Agriculture Reference
In-Depth Information
extent. Therefore, an increase in available mineral nutrients in soil can
play a major role in the effect following solarization, including improved
plant health and growth, and reduced fertilization requirements. Also, so-
larization also causes important biological changes in treated soils. Staple-
ton and DeVay (1995) reported the destruction of many mesophilic micro-
organisms creates a partial biological environment in which substrate and
nutrients in soil are made available for recolonization.
12.5
HORTICULTURAL IMPORTANCE OF SOIL SOLARIZATION
Soil solarization is effective when applied to land before and/or during the
establishment of new orchards or vineyards. Solarization been successful-
ly used on a large scale to reduce
Verticillium
wilt symptoms in young pis-
tachio nut orchards and has also been successfully used in vineyards (
Vitis
spp.), apple (
Malus
spp.), mango (
Mangifera
spp.), avocado, stone fruit,
citrus (
Citrus
spp.) and olive orchards. In an orchard or vineyard, clear
plastic is either placed around the bases of individual tree or connected to
strips placed within and between the tree rows. For best results, begin so-
larization as soon as trees are planted. Partial shading by young trees does
not prevent soil heating, nor does soil solarization appear to bother most
young trees during the treatment. However, solarising certain species of
trees, such as herbaceous perennials, avocado and apple, almond, mango,
and citrus trees, with clear plastic may result in plant damage especially
when trees are young. In addition to killing soil-borne pests, solarization
of orchards can greatly reduce the amount of water needed for irrigation
and increase the growth, large commercial orchards, the cost of postplant
solarization should be compared to the benefits before making a treatment
decision. Earlier research efforts have shown that pests that are not eradi-
cated by solarization may recolonize roots and soil, and pathogens and
nematodes may survive in roots remaining in the soil.
12.6
SOIL PREPARATION
Solarization is most effective when the plastic sheeting is placed in close
contact with a smooth soil surface. Ideal soil preparation involves disking
or turning the soil by hand to break up clods followed by smoothing the
