There are numerous studies of the use of plastic mulches in vegetable production, but there is little documentation of their
use with dry beans (
Phaseolus vulgaris
L.) in single and double cropping. The objective of this study was to grow dry beans
over two consecutive growing seasons using the same plastic mulch of different colors and examine the influence of soil
temperature on growth and yield. The experiment was conducted in Saltillo, Coahuila, Mexico, in the spring and summer
of 2008. The treatments included four colored plastic mulches: white-on-black, black, silver-on-black, aluminum-on-black,
and bare soil as a control. The experimental design was a randomized complete block with four replicates. The percentage
of photosynthetically active radiation (PAR) reflected from the plastic tended to be highest with the white-on-black mulch
and lowest with the black mulch. Mean soil temperature under the plastic mulch decreased with the increasing percentage
of reflected PAR. Mean soil temperature exhibited a relationship of 98% and 99% to yield in the first and second growing
season, respectively. Photosynthetically active radiation had a relationship of 98% and 86% to yield in the first and second
growing season, respectively. The effect of the colored plastic mulch on yield was significant (p ≤ 0.05) in the first growing
season but not in the second, where plastic mulch and bare soil treatments had similar yields, indicating that plastic mulches
do not always increase yield.
