Allyl Isothiocyanate and Carbon Dioxide Produced during Degradation of Brassica juncea Tissue in Different Soil Conditions

Abstract

<jats:p>A study was conducted to quantify volatiles generated from Indian mustard (<jats:italic>Brassica juncea</jats:italic> L. Czerniak) tissue incorporated into soils under controlled conditions. Mustard residues were incorporated into noncovered and covered soils that varied by texture, temperature, moisture, pH, or sterility (autoclaved or nonautoclaved). Sandy loam soil had 38% more allyl isothiocyanate (AITC) than clay loam soil. AITC concentration in 45 °C soil was 81% higher than in soil at 15 °C, and 56% higher in covered compared to noncovered treatments. The microbial catabolism of AITC was suggested by the result that AITC concentration in autoclaved soils was over three times that measured in nonautoclaved soils. The highest AITC level detected (1.71 μmol·L<jats:sup>–1</jats:sup>) occurred in the autoclaved covered soil. Several factors also influenced CO<jats:sub>2</jats:sub> evolution. At 30 or 45 °C, CO<jats:sub>2</jats:sub> concentration was at least 64% higher than at 15°C. The covered soil had over twice the CO<jats:sub>2</jats:sub> found in the noncovered soil, and the nonautoclaved soil treatment yielded twice the CO<jats:sub>2</jats:sub> measured in the autoclaved soil. There were no main effect differences among soil moisture, soil pH, and soil texture treatments for CO<jats:sub>2</jats:sub> concentrations. This information could be helpful in defining ideal soil conditions for field scale experiments. Additionally, this study demonstrates a sampling technique for testing fumigation potential of biofumigation and solarization systems that may have the potential to replace methyl bromide.</jats:p>

Duration of control of two soilborne pathogens following incorporation of above‐ and below‐ground residues of Brassica juncea into soil

“…The persistence of action of B. juncea residues might be expected to be shorter still in the present experiment since the residues were incorporated into a clay soil (Price et al ., 2005). Besides the fact that the structure of clay soils (small pore space and increased tortuosity) is supposed to lead to a slow diffusion of ITC (Price et al ., 2005), reduction of bioactive ITC may be caused by ITC adsorption to soil organic carbon (Borek et al ., 1995). In addition, the incubation temperature (10‐h day at 20°C/14‐h night at 13°C) was quite warm, shown to be a factor that decreases the aliphatic ITC half‐life in soil (Borek et al ., 1995).…”

Nutritional Utilization of Modified Carinata Brassica carinata Meals in Sunshine Bass Diets

“…Heating and drying during meal processing and feed manufacturing increase the volatilization of isothiocyanates (Price et al. ) and sinapine (Zeb et al. ).…”

Biofumigation for Plant Disease Control – from the Fundamentals to the Farming System

“…2-propenyl ITC) can represent a signifi cant source of loss from soil. Rapid incorporation, soil covering techniques and surface watering can serve to reduce this loss, while higher soil temperature will increase it (Price et al, 2005). As a result of their hydrophobic nature, ITCs are rapidly sorbed to organic matter in soil and not to clay and their pest control potential has been shown to be signifi cantly reduced in soils with higher levels of organic matter (Matthiessen & Shackleton, 2005).…”

“…(Matthiessen & Shackleton, 2005). Studies comparing loss from sterile and non-sterile soils demonstrate that ITCs are also degraded by microbes (Warton et al, 2003;Rumberger & Marschner, 2003;Price et al, 2005; and persistence in sterile soil is often increased from hours to days. Enhanced biodegradation by specialized organisms selected for by repeated use of synthetic or plant-derived ITCs provides further evidence of microbial degradation (Warton et al, 2003).…”