A technician and plant physiologist test colored
plastic mulches as yield boosters for tomatoes and other crops. Click image for
story to find out more.
Can Help Cotton, Carrots--and Basil, Too
By Luis Pons
September 5, 2003
Agricultural Research Service studies have
shed more light on how the color of plastic mulch can affect food plants.
Past ARS work showed that red mulch produced larger tomatoes and
sweeter-smelling, better-tasting strawberries. More recent work with cotton,
carrots and basil focused on how color can affect the roots, stems, leaves and
seeds, as well as the fruits, of many other food and crop plants.
The ARS studies were led by plant physiologist Michael J. Kasperbauer, who
recently retired from ARS' Coastal
Plains Soil, Water and Plant Research Center at Florence, S.C. According to
Kasperbauer, colored-mulch technology's controlling factor is not the colors
themselves, but how the colors change the amount of blue light and the ratio of
far-red (FR) to red light that plants receive.
Research on cotton showed that cotton fibers grew longer in bolls exposed to
increased FR-to-red light ratios. Another study, on carrots, revealed that
concentrations of nutrients and compounds such as beta carotene and vitamin C
in the roots of food crops could be modified by reflecting the right waves of
color onto the plants' leaves.
In studies with basil, the amounts of blue, red and FR light reflected onto
developing leaves affected their size, aroma and concentration of soluble
phenolics. The phenolics are natural compounds, including tannins and pigments
that can induce color, some flavors and odors, and antioxidant activity.
Basil leaves developing above red mulches had greater area, succulence and
fresh weight than those developing above black mulch. When grown above yellow
and green mulches, basil leaves developed significantly higher concentrations
of aroma compounds and phenolics than did those of plants grown above white and
Read more about colored mulch research in the September issue of
Agricultural Research magazine.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.