1,3‐dichloropropene distribution in soil when applied by drip irrigation or injection in pineapple culture

Abstract

The fumigant nematicide, 1,3-dichloropropene (l,3-D VL; 'Telone' 11) and a soluble liquid formulation, 1,3-D SL were tested in a pineapple field experiment to evaluate the vapor movement of the two formulations in soil gas as well as the movement and persistence of 1,3-D SL in soil profiles. Prior to planting, 1,3-D VL (407 kg ha-') was hand-injected into the soil in two parallel rows per planting bed to approximate the practice of chisel injection. 1,3-D SL (407 kg ha-') was applied with 6 mm of water by drip irrigation through a drip tube in the center of the bed. Post-plant applications of 1,3-D SL (113 kg ha-') were made at three-month intervals during a two-crop cycle. 1,3-D concentrations in soil gas were lower at the plant line in the drip treatment compared with the 1,3-D VL treatment, owing to differences in application method and fumigant placement. 1,3-D in the vapor phase reached peak concentrations 24 h after injection in the 1,3-D VL treatment compared with a peak at 48 h in the drip treatment. Post-plant applications of 1,3-D SL resulted in a three-fold difference in peak 1,3-D soil gas concentrations between replicate applications, the concentration being inversely related to soil moisture at the time of sampling. Drip application of 1,3-D SL resulted in a relatively uniform distribution of 1,3-D across the bed and to a depth of 45 cm. There was no effect of formulation on downward movement of 1,3-D and persistence in soil profiles sampled two weeks and one month after application. Rainfall which occurred 9 days after pre-plant 1,3-D fumigation resulted in leaching of 1,3-D to a depth of 150 cm in soil profiles. Due to the short half-life of 1,3-D, significant penetration of 1,3-D in the soil was observed only when irrigation or rainfall occurred soon after application.

Managing Agricultural Emissions to the Atmosphere: State of the Science, Fate and Mitigation, and Identifying Research Gaps

“…In addition to reducing atmospheric emissions, new emission‐reduction strategies need to minimize fumigant movement to surface or groundwaters, where they can also affect aquatic ecosystems (Merriman et al, 1991; Obreza and Onterman, 1991; Yon et al, 1991; Schneider et al, 1995).…”

Evaluating Surface Seals in Soil Columns to Mitigate Methyl Isothiocyanate Volatilization

“…Common methods used to reduce fumigant emission loss (off-gassing) to the atmosphere include using polyethylene (PE) tarps, other improved plastic barrier films, use of clear PE films for soil solarization (Chase et al, 1998;Gamliel et al, 1997;Nelson et al, 2000), soil amendment additions, drip application (Ajwa et al, 2002;Schneider et al, 1995), and surface water sealing. The on-farm fumigant emission reduction practice most readily used is the covering of the soil with PE plastic films.…”

“…To achieve success, drip fumigation requires that the fumigant is diluted in water below its solubility or carried in conjunction with an emulsifier and dispersed throughout the rooting depth of crops by water through the dripline. In crops and soils where drip irrigation lines are utilized, drip fumigation has the potential to use lower fumigant rates than shank injection (Ajwa et al, 2002;Gan et al, 1998b), while reducing the amount of labor needed to apply the fumigant where drip lines are pre-installed (Schneider et al, 1995).…”

Water and Methyl Isothiocyanate Distribution in Soil after Drip Fumigation

“…These application methods are under scrutiny because it has been shown that typical soil injection or sprinkler application can result in excessive soil fumigant release into the atmosphere (Nelson et al, 2001; Roberts et al, 1988; Saeed et al, 2000; Sullivan et al, 2004). Application of Met‐Na through drip irrigation systems can be more economical and environmentally friendly in comparison to conventional shank injection and chemigation (Ajwa and Trout, 2004; Schneider et al, 1995; Shaw and Larson, 1999). Changes in fumigant application methods, such as deeper soil application or surface water sealing, can reduce chemical application rates and lower the amount of fumigant released to the atmosphere (Gao and Trout, 2007; Sullivan et al, 2004).…”