We tested the efficacy of matrix based fertilizer formulations (MBF) that reduce NH
4, total phosphorus (TP), total reactive phosphorus (TRP) and dissolved reactive phosphorus (DRP) in leachate. The MBF formulations
cover a range of inorganic N and P in compounds that are relatively loosely bound (MBF1) to more moderately bound (MBF2) and
more tightly bound compounds (MBF3) mixed with Al(SO
4)
3 H
2O and/or Fe
2(SO
4)
3 and with the high ionic exchange compounds starch, chitosan and lignin.
Glomus interadicies, a species of arbuscular mycorrhizal fungal spores that will form mycorrhizae in high nutrient environments, was added to
the MBF formulations to increase plant nutrient uptake. When N and P are released from the inorganic chemicals containing
N and P the matrix based fertilizers likely bind these nutrients to the Al(SO
4)
3 H
2O and/or Fe
2(SO
4)
3 starch–chitosan–lignin matrix. We tested the efficacy of the MBFs to reduce N and P leaching compared to Osmocote
® 14-14-14, a slow release fertilizer (SRF) in sand filled columns in a greenhouse study. SRF with and without Al and Fe leached
78–84% more NH
4, 58–78% more TP, 20–30% more TRP and 61–77% more than MBF formulations 1, 2, and 3 in a total of 2.0 liters of leachate after
71 days. The concentration and amount of NO
3 leached among SRF and MBF formulations 1 and 2 did not differ. The SRF treatment leached 34% less NO
3, than MBF3. Total plant weight did not differ among fertilizer treatments. Arbuscular mycorrhizal infection did not differ
among plants receiving SRF and MBF formulations 1, 2 and 3. Although further greenhouse and field testing are called for,
results of this initial investigation warrant further investigation of MBFs.
Keywords starch - chitosan - lignin - mycorrhizae - aluminum sulfate - iron sulfate