Polyethylene Plastic Mulch Research Articles

A comprehensive life-cycle assessment of plastic mulching for maize

While plastic mulch (PM) can increase crop yield, there are negative environmental impacts associated with the production, use and disposal of PM films. There is currently a gap in the literature on the negative impacts of PM throughout its entire life cycle, with most studies focusing on the global warming potential (GWP) only. The objective of this study is to conduct a life-cycle assessment (LCA) of PM to investigate the environmental impacts of all stages of mulching. The LCA was conducted using the SimaPro with data obtained from the relevant literature and ecoinvent database. The system boundaries include the production, transportation, installation, operation, removal and disposal of PM. The results reveal that the field operation of PM has the highest impact in GWP. A sensitivity analysis was also conducted and the GWP impact was observed to be sensitive to changes in carbon dioxide and net ecosystem carbon dioxide budget. The production of PM has the highest impact in abiotic depletion, but this impact can be reduced through energy recovery. Incineration yields the least harmful impacts, but the results of the study may vary depending on the exact disposal method. The impact of PM can be mitigated through proper waste management and mitigation measures, including regulations on disposal.

Biobased Sprayable Mulch Films Suppressed Annual Weeds in Vegetable Crops

Biobased sprayable mulch (BSM) films are a potential alternative to herbicides, polyethylene plastic mulch film, and hand weeding for specialty crops. We developed a series of BSM films using locally available biomaterials [including corn (Zea mays) starch, glycerol, keratin hydrolysate, corn gluten meal, corn zein, eggshells, and isolated soy (Glycine max) protein] and tested their effects on weeds and crop yield during a total of seven greenhouse or field trials between 2017 and 2019 in Nebraska, USA. Application rates of BSM films applied in pots (greenhouse), planting holes in plastic film (field), or bed tops (field) ranged from 0.9 to 18.2 L⋅m−2; they were applied before and after the emergence of weeds. Weed control efficacy was variable, and results of greenhouse pots were rarely replicated under field conditions. Increasing the viscosity of the final suspension tested [BSM7; a mix of corn starch (72.8 g⋅L−1), glycerol (184.7 mL⋅L−1), keratin hydrolysate (733.3 mL⋅L−1), corn zein (19.8 g⋅L−1), and isolated soy protein (19.8 g⋅L−1)] reduced weed biomass by more than 96% in field-grown kale (Brassica oleracea var. sabellica) when applied to bare soil bed tops before or after weed emergence, but kale yield in treated plots was not different from the weedy control. The results demonstrated the potential for postemergence applications of BSM films, which increase application timing flexibility for growers. Further research is needed to explore the effects of BSM films on soil properties and crop physiology and yield.

Biodegradable and biobased mulch residues had limited impacts on soil properties but reduced yield of the following crop in a low fertility soil

AbstractBiodegradable 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.

End-of-Life Management Options for Agricultural Mulch Films in the United States—A Review

Polyethylene plastic mulches are widely used in specialty cropping systems in the United States due to the horticultural benefits they provide. However, polyethylene mulch is reapplied seasonally, generating large volumes of plastic waste that contribute to plastic pollution concerns. This review synthesizes scientific and industry findings to provide a state of current end-of-life options of polyethylene mulch in the United States and identifies opportunities that can improve plastic waste management with a special emphasis on soil-biodegradable plastic mulches. Major points discussed are: (1) polyethylene mulch use in specialty cropping systems, (2) economic, environmental and waste management impacts of polyethylene mulch use, (3) current common end-of-life pathways of used polyethylene mulch, (4) use of soil-biodegradable plastic mulch as an alternative to reduce the amount of plastic waste in the environment and offset the negative impacts associated with residual non-degradable plastics, (5) socioeconomic factors that reduce the adoption of soil-biodegradable plastic mulch, and (6) limitations of soil-biodegradable mulch. The results of this review conclude that recycling and upcycling of used polyethylene mulch can be a more sustainable disposal option, however cleaning and decontaminating used polyethylene mulch is costly and commercial technology is often not accessible nor economically viable in many regions in the current economic and political situation. To make recycling a viable pathway in the future, research and policy developments are necessary to refine and encourage recycling. Soil-biodegradable plastic mulches can offer an additional opportunity to help address these limitations, but they are not permitted in organic agriculture in the United States. Further studies are necessary to address the current knowledge gaps and gain a better understanding of the factors influencing the degradation of soil-biodegradable mulches under diverse field conditions. Improved end-of-life strategies should continue to be pursued that balance sustainable use of plastic mulch while minimizing environmental risks.

