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A hygrometer is an instrument which measures the humidity of air or some other gas: that is, how much of it is water vapor. [1] Humidity measurement instruments usually rely on measurements of some other quantities, such as temperature, pressure, mass, and mechanical or electrical changes in a substance as moisture is absorbed.
A simple soil moisture sensor for gardeners. Soil moisture sensors measure the volumetric water content in soil. [1] Since the direct gravimetric measurement of free soil moisture requires removing, drying, and weighing of a sample, soil moisture sensors measure the volumetric water content indirectly by using some other property of the soil, such as electrical resistance, dielectric constant ...
In agriculture, a soil test commonly refers to the analysis of a soil sample to determine nutrient content, composition, and other characteristics such as the acidity or pH level. A soil test can determine fertility , or the expected growth potential of the soil which indicates nutrient deficiencies, potential toxicities from excessive ...
The report A Comprehensive Assessment of Water Management in Agriculture [1] was published in 2007 by International Water Management Institute and Earthscan in an attempt to answer the question: how can water in agriculture be developed and managed to help end poverty and hunger, ensure environmentally sustainable practices, and find the right balance between food and environmental security?
Agricultural water balances are also used in the salt balances of irrigated lands. Further, the salt and water balances are used in agro-hydro-salinity-drainage models like Saltmod . Equally, they are used in groundwater salinity models like SahysMod which is a spatial variation of SaltMod using a polygonal network.
Capacitance hygrometers are not affected by most volatile chemicals and can be much smaller than other alternative sensors. They do not require cleaning, but are less accurate than dew point hygrometers (+/- 0.015 a w). They should have regular calibration checks and can be affected by residual water in the polymer membrane (hysteresis).
It forms part of a standard weather station and holds instruments that may include thermometers (ordinary, maximum/minimum), a hygrometer, a psychrometer, a dewcell, a barometer, and a thermograph. Stevenson screens may also be known as a cotton region shelter, an instrument shelter, a thermometer shelter, a thermoscreen, or a thermometer screen.
The Penman-Monteith equation approximates net evapotranspiration (ET) from meteorological data as a replacement for direct measurement of evapotranspiration. The equation is widely used, and was derived by the United Nations Food and Agriculture Organization for modeling reference evapotranspiration ET 0 .