Paper Mulch Research Articles

Visual Assessments of Biodegradable Mulch Deterioration Are Not Indicative of Changes in Mechanical Properties

The functionality of biodegradable mulch can be evaluated in agricultural field settings by visually assessing mulch intactness over time (a measure of deterioration), but it is unclear if mulch deterioration is indicative of mulch degradation as measured by mechanical properties (like breaking force and elongation). This 3-year study (2010–12) examined mulch percent visual deterioration (PVD) during the summer growing season in open-field and high tunnel production systems, and compared these to mulch mechanical properties at mulch installation (12–30 May), midseason (22 July–9 Aug.), and season end (6–25 Oct.), to determine if the field-based measures reliably predict degradation as revealed by changes in mulch mechanical properties. Four different types of biodegradable mulches [two plastic film mulches marketed as biodegradable (BioAgri and BioTelo); one fully biodegradable paper mulch (WeedGuardPlus); and, one experimental spunbonded plastic mulch designed to biodegrade (SBPLA)] were evaluated against a standard nonbiodegradable polyethylene (PE) mulch where tomato (Solanum lycopersicum L. cv. Celebrity) was planted as the model crop. Each year for the 3 years, PVD increased earlier for WeedGuardPlus than the other mulches in both the high tunnel and open field, and WeedGuardPlus had the greatest PVD in both high tunnels and the open field (6% and 48%, respectively). Mechanical strength of WeedGuardPlus also declined by the end of the season both in the high tunnel (up to 46% reduction) and in the open field (up to 81% reduction). PVD of BioAgri and BioTelo reached a maximum of 3% in the high tunnel and 28% in the open field by the end of the season. Mechanical strength of BioAgri and BioTelo did not change over the course of the season in either the open field or high tunnel, even though the ability of these mulches to elongate or stretch declined 89% in the open field and 82% in the high tunnel. SBPLA and PE mulches did not show a change in PVD or mechanical properties in either the high tunnel or the open field. Overall, PVD was three to six times greater by midseason in the open field than in the high tunnels. Although there were significant relationships between visual assessments and various mechanical properties for each mulch except SBPLA, the relationships differed for each mulch when evaluated separately and had coefficients of determination (R2) below 30%. Furthermore, PVD overestimated mechanical deterioration of BioAgri and BioTelo. Results of this study indicate that mulch visual assessments may reflect general trends in changes in certain mechanical properties of the mulch; however, visual assessment and mechanical properties provide different information on deterioration. Each should be used as needed, but not as a substitute for each other.

Above-soil and in-soil degradation of oxo- and bio-degradable mulches: a qualitative approach

Degradable materials have been suggested to overcome accumulation in the field of persistent plastic residues associated with the increasing use of polyethylene mulches. New degradable materials have been proven successful for increasing crop productivity; however, their degradation in the field has been hardly addressed. A qualitative scale was used in the present study to assess the above-soil and in-soil degradation of degradable mulches during the cropping season. Degradation was determined in three biodegradable plastic mulches (Biofilm, BF; Mater-Bi, MB; Bioflex, BFx), two paper sheet mulches (Saikraft, PSA; MimGreen, PMG) and one oxo-degradable plastic mulch (Enviroplast, EvP). Polyethylene (PE) mulch was used as control. Mulches were tested in five Spanish locations (Castilla-La Mancha, La Rioja, Navarra, Aragón and Catalunya), with three crop seasons of processing tomato. Biodegradable plastic mulches BF and MB degraded more and faster above-soil than paper mulches; among biodegradable mulches BF degraded more than MB, and MB more than BFx. The above-soil degradation of the oxo-degradable mulch EvP was highly dependent on location and crop season, and it degraded more than PE. Main environmental factors triggering above-soil degradation were radiation, rainfall and crop cover. In-soil, paper mulches and BF degraded more and faster than MB, whereas BFx and EvP barely degraded. Environmental factors triggering in-soil degradation during the crop season were rainfall and irrigation water. The effect of soil parameters (organic matter, nutrient availability) on degradation during the cropping season was not evidenced. The qualitative scale used proved convenient for determining mulch field degradation. A visual scale for supporting the qualitative evaluation is provided. In order to standardise parameters and criteria for future studies on field mulching degradation evaluation, a unified degradation qualitative scale is suggested.

