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

We tested the efficacy of matrix-based fertilizers (MBFs) to reduce Escherichia coli and Enterococcus spp., NH(4), NO(3), 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, Al(2)(SO(4))(3)18H(2)O, and/or Fe(2)(SO(4))(3)3H(2)O 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, NH(4), and NO(3) 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 Al(2)(SO(4))(3)18H(2)O or Fe(2)(SO(4))(3)3H(2)O-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.

Matrix based fertilizers reduce nitrogen and phosphorus leaching in three soils.

We compared the efficacy of matrix based fertilizers (MBFs) formulated to reduce NO3-, NH4+, and total phosphorus (TP) leaching, with Osmocoate 14-14-14, a conventional commercial slow release fertilizer (SRF) and an unamended control in three different soil textures in a greenhouse column study. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF 1) to more moderately bound (MBF 2) and more tightly bound compounds (MBF 3) mixed with Al(SO4)3H2O and/or Fe2(SO4)3 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 a Al(SO4)3H2O and/or Fe2(SO4)3 starch-chitosan-lignin matrix. One milligram (8000 spores) of Glomus intradices was added to all formulations to enhance nutrient uptake. In all three soil textures the SRF leachate contained a higher amount of NH4+, NO3- and TP than leachate from all other fertilizers. In all three soils there were no consistent differences in the amount of NH4+, NO3- and TP in the MBF leachates compared to the control leachate. Plants growing in soils receiving SRF had greater shoot, root and total biomass than all MBFs regardless of Al(SO4)3H2O or Fe2(SO4)3 additions. Arbuscular mycorrhizal infection in plant roots did not consistently differ among plants growing in soil receiving SRF, MBFs and control treatments. Although the MBFs resulted in less plant growth in this experiment they may be applied to soils growing plants in areas that are at high risk for nutrient leaching to surface waters.

Synthetic- and bio-polymer use for runoff water quality management in irrigated agriculture.

Low concentrations of synthetic- or bio-polymers in irrigation water can nearly eliminate sediment, N, ortho- and total-P, DOM, pesticides, micro-organisms, and weed seed from runoff. These environmentally safe polymers are employed in various sensitive uses including food processing, animal feeds, and potable water purification. The most common synthetic polymer is anionic, high purity polyacrylamide (PAM), which typically provides 70-90% contaminant elimination. Excellent results are achieved adding only 10 ppm PAM to irrigation water, applying 1-2 kg ha(-1) per irrigation, costing 4 dollars - 12 dollars kg(-1). Biopolymers are less effective. Using twice or higher concentrations, existing biopolymers are approximately 60% effective as PAM, at 2-3 times the cost. A half million ha of US irrigated land use PAM for erosion control and runoff protection. The practice is spreading rapidly in the US and worldwide. Interest in development of biopolymer surrogates for PAM is high. If the supply of cheap natural gas (raw material for PAM synthesis) diminishes, industries may seek alternative polymers. Also "green" perceptions and preferences favor biopolymers for certain applications.

Polyacrylamide + Al2(SO4)3 and polyacrylamide + CaO remove coliform bacteria and nutrients from swine wastewater.

Animal wastes are a major contributor of nutrients and enteric microorganisms to surface water and ground water. Polyacrylamide (PAM) mixtures are an effective flocculent, and we hypothesized that they would reduce transport of microorganisms in flowing water. After waste water running at 60.0 1 min(-1) flowed over PAM + Al2(SO4)3, or PAM + CaO in furrows, total coliform bacteria (TC) and fecal coliform bacteria (FC) were reduced by 30-50% at 1 and 50 m downstream of the treatments compared to the control. In a column study, PAM + Al2(SO4)3, and PAM + CaO applied to sandy, sandy loam, loam, and clay soils reduced NH4+ and ortho-P concentrations in leachate compared to the source waste water and the control. PAM + Al2(SO4)3 and PAM + CaO applied to sandy, sandy loam and loam soils reduced both total and ortho-P, concentrations in leachate compared to he source wastewater and control treatment. In a field study, PAM + Al2(SO4)3, or PAM + CaO treatments did not consistently reduce NH4+, NO3-, ortho-P, and total P concentrations in wastewater flowing over any soil compared to inflow wastewater or the control treatment. With proper application PAM + Al2(SO4)3 and PAM + CaO may be able to reduce the numbers of enteric bacteria in slowly flowing wastewater running off animal confinement areas, reducing the amount of pollutants entering surface water and groundwater.

Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants.

Waste streams associated with a variety of agricultural runoff sources are major contributors of nutrients, pesticides and enteric microorganisms to surface and ground waters. Water soluble anionic polyacrylamide (PAM) was found to be a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1-10 g m(-3) in furrow irrigation water. Water flowing from PAM treated irrigation furrows show large reductions in sediment, nutrients and pesticides. Recently PAM and PAM + CaO and PAM + Al(SO4)3 mixtures have been shown to filter bacteria, fungi and nutrients from animal wastewater. Low concentrations of PAM [175-350 g PAM ha(-1) as PAM or as PAM + CaO and PAM + Al(SO4) mixture] applied to the soil surface, resulted in dramatic decreases (10 fold) of total, coliform and fecal streptococci bacteria in cattle, fish and swine wastewater leachate and surface runoff. PAM treatment also filtered significant amounts of NH4, PO4 and total P in cattle and swine wastewater. This points to the potential of developing PAM as a water quality protection measure in combination with large-scale animal feeding operations. Potential benefits of PAM treatment of animal facility waste streams include: (1) low cost, (2) easy and quick application. (3) suitability for use with other pollution reduction techniques. Research on the efficacy of PAM for removal of protozoan parasites and viruses and more thorough assessment of PAM degradation in different soils is still needed to completely evaluate PAM treatment as an effective waste water treatment. We will present analysis and feasibility of using PAM, PAM + Al(SO4)3, and PAM + CaO application for specific applications. Our results demonstrate their potential efficacy in reducing sediment, nutrients and microorganisms from animal production facility effluents.

Influence of polyacrylamide application to soil on movement of microorganisms in runoff water.

Polyacrylamide (PAM) use in irrigation for erosion control has increased water infiltration and reduced soil erosion. This has improved runoff water quality via lower concentrations of nitrogen, phosphorous, and pesticides, and decreased biological oxygen demand. Since non-toxic high molecular weight anionic PAMs removed clay size sediment particles in flowing water, we hypothesized that PAM would effectively remove or immobilize microorganisms in flowing water. In an agricultural field, we determined the efficacy of PAM-treatment of furrow irrigation water to remove several categories of microorganisms in the inflow and runoff. Treatments were: (1) PAM application and a control; (2) three flow rates; (3) two distances from the inflow point; and (4) three times during each irrigation. After water traveled 1 m at 7.5 and 15.5 l min(-1), PAM-treatment reduced total bacterial and microbial biomass and total fungal biomass relative to the control treatment. After water traveled 40 m at 7.5, 15.5, and 22.5 l min(-1), PAM-treatment reduced algae, the numbers active and total bacteria, active and total fungal length, and total bacterial biomass, total fungal and microbial biomass relative to the control treatment. Although specific organisms were not identified or monitored in this study, the results clearly have implications for controlling the spread of soil-borne plant pathogens and other classes of harmful organisms within and among fields via irrigation water and in re-utilized return flows. Beyond furrow-irrigated agriculture, new methods to manage overland transmission of harmful microorganisms could potentially help control transport of pathogens from animal waste in runoff and groundwater.