Solarization
Stapleton, J. J., Molinar, R. H., Lynn-Patterson, K., McFeeters,
S. K., and Shrestha, A. 2005. Methyl bromide alternatives.
Soil solarization provides weed control for limited-resource and organic
growers in warmer climates. California Agriculture 59 (2):84-89. PDF
Abstract: This paper describes the use of soil solarization
technology for weed management, as conducted by the University of California
Kearney Research and Extension Center for 8 years. The project consists
of laboratory development, small-plot experimentation and on-farm validation
of data in San Joaquin Valley specialty crops. Based on the weed research
conducted and the small-scale tests on parsley, all of the solarization
treatments were equally effective in providing weed control, with weed
numbers reduced by 86-94% and weed biomass reduced by 94-99% over the
untreated control. Furthermore, in an on-farm study in Fresno-Clovis area
of San Joaquin Valley during 1997-99, solarization provided effective
weed control for strawberries at a much lower cost than methyl bromide,
with comparable yields.
Link: http://calag.ucop.edu/0502AMJ/pdfs/Solarization.pdf
Stapleton, J. J., Elmore, C. L., and DeVay, J. E. 2000. Solarization and biofumigation help disinfest soil. Calif. Agric. 54 (6):42-45. PDF
Abstract: Preplant soil fumigation
with methyl bromide is scheduled to be phased out by 2005. Chemical and
nonchemical alternatives are being researched and identified. Soil solarization
and/or biofumigation
can help fill the gap in certain cases. These alternative methods of soil
disinfestation are also of value to organic growers, home gardeners and
others who will not or cannot use the soil fumigation chemicals employed
by many conventional commercial growers.
Link: http://californiaagriculture.ucop.edu/0006ND/pdfs/solarize.pdf
Johnson, M.S. and Fennimore, S.A. 2005. Weed and Crop Response to Colored Plastic Mulches in Strawberry Production. HortScience Vol. 40(5).
Abstract: The phase out of methyl bromide has forced strawberry (Fragaria × ananassa Duchesne) growers to consider the use of cultural methods such as colored mulches to enhance weed control. Black plastic mulch controls most weeds; however, black mulch often does not warm the soil as well as clear mulch. Soil warming with clear mulch is desirable for early season markets, but clear mulch does not control weeds. Neither black nor clear mulches combine the ideal weed control and soil warming characteristics required. Seven colored mulches, as well as clear, black and no mulch were evaluated in California organic and conventional strawberries to identify mulch factors associated with weed control and soil warming. Laboratory and greenhouse experiments were also conducted to isolate the effects of light transmittance through mulch on weed germination and growth. The effect of mulch color on transmittance of photosynthetically active light (400 to 700 nm) through mulches was the key weed control factor, and was more important than the effect of mulch color effect on weed germination. Satisfactory weed control was provided by all mulches except clear, blue and red-brown laminated. Clear and black mulches provided the greatest soil warming in sunny and cloudy climatic conditions, respectively, although plants in clear mulched conventional production system plots produced the highest yield of marketable berries. Green and brown plastic mulches provided the best combinations of soil warming and weed control benefits at all trial locations.
Link: http://www.cababstractsplus.org/google/abstract.asp?AcNo=20053172310
Steam Treatments
For more information on steam treatments see, the UNEP Methyl Bromide Technical Options Committee 2006 report., sections 5.8 and 5.9.