水田のアゾラ農法および紙マルチ農法がクモ類の個体数に及ぼす影響

水田のアゾラ農法および紙マルチ農法がクモ類の個体数に及ぼす影響

Compost mulch no-tillage systems in organic vegetable production

With growing agricultural demands from both conventional and organic systems comes the need for sustainable practices to ensure long-term productivity. In Hungary small scale vegetable growers face challenges in producing their crops due to the lack of effective weed control practices and viable methods of sustainable soil fertility management based on local or regional soil amendment resources. There is a demand for cultural practices that reduce hand labor requirements and black plastic mulches whereas long-term productivity is held or increased. To identify effective alternative weed control and soil fertility management options for the management of intensive organic vegetable systems, our research focuses on the evaluation of compost and paper mulches, in conjunction with reduced-tillage practices. In 2015 determinate tomato (cv. Roma) is grown in five different soil treatments using yard waste compost (YWC) mulch and combination of YWC and paper mulch (PM) plus bare ground control under intensive and reduced tillage variants to evaluate their effectiveness on organic tomato marketable yield and weed suppression. Since most organic tomatoes at present are grown on small acreage in Hungary, and are direct-marketed, the application of organic mulches can be assumed financially feasible. Our results will show if the combination of organic mulching materials together with reduced tillage may be a viable option for organic vegetable growers. Keywords: alternative weed control, compost, compost mulch, paper mulch, organic, no tillage, vegetable, tomato

Effects of different paper mulches on soil temperature and yield of cucumber (Cucumis sativus L.) in the temperate zone

The effect of different paper mulches and two different biodegradable plastic mulches on the yield of field-grown cucumber (Cucumis sativus L.) was examined. The studies were conducted during two climatically different growing seasons 2011 and 2012 in Southern Finland. All the mulches increased the yield as compared to bare ground. In 2011, cucumbers on all the mulches with a dark upper surface produced higher yields than those on kraft paper alone. In 2012, when the average temperatures were lower than in 2011, there were no differences in yield between different types of mulches. Soil temperatures of the experimental plots were monitored throughout the growing seasons. The mulches with a dark-colored upper surface increased the soil temperature more than the ones with a light-colored upper surface. The soil warming effect of the mulches was greater during early season and diminished when the plants grew larger and their leaves covered most of the mulch surface. There was no need for weed control except in uncovered plots. In conclusion, during both years dark-colored paper mulch was comparable to biodegradable film in yield production and could replace it as a mulch material in cucumber production.

Mulch Effects on Floral Resources and Fruit Production of Squash, and on Pollination and Nesting by Squash Bees

Zucchini squash (Cucurbita pepo) has a high pollination demand, and the native, ground-nesting squash bee (Peponapis pruinosa) provides the majority of the crop’s pollination requirement in some environments. Squash bees nest directly in crop fields, and nests can be disturbed by tillage and other management operations. Mulches that use municipal waste materials may provide a weed control strategy for squash plantings that is more benign to squash bees than cultivation. Field and greenhouse studies were conducted in 2011 and 2012 to compare the effects of nontillage weed control methods including polyethylene black plastic, woodchips, shredded newspaper, a combination of shredded newspaper plus grass clippings (NP + grass), and bare soil (control) on soil characteristics, squash pollination and fruit production, and squash bee nesting. Woodchips, shredded newspaper, and NP + grass mulch decreased soil temperature, while soils beneath newspaper mulch retained more moisture. Unmarketable, misshapen fruit occurred more frequently in plastic than in the other mulch treatments. No measurable differences in floral resource production or crop pollination were found among treatments, suggesting that misshapen fruit resulted from high soil temperatures in black plastic plots rather than poor pollinator attraction. Squash bee nests were located within bare soil, newspaper, and NP + grass plots, indicating that these mulches did not prevent nesting. NP + grass mulch had a positive effect on plant growth and fruit production, possibly from an addition of plant-available nitrogen or the presence of preferable nesting ground. Shredded newspaper when combined with grass clippings performed as an effective mulch material that improved crop performance with no apparent negative impacts on squash bee nesting or on squash floral resources and pollination.

