Transparent Plastic Mulch Research Articles

Heat accumulation and soil properties as affected by transparent plastic mulch in Blackgram (Vigna mungo) doubled cropped with Groundnut (Arachis hypogaea) in sequence under rainfed conditions in Tamil Nadu, India

Though plastic film mulch technology has been used widely to increase crop productivity in dryland farming, the economical as well as environmental costs associated with plastic mulches is the major factor limiting the wider adoption of this technology. With the objective of reducing the cost of plastic films by growing more than one crop prior to its disposal, experiments were conducted over 3 years (2012–15) during South West monsoon (SWM) and North East monsoon season (NEM) with four treatments, T1- Transparent plastic mulch maintained for two crops (TPM I), T2- Transparent plastic mulch laid new for each crop(TPM II), T3- Non mulched beds maintained for two crops (NM I) and T4 – Non mulched new beds for each crop (NM II). The crops sown were Blackgram (Vigna mungo) in the first season (SWM) and Groundnut (Arachis hypogaea) in the second season (NEM). Results indicated that soil temperatures appeared highest under transparent mulch in different phenophases of both blackgram and groundnut from sowing to harvest. The mulch film was physically sound even upto the harvest of the second crop (Groundnut) in each year of the study. The light transmission through the transparent mulch maintained for two seasons (TPM I) was also not relatively reduced which has been evidently seen in the soil temperature observed. Both air Degree −Days (DD) and soil Degree –Days (DD) varied between mulched and non- mulched treatments at all the phenophases of observation. The physical properties such as rate of water loss/day, hydraulic conductivity, soil bulk density and percentage of pore space of the soil were also influenced by transparent plastic mulch. Transparent mulch, either newly laid or maintained for two seasons, had an impact on yields of both blackgram and groundnut. As a result the net return was highest with the transparent plastic mulch maintained for both the crops. These results suggest that double-cropping of transparent plastic mulches can be done without loss of crop yield and provide significant savings in cost of land preparation, materials and laying cost, labour and disposal costs.

The Responses of Mulch Closure on the Germination of Mindi (Melia azedarach Linn.)

One of the factors that determine the successful of the development of mindi is the availability of seedling. The seedlings can be propagated generatively by using seeds, however there is a problem related to the hardness of the testa that make it difficult to germinate, so it needs environment condition treatments to get optimal germination, one of this is mulching. The use mulch possibly get the improvement of temperature, humidity, infiltration and evapotranspiration. The study is aimed to determine the effect of mulch and to find out the best mulch type on the germination of mindi (Melia azedarach Linn.) seed. Randomized completely design was employed that arranged factorially, consisted of (A) mulch types factor and mulch thicknesses factor (B). There were 5 (five) types of mulch treatment i.e rice straws, transparent plastics, dark plastics, zeolite and without mulch. The thicknesses of mulch consisted of one layer and two layers of mulch. Germination capacity, germination speed and growth simultaneously were observed. The results showed, mulching effect on germination mindi the best type of mulch is black or transparent plastic mulch while the thickness of the mulch does not affect the germination. Mindi seed capable of germination in the dark and light conditions on the conditions of temperature and humidity high temperatures.

Yield-phenology relations and water use efficiency of maize (Zea mays L.) in ridge-furrow mulching system in semiarid east African Plateau

Yield-phenology relation is a critical issue affecting rainfed maize field productivity in semiarid east African Plateau (EAP). We first introduced Chinese ridge-furrow mulching (RFM) system to EAP, using three maize cultivars with early-, mid- and late-maturing traits as test materials. A two-year field experiment was conducted in a semiarid farm of Kenya from 2012 to 2013. Three treatments were designed: alternative ridge and furrow with transparent plastic mulching (FT), with black plastic mulching (FB) and without mulching (CK). We found that FT and FB significantly increased soil moisture and accelerated crop maturity across two growing seasons. Leaf area and shoot biomass were increased by 30.2% and 67.5% in FT, 35.2% and 73.5% in FB, respectively, compared with CK. Grain yield, water use efficiency and economic output were increased by 55.6%, 57.5% and 26.7% in FT, and 50.8%, 53.3% and 19.8% in FB, respectively. Optimal yield and economic benefit were observed in late-maturing cultivar due to increased topsoil temperature in FT in 2012 (cool), and in early-maturing cultivar owing to cooling effect in FB in 2013 (warm). Our study suggested RFM system, combined with crop phenology selection, be a promising strategy to boost maize productivity and profitability in semiarid EAP.

