A polyethylene mulch system that changes its predominant surface color
from black to white in the field has been developed and used to grow
tomatoes (Lycopersicon esculentum Mill. cv. Mountain Pride) and squash
[Cucurbita pepo var. melopepo (L,) Alef. cv. Dixie Hybrid]. The syste
m uses a black photodegradable polyethylene mulch placed on top of a w
hite nondegradable polyethylene mulch (photodegradable mulch overlay s
ystem), As the black photodegradable mulch degrades with increasing ex
posure to radiation, the white mulch surface is exposed, Differences a
mong plastic systems in the percentage that breaks down may be explain
ed by differential shading of the mulch by the vegetative growth of th
e crops, None of the formulations of the Plastigone brand photodegrada
ble mulches in the photodegradable mulch overlay system had an effect
on tomato or squash production, As the color of the system changed fro
m black to white, soil temperatures under the mulch decreased, Tomato
production remained unaffected in one of the two years as long as the
mulch remained black for at least the first 20 days during that season
. In year 2, the controlled mulch system color change affected neither
tomato nor squash production relative to nondegradable white and blac
k mulches used as controls.