Degradation of Potentially Biodegradable Plastic Mulch Films at Three Diverse U.S. Locations

For widespread adoption of biodegradable plastics as agricultural mulches, dependable biodegradation across contrasting conditions is necessary. The in situ degradation of four potentially biodegradable mulches (two commercially available starch-based films, one commercially available cellulose paper mulch, and one experimental spunbond polylactic acid mulch) were evaluated by measuring percentage of area remaining (PMAR) after burial for 6, 12, 18, and 24 months in high tunnel and open field tomato production systems at three geographically distinct U.S. locations (Knoxville, TN; Lubbock, TX; Mount Vernon, WA). The PMAR of the mulches did not differ between high tunnel and open field systems at any location, and PMAR of cellulose mulch was 0% within 12 months but >90% for experimental spunbond at 24 months. The PMAR of the two starch-based products did vary by location and was lowest at Lubbock (˜2%) compared to Knoxville (49%) or Mount Vernon (89%). Relative to the other two locations, Lubbock had the greatest soil diurnal temperature range, maximum daily soil temperature, an alkaline soil pH, and a microbial community structure characterized by a relatively high abundance of fungi. Mulch type and geographic location exerted a greater influence on PMAR than did production system, and abiotic and biotic variables influenced degradation.

Feasibility of paper mulches in crop production —a review

Mulching has become an important practice in modern field production. This article reviews the published research on paper mulches and discusses the opportunity that they offer for solving the problems of the immense use of plastics in agriculture and the associated environmental threat. Paper mulches break down naturally after usage and incorporate into the soil. Laying paper mulches in large scale farming is a problem to be solved. The quality of the paper needs to be adapted or improved for mulching purposes, and its price needs to be more competitive with that of plastic mulches. The review shows that there is considerable potential for using paper mulches in agriculture and horticulture.

Effective mechanical weed control in processing tomato: Seven years of results

AbstractOpen-air crops are important in Spanish horticulture. The limited number of herbicide active ingredients in minor crops, the waste problem of polyethylene (PE) plastic mulch and the high prices of biodegradable plastics leave hand-weeding and mechanical weed control as the most viable weed control methods. Different tools have been tested in northern European countries but their performance remains unknown in the edaphoclimatic situation of southern Europe. The objective of this work was to test novel physical weed control methods on processing tomato in northeastern Spain compared with other effective control methods, i.e., plastic and paper mulches. A first sequence of field trials was established from 2005 to 2008 at Zaragoza (Spain) to select the best physical control methods out of flamer, torsion weeder, finger weeder, flex-tine harrow and brush hoe used alone or in combination. The best method was the brush hoe which was then compared from 2009 to 2011 with PE mulch, biodegradable plastic mulch and paper mulch. Flamer, flex-tine harrow, torsion weeder and finger weeder performed quite irregularly due to crusty soil conditions and needed additional tools or repeated treatments to increase weed control efficacy. The brush hoe performed best in this soil situation working at about 5 cm depth. Weed biomass reduction was higher than 80% in 6 out of 7 years and similar yield was obtained in the brushed plots compared to the yield obtained with PE, biodegradable plastic and paper mulch. The brush hoe is thus a suitable option for weed control in processing tomato while the other tools were too weak to control aggressive summer weeds in the tested conditions.