Evaluation of the use of polyethylene mulches in the production of organic flue‐cured tobacco

AbstractWeed and insect pest management in organic flue‐cured tobacco (Nicotiana tabacum L.) is challenging due to lack of effective and affordable approved control options. Polyethylene plastic mulches are used in vegetable and berry production to manage in‐row weed populations, buffer soil temperatures, limit rain‐induced soil loss, and maintain soil moisture. Mulch color can affect plant growth, soil temperature, and insect pest populations in vegetable crops. Field trials were conducted in Kinston, NC, in 2019 and 2020 and Whiteville, NC, in 2020. Red, white, black, and silver polyethylene mulch (with drip irrigation) and bare ground with and without drip irrigation were compared to evaluate effects on tobacco yield, quality, and pests. Tobacco yields were elevated by at least 290% in mulch treatments compared with bare ground with irrigation in 2020 (p < .05), but did not differ in 2019 due to precipitation and temperature differences that conveyed an increased benefit in 2020. Opaque mulches successfully suppressed weed emergence. Fewer aphids were present in highly reflective silver mulch than all other treatments with irrigation in both years. Black and red mulch warmed soils while silver cooled them, affecting nitrogen mineralization rates. Higher levels of plant available nitrogen were maintained in mulch treatments, but tobacco nitrate levels and overall quality were not affected. These results are consistent with plasticulture research in other crops. The factors that make plasticulture well suited to intensively managed, high value crop production may benefit organic flue‐cured tobacco production especially when grown in rotation with other intensively managed crops.

Comparing Overhead versus Drip Irrigation for Production of Three Cultivars of Romaine Lettuce on Biodegradable Plastic Mulch

Growers seeking alternatives to traditional polyethylene plastic mulch may use biodegradable plastic mulches (BDMs). However, plasticulture systems typically also use plastic drip tape underneath the mulch, which must be removed from the field and disposed of at the end of the season, making tilling the BDM into the soil more difficult and expensive. A potential solution to this dilemma may be to use other irrigation methods, such as overhead sprinklers, that could be more easily removed from the field and reused from year to year. At Knoxville, TN, in 2019 and 2020, we grew three cultivars of romaine lettuce (Lactuca sativa) on BDM with two irrigation systems (overhead sprinklers above the mulch and drip irrigation tape under the mulch) to compare water use, disease, and yield in these two irrigation systems. Water use was higher in overhead vs. drip irrigation in both years; however, the difference in water use was much smaller in 2019 due to higher rainfall amounts during the time period the lettuce was growing in the field (March to May). Disease incidence and severity were very low both years for both irrigation systems. There were no differences in marketable yield (number of heads) between irrigation treatment in 2019. In 2020, marketable yield by number was greater in the drip vs. overhead irrigation treatment. Unmarketable yield in 2019 was due to heads that were too small; in 2020, unmarketability was predominantly due to tipburn in overhead irrigated ‘Jericho’. Overall, marketable lettuce yield did not differ between irrigation treatments in 2019 and was similar for ‘Parris Island Cos’ in 2020. Although quantitative weed counts were not made, observations of weed pressure between rows showed that weed pressure was higher in overhead irrigated compared with drip irrigated subplots. This highlights the need to have a between-row weed management program in place. The results of this study suggest that with attention to cultivar and weed management, overhead irrigation could be a viable alternative to drip irrigation for lettuce production on BDM, especially for early spring lettuce when rainfall is historically more plentiful.

Effect of polyethylene plastic mulch on yield and fruit quality parameters of tomato

The greenhouse experiment was conducted to evaluate the effect of black polyethylene (PE) plastic mulch on yield and some quality parameters of tomato. In the study, black PE mulch material was laid on raised beds and bare soil (not mulched) was used as control. Mulch did not affect plant height, fruit shape index, chroma and hue angle, firmness, soluble solids content, titratable acidity. Black PE plastic mulch had a positive influence on yield. Significantly higher stem diameter and yield were obtained from the black PE mulch application (17.23 mm and 18.78 kg da-1, respectively) compared to the control (15.30 mm and 16.75 kg da-1, respectively). On the other hand, vitamin C was higher in control (41.13 mg 100 g-1) than in the black PE mulch application

A new method for detecting micro-fragments of biodegradable mulch films containing poly(butylene adipate-co-terephthalate) (PBAT) in soil.

