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bioplasticsMAGAZINE_1306

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bioplasticsMAGAZINE_1306

People Films | Flexibles

People Films | Flexibles | Bags Infrared transparent colors By Dr. J. Carlos Caro Export Manager, Grafe Color Batch GmbH Blankenhain, GERMANY Mulch films can be used when cultivating crops in order to achieve earlier and higher yields as well as to enhance the quality of many different types of vegetables, such as tomatoes, eggplants, water melons, peppers and cucumbers. Listed below are the advantages of using plastic mulch films as described by W.J. Lamont, of the Department of Horticulture at Kansas State University (www. agnet.org). 1. Earlier yields: Raising the temperature of the soil makes it possible to achieve earlier yields. Using a black plastic mulch film can result in a 7 to 14-day earlier yield. Transparent mulch films can reduce time to yield by 21 days. 2. Soil moisture: The use of plastic mulch films considerably decreases the loss of soil moisture through evaporation. This means that the soil remains moist and the cost of irrigation can be reduced. Under these conditions, vegetable yields can be almost doubled in comparison to the yields of crop plantings without plastic mulch. 3. Weeds and unwanted flora: Black and combinations of black / white plastic mulch films prevent unwanted flora from appearing and suppress the growth of weeds. 4. Leaching of agrochemicals and fertilizers: The protection provided by plastic mulch films prevents leaching and run off of valuable agrochemicals and fertilizers. 5. Reduced soil compaction: The protective mulch film keeps the soil below it loose. There is reduced soil compaction because of low moisture loss. Formation and growth of roots is guaranteed by the improved absorption of oxygen and the production of nutritive mediums. 6. Control of roots: Outside of the areas covered by plastic mulch film, the formation of undesirable weed roots can be kept under control through the use of pesticides and agrochemicals. 7. Cleaner produce: Fruit and vegetables under plastic mulch films can be kept cleaner as they are protected from dirt and soil. 8. Higher growth and yield: Photosynthesis for plant growth requires the absorption of CO 2 and its transformation into oxygen. The use of plastic mulch raises the CO 2 concentration beneath the film as the gas cannot diffuse out of the film. This allows the green leaves to perform the process of photosynthesis. 9. Retention of gaseous nutrients and fertilizers: Plastic mulch films protect sprayed chemical fertilizers from diffusing out through the film so that they can be better absorbed. 10. Flooding: Fields covered with plastic mulch are typically laid out with drains so that excess water can run off in the case of heavy rains. This reduces the danger of flooding and the risk of crops drowning. 18 bioplastics MAGAZINE [06/13] Vol. 8

From Science & Research for mulch films Colored plastic mulch and its effects on plant growth by means of photoselectivity are now, and have been for years, the subject of numerous studies. The theory maintains that colored plastic mulch, when it is transparent, displays advantages over traditional black plastic mulch due to the transmission and absorption of certain wavelengths of light. This can lead to higher temperatures in the earthbanks and under the earth. There have been many more studies done on this topic in the USA and Israel than here in Europe. The range of commercially available products supplied by film manufacturers and plastic granulate producers is also more extensive in these countries. Plastika Kritis and Kafrit are two manufacturers of additive and color masterbatches for agrofilms that have supplied similar products in earlier years. Plastika Kritis offers the products Brown 70964 and Brown 70869 as masterbatches. Recommended addition is 20% for mulch films with a thickness of 20-30 µm. Both masterbatches suppress weed growth due to the dark color and keep the underlying soil warmer by allowing heat to pass through. 70964 contains an additional IR absorber (such as chalk / talc) which traps the warmth by preventing heat from escaping at night. Kafrit in Israel added the product LDPE MB Brown & PA L -8660 to its portfolio in 2006. This is also a color masterbatch that is used to produce brown plastic mulch. Kafrit recommends adding 5 to 15% depending on the film thickness of the mulch and on the desired degree of heat permeability. Research being conducted in the Department of Horticulture at Pennsylvania State University is also worth mentioning. M.D. Orzolek and L.Otjen have been performing extensive research on tomatoes using different colored polyethylene mulches. Studies performed at the Weihenstephan University of Applied Science (under the direction of Ms. K. Kell) in 2006 examined the effect of different colored plastic mulches on the cultivation of kohlrabi and lettuce and looked at the influence of temperature on growth. An article published in the year 2007 (bioplastics MAGAZINE issue 02/2007) by FKuR introduced an innovative black plastic mulch made of polylactide. FKuR announced that it had been working together with Oerlemans Plastics and the Fraunhofer UMSICHT since 2004 on the development of this product and was now ready for market launch. The release described the PLA blends as a mixture of PLA (polylactide) and other biodegradable polymers and additives. Oerlemans Plastics b.V. Genderen, Netherlands, had carried out the industrial production and application testing of the PLA mulch. It was reported that the innovative mulch film had the advantage over other biodegradable films, of decomposing significantly slower and being more resistant to fluctuating climatic conditions. Already in the year 2004, the FKuR Kunststoff GmbH had begun with the first tests for biodegradable mulch films. The degradation behavior of the film under open-air conditions was studied in the lab. The bioplastics MAGAZINE [06/13] Vol. 8 19

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