Vinyl House Research Articles

Volatilization of Nitrous Acid from Upland Soils

In order to identify the chemical form of the toxic nitrogenous gas volatilized from upland soils especially from vinyl house soils, laboratory experiments were carried out with two Andosols collected from vinyl houses in Ibaraki Prefecture. Results were as follows. 1) Nitrite ion was detected in the alkaline absorbents which absorbed nitrogenous gas volatilized from the soils, but nitrate ion was not detected in these absorbents. 2) The same amount of nitrite-N and nitrate-N was found in the alkaline solution which absorbed nitrogen dioxide (NO2) gas. 3) When sodium nitrite was added to the buffer solutions with various pH (4, 5, and 6), nitrogenous gas volatilization occurred even at pH 6, and nitrite ion was found in the alkaline absorbents whereas nitrate ion was not detected. From the results obtained, it is suggested that nitrous acid is the chemical form of the nitrogenous gas volatilized from upland soils.

Air Concentration and Deposit by Different Applications of Procymidone to Fruit Vegetables in Vinyl House

Air Concentration and Deposit by Different Applications of Procymidone to Fruit Vegetables in Vinyl House

Formulations for vinyl house siding: History, present, future

AbstractIn the early 1960s, vinyl house siding was first commercialized. The colors were pastels and included white, green, yellow, and gray. All siding tended to bleach and fade (oxidize) to an extent where medium and dark colors were unacceptable, since the fading is more noticeable in deeper colors. All the early siding was made from cubes on single‐screw extruders. Powder compounds were first introduced in the late 1960s, as was twin‐screw extrusion. At the same time higher processing temperatures were used on, both twin‐ and single‐screw extruders. That led to a well‐fused and tougher product. Formulation changes reduced bleaching and fading and permitted such medium‐depth colors as tan, gold, beige, blue, and olive.This technology allowed rapid growth in the vinyl siding industry in the late 1970s. Surface distortion (oil canning) was recognized as a potential problem with the early gray color and recognized as a major problem with dark colors; it was resolved only by understanding the fundamental principles involved. Another major problem was the fading in dark colors and here again extensive research into the principles of weathering led to the use of a thin, highly weatherable capping as a cost‐effective solution.For the future, many technical developments can be expected in this rapidly growing market. However, judging by the occasional withdrawal of a formulation from the market, and by an occasional homeowner complaint, present performance in several properties must be judged as just adequate. For this market to continue its rapid growth, future performance should be better than today's. This can be accomplished without hurting economics by careful understanding of all parameters involved. Formulation changes will allow better performance. Standards must be raised to control product performance, especially surface distortion and color stability in darker colors, and to insure retention of physical properties after long‐term weathering.

Recent Demonstration Of Helminth Eggs And Larvae From Vegetable Cultivating Soil.

A survey on soil samples collected from the vegetable gardens and vinyl houses in the vicinity of Taegu was conducted for the discovery of helminth eggs and larvae from October 1981 to September 1982. The samples collected were examined utilizing the "Commonly Employed" and Kamiya's techniques. The details of comparative features of larval nematodes are taken from the handbook of parasitology by Matsubasyhi et al. (1965). The results were compared with the data obtained from soil samples collected at the same area by Lee(1976). Five kinds of helminth eggs, ascarid, hookworm, liver fluke, Trichostrongylidae, and whipworm and undetermined eggs were found. Of these, the incidence of ascarid eggs was found to be the highest, 70.5 per cent, followed by whipworm and hookworm eggs, 9.9 and 9.2 per cent, respectively. The average number of ascarid eggs per 100 grams of soil was higher in the vinyl houses, compared with the number in the vegetable gardens than in the vinyl houses. By contrast, the number of hookworm eggs was relatively high in the vegetable gardens. In the monthly incidences of helminth eggs, ascarid eggs were found every month, continuing fairly high incidences all the year round. However, hookworm eggs was found for 8 months from February and September, with low monthly incidences between 4.0 and 22.2 per cent, and Trichostrongylidae eggs were found for 6 months from April to September, with lower incidences than those of hookworm. Three kinds of larval nematodes, the filariform and rhabditoid larvae of hookworm, Trichostrongylidae, and undetermined larvae were found in the soil of farms, but the incidences of larvae were quite low. The average number of larvae per 100 grams of soil was 0.05. When the number of eggs per 100 grams of the soil in 1976 were compared with 1982, pronounced reduction of the number was encountered in all helminth eggs. However, the incidences and the average number of larvae per 100 grams of the soil were so low that it was impossible to compare the data between 1976 and 1982.