Biodegradable mulch (BDM) is a potentially sustainable alternative to polyethylene plastic mulch film for intensive crop production. Certified BDMs must demonstrate>90% biodegradation in compost and agricultural soil, but the environmental fate of BDM micro-fragments is usually not measured. While using fatty acid methyl ester (FAME) analysis to study changes in soil microbial communities under different BDMs and management conditions, two peaks were detected by gas chromatography that were derived from a BDM containing poly(butylene adipate-co-terephthalate) (PBAT). The largest peak was identified as 1,4-benzenedicarboxylic acid, dimethyl ester, or dimethyl terephthalate (DMT). The smaller peak was hexanedioic acid dimethyl ester or dimethyl adipate. From this observation we hypothesized that the FAME method could be used to detect and quantify micro-fragments (<5mm in length) of PBAT-containing BDM in soil. To test this, fragments of two commercially available BDMs were added to soil and extracted for FAME analyses. Linear relationships were observed between DMT and mulch mass added to soil for both BDMs when the initial mass of fragments was<3.5mg (r2 >.99). Based on our findings, the FAME method could be redeployed to study the environmental fate and possible accumulation of BDM micro-fragments in soil over time.

Effects of compost, cover crops, and local conditions on degradation of two agricultural mulches in soil

AbstractBiobased 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 cm2and 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.

Assessing Biodegradable Mulch Duration and Nutsedge Suppression during Late Summer Cucumber Production in Mississippi and Louisiana

Environmental concerns as well as labor costs associated with the use of polyethylene plastic mulch have turned producers’ focus to alternative mulch treatments. A preliminary study was conducted to evaluate nutsedge control, mulch degradation, and cucumber yields on biodegradable mulches at two locations (Louisiana and Mississippi). Mulch treatments included two paper-based mulch products, two biodegradable plastic mulches, the industry standard non-biodegradable black plastic mulch, and an unmulched control. The heavy weight paper-based mulch and light weight paper mulches in the Louisiana location were reduced to 50% or less coverage at the end of the study. Similarly, the paper-based mulches both degraded below 40% at the conclusion of the study at the Mississippi location. The heavy weight paper mulch was able to hold back nutsedge (p ≤ 0.05) at similar rates as the two biodegradable plastic mulches and industry standard plastic mulch, while the light weight paper mulch and unmulched plots were ineffective at reducing emerged sedges. There were no statistical differences in nutsedge control (averaging &lt; 14 emerged plants per 1.5 m subplots) between all mulch materials at the conclusion of the study in the Mississippi location. Combining both states yield data, the heavyweight mulch (8.7 fruit, 5.3 lb) performed comparably to the industry standard plastic mulch (5.8 fruit, 3.5 lb) in terms of both average fruit number and average weights harvested off 9.1 m rows at each harvest date.

Agronomic performance of polyethylene and biodegradable plastic film mulches in a maize cropping system in a humid continental climate

Plastic polyethylene mulch has been widely used in crop production, but also causes environmental pollution if plastic residues accumulate in soil. Biodegradable plastic mulches (BDM) are a potential solution to problems caused by polyethylene mulches, as BDMs are designed be tilled into the soil after the growing season and then biodegrade. However, the agronomic performance of BDMs still needs to be tested for comparison to polyethylene mulch. We carried out a two-year field experiment in 2018 and 2019 in a typical humid continental climate in Northeast China. Maize was planted in a ridge-furrow pattern, with mulching treatments consisting of no mulch (control), clear BDM, black BDM, clear polyethylene, and black polyethylene. Clear mulches increased soil temperature when compared to no mulch control treatments, while black mulches decreased or did not change soil temperature during the early growing season. Soil temperature and root morphology were similar between BDM and polyethylene mulches for a given type of plastic color. Maize yield did not differ across all the treatments. Maize protein, fat, N and P contents were generally higher for black BDM than other treatments, suggesting that maize quality benefited especially from black BDM. Overall, these results show that, in a humid continental climate, the agronomic performance of clear and black BDMs was equivalent to, or better than, that of polyethylene plastic mulches for maize production.

