Effect of Organic Amendments on Degradation of Atrazine

Abstract

Pesticide contamination of soil and ground water at or near the agricultural fields is a major problem world wide. The ability of several amendments like rice straw, manure, saw dust and charcoal were used to stimulate the degradation of atrazine in soil. Field soil fortified with pesticide at two concentration levels were amended separately with rice straw, farm yard manure, saw dust and charcoal at rates of 2.5% (w/w) and maintained at field capacity moisture regime and kept at ambient temperature 25 +/- 5 degrees C. The results indicate 89.5% degradation of atrazine in farm yard manure during 60-day period followed by rice straw, saw dust charcoal and recording 87.2% and 83.8%, 67.7%, respectively, as compared to unamended treatment where 63.3% degradation was observed. The FYM was found to be most effective in soil and enhances the degradation as compared to the other amendments. Although addition of organic manures has been an integral part of sustainable agriculture practices; the present findings give a new dimension of it's utilization for removal of persistent pesticides.

Impacts of Biochar (Black Carbon) Additions on the Sorption and Efficacy of Herbicides

“…Guo et al (1991) suggested that atrazine and alachlor degradation could be inhibited by the presence of waste activated carbon, and stimulated by other uncharred amendments, such as municipal sewage sludge and manure. An increase on atrazine degradation by the addition of organic amendments to a sandy loam soil was also reported by Mukherjee (2009). Among the amendments studied, charcoal was included, although it was the amendment that had a lower decrease in atrazine degradation, as compared to rice straw, sawdust and farm yard manure.…”

“…For clomazone, a rice crops herbicide, Xu et al (2008) reported an increase in sorption with the addition of burned rice straw to the soil, with an increase of 1.5 and 3 times in the K f values when a silt loam soil was amended with the 0.1 and 0.5% (w/w) respectively. The acidic herbicide MCPA and the effect of wheat ash as soil amendment on its sorption were studied by Hiller et al (2007;2009). The authors observed that the isotherms of MCPA on wheat ash fitted to a Langmuir equation, but sorption on soil and ash amended soil did not fit to any model and calculated the K d values, with a 15 and 10 fold increase when the sandy loam and the sandy soil were amended with 1% (w/w) of wheat ash.…”

“…The successive desorption isotherms could be fitted to the Freundlich, Langmuir, and a combination of both equations. Desorption of MCPA is influenced by the presence of wheat ash in a sandy and sandy loam soil, decreasing MCPA desorption from 77 to 21% in the non amended and wheat ash amended sandy loam soil, and from 45 to 11% in the non amended and amended sandy soil (Hiller et al, 2007;2009). MCPA desorption at high concentration (57 mg L -1 ) the percentage of herbicide desorbed from the wheat ash was similar to the percentages desorbed from the amended soils, however, at the low concentration (5.7 mg L -1 ) decreased the desorption of MCPA from the amendment.…”

“…In gasification the temperature is higher, around 800 ºC and the residence time is longer, more than 5 minutes (Bridgwater, 2006). Although the process with lower temperature yields the higher amount of char, temperatures lower than 400 ºC produces biochar with low pH, CEC, and small surface area, which make it not suitable for improving soil quality (Lehmann, 2007), or increasing pesticide sorption on soil, decreasing its dissipation and availability (Yu et al, 2006;2009;Wang et al, 2010;Yang et al, 2010). According to Sohi et al (2010) feedstock is an important factor to determine the function of biochar in soil, but there is no consensus about the optimal feedstock in terms of soil use and energy production.…”

Biostimulation for the Enhanced Degradation of Herbicides in Soil

“…Farm yard manure was found to be the most effective for the degradation of herbicide (89.5% degradation in 60 days) [50] Additional evidence for the successful biostimulation of herbicide degradation was reported by Lipthay et al [51]. The authors showed that the mineralization rate of a greater herbicide concentration was significantly stimulated by the addition of nutrients.…”