Studies on the Ecology of Vegetable Diseases in Vinyl Houses and the Improvement of their Chemical Control Methods

Studies on the Ecology of Vegetable Diseases in Vinyl Houses and the Improvement of their Chemical Control Methods

Comparison of smoking and liquid formulations in controlling some cucumber diseases in vinyl houses

Comparison of smoking and liquid formulations in controlling some cucumber diseases in vinyl houses

A Test for Chemical Effect Using Cucumber Fruit to Multiple-Host Fungi

A method was developed for testing chemical effect by using cucumber fruits to multiplehost fungi, Botrytis cinerea Persoon, Sclerotinia sclerotiorum (Libert) de Bary, Corticium rolfsii (Saccardo) Curzi and Rhizoctonia solani Kühn. Each fungus was seeded on PSA medium in petri dish, 9cm in diameter, and incubated for 3 days at 25°C until the fungus developed to whole petri dish. Cucumber fruits were cut to pieces 4-5cm in length and dipped in test solutions of chemicals for 1-10 minutes. After being dried, the cucumber fruit pieces were placed on the above fungus. After incubating for 72-96 hours in a high moisture at 20-25°C, the height of colored parts or mycelial growth on cucumber fruits was measured. The height of colored part on chemical-treated cucumber fruits was compared with that on nontreated ones. The method is very simple for testing chemical effect to the fungi described above. The result obtained by the method on testing chemical effects to B. cinerea corresponded to the effect of chemicals practically used by spraying for protection of cucumber gray mold in a vinyl house. The method is, therefore, able to be used practically for screening effective chemicals.

Demonstration Of Helminth Eggs And Larvae From Vegetable Cultivating Soil

In order to clarify the contamination of vegetable gardens with human intestinal helminths, the soil samples were examined for the presence of eggs and larvae during the period from September 1973 to August l974. When soil samples collected from the vegetable gardens in Taegu were examined, four species of helminth eggs (ascarid, whipworm, hookworm and liver fluke) and a number of unknown eggs were found. Ascarid was found to be highest in the rate of detection(82.5%), followed by whipworm. The rates of hookworm, liver fuke and Trichostrongylus species were unexpectedly low. There was no difference between detection rate of vegetable gardens and that of vinyl green houses. However, the average number of helminth eggs detected from the soil of vinyl green houses was higher than the number of vegetable gardens. In the monthly incidence of ascarid eggs, the highest rate was found in September, and the least often was observed in August. While, the peak in the average number of the egg was encountered in August. There was no distinct trend in the monthly incidence of whipworm. However, it is likely that the detection number of whipworm per 100 gm of soil examined was relatively abundant in a period from May to August, and very little from October to April of next year. When the soil of vegetable gardens was divided into superficial, intermediate and deep layers and examined for presence of ascarid egg. The average number of the eggs found of the superficial layer was more abundant than those of the intermediate and deep layers, but the rate for the former was similar with the latter. In the demonstration of larval nematodes from the soil of vegetable gardens and vinyl houses, there found the filariform and rhabditoid larvae of hookworm and the larvae of Trichostrongylus species and unknown one. The majority of the larvae detected was belonged to unknown species, followed by hookworm larvae. The least was found in the rate of Trichostrongylus species. Generally, the filariform larva of hookwom could be detected during the hot season from May to August, but no larva was found in the winter. This suggests that the soil of vegetable gardens and vinyl green houses in Taegu is contaminated with human intestinal helminths.

Marginal Blight of Cucumber Caused by a Strain of Pseudomonas marginalis (Brown) Stevens

A bacterial disease was found on matured lower leaves of cucumber grown under vinyl house conditions in winter of 1974. The disease rarely occurred on inmature leaves soon after unfolding. The disease usually started from leaf edges near hydathodes and quickly enlarged to form V-shaped lesions frequently surrounded by chlorotic areas. These lesions finally coalesced to form the severe blight along the whole margin of the leaf. From these symptoms, “marginal blight of cucumber” was proposed as the disease name. The cultural and biochemical characters of the pathogen were compared with those of Pseudomonas lachrymans, the pathogen of angular leaf spot of cucumber. These two bacteria differed in the important characteristics such as production of fluorecin, degree of gelatin liquefaction, levan formation, margarine hydrolysis, arginine dihydrolase reaction, potato rot, and utilization of sucrose, sorbitol and tartarate. The marginal blight pathogen was rather close to soft-rotting pseudomonads in bacteriological properties. Although the similarity was not complete, therefore, we are inclined to identify the present bacterium as a strain of Pseudomonas marginalis (Brown) Stevens based on the detailed survey of pathological, cultural and physiological characteristics. The isolates of P. lachrymans used in the study showed also some conflicts in physiological properties with the description of the type culture suggesting the presence of strains in this bacterium.

The Mechanization of Transport in Vinyl House (V)

The Mechanization of Transport in Vinyl House (V)

Control of cucumber diseases by fungicides with two types of electric thermo smoker in vinyl house

Control of cucumber diseases by fungicides with two types of electric thermo smoker in vinyl house

The Mechanization of Transport in Vinyl House (VI)

The Mechanization of Transport in Vinyl House (VI)

Control of the root-knot nematode of cucumber in the vinyl house

Control of the root-knot nematode of cucumber in the vinyl house

On the Air Change of a Plastichouse by Wind.