Transparent, Black and Organic Mulches Effect on Weed Suppression in Green Pepper (Capsicum annuum) in Western Kenya

Weed suppression through physical methods in cultivation constitutes of many methods but this experiment focused on application of various mulches. Recently, herbicide-free weed control methods in the world are getting more attention due to environmental and ecological factors. Green pepper production requires good management practices in order to attain potential yields. Most of the known physical practices of weed control cause both positive and negative effects. Therefore, great attention should be paid when selecting the appropriate mulch with the aim of weed suppression in any specific cultivation. Three types of mulches were examined for weed control namely; black plastic mulch, transparent plastic mulch, straw mulch and bare soil as control during the 2015 short and long raining seasons in Busia County. In both seasons, the black plastic mulch treatment significantly (P<0.05) showed the lowest number of weed species (3) per m2 quadrat while the control had the highest with a maximum of 8 and 7 during the long and short raining seasons respectively. The number of species reduced after four weeks from transplanting when the first sampling was carried out. The lowest weed vigor was exhibited in the plastic treatments for both seasons at 4, 6 and 8 weeks after transplanting. Control had the highest weed fresh biomass for both seasons at all the sampling stages with the highest observed during the short raining season with 1626 g/m2 at 4 weeks after transplanting. This also translated to the highest weed dry biomass for both seasons in the control plots with the lowest recorded in the black plastic mulch. Out of several physical methods of weed control, mulching seems to be the most appropriate with the black plastic mulch being the best.

Mulch effect on successive crop yields and soil carbon in Tonga

AbstractIntensification of crop production in Tonga has resulted in a move to mechanical soil preparation, often with a rotary hoe, and a consequent loss in both chemical physical fertility. An experiment was conducted on a clay loam soil (Typic Argiudoll) on the Forestry Vaini Research Station, Tongatapu Island, Tonga, to investigate the effect of a once‐off application of mulch on yield and quality of watermelon, maize and capsicum grown in rotation over a 1‐yr period. The treatments applied were a nonmulched control, transparent plastic and 200‐mm‐thick applications of locally available coconut sawdust, guinea grass and mature coconut fronds. The fresh fruit yield of watermelon in all the mulch treatments was 7.3–18.1% higher than in the nonmulched control. There was no significant effect of thick vegetative mulch on maize grain dry matter yield; however, the maize yield was significantly lower in the transparent plastic mulch than in the other treatments. The capsicum marketable fruit yield in the following crop was increased by 49–73% in all the vegetative mulch treatments compared to the non‐mulched control. The higher crop yields with the vegetative mulch were attributed to the measured lower soil temperatures and higher soil moisture in these treatments. There was no effect of mulch on soil total N (TN), but soil total C (TC), soil labile C (LC) and the carbon management index (CMI) were increased.