The Effects of Biodegradable Mulch Film on the Growth, Yield, and Water Use Efficiency of Cotton and Maize in an Arid Region

Plastic residual film pollution in China is severe, and the use of degradable mulch film instead of plastic mulch can effectively alleviate this situation. The substitution of common polyethylene plastic mulch film with biodegradable mulch film in the agricultural production of cotton and maize in an arid region was investigated in the present study. Using bare soil as the control, we compared the effects of common polyethylene plastic film and biodegradable mulch film on crop growth, yield, and water use efficiency (WUE) in maize and cotton. The results indicated that: (1) the biodegradable mulch film in this region remained intact for 60 days after being laid down, significantly degrading after 120 days, and was associated with increased soil temperature, moisture conservation, and degradability in comparison to a bare soil control; (2) Both the biodegradable mulch film and the polyethylene plastic film significantly increased various physiological parameters, such as crop height, stalk diameter, and leaf area; (3) The biodegradable mulch film had a significant effect on crop yield by 69.4–76.2% and 65.2–71.9%, respectively, compared to the bare soil control. (4) Compared to the bare soil control, the biodegradable mulch film effectively increased WUE in the crops by 64.5–73.1%. In summary, biodegradable mulch film had comparable results to the common polyethylene plastic film in increasing crop growth, yield, and WUE. As the biodegradable mulch film causes no residual pollution, it is thus preferable to common plastic mulch film for agricultural applications in arid regions and supports the sustainable development of agroecosystems. Therefore, the use of degradable mulch films in agricultural production is more environmentally friendly and more conducive to the sustainable development of agricultural systems.

Rationalization of Water Consumption for Taro Plant through the Rationing of Irrigation and Expand the Plant Ability to Resist Stress Conditions

A field experiments were conducted at Horticulture Research Station, El-Kanater El-Khiria, Horticulture Research Institute, Agriculture Research Centre, Egypt during 2016 and 2017 seasons to investigate the effect of different irrigation water levels i.e.,100, 75 and 50% of the crop evapotranspiration (ETc) and foliar application with some stimulant substances i.e., proline at 150 mgl-1, potassium silicate at 2500 mgl-1 and putrescine at 10 mgl-1 as well as mulching treatments i.e., black polyethylene plastic, rice straw and sawdust mulches individually or in combination of treatments on vegetative growth characteristics, some bioconstituents, total yield and its components of taro plant under drip irrigation system and results interpreted. The results showed that that increasing water stress level from 75% to 50% of Etc decreased gradually all studied growth characteristics of taro plant (plant height, leaves number plant-1, lamina dry weight plant-1 and leaf area (cm2) plant-1 in the two seasons. In addition, increasing irrigation water stress resulted in decreasing of photosynthetic pigments (chlorophyll a, b and carotenoids) content in taro leaves. Moreover, the increase in water shortage is regularly increased the proline content and antioxidant enzymes activity i.e., superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in taro leaves compared to the full irrigation level (100% of ETc). Furthermore, different estimated yield characteristics of taro plant i.e., main corm length (cm), main corm diameter (cm), corms number plant-1, corms fresh weight (kg) plant-1, main corm fresh weight (g), corms fresh weight (kg) plot-1, corms fresh yield (ton) fed.-1 and corm dry matter % as well as taro corm bioconstituents of N, P, K, crude protein and starch contents decreased by reducing irrigation water levels. In this respect, water stress level at 50% of ETc recorded the highest reductions in different estimated characteristics compared to 75% of ETc level and unstressed plant (100% of ETc).&#x0D; Regarding, the effect of foliar application with stimulant substances and mulching treatments, proline at 150 mgl-1 followed by potassium silicate at 2500 mgl-1 and putrescine at 10 mgl-1 as well as black polyethylene plastic mulch were the most effective treatments, respectively.&#x0D; As for the effect of interaction, the results showed that all the interactions between irrigation water levels and foliar spray with the stimulant materials as well as mulching treatments increased different estimated traits of taro plant i.e., vegetative growth characteristics, bioconstituents, yield and its components as well as water use efficiency compared to the control. In this respect, foliar spray with proline at 150 mgl-1 was the most superior treatment followed by putrescine at 10 mgl-1 and potassium silicate at 2500 mgl-1 under water stress levels i.e., 75 and 50% of ETc when compared with the untreated plants during 2016 and 2017 seasons.&#x0D; In general, it could be noticed that the applied stimulant substances i.e., proline, putrescine, potassium silicate and black plastic mulch treatments could partially reduce the harmful effects of drought stress on growth, bioconstituents, corms yield and its quality of taro plant.

