Matrix-based fertilizers reduce nutrient and bacterial leaching after manure application in a greenhouse column study

Abstract

We tested the efficacy of matrix-based fertilizers (MBFs) to reduce Escherichia coli and Enterococcus spp., NH₄, NO₃, dissolved reactive phosphorus (DRP), and total phosphorus (TP) in leachate and soil after dairy manure application in greenhouse column studies. The MBFs are composed of inorganic N and P in compounds that are relatively loosely bound (MBF8) to more tightly bound (MBF9) mixtures using combinations of starch, cellulose, lignin, Al₂(SO₄)₃18H₂O, and/or Fe₂(SO₄)₃3H₂O to create a matrix that slowly releases the nutrients. One day after the first dairy manure application, E. coli numbers were greater in leachate from control columns than in leachate from columns receiving MBFs. After three dairy manure applications, E. coli and Enterococcus spp. numbers in leachates were not consistently different between controls and columns receiving MBFs. When MBF8 was applied to the soil, the total amount of DRP, TP, NH4, and NO₃ in leachate was lower than in the control columns. Bermudagrass receiving MBFs had greater shoot, root, and total biomass than grass growing in the control columns. Grass shoot, root, and total biomass did not differ among columns receiving MBFs. Nitrogen and phosphorus bound to the Al₂(SO₄)₃18H₂O or Fe₂(SO₄)₃3H₂O–lignin–cellulose matrix become gradually available to plants over the growing season. The MBF8 and MBF9 formulations do not depend on organic or inorganic coatings to reduce N and P leaching and have the potential with further testing and development to provide an effective method to reduce N and P leaching from soils treated with animal waste.