Effect of different mulching materials on weeds and yield of Chili cultivars

To evaluate the effect of different mulching materials on the weeds and yield of chili cultivars, an experiment was conducted at Horticulture Research Farm at University of Agriculture, Peshawar, during the year 2014. The experiment was carried out in Randomized Complete Block Design (RCBD) with three replication.. There were two factors i.e. mulching materials (Wheat straw, Saw dust, Transparent plastic, Black plastic, Unmulched) and chili cultivars (PusaJawala, Sky Star, Hot Green, Green Star).Minimum weed density m -2 (19), maximum yield tons ha -1 (3.07) were found when black plastic was used, while maximum weed density m -2 (209), were found, when transparent plastic was used. Highest soil moisture content (%) was found under black and transparent plastic mulch. Wheat straw and saw dust also increase growth and yield components of chili as compare to Unmulched plots. Lowest soil moisture content (16.1 %) and minimum yield tons ha -1 (0.70) were recorded from Unmulched plots. In case of cultivars maximum yield tons ha -1 (2.33) were noted in cultivar Sky Star. It is concluded from the results that cultivar Sky star along with black plastic mulch proved better with respect to weed control and yield and should be used for higher production of chili under the agro climatic conditions of Peshawar.

Influence of different plastic film mulches and wetted soil percentages on potato grown under drip irrigation

Potato (Solanum tuberosum L.), an important food crop of Northwest China, is commonly grown using transparent plastic film mulch for water conservation since both irrigation water and precipitation are scarce. In order to improve production efficiency, field experiments were conducted at Shiyanghe Experimental Station, China Agricultural University, Wuwei, Gansu Province, China using plastic mulch and drip irrigation to study the influence of two typical plastic mulches (transparent and black) and three wetted soil percentages on potato root distribution, evapotranspiration, tuber yield and quality, and water use efficiency (WUE) in 2014 and 2015. Using a wetted soil percentage of 55%, three soil surface treatments were tested: transparent plastic mulch, black plastic mulch, and a non-mulched check. With the transparent plastic mulch, three wetted soil percentages 35%, 55%, and 75% were evaluated. The soil retained moisture better in the mulched treatments than in the non-mulched treatment. As the plant canopy increased, the differences diminished. Potato grown without plastic mulch developed more roots than potato grown with mulch. The soil water fluctuations in the top of the bed with black plastic mulch were greater than with transparent plastic mulch. Potato grown with either plastic mulch had greater yield and WUE than potato grown without plastic mulch. Potato grown with transparent plastic mulch had 10% and 7% greater WUE in 2014 and 2015, respectively than potato grown with black plastic mulch but the differences were not statistically significant. For different wetted soil percentages, the irrigation frequency was higher with the 35% wetted soil treatment than with 55% or 75%. The irrigation at 35% principally only affected the soil water in the upper soil in contrast to the 55% or 75% treatments. The 35% wetted soil treatment had more root development in 2015. Potato evapotranspiration increased as the wetted soil percentage increased. The 75% wetted soil treatment had significantly more evapotranspiration than the 35% wetted soil treatment in 2015. The 35% wetted soil treatment had the highest WUE, 17% and 25% higher than the 75% wetted soil treatment in 2014 and 2015, respectively. The 35% wetted soil percentage irrigation regime combined with transparent plastic mulch merits wider testing for potato production in arid Northwest China.

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weight of fresh pods per plant (44.17 g), number of gains per pod (8.02) and 100-grains weight (50.73 g) were recorded in hand weeded plots. Hand weeding recorded substantial increase in pod yield (8.63 t ha -1 ) which was significantly the highest from all other treatments. In 2012-13, the significantly highest number of days taken to 50% flowering (65.33) was recorded in plots covered with white plastic. The lowest weed density (14.20 g/m 2 ), least fresh weed biomass (42.32 g/ m 2 ), the lowest dry weed biomass (15.19 g/ m 2 ), m aximum number of pod per plant (14.76), the highest weight of fresh pods per plant (44.17 g ), the longest pods (6.97 cm), maximum number of gains per pod (6.43) and the highest 100-grains weight (52.06 g) were recorded in hand weeded plots. Significantly the highest pod yield (7.66 t ha -1 ) was also recorded in h and weeding . It was concluded that during both the years, hand weeding surpassed all other techniques in minimizing weeds density, weeds fresh and dry biomass enhancing all other growth and yield parameters followed by transparent plastic mulch, black plastic mulch, Dual Gold and Stomp.