Abrasive Grit Application in Organic Red Pepper: An Opportunity for Integrating Nitrogen and Weed Management

Weeds are a top management concern among organic vegetable growers. Abrasive weeding is a nonchemical tactic using air-propelled abrasive grit to destroy weed seedlings within crop rows. Many grit types are effective, but if organic fertilizers are used, this could integrate weed and nutrient management in a single field pass. Our objective was to quantify the effects of abrasive grit and mulch type on weed suppression, disease severity, soil nitrogen availability, and yield of pepper (Capsicum annuum L. ‘Carmen’). A 2-year experiment was conducted in organic red sweet pepper at Urbana, IL, with four replicates of five abrasive grit treatments (walnut shell grits, soybean meal fertilizer, composted turkey litter fertilizer, a weedy control, and a weed-free control) and four mulch treatments (straw mulch, bioplastic film, polyethylene plastic film, and a bare soil control). Abrasive weeding, regardless of grit type, paired with bioplastic or polyethylene plastic mulch reduced in-row weed density (67 and 87%, respectively) and biomass (81 and 84%); however there was no significant benefit when paired with straw mulch or bare ground. Despite the addition of 6 to 34 kg N/ha/yr through the application of soybean meal and composted turkey litter grits, simulated plant N uptake was most influenced by mulch composition (e.g., plastic vs. straw) and weed abundance. Nitrogen immobilization in straw mulch plots reduced leaf greenness, plant height, and yield. Bacterial spot (Xanthomonas campestris pv. Vesicatoria) was confirmed on peppers in both years, but abrasive weeding did not increase severity of the disease. Pepper yield was always greatest in the weed-free control and lowest in straw mulch and bare soil, but the combination of abrasive weeding (regardless of grit type) and bioplastic or polyethylene plastic mulch increased marketable yield by 47% and 21%, respectively, compared with the weedy control. Overall, results demonstrate that when abrasive weeding is paired with bioplastic or polyethylene mulch, growers can concurrently suppress weeds and increase crop N uptake for greater yields.

2018 AFHVS presidential address

In this address I discuss agricultural plastic use and plastic pollution mitigation strategies. I focus on agricultural plastic mulches, which offer many benefits to farmers, such as weed control, better moisture retention, and increased yield. The removal and disposal of widely used polyethylene (PE) plastic mulch, however, have detrimental environmental and health impacts. Are biodegradable plastic mulches a promising alternative? Biodegradable plastic mulches ideally offer the same benefits as PE plastic mulch, but biodegrade in soil or composting environments. I describe social science research findings from a large USDA-funded project focused on the performance and adoptability of biodegradable plastic mulches for U.S. specialty crop production. I also provide agrifood scholars with ideas for future research on plastics.

Deterioration pattern of six biodegradable, potentially low-environmental impact mulches in field conditions

Polyethylene plastic mulches are widely used in agriculture due to the countless advantages they have. However, the environmental problems associated with their use have led us to look for alternative mulch materials which degrade naturally and quickly, impact the environment less and function satisfactorily. To this end, biodegradable plastics and paper mulches are being used, but aspects related to their degradation should be studied more in-depth. This work provides the deterioration pattern of six biodegradable mulch materials (i.e. vegetable starch, polylactic acid plastic films or paper mulches) in horticultural crop in the edaphoclimatic conditions of Central Spain in two situations: over the lifetime of the mulches and after being incorporated into the soil. In the first situation, the deterioration levels were evaluated by recording the puncture resistance, weight and area covered in the above-soil and the in-soil part, and after soil incorporation by the number of fragments, their surfaces and weight. In the above-soil part, biodegradable plastics experienced further deterioration, particularly with no crop, while the paper mulch remained practically intact. However, the in-soil paper experienced complete and rapid degradation. At 200 days after soil incorporation, mulch residues were scarce, with the environmental effects it entails. These findings offer practical implications regarding the type of crop. The measurement of the surface covered, rather than the weight, was shown to be a more reliable indicator of the degradation of mulches. Furthermore, visual estimation was found to underestimate the functionality of mulches in comparison to that of the measurement of the surface covered.

EFFECT OF POLYETHYLENE BLACK PLASTIC MULCH ON GROWTH AND YIELD OF TWO SUMMER VEGETABLE CROPS UNDER RAIN-FED CONDITIONS UNDER SEMI-ARID REGION CONDITIONS

