Diagnosing Abiotic Disorders II
In this blog I continue to examine maladies caused by environmental conditions in the absence of a disease agent or insect.
Salinity
Salt in soils or water is simply the presence of too many soluble ions in the soil-water solution. This tends to happen in dry climates where evaporation rates exceed precipitation rates. In these climates salts accumulate in soil when surface waters pick up minerals from soil that is high in precipitated salts. In wetter climates water leaches salts from soil so surface waters (rivers and lakes) have fewer dissolved salts. Also, in dry climates irrigation is often a must and irrigation sources usually have high amounts of dissolved salts. In high salt environments plants must use energy to increase their own salt balance at the root interface to make uptake of fresh water through their membranes possible. This energy is thus not available for growth. Salt affected plants are often smaller, even stunted depending on salinity levels and are more susceptible to root pathogens as their roots are more likely to be “leaky” giving pathogens chemical signals of their susceptibility. Salt damaged leaves often show “edge” necrosis or burning on the oldest leaves.
Salt affected soils should not be allowed to dry out as roots will be damaged. Leaching to dissolve salts and move them below the root zone is one approach to prevent further symptoms.
Soil compaction
Soil compaction is the increase in soil bulk density beyond a point where roots function and grow. Bulk density is a measure of soil compactness and is calculated as the weight of dry soil per volume…
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