“Be it deep or shallow, red or black, sand or clay, the soil is the link between the rock
core of the earth and the living things on its surface. It is the foothold for the plants we
grow. Therein lays the main reason for our interest in soils.” --- Roy W. Simonson,
USDA Yearbook of Agriculture, 1957.
The British naturalist Charles Darwin (1809–1882) was probably the first scientist to
examine a soil profile and suggest factors responsible for the structure of the various
THE CYTOKININS WERE DISCOVERED in the search for factors that stimulate plant cells to divide (i.e., undergo cytokinesis). Since their discovery, cytokinins have been shown to have effects on many other physiological and developmental processes, including leaf senescence, nutrient mobilization, apical dominance, the formation and activity of shoot apical meristems, floral development, the breaking of bud dormancy, and seed germination.
Every year, farm operators apply more than 12 million tons of nitrogen fertilizer and 8 million tons of phos-
phorus fertilizer to agricultural land in the U.S.
Unless carefully managed, much of it is carried off the fields
by runoff or percolates into drainage systems, eventually ending up in streams, rivers, lakes and underground
aquifers. Animal manure from livestock is also an important contributor to nutrient pollution, particularly phos-
This book is a compilation of 29 chapters focused on: pesticides and food production, environmental effects of pesticides, and pesticides mobility, transport and fate. The first book section addresses the benefits of the pest control for crop protection and food supply increasing, and the associated risks of food contamination.
Cushing's Syndrome is a disease caused by an excess of cortisol production or by excessive use of cortisol or other similar steroid (glucocorticoid) hormones. Cortisol is a normal hormone produced in the outer portion, or cortex, of the adrenal glands, located above each kidney. The normal function of cortisol is to help the body respond to stress and change. It mobilizes nutrients, modifies the body's response to inflammation, stimulates the liver to raise the blood sugar, and it helps control the amount of water in the body.
The residence time that contaminants and nutrients remain in lichen tissue differs among elements (Pucket
1985). Macronutrients, such as nitrogen, sulfur, potassium, magnesium and calcium are comparatively
mobile and easily leached and therefore measurable changes in tissue concentrations can occur over weeks
or months with seasonal changes in deposition (Boongaprob et al. 1989). In one study, mobile elements
reached the same levels in transplants as the indigenous lichens within four to six months (Palomäki et al.