The Influence of Planting and Soil Characteristics on Mineralization of 2,4,5-T in Rhizosphere Soil
- Jay J. Boyle and
- Jodi R. Shann *
Phytoremediation is a potential means of addressing soil contamination. It is not understood, however, what limits or fosters the degradation of xenobiotics in planted soil. This study examined the relative influence of plant species and soil type on biodegradation in the rhizosphere. In a complete design, three plant species (sunflower, Timothy grass, and red clover) were grown in three field-collected soils (Jules silt loam [a coarse-silty, mixed (calcareous), mesic Typic Udifluvent]; Miamian clay loam [a fine, mixed, mesic Typic Hapludalf]; Parke silt loam [a fine-silty, mixed, mesic Ultic Hapludalf]). Soil characteristics and microbial activity, biomass, and mineralization of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), were determined in soil before and after planting. In general, the characteristics of an unplanted soil were correlated to its microbial biomass and activity. Not suprisingly then, soil type was the most significant determinant of xenobiotic degradation in both planted and unplanted systems. In spite of this strong soil effect, planting always resulted in a significant increase in 2,4,5-T mineralization. The magnitude of this effect varied with soil. The soil initially low in organic matter, K, and P, appeared to gain the most from being planted. The plant species used produced a minor effect, but resulted in significant (mineralization) differences only in higher fertility soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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