- Available water capacity
Available water capacity or available water content (AWC) is the range of available water that can be stored in soil and be available for growing crops. [cite book |author=Richards, L.A. and Wadleigh, C.H. |year=1952 |chapter=Soil water and plant growth |title=Soil Physical Conditions and Plant Growth |editor=B.T. Shaw (Ed.) |series=American Society of Agronomy Series Monographs, Volume II |pages=74–251 |publisher=Academic Press |location=New York]
The concept, put forward by Frank Veihmeyer and Arthur Hendrickson, [cite journal |author=Veihmeyer, F.J. and Hendrickson, A.H. |year=1927 |title=The relation of soil moisture to cultivation and plant growth |journal=Proc. 1st Intern. Congr. Soil Sci. |volume=3 |pages=498–513 ] assumed that the water readily available to plants is the difference between
water contentat field capacity(θfc) and permanent wilting point(θpwp):
:θa ≡ θfc − θpwp
Daniel Hillel criticised that the terms FC and PWP were never clearly defined, and lack physical basis, and that soil water is never equally available within this range. He further suggested that a useful concept should concurrently consider the properties of plant, soil and meteorological conditions.
Lorenzo A. Richards[cite journal |author=Richards, L.A. |year=1928 |title=The usefulness of capillary potential to soil moisture and plant investigators |journal=J. Agr. Res. |volume=37 |pages=719–742 ] remarked that the concept of availability is oversimplified. He viewed that: the term availability involves two notions: (a) the ability of plant root to absorb and use the water with which it is in contact and (b) the readiness or velocity with which the soil water moves in to replace that which has been used by the plant.
Permanent wilting point
Nonlimiting water range
Wikimedia Foundation. 2010.
Look at other dictionaries:
available water — The water available to plants in the soil zone as defined by the interval between field capacity and wilting point  … Lexicon of Cave and Karst Terminology
Water supply and sanitation in Israel — is intricately linked to the historical development of Israel in the context of scarce water resources. Because the coastal plain of historical Palestine had few water resources, Theodor Herzl already envisioned the transfer of water from the… … Wikipedia
Water resources — A natural wetland Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial … Wikipedia
Water crisis — For other uses, see Water crisis (disambiguation). Deforestation of the Madagascar Highland Plateau has led to extensive siltation and unstable flows of western rivers. Water crisis is a general term used to describe a situation where the… … Wikipedia
Water supply and sanitation in Bangladesh — Even though the water supply and sanitation sector in Bangladesh is expanding its coverage, it is difficult to keep pace with the rapid population growth. The country used to rely mainly on groundwater, which is why the discovery of arsenic in… … Wikipedia
Water — This article is about general aspects of water. For a detailed discussion of its properties, see Properties of water. For other uses, see Water (disambiguation) … Wikipedia
Water content — Soil composition by phase: s soil (dry), v void (pores filled with water or air), w water, a air. V is volume, M is mass. Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture),… … Wikipedia
water resource — Any of the entire range of natural waters (vapour, liquid, or solid) that occur on the Earth and that are of potential use to humans. These resources include the waters of the oceans, rivers, and lakes; groundwater and deep subsurface waters; and … Universalium
Water conflicts — IntroductionAccording to the Heidelberg Institute for International Conflict Research, [Heidelberg Institute for International Conflict Research (Department of Political Science, University of Heidelberg); Conflict Barometer 2007:Crises – Wars –… … Wikipedia
Water heating — is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating. In industry, both hot water and water heated to steam have… … Wikipedia