Water use efficiency in agriculture can be enhanced by several strategies mainly by reducing evaporati on from the soil surface. The mulching techniques were bein g used widely in irrigated crop production worldwid e. The mulching techniques can be also implemented in summer vegetables production under rain-fed conditions. The current study aimed at evaluating the effect of pol yethylene black plastic mulch on growth and yield o f okra, Abelmoschus esculentus and summer squash, Cucurbita pepo L. under rain-fed conditions of Jordan. Two field experiments were conducted during summer growing season at Al-Rabbah Agricultural Research Station, Mu’tah University, Jordan. Soil cover treatments we re polyethylene black plastic mulch and no mulch (b are soil). The results indicated that the mulched plots had higher soil moisture content than bare soil pl ots, which has positively reflected on vegetative and yield pa rameters. Using polyethylene plastic mulch had pronounced positive effect on yield of okra and squash as comp ared to bare soil. Early, middle, late and total yi eld of both vegetable crops were significantly increased in plo ts covered with plastic mulch. In addition, fruit n umber and weight had also an increasing trend as fruit yield. Plots covered with black plastic mulch were produc ed higher fresh and dry weights of both vegetable crops. It b an be concluded that using black plastic mulch as a soil cover increased okra and squash vegetative growth a nd yield under rain-fed conditions.

Barriers and bridges to the adoption of biodegradable plastic mulches for US specialty crop production

AbstractCommercial farmers have been using polyethylene plastic mulch since the 1950s. Despite the affordability and effectiveness of polyethylene mulch, the disposal process is financially and environmentally costly. Biodegradable plastic mulches, an ecologically sustainable alternative to polyethylene mulch films, were introduced in the 1980s. Biodegradable plastic mulches can be tilled into the soil or composted at the end of the season, reducing the labor and environmental costs associated with plastic removal and disposal. However, research results are mixed as to the effectiveness, degradability and ease-of-use of biodegradable plastic mulches. In 2008–2012, researchers, funded by a USDA Specialty Crop Research Initiative grant, conducted surveys and focus groups in three different agricultural regions of the USA to better understand the barriers and bridges to the adoption of biodegradable plastic mulches for specialty crop production systems. Data on the experiences and views of specialty crop growers, agricultural extension agents, agricultural input suppliers, mulch manufacturers and other stakeholders showed that the major adoption barriers were insufficient knowledge, high cost and unpredictable breakdown. The major bridges to adoption were reduced waste, environmental benefits and interest in further learning. These findings are discussed with reference to the classic innovation diffusion model, specifically work on the innovation–decision process and the attributes of innovations. The study results can be used to guide the activities of those involved in the design, development and promotion of biodegradable plastic mulches for US specialty crop production systems.

Effects of mulching materials on the growth, development and yield of white yam

Two similar experiments are described in which the effects of different mulching material and staking on the growth, development and yield of white yam ( Dioscorea rotundata ) Minisetts were studied. One white yam cultivar TDR 131 was used and the treatments were: black and white embossed polyethylene plastic (Visqeen 38 mu) with either black or white surface up; light weight black polyethylene plastic, rise straw; staking but no mulch, and no staking and no mulch. Each experiment was laid out in a randomized complete block design with four replications. Polyethylene plastic mulch with white surface up was superior to all other treatments. Total dry matter per plant and total fresh tuber yield were all consistently higher in plants grown under the white surface polyethylene plastic mulch. in 1985, mean tuber size was more than 34% larger than in the traditional staking system and nearly double the value obtained with no staking no mulch treatment. In 1986, mean tuber size was again larger with white surface plastic mulch but not significantly different from those of the staking and rice straw treatments. Plants in all treatments attained peak leaf area index (LAI) about 100 days after planting and those in the white surface plastic mulch maintained a higher LAI for most of the growing season. White surface polyethylene plastic mulch gave the larger Leaf Area Index and Greater Leaf Area Duration which ensure a high bulking rate over a comparatively longer period. It is suggested that under tropical conditions, farmers would obtain better seed yam yields through the use of white surface polyethylene plastic mulch.

Effect of Soil Temperature on K and Ca Concentrations and on ATPase and Pyruvate Kinase Activity in Potato Roots

Potato (Solanum tuberosum L.) `Spunta' plants were grown with the root zone covered by different types of polyethylene plastic mulches. The plastic mulches used were transparent, white, co-extruded black and white, and black. As a control, plants were grown without plastic mulch. The parameters analyzed were soil temperature, root concentration of K and Ca, and enzymatic activities of ATPase and pyruvate kinase (PK), measured as basal and in the presence of K+ and Ca2+. The physical characteristics of the plastic mulches directly influenced soil and root temperatures in potato plants. In addition, the concentration of cations in the roots (particularly Ca2+) and basal ATPase activity were affected by soil temperature, whereas basal PK was not affected by soil temperature. The use of co-extruded black and white plastic mulch improved the nutritional status of Ca in the roots of potato plants. Finally, the basal ATPase and PK activities in the presence of K+ and Ca2+ were related with the root levels of these cations.