Potential Movement of Pesticides Related to Dissolved Organic Matter from Fertilizer Application on Turf

Transcription

1 Potential Movement of Pesticides Related to Dissolved Organic Matter from Fertilizer Application on Turf Kun Li*, William A. Torello, J. Scott Ebdon and Baoshan Xing Dept. of Plant and Soil Sciences University of Massachusetts Amherst

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3 What is golfer s expectation? 1. Speed 2. Uniformity

4 Stress Turfgrass Management Low mowing heights Double cut mowing Use of growth regulators Less nutrient input Rolling of turf Intensive foot traffic Increased pesticide usage

5 What is Fate of Applied Chemicals on Turf?

6 Processes that influence the fate of applied pesticides Sorption Degradation Plant uptake Volatilization Runoff Leaching Environmental Impacts

7 USGA Putting Green Particle Diameter mm mm Recomm. (by weight) < 10%, and < 3% fine gravel mm mm > 60% mm < 20% mm < 5% mm < 5% < mm < 3% Very fine sand + silt + clay 10%

8 Introduction Incorporation organic fertilizers /amendments on turfgrass management. Organic turfgrass management

9 Introduction Leaching rates of napropamide from sewage sludge amended soil was twice as great as that of none sewage sludge amendments due to enhanced transport by sewage sludge-derived dissolved organic matter (DOM) (Nelson et al., 1998). Petrovic et al. (1996) reported that with addition of peat amendments to sand based putting greens, a 55% increase in fungicide (metalaxyl) leaching occurred compared with sand alone.

10 Detrimental Effects of DOM Water body contamination Formation of by-products during water treatment DOM acts as precursors in the formation of trihalomethanes (THMs) and other disinfection by-products (DBPs) during the disinfection of municipal water Reduced sorption of pesticides by soil

11 Reduced Sorption of Pesticides DOM increases solubility of pesticides (Chiou, 1987; Guetzloff and Rice, 1996; Cho et al., 2002). DOM-pesticide interactions and/or competition between DOM molecules and pesticide molecules for sorption sites (Nelson, et al., 1998; Celis et al., 2000; Williams et al., 2002). DOM may serve as a carrier in soil solution that could result in rapid flow of pesticides through soil profiles (Dunnivant et al., 1992)

12 Objectives To evaluate the potential effect of organic fertilizer derived - DOM on pesticide movement in USGA putting green mix. Overall goal To develop the best management program (BMP) for properly using organic fertilizer on turfgrass management

13 Fertilizer types Milorganite (6-2-0) (Milwaukee, WI) NatureSafe (8-3-5) (Griffin Industries Inc., Cold Spring, KY ) Sustane (8-2-4) (Natural Fertilizers of American Inc., Cannon Falls, MN) DOM 2.2% 0.75% 0.63%

14 DOM extraction Solid to solution ratio 1:10. Mixed on shaker for 30 min. at 200 rpm. Centrifuged at 3000 x g for 30 min. Filtered through nitrocellulose filter paper with 0.45 µm pore size. Total organic carbon was analyzed by a Shimadzu TOC-5000A analyzer.

15 Materials and Methods SORBENT: USGA Sand (SOM, 0.6%) Amherst Soil (Silt loam, SOM, 10%) SORBATE: 14 C labeled and unlabeled Dursban (chlorpyrifos) (O,O-diethyl O-3,5,6-trichloro-2- pyridyl phophorothioate ) and 2,4-D (2,4- dichlorophenoxy acetic acid)

16 Materials and Methods SOLUTIONS: 0.01 M CaCl2 (background solution) 0.01 M CaCl2 + different concentrations of DOM

17 Isotherm Construction Batch equilibration; mixed with hematology mixers (Xing and Pignatello 1997). Isotherm fitting model: S = K f C N (Freundlich equation) Log S = Log K f + N Log C

18 Sorption Isotherm of Chlorpyrifos Sorbed Chlorpyrifos (mg/kg) M CaCl m CaCl mg/l DOC 0.01 M CaCl mg/l DOC 0.01 M CaCl mg/l DOC Solution Concentration (mg/l)

19 Calculated Parameters of Chlorpyrifos Sorption Isotherm Sorbent Sorption Log K F N r 2 Ce rang (µg L -1 ) K oc (ml g -1 of OC) Ce=0.001 Ce =0.01 Ce = 0.1 mg L -1 mg L -1 mg L -1 USGA Sand 1.42 (0.03)* USGA sand M120 (0.03) USGA sand M60 (0.03) USGA sand M30 (0.02) (0.02) (0.02) (0.04) (0.01) The values shown in parentheses are 95% confidence intervals, OC = organic carbon.

20 pure sand pesticide

21 Chlorpyrifos breakthrough curve for USGA sand Chlorpyrifos Concentration (mg/l) Relative Pore Volume (V/Vo) 0.01 M CaCl M CaCl mg/l DOC from Milorgantie 0.01 M CaCl mg/l DOC from NatureSafe

22 Parameters of column leaching experiment of chlorpyrifos Treatment Total leached out (%) 0.01 M CaCl (1.0) 0.01 M CaCl M120 (4.2) 0.01 M CaCl N60 (3.6) Max. conc. (mg L -1 ) Total recovery (%)

23 Surface tension of different DOM 75 Surface Tension (nn/m) Milorganite NatureSafe Dissolved Organic Carbon Concentration (mg/l)

24 Diffuse Reflectance Fourier Transform Infrared (DRIFT) spectra of different DOM NatureSafe Milorganite Kubelka Munk Unit cm Assignment Aromatic CH Aromatic C=C Aromatic C=C -CH2- -CH2- -CH3 Aliphatic OH Aliphatic C-C Wavenumbers (cm -1 )

25 Conclusions DOM extracted from organic fertilizers reduced surface tension with increasing DOM concentration. DOM extracted from organic fertilizers enhanced pesticide leaching in USGA sand, even at DOM concentration as low as 60 mg/l.

26 Recommendations Do not overapply organic fertilizers/ amendments at one time Do not apply organic fertilizers/amendments immediately after pesticide application

27 Future studies Field trials to monitor pesticides and DOM in leachates under different golf green management programs. Characterization of DOM from different sources to clarify the effect of DOM on pesticide movement.

28 Acknowledgments Massachusetts Water Resources Research Center for the financial support.