Plastics mulch

Solarization effects on weed population was hypothesized to be due to different mechanisms, such as changes in cell metabolism and ultrastructure (Singla et al. 1997), microbial parasitism on seeds weakened by sublethal temperatures, seed dormancy interruption by raising temperatures, and foliar scorching of weeds under the plastic mulch (Egley 1990 Katan and DeVay 1991). Moreover, imbalance of 02 and C02 or release of acetaldehyde, ethylene, and other volatile toxic compounds were also reported as accounting for weed death (Rubin and Benjamin 1984 Gamliel et al. 2000). 

Ham JM, Kluitenberg GJ (1994) Modeling the effect of mulch optical properties and mulch-soil contact resistance on soil heating under plastic mulch culture. Agric For Meteorol 71 403 124. doi 10.1016/0168-1923(94)90022-1... 

Lamont WJ Jr (1993) Plastic mulches for the production of vegetable crops. HortTecnology 3 35-39... 

Waggoner PE, Miller PM, De Roo HC (1960) Plastic mulching principles and benefits. Conn Agric Exp Stn Bull 643... 

Mulching is a key technique in organic soil management but it is also an incredibly useful way of suppressing weeds. A thick covering of a loose mulch will prevent weed seeds in the soil from germinating. A mulch membrane—such as cardboard or permeable plastic—laid over the soil will prevent weed growth. 

Woven plastic provides medium-term weed control and allows water to penetrate. Cover with loose mulch to extend life. 

Kept in the dark Just as potatoes are earthed up while growing (seep.249)—or grown under mulches—to prevent the tubers from being exposed to the light, so they must be protected in storage. Clear plastic bags are the worst form of storage. Always close the sack once you have taken what you need. 

Mulches, both plastic and organic, can serve as a barrier against diseases that are spread partially by soil splashing onto plants. Early blight and buckeye rot of tomatoes are examples. Mulches will not eliminate these diseases, bnt may delay their onset and eventual severity. Organic mulch applied around tomatoes while the soil is still cool may delay ripening a few days, but black plastic mulch will warm the soil and speed ripening. 

Gardeners should be aware that mulches can serve as hiding places for some insects and increase the incidence of some diseases by retaining too much water around plant roots. Black plastic, for example, may increase damping off and root rot of peas and... 

Reflective plastic mulch in various colors and aluminum foil mulch can be used to repel thrips and aphids on some vegetables. Reducing aphid and thrips infestations may also reduce the spread of virases carried by these insects. These mulches apparently confuse thrips and aphids, making it more difficult for them to locate vegetable plants. 

There are two kinds of mulches, organic and inorganic. Black plastic is the most common inorganic mulch. It absorbs sunlight and increases soil temperature compared to un-mulched soils. In addition to controlling weeds and retaining soil moisture, mulch reduces erosion and the need to cultivate. 

Plastic mulch is applied over moist, worked, fertilized soil a week or so before planting. Because soil beneath plastic remains moist, plant roots grow more profusely near the surface. Crusting is reduced. Earthworms and soil microbes are also encouraged by plastic mulches. The result is that soils beneath black plastic mulch generally are looser, easier to work and have better tilth than un-mulched soil. 

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