Why is microbial activity less in dry soil?
Researchers investigate how
microbes respire in
dry conditions. Research has shown that
microbial activity in
soil reduces as
soil moisture levels decrease
, a result of both physiological stress and physical factors.
Letting your
soil dry out is like a human not drinking water for a week. Its not going to kill
you but
you will not function properly. Once peat based mixes
dry out they become very water repellent, and as
it may seem as if your watering alot, its just running right
out the bottom....
Dry soil conditions impact on nutrient availability
These extended periods of very dry soil conditions can reduce Nitrogen (N), Phosphorus (P) and Potassium (K) availability to plants.
Nitrogen
For N, low soil moisture decreases soil microbe activity. Microbes play an important role in breaking down organic matter and converting organic N to inorganic nitrate nitrogen, a process called mineralization. In dry soils with low N mineralization, there could be less plant available N in the form of either ammonium (NH4+-N) or nitrate (NO3--N) nitrogen. In dry soils, the risk of NO3--N loss through leaching or denitrification is reduced. While this means there is more soil N available to crops, plant uptake can be reduced. When the rains return there a can be a sudden increase in soil nitrogen. If this occurs late in the season it may be detrimental for perennial crops going into dormancy.
Phosphorus
Reduced soil microbial activity in soils with low moisture can reduced organic matter decomposition and the mineralization of organic P to inorganic P. Phosphorus moves from higher concentrations in the soil to lower concentrations in plant roots by diffusion. As soils become drier, less diffusion occurs. This is because the water film around the soil particles becomes thinner, making diffusion to the plant root more difficult.
Potassium
Decreased movement of K to the plant roots occurs in dry soil. As soil dry, clay minerals become dry and shrink, trapping K tightly between mineral layers. Once trapped, K is unavailable to plant roots for uptake. This K is released and plant available again when the soil moisture increases. Reduce K uptake during extended dry soil conditions can show up as low K levels in tissue samples or high K levels in a post-harvest soil sample.
Remember
" what is visible represents what is invisible " 
a have a little purple bud to try at 4.20pm
.. i think i have another seed from same pack i might self it this is the white widow 