Exploring micro-field water-harvesting farming system in dryland wheat (Triticum aestivum L.): An innovative management for semiarid Kenya

Micro-field rain-harvesting farming system (MRFS) has demonstrated great potentials to enhance field productivity and profitability of dryland wheat (Triticum aestivum L.) in semiarid eastern Asia, yet little is known whether this system results in desired effects in semiarid Africa such as Kenya. A two-year field experiment was conducted during 2012 and 2013 growing seasons to evaluate the effects of introduced MRFS on water availability, field productivity and economic benefits using a local wheat (T. aestivum L.) cultivar DUMA in a semiarid site of Kenya. Five treatments were designed as: 1) ridge and furrow with transparent plastic mulching (RFT); 2) ridge and furrow with black plastic mulching (RFB); 3) ridge and furrow with grass straw mulching (RFS); 4) ridge and furrow without mulching (RF); and 5) traditional flat planting (CK). The results showed that mulching treatments (RFT, RFB and RFS) significantly decreased the evapotranspiration (ET) by 11.4–88.5mm, increased wheat grain yield by 60%–163%, above-ground biomass by 58%–104% and water use efficiency for grain by 68%–271%, compared with CK over two growing seasons. RFT and RFB treatments resulted in maximal soil water storage at 1-m depth and the greatest harvest index among all treatments. Linkage analyses indicated that grain yield showed significantly positive correlation with plant height, leaf area and major spike components (P≤0.05), suggesting that plant type of wheat was altered for better yield production as a result of MRFS operation. More importantly, economic ratios of output to input were also calculated and compared. The average ratio of output to input for CK was 3.86, slightly lower than 4.28, 4.06, 5.86 and 5.34 for RFT, RFB, RFS and RF, respectively across two growing seasons. In particular, net incomes in MRFS (RFT, RFB, RFS and RF) were increased by 145%, 128%, 117% and 82% respectively, compared with that of CK. In conclusion, on-field rain-harvesting farming system provides an innovative management to boost the productivity and profitability of dryland wheat, and a potential solution to cope with food security in semiarid Kenya.

Temperatura do solo afetada pela irrigação e por diferentes coberturas

RESUMO A irrigação suplementar e a cobertura do solo ("mulching") são práticas de manejo comumente usadas na agricultura. O objetivo deste trabalho foi quantificar a temperatura do solo desnudo com e sem irrigação, e sob diferentes coberturas do solo. Um ensaio de campo foi conduzido em Santa Maria-RS (29o 43' S latitude, 53º 42' W longitude e 95 m de altitude), com seis diferentes áreas: solo desnudo sem e com irrigação, solo com "mulching" de plástico transparente (espessura 100 µm), "mulching" de plástico opaco preto (espessura 110 µm), "mulching" de plástico opaco branco (espessura 150 µm) e cobertura vegetal com palha na dose de 5 t ha-1. A temperatura do solo foi medida a 0,05 m de profundidade, diariamente, às 15h (18 UTC), no período de 10-10-2011 a 31-05-2012. Foram também realizadas medidas horárias de temperatura do solo em quatro dias sem nebulosidade, em outubro e novembro de 2011, e janeiro e março de 2012. A temperatura do solo diurna seguiu a sequência: plástico transparente (42,4 oC) > plástico opaco preto (37,8 oC) > solo desnudo sem irrigação (33,4 oC) > solo desnudo com irrigação (29,2oC) > palha (27,0 oC) > plástico opaco branco (24,6 oC). A região de Santa Maria-RS, tem potencial físico de aquecimento do solo com a técnica da solarização.

TheEffect of Color Plastic Mulches onGrowth, Yield and Quality of Two Hybrids of Summer Squash (cucurbita pepo l.)

