Black mulching films

Stapleton JJ, Ferguson L (1996) Solarization to disinfest soil for containerized plants in the inland valleys of California. In Proceedings of the annual international research conference on methyl bromide alternatives and emissions reduction. Orlando, FL, 4-6 November 1996, p 6 Stapleton JJ, Garza-Lopez JG (1988) Mulching of soils with transparent (solarization) and black polyethylene films to increase growth of annual and perennial crops in southwestern Mexico. Trop Agric 65 29-33... 

Several years ago, Princeton Polymer Labs. contracted with a client to develop a degradable agricultural mulch film. A first generation additive system was developed and some 12,000 sq. ft. of polyethylene film containing the additive was tried out in 14 states in the U.S.A. Both black and clear films... 

The European Union (EU) countries use 160,000 tons in transparent crop covering, 148,000 tons in black silage film, 60,000 in transparent mulch films, and around 33,000 in stretch films [44]. 

The incorporation of UV stabilizer is necessary for protection against UV degradation. Enhanced UV light stability can affect the color stability and the mechanical properties of plastics. UV stabilizers protect PE from damage by sunlight in outdoor environments. Similarly, carbon black in PE mulch film protects and blocks the penetration of radiation. 

Eastar Bio meets the requirements of DIN V 54900 [31] as compostable material and is certified by DIN CERTCO (Eastar Bio 14766, max 127 pm films, Reg. No. 7W0022). The behaviour of carbon-black-filled mulching films of Eastar BIO 14766 under outdoor weathering conditions were investigated by Tocchetto and coworkers [95]. 

Figure 4 shows data for samples of PE mulch film exposed to artificial UV ageing in a Xenon weatherometer. The lifetime to embrittlement of transparent films can be reduced significantly by using the appropriate additive. Addition of carbon black to unmodified film produces a major stabilizing effect, which can easily be overcome by the additive. 

Figure 4. Performance of three different Envirocare systems in UV ageing. 25 im LLDPE mulch film with and without carbon black (3 wt%). Exposure WOM (BPT 63 3°C)...

Carbon black is used as a stabilizer in a limited number offormulations where color is not a criterioiL It not only absorbs light, but it can also react with free-radical species that might be formed. The weathering properties of polyethylene are improved by the incorporation of carbon blacks (at 2%-3% concentration). Weather-resistant wire and cable insulation, pipe for outdoor applications, films for mulching, and water conservation in ponds and canals may be made from polyethylene containing carbon black. 

Fig. 8.3. Photodegradation clear films (a) (MDPS) soil sterilization by solar heating (strawberry) and (b) mulching of Italian vegetable marrow by photodegradable black film (LDPE) [2344]. (MDPS=medium density polystyrene LDPE=low density polyethylene.)...

Plastic films are used with field mulches by growers since they help in the growth of plants and then photodegrade in the fields without the cost of removal. We can control the moisture, reduce weeds, and increase the soil temperature this improves the rate of growth in plants. For example, in a 6 ha melon farm, the yield increased by two- to threefold. Also ripening was controlled by using black polyethylene mulch (Sullivan, 2011). 

By removing weeds and eliminating soil compaction, mulch eliminates the need for cultivation. By this we further avoid damage to roots and stunting or killing of plants. Not only this, fertilizer and water requirements of the field get controlled. To trap heat, transparent polyethylene is more effective compared to black or smoke-grey films. Due to clear films, soil temperature may rise to 5.58°C, but under black Alms, it is 1.7-2.78°C. The temperature of the atmosphere will be maintained by the polymer bags. 

---