Mulch materials in processing tomato: a multivariate approach

Mulch materials of different origins have been introduced into the agricultural sector in recent years alternatively to the standard polyethylene due to its environmental impact. This study aimed to evaluate the multivariate response of mulch materials over three consecutive years in a processing tomato (Solanum lycopersicon L.) crop in Central Spain. Two biodegradable plastic mulches (BD1, BD2), one oxo-biodegradable material (OB), two types of paper (PP1, PP2), and one barley straw cover (BS) were compared using two control treatments (standard black polyethylene [PE] and manual weed control [MW]). A total of 17 variables relating to yield, fruit quality, and weed control were investigated. Several multivariate statistical techniques were applied, including principal component analysis, cluster analysis, and discriminant analysis. A group of mulch materials comprised of OB and BD2 was found to be comparable to black polyethylene regarding all the variables considered. The weed control variables were found to be an important source of discrimination. The two paper mulches tested did not share the same treatment group membership in any case: PP2 presented a multivariate response more similar to the biodegradable plastics, while PP1 was more similar to BS and MW. Based on our multivariate approach, the materials OB and BD2 can be used as an effective, more environmentally friendly alternative to polyethylene mulches.

Mobility of Olive Fruit Fly (Diptera: Tephritidae) Late Third Instars and Teneral Adults in Test Arenas

The mobility of olive fruit fly, Bactrocera oleae (Rossi), late third instars before pupation, teneral adults before flight, and mature adults restricted from flight were studied under mulches in greenhouse cage tests, in horizontal pipes, vertical bottles and pipes filled with sand, and by observation on smooth laboratory surfaces. Percentage adults emerging from pupae and percentage adult females that escaped soil, fabric, and paper mulches over a soil or sand substrate ranged from 63 to 83, and 40-53%, respectively. Percentage adults emerging from pupae and percentage adult females that walked through the open interior of 1.52-6.10-m horizontal pipes of 1.5-2.0-cm inner diameter ranged from 57 to 81, and 27-61%, respectively. Percentage adults emerging from pupae that escaped through sand depths of 2.5-10.2, and 12.7-20.3 cm, ranged from 68 to 87, and 12-88%; and percentage adult females that escaped ranged from 46 to 58, and 38-70%, respectively. In 15.4-cm-inner-diameter pipes filled with different heights of sand, the highest percentage of the total number of adults that emerged in the control were found from 0 to 20.3 cm, and ranged from 37 to 71%. Ten to 47% of adults were found from 20.3 cm to below the surface, and 6-21% escaped to the top of 20.3-50.8 cm high sand columns. In column heights of 55.9 and 61 cm, pressures at the bottom caused by the weight of the sand above were 91.4 and 99.7 g/cm(2), respectively, and a mean of <1 adult escaped to the top. Before pupation, the late third instars were found to travel continuously for 6.9 h over 23.9 m at a speed of 6.0 cm per min, when placed on a smooth surface, at 22.2°C. Teneral females and males that could not fly, made ≍7 stops totaling 11-13 min, walked at a speed of 57-62 cm per min, and began a rest period of 83-84 min duration, at 85-89 min before flight. Males walked a distance of 13.1 m in 22 min, which was greater than females that walked for 9.6 m in 17 min, at 20-22°C and 35% RH. The mobility of the third instars and the teneral adults is discussed in relation to potential control techniques in olive orchards.