This experiment was carried out at the vegetable research farm of Horticulture Department/ Faculty of Agriculture /Duhok University on two hybrids of summer squash during spring in the season of 2014, to study the effect of five color plastic mulches (without cover, transparent, black, red and blue) on two hybrids of summer squash (Amjed and Alexandra F1). The results showed that covers plastic mulches led to positive significant differences in leaf area (cm2), leaves chlorophyll content%, , fruit number/plant, early yield and total yield as well as fruit weight (g ), fruit length (cm) and fruit diameter (mm) as compared to without cover. There were no significant differences between the two hybrids in all detected traits. The interaction between covers plastic mulches and two hybrids was significantly enhanced all detected traits, since summer squash (Alexandra hybrid) covered with transparent plastic mulch were characterized by the highest values of leaf area (cm2), leaves chlorophyll content% and fruit diameter (mm), and summer squash (Amjed hybrid) covered with blue plastic mulch gave positive significant of fruit number/plant and total yields ton/ hectare

EFFECT OF MULCHING AND EMITTER SPACING ON WATER USE EFFICIENCY AND YIELD OF SQUASH

Influences of two plastic mulch practices (transparence and black mulching) using trickle irrigation and three emitter spacings (35, 50 and 65 cm) on squash yield, soil water availability and WUE were assessed using experimental plots. In comparison to trickle irrigation and conventional surface irrigation, the transparence and black mulching significantly increased squash fruit yield, soil moisture storage (0–60 cm) and WUE. Results indicated that non-mulched treatments (trickle irrigation, DI, at emitter spacings 35, 50 and 65 cm and surface irrigation, SI, received an average of 328.5 mm for first three treatments and 698.6 mm for forth treatment, respectively to produce 21.754, 18.989, 17.336 and 16.054 t/ha squash, respectively, whereas treatments with transparent and black plastic mulching (TMD and BMD) consumed an average of 286.6 mm and 299.2 mm water for all emitter spacings (35, 50 and 65 cm), respectively, and yielded average of 33.445, 31.067, 22.816, 33.338, 29.065 and 25.434 t/ha, respectively at same emitter spacings.

Responses of drip irrigated tomato (Solanum lycopersicum L.) yield, quality and water productivity to various soil matric potential thresholds in an arid region of Northwest China

Considering the current water scarcity of Northwest China, aiming at sustainable agricultural development in this region, it is required to identify and apply the most appropriate practices for water-saving, and yield and water productivity improvement. Relative to the tomato crop, a two-year field experiment was conducted in an arid region of Northwest China using drip irrigation and transparent plastic mulch to study the impacts of various soil matric potential thresholds (−10, −20, −30, −40 and −50kPa) on yields, fruit quality and water productivity. A soil water balance was performed to estimate the seasonal actual ET (ETa) for every treatment and to relate it with the volume of water applied and yields achieved. Crop coefficients were determined from the crop density and height; for the non-stressed treatment the values of 0.30, 1.10 and 1.05 were obtained for the initial, mid-season and late season stages, respectively. A linear relationship between seasonal ETa and applied water was obtained. Tomato yields and ETa decreased with decreasing applied water but fruit quality did not: it was best under mild to moderate water stress (−30 to −40kPa). Water productivity based on marketable-quality yields was the greatest when applied irrigation was 90% of the amount of irrigation required for no stress. This condition corresponds to a soil matric potential threshold of −40kPa. However, a smaller stress may be desired in terms of irrigation management and a threshold of −30kPa is then recommended.

Seedling protection and field practices for management of insect vectors and viral diseases of hot pepper (Capsicum chinense Jacq.) in Uganda