The natural air change of a vinyl house at various wind conditions was measured.The effect of the opening and closing of doors at east and west sides of the house has been investigated by the CO2gas tracer method.1) The number of air change of 2.4-5.4 times per hour has been observed when both doors were closed, with comparatively little influence due to the speed (<6m/sec) and different directions of outside wind. On the other hand, it was found that the air leakage through the openings in the walls was rather large.2) When the door of one side was open, the number of air change was 10-17 times per hour with considerable scatter. The influence of wind direction was not clear.3) The largest number of air change of 19-40 times per hour was found when both doors were open.4) On the whole, the linear relationships were found between the wind speed and the number of air change and also between the area of open door and the number of air change.5) The number of air change was simply calculated from the observed relationship between the sudden opening and closing of door and the change of house air temperature, but the acceptable value of the number of air change has not been obtained.

The Mechanization of Transport in Vinyl House (IV)

The Mechanization of Transport in Vinyl House (IV)

Effect of soil fumigation with methyl bromide in vinyl house

Effect of soil fumigation with methyl bromide in vinyl house

Influence of fungicide application method on humidity in vinyl house. (2)

Influence of fungicide application method on humidity in vinyl house. (2)

Micro Scale Analysis about the Formation of Horticulture in the Eastern Kochi-Plain

Today some kinds of vegetables are produced all the year round. Even in winter they are grown and harvested with the aid of hot houses. Because of the fine winter climate, there are many hot houses on the Pacific coast of Japan. Even though Kochi Prefecture was far from the urban market, truck gardening has been practiced there since about 1907. Today, Kochi Prefecture ranks first in Japan in supplying a winter hot house vegetables.The author studied the areal type of vegetable production, especially in hot houses. The farmer who operates a hot house holds a small amount of arable land, about 0.1 to 1.0ha. 50 years ago, many fishing villages changed to horticulture, and there, today, on the sandy beach, hot houses stand side by side. These villages have ranked first in truck farming in Kochi Prefecture since this type of production began. Where the horticulture began earlier, almost all farmers usually engage in hot house production. The hot houses are not so large; each one of which is 1 to 5 are. The unit of co-operative which has been organized for the shipment of vegetables has been small; each co-operative is based on one hamlet.After 1960, some changes have been observed in truck farming of Kochi Prefecture. Above all, oil rubbed paper was rapidly replaced by vinyl film as house cover material. As a result, the truck gardening region has spaced all over the plains of the prefecture. Even far from the coast numerous vinyl houses have been built. In the district where horticulture was recently began to be carried on, we find some new aspects of production in contrast to the older methods of production. For example, a large sized hot house is equipped with automatic oil heater keeping warmth at night, irrigation pipes, and a fan for ventilation. Such a hot house requires from 10 to 20 are of floor space; thus a large amount of capital and skilled man power is also necessary in a hot house production. Therefore every farmer doesn't always operate a big sized house for vegetable growing. Standing on the hills in spring, we can see that the paddy fields are dotted with the big houses. In the newly developed horticultural districts, the agricultural co-operatives have more extensive areas under their control than in the older horticultural districts. In Japan local administrative units have had the tendency to unite with each other since 1954. This has resulted in the smaller co-operatives being incorporated into the bigger ones. By way of example the author has intensively researched into the areal formation of horticulture in Noichi-cho (town). In that town, while the production of vegetables has recently increased, the number of the farmers engaging in tobacco planting, dairying, chicken raising, as well as biannual harvesting of paddy fields has been decreasing. In the hot house of big size such crops as pimientos or peppers, cucumbers, and eggplants are raised. Moreover we can see new practices of growing vegetables using the easier means of keeping warmth, such as small vinyl honses or vinyl tunnels or hot frames or vinyl mulching only. Thus a gynmigit (Japanese; nira), sweet poteto, taro, garlic, kidney bean, celery, and garden asparagus are available for sale in the season when vegetables are scarce. Farmer who operates the large sized house with the heater differs from the farmer who produces the vegetables by lower cost equipment. The former, mostly young men, engage in farming as a regular occupation, while the latter, being old or female workers in many cases, are part-time farmers.Although the farmers in this district choose various kinds of crops and means of production, the region as a whole appears as a densely concentrated area of vegetable production.

Influence of Radiation Shelters on Temperature Measurements by Thermometers in a Vinyl House

Three types of the radiation shelter as shown in Fig. 1 were tested to make clear its influence upon the air temperature measurements in a vinyl house for vegetative crops. The readings of each thermometers with and without the radiation shelter were compared with that of Assman aspirated psychrometer. It was found that the readings of each thermometer were always higher than that of Assman psychrometer. The thermometers in the radiation shelters of bamboo cylinder and aluminum cup gave air temperature higher than those obtained by other thermometers. The air temperature in the radiation shelter of aluminum cylinder was nearly equal to that in the vinyl house. However, temperature of thermometer within the aluminum radiation shelter was always higher than the air temperature in the shelter.Heat balance analysis was made in order to search the main cause for such a difference in temperature reading between thermometers. It was found that short-wave radiation reaching the thermometer and the radiation shelter played an important role in heat balance. The contribution of heat exchange due to both the convection and the long-wave radiation was little in comparing with those from short-wave radiation and ventilation.

Control of the air-borne diseases of vegetable crops with application by fungicidal smokes in the vinyl house

Control of the air-borne diseases of vegetable crops with application by fungicidal smokes in the vinyl house