Purple nutsedge (Cyperus rotundus L.) control with paper mulch in processing tomato

Purple nutsedge (Cyperus rotundus L.) is a serious weed capable of piercing polyethylene (PE) plastic mulch used in horticulture. A biodegradable plastic, PE and four different papers were tested for 2 years in fields highly-infested with C. rotundus in Zaragoza (Spain). All four papers were able to withstand all weed species. C. rotundus plants penetrated the biodegradable plastic mulch most, possibly because this material had least resistance to slow perforation. Differences in weed biomass between mulching materials were lower because of small size and weight of C. rotundus. Therefore all mulching treatments had a similar impact on weed biomass reduction 63 days after transplanting; biodegradable plastic had most biomass and papers the least, the differences being significant some years, only. Tomato yield was very similar for all mulching treatments and significantly higher than in the non-mulched plots. No effect of treatment was observed on fruit quality parameters. Commercial paper used as mulch without special additives can satisfactory control C. rotundus in processing tomato provided that climate is appropriate to maintain the paper dry during most of the time. Also the crop needs to cover the soil fast enough before the buried part of the mulch degrades allowing wind to lift and tear the mulch.

Evaluation of Best Management Practice Products in Preventing Discharge of Metals: A Laboratory Evaluation

Heavy metal accumulation in soil poses serious environmental and health risks, as metals are carried with eroded soils. In this study, 17 different soil erosion and sediment control products were investigated for their effectiveness in controlling transport of particulate heavy metals (Cu, Zn, Pb, Cd). Among the treatments investigated, wood mulch and tackifiers were found to be the most effective in reducing total suspended solids (TSS) and total heavy metal losses. They reduced TSS to an undetectable level during short-term simulation tests. Paper mulch was the only treatment that had no significant reduction in both total metal loss and TSS. Fiber rolls, silt fences, and gravel bags were effective in reducing sediment loss. Although the netting/blanket treatments were not effective in reducing total metal discharge, they significantly reduced sediment loss compared with the control.

Effect of fertilization and mulching in fallow period on nitrogen accumulation of dryland wheat

Understanding mulching influences on nitrogen (N) accumulation in soil is important for developing N management strategies for dryland wheat yield. A two year field experiment was carried out to investigate the effect of three mulching materials (film mulching, nylon mulching, and paper mulching) and different fertilizer (with or without fertilizer) on N accumulation in a winter wheat-fallow system. The results showed that the organic fertilizer application in fallow period could lead to a serial positive effect compared with the non-fertilization including increased N content of wheat at wintering stage, heading stage, and maturity stage, N accumulation at different growth stages, the ratio of N accumulation from emergency to jointing under the condition of film and nylon mulching, the ratio of N accumulation from anthesis to maturity under all mulching, pre-anthesis N translocation amount, post-anthesis N accumulation, and the contribution of post-anthesis N accumulation to N in grains under the condition of nylon mulching, paper mulching and no mulching. In addition, our results also showed that regardless of fertilization, N content of wheat at maturity, N accumulation in plant at anthesis and maturity, N accumulation and its ratio from jointing to anthesis under the film mulching treatment were all greater than those in the other treatments. Mulching increased post-anthesis N accumulation and the contribution of post-anthesis N accumulation to N in grains. In the context of organic fertilizer application, the contribution of post-anthesis N accumulation to N in grains under the treatment of nylon mulching was greater than that in the other treatments. However, without fertilizer, film mulching seemed to be better than other treatments. Therefore, organic fertilizer application and film mulching may be effective strategies for increasing N accumulation in grains, and the quality and yield of dryland wheat. Key words: Fallow period, fertilizer, mulching, winter wheat, N accumulation.

Biodegradable mulch instead of polyethylene for weed control of processing tomato production