The focus of this study was on nursery and field management of seed and insect vectors of viruses on hot pepper. Seedlings raised from hypochlorite-treated seeds under a net tunnel nursery were compared with seedlings raised from untreated seeds in an open nursery. The two groups of seedlings were used to evaluate field practices in a split plot randomized controlled block design: (i) weekly foliar applications with dimethoate; (ii) close plant spacing of 60 cm × 50 cm); (iii) 1.5-m high net perimeter screen; (iv) transparent plastic mulch; (v) untreated control. Whiteflies were the vectors most affected by the treatments, showing 28%, 38%, 43% and 36% reductions in occurrence by seedling protection, net screens, transparent plastic mulch and close plant spacing, respectively. Aphids were only responsive to close plant spacing and chemical treatments, with a reduction in incidence of up 43% by the former. The lowest virus disease incidence (12%) was on plants raised unprotected in the nursery but grown under the close plant spacing in the field. Plants from protected seedlings had a marginally higher fruit yield (2.1 kg/plant) compared with plants from unprotected seedlings (1.7 kg/plant)

Modelling the effects of plastic mulch on water, heat and CO2 fluxes over cropland in an arid region

Plastic mulches are often used to improve agricultural production by suppressing soil evaporation in the vast arid and semi-arid regions. As a special surface cover, plastic mulch evidently affects the surface albedo and prevents vapour exchange between the land surface and the atmosphere, but these physical processes were not contained in the present land surface models. Therefore, simulations remarkably deviate from observations when land surface models are applied to areas with underlying plastic mulch covering. Investigating the effects of various plastic mulches assists in better understanding the atmosphere-land interaction. In this study, a detailed plastic mulch layer model, which considers the effect of plastic mulch on the radiation and heat transfer is constructed and incorporated into a land surface model Two-Big-Leaf-SHAW (TBLSHAW) to simulate the water (H2O), heat and CO2 (carbon dioxide) fluxes in an agro-ecosystem covered by plastic mulch. Data collected by Gulang Heterogeneous Underlying Surface Layer Experiment (GHUSLE) at a plastic mulch-covered cropland site in an arid region were employed to verify the model; simultaneously, the TBLSHAW model was run with the same atmospheric forcing as a comparison to investigate the effect of the plastic mulch. Results suggest that the model can appropriately simulate the water, heat and CO2 fluxes over an arid cropland. The model efficiency is high, and the mean bias error and root mean bias error between the simulated and the observed values are minor. Compared to TBLSHAW simulations, the plastic mulch with special optical properties obviously influenced the surface albedo and radiation balance. By limiting the underside soil evaporation, plastic mulch changes the energy and water transfer between the atmosphere and the land surface. The soil temperature and soil moisture are improved by the transparent plastic mulch, and the plastic mulch not only suppresses the CO2 generated by soil respiration but also affects CO2 budget as a result of the net assimilation controlled by the soil water and heat conditions.

Duration of plastic mulch for potato growth under drip irrigation in an arid region of Northwest China

Field experiments were conducted to examine the effect the duration of plastic mulching has on soil temperature, evapotranspiration, potato ( Solanum tuberosum L.) growth and yields, and water use efficiency (WUE), under drip irrigation in an arid region of Northwest China in 2006 and 2007. The duration of coverage with 0.0075 mm thick, transparent plastic mulch on potato beds varied from zero days (i.e. no cover) to the entire season. The average daily air temperature during the two growing seasons was adequate for potato growth, but there were days when the maximum air temperature was above 30 °C. Daily mean soil temperature under the plastic mulch was 2–9 °C higher than for non-mulching conditions. The mulch effect on soil temperature was greatest during the early growth and became less as the plant canopy increased. Differences in the air and soil temperature between years could explain the difference of potato growth under different mulch durations for the two growing seasons. Mulch reduced irrigation water required and evapotranspiration; however, extending mulch duration beyond 60 days had little effect on evapotranspiration. Both tuber yield and WUE demonstrated benefiting from early plastic mulching. Mulch cover for 60 days was favorable for potato production in both years compared to potatoes grown without mulch.

SURVIVAL OF FUSARIUM PROLIFERATUM FROM ASPARAGUS AFTER SUBLETHAL HEATING OR SOLARIZATION

The survival of Fusarium proliferatum propagules after soil solarization or after heat-treatment at sublethal temperatures was evaluated. Soil solarization with transparent plastic mulch was applied for 69 days. At 10 cm depth the survival of F. proliferatum in the uncovered control than in solarized plots. The population of the fungus was eradicated by soil solarization. In the heat-treatment experiments at 35, 40, 45 and 50° C for 10, 20 and 30 min the population of F. proliferatum was significantly decreased only at the temperature of 50° C. No differences were found among the different exposure time periods.

