant weight and shoot and root nutrient concentrations are presented for fertilizer treatments because general linear models (GLMs) models showed that these interactions were significant at P ≤ .05 [17, 18]. plants growing in soils receiving slow release fertilizer (SRF) had greater shoot, root, and total biomass than all fertilizer formulations; MBF4 and MBF5 decreased shoot biomass by 53% and 76%, decreased root biomass by 4% and 46% and total plant biomass by 51% and 74% compared to the SRF (Table 3)
Arbuscular mycorrhazal infection in plant roots did not consistently differ among plants growing in soil receiving SRF and all matrix-based fertilizers (MBFs) formulations and plants growing in soils receiving no fertilizer

Summary

Introduction

Transport of N and P from agricultural soils to surface waters has been linked to eutrophication in fresh water and estuaries [1,2,3]. Eutrophication accounts for about 50% of the impaired lake area and 60% of the impaired rivers in the United States It is the most widespread pollution problem in estuaries [4]. The incidence of harmful algal blooms in lakes, streams, and coastal oceans has dramatically increased in recent years [4]. This increase is linked to eutrophication and other factors, such as changes in aquatic food webs that may increase decomposition and nutrient recycling or reduce populations of algae-grazing fish. Increasing conversion of native lands to agriculture or development has increased the land area receiving fertilizer and contributes to N and P pollution of surface waters

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