Black polyethylene (PE) film is used for mulching in processing tomato (Lycopersicon esculentum P. Mill.) in Spain achieving a generally high weed control but causing a serious waste problem. Few herbicides are available for tomato, so that a biodegradable mulching is the desired solution which should provide high yield, high weed control and be economically available. For 3 years, the same field trial was carried out in four areas of Spain using the following mulch materials in processing tomatoes: (1) untreated control, (2) manual weeding, (3) PE, black, 15 μm thick, (4) and (5) two types of biodegradable plastic mulch, black, 15 μm, (6) oxo-degradable plastic mulch, black, 15 μm, (7) paper mulch, black, 85 g m−2, (8) kraft paper mulch, brown, 140 g m−2 and (9) barley straw, 1 kg m−2.. Weed control, yield and economic aspects were analysed. Most frequent weed species were Convolvulus arvensis, Chenopodium album and Amaranthus spp. Here, we showed that despite differences in weed species, soil type and years, weed competition caused a similar yield decrease in all locations. A common regression coefficient could be estimated indicating that weed competition was responsible for a yield decrease of 3.3 to 4.4 t ha−1 for each 10% of efficacy loss. Weed control was high for biodegradable plastics, paper mulches and PE ranging between 80% and 100% for all of them; also, yield was similar for all plastic and paper mulching treatments ranging between 72% and 108% of the yield achieved by PE. Here, we demonstrate that technically viable biodegradable alternatives exist for all four locations. From the economic point of view, PE gave highest benefits, mainly due to its low market price and to high yields despite removal costs, showing that its substitution will depend on prohibition. For locations with low-density weed infestations, manual weeding can be an alternative.

Mulch and Organic Herbicide Combinations for In-Row Orchard Weed Suppression

Trials were established at two locations to evaluate weed control provided by mulches and organic herbicides alone or in combination. Mulch treatments included barley straw, pine wood chips, paper, and no mulch (bare-ground control). Herbicide treatments included three organically certified herbicides: lemon grass oil (14% v/v), clove oil (8% v/v), and two rates of acetic acid (10 and 15% v/v). Other treatments included pelargonic acid (7% v/v), glyphosate (1.06 kg ai/ha), and no-herbicide (control). Individual herbicide treatments were applied according to weed pressure and were determined every 7 to 10 days. Herbicide applications were made two and three times in 2009 at Logan and Kaysville, respectively. Treatments were carried out for a second year at both locations with herbicide treatments applied a maximum of four times. A third trial was established in 2010 at Kaysville with four application times. Weed control evaluations were made once a month, and weed population densities were evaluated at the beginning and end of the season. Weed biomass and percent weed cover were collected at the end of the 2010 season. Mulches each provided significant weed suppression in the first year, but each mulch presented unique challenges over time. For example, paper mulch effectiveness decreased over time as cracks developed during wet-dry cycles allowing weed seedlings to emerge. Volunteer barley became problematic in straw mulch plots in the first year of each trial, and annual weed seed germination on top of the wood chip mulch became problematic in the second year. The straw mulch consistently provided among the highest weed control and the least end-of-season weed biomass. Glyphosate and pelargonic acid gave near 100% weed control among all mulch treatments, including the non-mulched plots. Lemon oil and clove oil displayed the same weed control ratings as the no-herbicide treatment in the three mulches (straw, wood chip, and paper), but displayed 41–95% weed control when applied without mulch. While organically certified herbicides generally did not provide sufficient weed control alone, some mulches and organic herbicide combinations provided weed suppression similar to conventional herbicide application.

Effects of green manure crops and mulching technology on reduction in herbicide and fertilizer use during rice cultivation in Korea

Green manure crops are primarily used in environmentally friendly agricultural practices to reduce the application of chemical fertilizer and herbicide. In this study, a two-year field experiment was conducted to evaluate the effects of paper and plastic mulching with hairy vetch alone or in combination with barley on weed control and rice yield. In addition, treatment effects on soil redox potential (Eh) and the concentration of ammonium (NH 4 + ) in rice paddy were investigated. The results showed that plastic film (10 or 20 μm) and paper mulching with hairy vetch alone had no significant effects on weed density and rice yield when compared with conventional practice (herbicide and fertilizer application) during the first year. However, during the second year, plastic film (20 μm) with partial tillage of hairy vetch alone increased rice yield and decreased weed occurence; but barley and hairy vetch mixture showed opposite trends. Plastic film mulching led to a decrease in soil redox potential, mainly due to the decomposition of soil organic matter. In addition, plastic film mulching increased NH 4 + -N contents in rice paddy soil. These results suggest that the combination of plastic film with hairy vetch and barley mixture can be used in rice fields to reduce the use of chemical fertilizer and herbicide. Keywords: Green manure, hairy vetch, mulching, rice, weed con

