Vegetable production on plastic mulch in Georgia often combines fumigation, drip tape, raised beds, and plastic mulch, where three to five high-value crops are produced over 2 yr. With the elimination of methyl bromide as a soil fumigant, herbicides applied over plastic mulch before crop transplanting have become essential to maintain weed control. However, proper care must be taken to avoid crop damage from any herbicide residue. Experiments using simulated vegetable beds covered with totally impermeable film (TIF) were conducted to quantify the concentration of halosulfuron-methyl, glufosinate, glyphosate, S-metolachlor, and acetochlor remaining on the mulch and the amount of each herbicide that moved into the crop transplant hole when irrigation water was applied. With 0.63 cm of water irrigation, glufosinate > halosulfuron-methyl > S-metolachlor > acetochlor. All herbicide concentrations were below 1.0 mg ai/ae in the transplant hole regardless of irrigation volume. For halosulfuron, glyphosate, and glufosinate, these concentrations were equal to a 1.3 to 8.9 times the field use rate washing into the transplant hole. Acetochlor and S-metolachlor concentrations in the transplant hole were equivalent to 0.1x to 0.7x of field use rates, respectively. With further evaluations, the quantified herbicide concentrations in the transplant hole can be used to make changes to recommended rates and potentially create new options for growers to utilize.

Featured Application Recycling plastic film used in agriculture for crop protection is currently hindered by contamination with agrochemicals. Experimental tests conducted confirmed that film mechanical characteristics weakened with aging, even if samples treated with double spraying followed slower degradative kinetics. The Carbonyl Index was confirmed as a useful aging indicator.Abstract Plasticulture is a technique widely affirmed throughout Europe and the rest of the world that employs plastic material for protecting agricultural cultivations, e.g., soil mulching, low/middle tunnel covering, and greenhouse farming. Because of their effects on the sustainability of agricultural production, these materials present serious environmental drawbacks. Even if plastic recycling is a consolidated technical solution, several obstacles hinder the mechanical recycling of film used in plasticulture. Mostly, the degradation of its mechanical characteristics, due to aging and simultaneous contamination with agrochemicals used for fighting plant disease and ensuring crop health, plays a major hampering role. In the present paper, the results of laboratory tests on agricultural PE-LD plastic film for greenhouse covering, artificially aged for different lengths of time and treated with two different agrochemicals (fungicide and anti-aphid), are presented. The contamination with agrochemicals resulted in a considerable reduction in mechanical properties throughout the usage phase even if in samples that underwent twofold spraying, slower degradative kinetics were observed. In conclusion, based also on the measured changes in the Carbonyl Index value, it is doubtful that this plastic film would be included in a mechanical recycling process.

Plastics are extensively used in agriculture, but their weathering and degradation generates microplastics (MPs) that can be carried by runoff into water bodies where they can accumulate and impact wildlife. Due to its physicochemical properties, biochar has shown promise in mitigating contaminants in agricultural runoff. However, few studies have examined its effectiveness at removing MPs. In this study, we assessed MP pollution (>30 mu m) in runoff from a farm in the Mississippi Delta and examined the effectiveness of biochar (pinewood and sugarcane) to remove MPs from aqueous solutions. Using micro-Fourier Transform Infrared spectroscopy (mu -FTIR), we observed an average of 237 MPs/L (range 27-609) in the runoff, with most particles identified as polyethylene, polyamide, polyvinyl chloride, polyurethane, acrylonitrile butadiene styrene, and polyarylamide. Biochar columns effectively removed MPs from runoff samples with reductions ranging from 86.6% to 92.6%. MPs of different sizes, shapes, and types were stained with Nile red dye (to facilitate observation by fluorescence) and quantified their downward progress with multiple column volumes of water and wet/dry cycles. Smaller MPs penetrated the columns further, but >= 90% of MPs were retained in the similar to 20 cm columns regardless of their shape, size, and type. We attribute these results to physical entrapment, hydrophobic behaviors, and electrostatic interactions. Overall, this proof-of-concept work suggests biochar may serve as a cost-effective approach to remove MPs from runoff, and that subsequent field studies are warranted.