Hopefully the drought is coming to an end in Central California. For our native oak tree population, as well as other deciduous trees, we offer the following information:
The above ground level effects of drought on plants can be easily seen. They include wilting, leaf scorch, some defoliation, stunted growth, branch die-back, and possible death of the plant. The below ground level soil life affected by drought is less obvious and can be unknown.
As soils become dry, the fine feeder roots in the upper soil surface will begin to die if soils remain dry, thus putting the root system out of balance with the amount of foliage found above ground. When rain does return, the plant may not be able to take full advantage of this much-needed water because of its reduced root mass and reduced soil biology.
Soil biology is vital to rapid healthy root growth. Soil microbial communities (soil foodweb) improves water holding capacity by binding soil particles together forming aggregates. They also aid roots by keeping nutrients near root zones and compete with disease-causing microbes. They filter and degrade pollutants as water flows through soil, break down complex carbons. Mycorrhizae fungi assist in plant roots development.
Beneficial soil microbes are found most concentrated in properly made compost. Quality control in the balancing of energy (carbon, C) and nutrients (primarily nitrogen, N) is the beginning point. Then having adequate moisture and sufficient oxygen to support an aerobic environment is critical.
-Cristy, Black Diamond VermiCompost