Growth and Yield Responses to Mulches and Cover Crops under Low Potassium Conditions in Drip-irrigated Apple Orchards on Coarse Soils

Fertigated ‘Gala’ apple trees on M.9 (Malus domestica Borkh.) rootstock, planted in 1998, were grown on a coarse soil for 6 years (1998 to 2003) and exposed to eight orchard floor vegetation management treatments within the tree row. These consisted of a glyphosate control; three waste paper mulch treatments [spray-on mulch paper mulch (SM), SM incorporated with dichlobenil, SM applied over uniformly spread shredded office paper (SOP)]; and four living cover crop mulch treatments [dwarf white clover (WC), sweet clover (SC), hairy vetch (HV), and annual rye]. There were no significant treatment effects on leaf nitrogen (N) and phosphorus (P) status; however, leaf potassium (K) levels were negatively affected by the living mulch treatments in 2 of 5 years. Tree vigor was diminished by several of the orchard floor vegetation management systems in 5 of 6 years. Trees receiving an SM treatment grew more rapidly than trees receiving the ground cover treatments and trees receiving a glyphosate treatment had relatively poor but comparable growth to several of the cover crop treatments. Growth response in trees receiving SM were observed in all production years. After 6 years, cumulative yields were highest from trees receiving any of the three SM or glyphosate treatments and significantly less for any of the ground cover treatments. Weed growth within the rye cover crop was significantly reduced in comparison with the other living mulches; however, it remained sufficiently competitive to contribute to diminished overall yield and tree growth in comparison with the SM and gylphosate control treatments. Overall, response of leaf K concentration to mulch treatments was insufficient to prevent low K levels after 5 years. The addition of K through the organic mulches or recycling of K by cover crops was insufficient to avoid the development of low leaf K levels. Annual fertigation of K, in addition to N and P, appears necessary to maintain adequate vigor and yield when using mulches or cover crops in intensive, drip-irrigated apple orchards grown on coarse soils.

