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Dr. M.K. Mahendrappa
Soil is the Basis
of Life
Dr. Mahendrappa's research focuses on understanding the nutrient
cycling processes in the forest ecosystems. Using this basic information
he is seeking means to establish relationships between forest harvesting
options and soil productivity, specifically:
- consequences of removing varying intensities
of forest biomass from harvested areas
- alternative harvesting options
- impacts on soil chemistry and soil productivity
Dr. Mahendrappa employs a special tool,
called a lysimeter, to collect soil solution samples without disturbing
the soil. Various nutrients/elements are measured in the soil solution
to evaluate the potential impacts of different types of harvesting
regimes.
- Lysimeters collect leachate from the soil,
which can then be analyzed for nutrient content.
- Lysimeters consist of a glass housing,
6 cm in diameter, fitted with a fritted glass disk fused in place.
The fine pores in the fritted disks allow only soil solutions
through and keep soil particles out. The lysimeter connected to
a sample collection bottle, to a vacuum generating system is called
a lysimeter system.
- By analyzing the concentrations of nutrients
in leachates collected in the forests subjected to various harvesting
regimes, we can evaluate the potential effects of harvesting and
site preparation methods on soil quality.
Soil is the basis of life on earth. The
soil is a living entity, containing millions of organisms essential
to the cycling of nutrients. The soil acts as a filter protecting
lakes and streams.
- Results of studies indicate that a high
proportion of inherent nutrient reserves is removed from forests
in whole-tree harvesting, compared to conventional (stem only)
harvesting.
- Nutrient depletion of the soil leads to
reduced soil fertility.
- As a result of whole-tree harvesting,
the surface soil temperature increases, which in turn causes faster
decomposition of soil organtic matter (OM)- the storage of all
nutrients.
- Increased incidence of solar radiation
results in faster biochemical reactions that ultimately lead to
(OM) decomposition and site degradation.
- Degraded (acidified) soils are incapable
of sustaining healthy tree growth during subsequent rotations.
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