Effects of earthworm (Eisenia fetida) and wheat (Triticum aestivum) straw additions on selected properties of petroleum‐contaminated soils

Current bioremediation techniques for petroleum-contaminated soils are designed to remove contaminants as quickly and efficiently as possible, but not necessarily with postremediation soil biological quality as a primary objective. To test a simple postbioremediation technique, we added earthworms (Eisenia fetida) or wheat (Triticum aestivum) straw to petroleum land-farm soil and measured biological quality of the soil as responses in plant growth, soil respiration, and oil and grease (O&G) and total petroleum hydrocarbon (TPH) concentrations. Results indicated that plant growth was greater in earthworm-treated land-farm soil. Furthermore, addition of wheat straw resulted in greater total respiration in all soils tested (land-farm soil, noncontaminated reference soil, and a 1:1 mixture of land-farm and reference soils). We observed a 30% increase in soil respiration in straw-amended oily soil, whereas respiration increased by 246% in straw-amended reference soil. Much of the difference between oily and reference soils was attributable to higher basal respiration rates of nonamended oily soil compared to nonamended reference soil. Addition of earthworms resulted in greater total respiration of all soil and straw treatments except two (the land-farm and the 1:1 mixture soil treatments without straw). Straw and earthworm treatments did not affect O&G or TPH concentrations. Nevertheless, our findings that earthworm additions improved plant growth and that straw additions enhanced microbial activity in land-farm soil suggest that these treatments may be compatible with plant-based remediation techniques currently under evaluation in field trials, and could reduce the time required to restore soil ecosystem function.

[1]  S. Stockdill.  Effects of introduced earthworms on the productivity of New Zealand pastures , 1982, Pedobiologia.

[2]  J. Cortez,et al.  C and N transfer in soil with or without earthworms fed with 14C- and 15N-labelled wheat straw , 1989 .

[3]  R. M. Morris,et al.  The earthworm inoculation unit technique: an integrated system for cultivation and soil-inoculation of earthworms , 1997 .

[4]  Dallas E. Johnson,et al.  Analysis of messy data , 1992 .

[5]  G. Hofman,et al.  Nitrogen cycling associated with the decomposition of sunflower stalks and wheat straw in a Vertisol , 2004, Plant and Soil.

[6]  A. Saterbak,et al.  Ecotoxicological and analytical assessment of effects of bioremediation on hydrocarbon‐containing soils , 2000 .

[7]  C. Gestel,et al.  Handbook of soil invertebrate toxicity tests , 1998 .

[8]  J. Salanitro.  Bioremediation of petroleum hydrocarbons in soil , 2001 .

[9]  P. Saetre.  DECOMPOSITION, MICROBIAL COMMUNITY STRUCTURE, AND EARTHWORM EFFECTS ALONG A BIRCH–SPRUCE SOIL GRADIENT , 1998 .

[10]  J. Lawton,et al.  Organisms as ecosystem engineers , 1994 .

[11]  P. Lavelle,et al.  Stimulation of plant growth by tropical earthworms , 1992 .

[12]  S. Radwan,et al.  Oil biodegradation around roots , 1995, Nature.

[13]  P. Hendrix,et al.  Earthworm (Lumbricus rubellus and Aporrectodea caliginosa) effects on carbon flux in soil , 1995 .

[14]  William D. Shuster,et al.  Effects of vermicomposts and composts on plant growth in horticultural container media and soil , 2000 .

[15]  Clive A. Edwards,et al.  potential of earthworm composts as plant growth media , 1988 .

[16]  J. Haimi,et al.  Effects of endogeic earthworms on soil processes and plant growth in coniferous forest soil , 1992, Biology and Fertility of Soils.

[17]  J. Salanitro,et al.  Temporal ecological assessment of oil contaminated soils before and after bioremediation. , 2000, Chemosphere.

[18]  D. E. Johnson,et al.  Analysis of Messy Data Volume I: Designed Experiments , 1985 .

[19]  J. Curry,et al.  Earthworms and land reclamation , 1983 .

[20]  M. Huesemann,et al.  Crude Oil Hydrocarbon Bioremediation and Soil Ecotoxicity Assessment , 1997 .

[21]  P. Hendrix,et al.  Impact of earthworms (Diplocardia: Megascolecidae) on cycling and uptake of nitrogen in coastal plain forest soils from northwest Florida, USA , 1998 .

[22]  J. Satchell.  Earthworm Ecology: From Darwin to Vermiculture , 1983 .

[23]  G. Petersonc,et al.  Fungal translocation as a mechanism for soil nitrogen inputs to surface residue decomposition in a no-tillage agroecosystem , 2022 .