벼 친환경재배에서 다양한 유기자원별 잡초방제효과

본 연구의 목적은 벼 친환경재배 농가에서 사용되고 있는 다양한 유기자원들에 대한 잡초방제 효과와 문제점을 구명하여 친환경 벼 재배지에서 잡초관리기술을 확립하기 위하여 수행하였다. 친환경 벼 재배지에서 잡초발생밀도와 종류가 서로 다른 조건하에서 다양한 유기자원을 처리한 결과 왕우렁이, 종이멀칭 및 기계제초의 잡초방제 효과는 유사하였으나 쌀겨 및 EM당밀처리에서는 잡초발생량이 많은 처리구에서 적은 처리구에 비해 잡초방제 효과가 높았다. 일반적으로 유기자원처리에 의한 잡초방제 효과는 왕우렁이(97~100%) > 종이멀칭(93~98%) > 기계제초(73~75%) > 쌀겨(15~80%) > 당밀(7~31%) 순이었다. 왕우렁이는 여뀌를 제외하고 모든 초종에 대하여 높은 방제효과를 보였고, 종이멀칭도 피와 여뀌바늘, 올방개 등이 다소 발생하나 비교적 우수한 효과를 보였으며, 기계제초는 잡초종에 관계없이 전반적으로 70%의 방제효과를 보였다. 쌀겨/기계 및 EM/기계의 체계처리에 의한 잡초방제 효과는 각각의 단독처리에 비해 차이가 없었으나 쌀겨/ 왕우렁이 및 EM/왕우렁이 체계처리에 의해 100% 방제효과를 보였다. 다양한 유기자원 처리에 의한 벼 피해율은 왕우렁이와 기계제초(10~20%) > 쌀겨(10~15) > 종이멀칭 및 EM당밀(5~7%) 순으로 높았다. 피해증상은 유기자원에 따라 다소 다르지만 생육저해, 분얼경 가해 및 결주 등이다. 왕우렁이, 쌀겨, 당밀 및 종이피복의 잡초방제 비용은 제초제에 사용에 소요된 비용보다 각각 2.1, 3.1, 2.3 및 13.2배 높게 나타났다. 따라서 다양한 유기자원 중 친환경 벼 재배지에서 왕우렁이를 이용하여 잡초를 방제하는 것이 가장 적합할 것으로 사료된다. 추후 왕우렁이 농법 사용시 발생되는 제초비용과 벼 피해를 줄일 수 있는 연구가 수행되어야 할 것이다. The objective of this research was to find out the weed management techniques in environment-friendly rice paddy fields through the study on herbicidal effects and problems of various organic materials. This experiment was conducted under different conditions of weed species and weed densities in environment-friendly rice paddy fields. There was no difference in weedy efficacy on golden apple snail (GAS), paper mulching (PM), and machine weeding (MW) between low and high weed densities. However, the effect of weed control in rice bran (RB) and effective microorganism (EM) + molasses was higher in high weed density than in low weed density. In general, the effect of weed control as affected by various organic materials was in the order of GAS (97-100%) > PM (93-98%) > RB (15-80%) > EM (7-31%). GAS provided excellent control of all weed species tested except for Persicaria hydropiper. PM gave acceptable control of the weed species except for Echinochloa crus-galli, Ludwigia prostrata, and Eleocharis kuroguwai. However, MW gave fair control (70% biomass reduction) of all weed species tested. BR followed by MW or EM followed by MW treatments had similar effect on weed control compared to each treatment alone. However, BR followed by GAS or EM followed by GAS provided 100% control of weed species tested. The level of rice foliar injury caused by various organic materials was in the order of GAS and MW (10-20%) > RB (10-15%) > PM and EM (5-7%). Typical symptoms of organic materials are wilting, inhibition of growth, missing hill, and reduction of tiller. Cost for weed control of GAS, RB, EM, and PM were 2.1, 3.1, 2.3, and 13.2 times higher than that of the herbicide. These data indicate that GAS was the best method for weed management in environmentfriendly rice paddy fields. Further study is required to elucidate the mechanisms underlying the rice injury as affected by GAS.

Effect of Biodegradable Mulch Materials on Weed Control in Processing Tomatoes

Three years of field trials have been carried out in Zaragoza, Spain, using different biodegradable mulch materials in processing tomatoes. The aim was to evaluate weed control with several biodegradable mulches as alternatives to black polyethylene (PE) mulch. The treatments were rice straw, barley straw, maize harvest residue, absinth wormwood plants, black biodegradable plastic, brown kraft paper, PE, herbicide, manual weeding, and unweeded control. Assessments focused on weeds and on crop yield. A laboratory study showed that 1 kg/m2of organic mulch was sufficient to cover the soil for rice, barley straw, and maize harvest residue. The most abundant weed species in the field were purple nutsedge, common purslane, common lambsquarters, and large crabgrass and a change in weed composition was observed between treatments and years. Most weed species were controlled by the mulching materials except that purple nutsedge was controlled only by paper mulch. The other species were well controlled by PE and biodegradable plastic and also by some of the organic mulch treatments. Best weed control and lowest weed biomass were achieved by paper followed by PE and biodegradable plastic. The best organic mulch was rice straw and the worst weed control was from absinth wormwood. Tomato yield was highest for PE followed by paper, manual weeding, biodegradable plastic, and rice straw and was clearly related to weed control. Paper, biodegradable plastic, and rice straw are potential substitutes for PE and herbicides.