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Mulch film generally used to eliminate
weeds around plants has been predominantly in black colour. Coextruded
white (for exterior) and black (for interior) mulch films have been
in use for the last 2-3 decades, to prevent burning of plants due
to excessive heat absorption through black colour. Israel, was the
first in developing coloured mulch films for modification of light
energy to achieve higher yields. Infact, Israel made the desert
bloom with the coloured mulch films. Experimental work, that has
been going for the last 1-2 decades, with different colours for
different products has shown that tomatoes grow more with red colour,
while green produces similar results with melons and green chillies.
Apparently, blue film improves productivity of brinjal. Metallized
silver colour film seems to improve growth of strawberries. Interestingly,
colored mulch films have better impact on productivity in colder
climates as compared to tropical regions. Research is being conducted
to develop photo-selective films that preferentially absorb or reflect
different wavelengths of light energy. These photo-selective mulch
films are designed for specific crops, climatic conditions etc.
New developments on mulch film include barrier films that are impervious
to Methyl Bromide used as fumigant to kill bacteria, such films
helps in retaining Methyl Bromide under the cover. Infact, "VIF"
(known as Virtually Impermeable Film) is now commercially used in
Europe. Such films have multiple layers, including a Polyamide barrier
layer.
Continuing developments in mulch films could bring about radical
changes in the future from the pioneering concept of black film
to only kill weeds and thereby achieve higher growth of agricultural
products.
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