Search results
Results From The WOW.Com Content Network
Because grass grub build up large colonies in the soil, disease can spread quickly and be devastating to the population. The most common disease of the New Zealand Grass Grub is Amber disease . Amber disease is a chronic infection of the stomach of grass grub larvae, and is caused by two strains of bacteria, Serratia entomophila and S ...
An air gap, as related to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture. [1] Air gaps of appropriate design are legally required by water health and safety regulations in many countries. An air gap is the simplest form of a backflow prevention device.
Soil bulk density is equal to the dry mass of the soil divided by the volume of the soil; i.e., it includes air space and organic materials of the soil volume. Thereby soil bulk density is always less than soil particle density and is a good indicator of soil compaction. [ 47 ]
The pore space of soil contains the liquid and gas phases of soil, i.e., everything but the solid phase that contains mainly minerals of varying sizes as well as organic compounds. In order to understand porosity better a series of equations have been used to express the quantitative interactions between the three phases of soil.
If a soil sample has distinct gaps in the gradation curve, e.g., a mixture of gravel and fine sand, with no coarse sand, the sample may be gap graded. Uniformly graded and gap graded soils are both considered to be poorly graded. There are many methods for measuring particle-size distribution. The two traditional methods are sieve analysis and ...
At the low field, the permeable iron in the magnetic circuit of the generator is not saturated, therefore the reluctance almost entirely depends on the fixed contribution of the air gap, so the part of the curve that starts at the point of origin is a linear "air-gap line" (output voltage is proportional to the excitation current).
Soil is dry for at least half of the growing season and moist for less than 90 consecutive days; common in arid (desert-like) regions. Xeric: Soil moisture regime is found in Mediterranean-type climates, with cool, moist winters and warm, dry summers. Like the Ustic Regime, it is characterized as having long periods of drought in the summer.
Soil macropores are a vital part of soil structure and their conservation is critical to sustainable management of our soil resources. This is particularly true to soils that are constantly subject to human disturbance, such as tilled agricultural fields where the shape and size of macropores can be altered by tillage.