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Polyethylene mulch use is common in vegetable production, but disposal of mulch is problematic for growers and of significant environmental concern. Biodegradable fabrics and plastic films are compostable and can be incorporated into the soil at the end of the growing season, but questions remain about the durability, performance, and rate of decomposition of these products after soil incorporation. Three trials were conducted in field and high tunnel cucumber (Cucumis sativus) cropping systems to compare performance and decomposition after use among two bioplastic films and four experimental spunbond, nonwoven biofabrics. Soil temperature and moisture, mulch durability and deterioration, weed suppression, and crop yield data were collected in each growing season. All biomulches were soil incorporated after the growing season and recovered up to 11 months after incorporation to estimate relative rates of decomposition. One bioplastic film increased field soil temperature by 2 °C in 2013, but temperatures under the biofabrics were not different from bare soil. Bioplastics and biofabrics increased soil moisture relative to bare soil. Bioplastic films were less durable and deteriorated sooner than biofabrics, especially in the field environment (as early as 34 days after transplanting). All biomulches suppressed weed emergence relative to bare soil, but weeds were visibly growing beneath the most translucent biofabric. Marketable yield of cucumber was trending highest in the most durable and opaque biofabric (1827 g·m−2), but was not significantly different from weed-free bare soil (1251 g·m−2). Relative rate of mulch decomposition up to 11 months after soil incorporation was not different among bioplastic and biofabric products. Results suggest that the tested biofabrics will be most useful to growers when soil warming is not necessary (e.g., warm climates), but moisture conservation and weed control are critical (e.g., organic cropping systems). Moreover, biofabrics are permeable and may be useful to growers dependent on sprinkler irrigation or rainfall to meet crop water demands.

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Biobased and biodegradable mulches (BDM) are a potentially sustainable alternative to polyethylene plastic mulch because they can be tilled into the soil at the end of the growing season. However, their degradation rate in the soil is uncertain, limiting their on-farm adoption. The objective of this study was to determine whether organic soil management practices could be leveraged to speed degradation of two potentially BDM across two diverse agroecoregions [Lincoln (LNK) and Scottsbluff (SBF), NE, USA]. Management treatments included compost, compost extract, cover crops, all three of these practices combined and a control. The two mulch types studied were a nonwoven polylactic acid fabric with embedded wood particles (PLA), and a starch-polyester mulch film (BLK). Mulches were applied in spring 2017 for vegetable production and removed in fall after harvest. Recovered mulch was sectioned into squares 10 cm2 and buried in mesh bags for 22 months. Mulch degradation, and soil chemical, physical and biological properties were measured at four times over 2 years. Management treatments applied seasonally across 2 years led to expected changes in soil properties, yet they had no effect on mulch degradation. Instead, mulch degradation was driven by the interaction of location and mulch type. The BLK mulch had degraded by 98% at LNK after 12 months, but only by half after 22 months at SBF. Degradation of PLA after 22 months was similar between locations with 29 ± 4% mulch mass remaining at SBF and 33 ± 4% remaining at LNK. Climate and soil characteristics at each location were strong determinants of mulch degradation. Specifically, soils at LNK were finer textured, lower in pH, higher in soil water content, organic matter and nitrates, and with greater bacterial abundance compared to SBF. The strong location by mulch type interaction observed could inform the development of regionally specific predictive models of degradation.

Loss of proppant from the near wellbore region of a fracture results in fracture pinch out and a noticeable decrease in well productivity. Downhole and surface equipment can be damaged when proppant flowback occurs as well. Resin coated proppant (RCP), fibers, deformable particles, resin on the fly, etc have been used to improve proppant pack stability. Selection of the appropriate proppant flowback control technology is made with consideration of engineering factors such as fluid compatibility issues, setting time, resistance to cycling stress-loading issues, and conductivity damage. The goal of the current work was to combine the beneficial features of mechanical proppant flowback control with chemical adhesive flowback control products. With mechanical features, the proppant pack stability is enhanced by blending fibers with proppant, thus increasing particle-particle interaction, and increasing the stability of proppant arches. This mechanism can enable aggressive flowback while providing an instantaneous, albeit a modest level of proppant flowback control. With the addition of an adhesive bonding mechanism to a mechanical flowback control material, the bicomponent material substantially increases proppant pack stabilization. Using a high temperature, high pressure proppant flowback control apparatus, we show the impact of particle bonding on the dosing required to achieve a specific level of proppant pack stability. We also show the impact of the flexible nature of bonded matrix on the proppant pack stability and tolerance to cyclic loading. A mechanistic proppant pack stability model was developed based on our experimental study. We discuss this model and its application towards the selection of the appropriate proppant flowback control technology for specific well conditions. We conclude the paper by discussing field cases of effective proppant flowback prevention techniques deployed as a result of model recommendation.

Manufactured biobased mulch (biomulch) films and fabrics are useful non-chemical weed management tools, but are not typically used for high-density plantings of vegetables such as lettuce (Lactuca sativa L.) and carrot (Daucus carota L. subsp. sativus). However, it may be possible for crop roots to grow through a permeable biomulch membrane. Our objective was to demonstrate the potential for lettuce and carrot to germinate on and grow through biomulch, and assess changes in crop growth and yield. Biomulches included a 100% polylactic acid (PLA) biofabric and a PLA (37%) + soybean meal (63%) biofabric (PLA + SOY). Seeds were placed directly on biomulch and top-dressed with a soil mix or compost. Crop roots grew through the biomulch (despite visible constriction in carrot), and total yields were either the same or greater than those in the no-mulch control. PLA + SOY increased lettuce yield by 72% and also degraded faster than the PLA mulch. Results hold promise for improving weed control and reducing labor in high-density vegetable plantings.

Biodegradable and biobased mulch films and fabrics (BDMs) are potentially sustainable alternatives to polyethylene plastic mulch film (PE) in vegetable production because BDMs can be incorporated into the soil by tillage at the end of the growing season for decomposition. However, grower adoption has been limited in part by concerns about slow degradation rates and possible adverse effects on soil health and productivity. The objective of this study was to measure the effects of soil incorporated residues from two BDMs and compost on soil chemical and physical properties and vegetable crop yield across two diverse locations [Lincoln (LNK) and Scottsbluff (SBF), NE, USA] during a 2-yr study. The BDMs, including a polylactic acid biofabric with embedded wood particles (PLA; 1.14 mm thick and 298 g m−2), and a starch-polyester bioplastic mulch film (STP; 0.015 mm thick and 20 g m−2), were applied in May 2017 for vegetable production. Mulches were incorporated in soil by tillage in September 2017 in half of the experimental plots and removed in the other half as a control. Compost was applied in fall 2017 and 2018 at rates between 42 and 60 Mg ha−1 to establish high and low (no compost) fertility soil environments within each location. Sweet corn (Zea mays) was grown in 2018 and cabbage (Brassica oleraceae) in 2019, and yield data were collected. The soil was sampled at ~6 month intervals for two years. The BDM residues had little effect on soil pH, organic matter or physical properties, but the incorporation of PLA in the soil at SBF reduced soil nitrate 6 months after the incorporation of residues. Nitrogen immobilization likely contributed to the 16% ± 5% reduction in sweet corn yield observed at SBF in plots without compost where BDM residues were incorporated compared to removed. No additional yield differences were detected in sweet corn (2018) or cabbage (2019) across locations or treatments, which suggests that BDM residues are less likely to immobilize nitrogen and reduce yield in high fertility soil environments. Given the potential environmental benefits of BDMs as an alternative to PE, future research should seek to mitigate the negative effects of BDM residues on crop yield, particularly in lower fertility soils.