Robert Marvel
     P
lastic Mulch  

Phone 717-838-0976
Toll free 1-800-478-2214


               Your source for all your plastic mulch and drip irrigation needs!


"Not only do we sell these fine products we also use them. We are farmers too! We know these products perform!"


Why Plastic Mulch?

BLACK, WHITE OR COLORED, PLASTIC MULCH WORKS FOR VEGETABLES

In the years following its discover in the 1950’s, plastic mulch took over the vegetable fields of America – and the world – as growers discovered the wonderful things long strips of plastic could do when laid down in rows with plants set into slits and holes.

By the 1970’s, growing vegetables over plastic had become common, and by the end of the last century most of the uses were pretty well understood.

Still, new uses and surprises come along now and then.

University of Illinois Senior Research Specialist Bill Shoemaker and Extension Educator Maurice Ogutu maintain test plots at the St. Charles Horticultural Research Center each year.

“We still find a few surprises” Shoemaker said. “Blue mulch particularly has really stimulated the growth and productivity of melons; more than 1 thought it would.”

He’s also working with metalized silver reflective mulches in growing pumpkins. The reflected light seems to prevent aphids from seeing the green pumpkin plants. Fewer aphids feeding on the plants can mean fewer viruses vectored into the plants, extending the vitality of the vines and increasing pumpkin yields.

A new plastic film called Blockade from Pliant Corp. provides an effective barrier that keeps methyl bromide in the soil. Mark Jordan, sales director for agricultural and industrial films for Pliant, said the film makes more effective use of the fumigant, which saves dollars for growers and prevents escape of the gas into the atmosphere.

Methyl bromide was identified years ago as a deplete of ozone in the atmosphere, and by worldwide agreements its use is being phased out. Growers who can’t get along without it can apply for Continued Use Exemptions – and efforts to use the gas conservatively and wisely play a role in their continuing to get them.

Other films also work as a barrier against the escape of methyl bromide, but Jordan said the Blockade is five to 20 times as effective as metalized films, and much more grower-friendly-less stiff and easier to lay tight to the ground.

Much work with plastic films was done in the 1990s at Penn State University, and research findings can be found at the Center of Plasticulture’s Web site, www.plasticulture.org.

A key issue in choosing to use colored mulch is cost, said Mike Orzolek, director of the center. Black mulch remains far cheaper because the key colorant carbon black is less costly than dyes and does double duty because it effectively stops photodecomposition.

It costs about $160 to put down an acre of black plastic on 6-foot row centers, he said, and about $240 to do it with colored mulch.

Biodegradable mulch is also making headway, he said. Despite its higher initial cost-about twice-it is worth at least $100 an acre more because it eliminates the retrieval and disposal costs of conventional plastic mulch. You just rototill it into the soil when the season ends.

“Plastic mulch has become a standard cultural practice for many vegetable crops”, Shoemaker said. “Since its discovery in the late ‘50’s, it has developed into a very useful tool for growers”.

“It can provide excellent weed control within the planted row, which by itself may be worth its price in some cases. It also holds moisture in the soil (and) it makes drip irrigation more efficient as it virtually eliminates evaporation of the irrigation water”.

“But the most powerful feature of plastic mulch is the impact it has on light”.

“Light is responsible for creating both heat and color. Plastic mulch can impact the development of heat, increasing it or decreasing it, depending on mulch color, Shoemaker said.

With white or reflective film the light is largely reflected away with reduced conversion of light to heat. Heat-sensitive crops such as lettuce can sometimes benefit from this soil-cooling trait, he said.

Other colors of plastic mulch films have been investigated for their impact on crops. Each color film reflects the wave-length that gives it the color we perceive. Green looks green because it reflects green light, he said.

“These wavelength differences have subtle, and sometimes profound, impacts on plant growth and development”, Shoemaker said. “Early research on red films found that they impacted tomatoes by forcing more compact growth, early flowering and earlier productivity. Recent research at St. Charles by Maurice Ogutu and me shows that blue films seem to stimulate productivity in muskmelons”.

Yellow has been shown to attract insects – but that can be a good idea. Some growers are using yellow-mulched rows to attract insects to a location where they can be killed, Jordan said, reducing the need to spray nearby rows of the same crop planted on mulch of other colors.

There are plenty of colors to choose from: black, white, silver, red, blue, brown IRT (infrared thermal). Green IRT, clear and yellow.

In an article on the Center for Plasticulture Web site, director Orzolek and associate director William J. Lamont Jr. summarize the state of knowledge about choosing the color of a plastic film, based on their years of field research at the Horticulture Research Farm in Rock Springs, PA.

Some generalities that can be made regarding color are 1) silver repels aphids,
2) Blue attracts thrips but has been very effective in greenhouse tomato production and
3) Yellow attracts insects. There also appears to be some reduction in disease pressure with crops grown on specific colors.

They recommend the following colors for specific crops: Tomatoes responded to red mulch compared to black, with an average 12 percent increase in marketable fruit yield and fruit size over a three-year study. There appeared to be a reduction in early blight in plants grown on red.

Peppers responded more to silver mulch compared to black, with an average 20 percent increase in marketable fruit yield and fruit size over a three-year study. Lowest yield or marketable peppers were harvested from plants grown on either white or light blue mulch. In more southern climates, below North Carolina, pepper plants grown on green IRT had similar marketable fruit yields compared to plants grown on black.

Eggplant appeared to respond more to red mulch compared to black with an average 12 percent increase in marketable fruit yield over two years. Greatest response occurred when plants were growing under temperature and water stress conditions. There may be a varietal response of eggplant to the use of plastic mulch, they said.

Cantaloupe responded more to green IRT or dark blue mulch compared to black, with an average 35 percent increase in marketable fruit yield over three years. Lowest yield of marketable cantaloupe were harvested from plants grown on either white or black mulch at this location. In more southern climates, below North Carolina, cantaloupe response to white or black mulch would be entirely different, they said.

Cucumbers and summer squash seemed to responded more to dark blue mulch compared to black, with an average 30 percent increase over three years in marketable fruit yield for cucumbers and 20 percent for zucchini. Lowest yield were harvested from plants grown on yellow mulch at the Pennsylvania farm, but, they said, in more southern climates-below North Carolina – these crops’ response to yellow mulch might be entirely different.

Onions and potatoes responded to several mulch colors including red, metalized silver and black compared to no plastic mulch, with an average 24 percent yield increase in marketable bulb or tuber yield. There was a significant difference in yield response between specific onion varieties.

Potatoes grown on the metalized silver mulch showed the highest marketable tuber yields, the coolest soil temperature and the least number of Colorado potato beetle adults. However, they said, the metalized silver mulch can be difficult to lay in the field and obtain a tight fit over a raised bed. In cool years the metalized silver mulch may also cause poor plant emergence. There was a significant difference in yield response between specific potato varieties and mulch color. Use of black or possibly red plastic mulch will reduce the highest yield of quality potatoes, they said.


 



 

 

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