Effect of Soil Temperature on Growth and Yield of Squash Under Different Mulch Applications in Plastic Tunnel and Open-Air

Soil temperature is one of the important factors which affects plant growth and yield. In this study, soil temperature variations in different soil depths were monitored through growing period. Then, effetcs of soil temperature variations on growth and yield of squash (Cucubita pepo L.cv. Jedida F1) were investigated under different cover types. High plastic tunnel, low plastic tunnel and control cover types with transparent plastic mulch, black plastic mulch and mulchless applications have been used in this research. Accoding to results, the most suitable soil temperature distribution was obtained from transparent plastic mulch application of high plastic tunnel. On the other hand, there is no statistically difference between tunnels types aspects of plant growth and yield. Transparent plastic mulch in all tunnel types was found more efficient on first blossoming time, first harvesting time, leaf area and total yield than other mulch applications. Especially, mulchless appilcations in all tunnel types showed the lowest plant growth and yield values.

Yield of Three Cultivars of Muskmelon Growth on Transparent Mulch and Floating Rowcover in a Tropical Region

Muskmelon (Cucumis melo L.) is the major cucurbit crop in the Colima state, Mexico. The use transparent plastic mulch continues to increase in that region for high production technology systems of muskmelon, and more recently floating rowcovers were introduced to protect cucurbits from insects (direct pests or vector of viruses) and to increase yield of cucurbit crops. During 1993, yield was evaluated of three cultivars of muskmelon (`Crushier', `Laguna', and `Durango') growing on transparent polyethylene mulch alone or with floating rowcover. The cultivar Crushier showed the higher yield 40 ton/ha (77% for export market), followed by `Durango' with 28.5 ton (77% for export quality) and `Laguna' with about 23 ton (only 40% of export fruit). There was no significant difference in yield between cultivar growth on transparent mulch plots alone and combined with floating rowcover. Also, floating rowcover excluded (until perfect flowering) beetles leafminers, sweetpotato whitefly, and aphids, reducing the use of insecticide by 50%.

The Effect of Plastic Mulch and Greenhouse‐Raised Seedlings on Yield of Maize

AbstractThe yield of maize (Zea mays L.) can be increased appreciably if canopy closure is brought forward. In France and Germany, the use of plastic mulch has boosted dry matter yields of silage maize by approximately 4 t/ha. In Germany, the grain yield of maize plants grown from greenhouse‐raised seedlings was 2.4 t/ha more than that of plants grown conventionally. The present study aimed to review and quantify the effect of the use of plastic mulch and greenhouse‐raised seedlings on yield of maize. In field trials the effect of a photo‐degradable transparent plastic mulch on the yield of two hybrids: Clipper (early‐maturing) and Dea (late‐maturing) was tested. In two of these trials the effect of using seedlings raised in the greenhouse up to the five‐leaf stage was also tested. Crops with plastic mulch required 10 % fewer growing degree days from planting to silking than the unmulched crops, and this number was more constant between years and sites. On average, plastic mulch increased whole plant dry matter content from 29 % to 33 %, and the dry matter of the ear from 45 % to 52 %. In Dea, dry matter yields of the whole plant and of the ear rose by 2.6 and 2.1 t/ha respectively. In Clipper the yield increases were half as large. The regression of whole plant dry matter yield on the sum of global radiation from silking to harvest was similar for mulched and unmulched crops. This suggests that the yield increases obtained with the plastic mulch were largely attributable to advancement of canopy establishment. The whole‐plant dry matter yield of plants initially raised in the greenhouse was similar to that of maize sown in situ, but the ear dry matter yield was 2.4 t/ha higher.