soil moisture

Old Rocks

Diamond Member
Oct 31, 2008
63,085
9,749
2,040
Portland, Ore.
http://www.eurekalert.org/pub_releases/2010-10/osu-lt100110.php

Public release date: 10-Oct-2010
[ Print | E-mail | Share ] [ Close Window ]

Contact: Beverly Law
[email protected]
541-737-6111
Oregon State University

Land 'evapotranspiration' taking unexpected turn: huge parts of world are drying up
CORVALLIS, Ore. – The soils in large areas of the Southern Hemisphere, including major portions of Australia, Africa and South America, have been drying up in the past decade, a group of researchers conclude in the first major study to ever examine "evapotranspiration" on a global basis.

Most climate models have suggested that evapotranspiration, which is the movement of water from the land to the atmosphere, would increase with global warming. The new research, published online this week in the journal Nature, found that's exactly what was happening from 1982 to the late 1990s.

But in 1998, this significant increase in evapotranspiration – which had been seven millimeters per year – slowed dramatically or stopped. In large portions of the world, soils are now becoming drier than they used to be, releasing less water and offsetting some moisture increases elsewhere.

Due to the limited number of decades for which data are available, scientists say they can't be sure whether this is a natural variability or part of a longer-lasting global change. But one possibility is that on a global level, a limit to the acceleration of the hydrological cycle on land has already been reached.

If that's the case, the consequences could be serious.

.....................................................................................................................

###

This study was authored by a large group of international scientists, including from OSU; lead author Martin Jung from the Max Planck Institute for Biogeochemistry in Germany; and researchers from the Institute for Atmospheric and Climate Science in Switzerland, Princeton University, the National Center for Atmospheric Research in Colorado, Harvard University, and other groups and agencies.

The regional networks, such as AmeriFlux, CarboEurope, and the FLUXNET synthesis effort, have been supported by numerous funding agencies around the world, including the Department of Energy, NASA, National Science Foundation, and National Oceanic and Atmospheric Administration in the United States.


Editor's Note: The study citation is: Jung, M., M. Reichstein, P. Ciais, S.I. Seneviratne, J. Sheffield, M.L. Goulden, G. Bonan, A. Cescatti, J. Chen, R. de Jeu, A.J. Dolman, W. Eugster, D. Gerten, D. Gianelle, N. Gobron, J. Heinke, J. Kimball, B.E. Law, L. Montagnani, Q. Mu, B. Mueller, K. Oleson, D. Papale, A.D. Richardson, O. Roupsard, S.W. Running, E. Tomelleri, N. Viovy, U. Weber, C. Williams, E. Wood, S. Zaehle, K. Zhang. 2010. A recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature xxxx: xxx-xxx. DOI 10.1038/nature09396.
 
Last edited:
Global warming is going to cause massive changes in the world, no question.

What happened in Russia this summer may be just a small example.
 
Crops don't need soil moisture, and haven't needed it for quite some time. They absorb moisture from the air. The ground is so polluted from agri-chemicals that it is sterile and merely serves as a physical support mechanism for roots. It's no longer referred to as agriculture, but terra- culture.

You know- like aqua-culture only without the water?
 

I put that very same concept to a friend of mine whose family has been farming for three generations now. He said "yeah that's about right".

I work side by side with agriculture. I have dug their dirt and have examined the turned soil. I have yet to see a single worm or any other form of life. It's dead loam.

Get your knees dirty, O.R. Get down and dirty, bitch. :D
 
Well, I have not examined the farms of the Mid-west and East that closely. If the farmers have used the chemicals to the degree that they have killed the soil, then they have destroyed their primary resource. A real golden goose situation.

The agriculture with which I am most familiar is that of the ranchs in Eastern Oregon. The areas there are irrigated, alfalfa, and their gardens, have a huge worm population, which I have slightly depleted, on occasion, for fishing.

I do remember an area that I saw driving between Philadelphia and Gettysburg, in the Amish country, that was incredibly lush looking. I would assume the soil is still in good shape there.
 
Planting Kudzu is another good soil conservator in areas prone to landslides and mudslides...
icon_cool.gif

UN: Lentils, Chickpeas Can Help Reverse Dangerous Trend of Soil Erosion
December 06, 2016 — Planting more lentils, chickpeas and other pulses will improve the health of the world's soils that have reached critical levels, threatening to worsen hunger and poverty levels, the U.N. Food and Agriculture Organization (FAO) said on Monday.
About a third of the world's soils are degraded because of soil erosion, contamination, urbanization and other issues. This is a rise from the early 1990s, when it was estimated to be between 16 and 24 percent, said Ronald Vargas, soils and land officer at the U.N. agency, and co-editor of a report published on Monday. With cities expanding and taking up more land, and the population growing and needing more food, the pressure on remaining land is growing. "If our soil is not healthy enough, we will have serious issues," Vargas told the Thomson Reuters Foundation. It will take 15 years or more and a huge amount of investment to restore the soil, he said.

Pulses transfer nitrogen from the atmosphere to the soil and can be grown practically anywhere. Cereals grown after pulses yield 1.5 tons more per hectare, equivalent to adding 100 kilos of nitrogen fertilizer, the FAO report said. "Soils and pulses embody a unique symbiosis that protects the environment, enhances productivity, contributes to adapting to climate change and provides fundamental nutrients to the soil and subsequent crops," FAO director-general Jose Graziano da Silva said in a statement. The main form of degradation is soil erosion - the loss of the topsoil by wind, rain or excessive use of machinery. The world is currently losing soil 10 to 20 times faster than it is replenishing it, according to the FAO report.

CB2CB3F2-4AA4-42F7-8A66-A75A761444BE_w250_r1_s.jpg

An employee collects lentils from a container inside a grocery store at a residential area in Mumbai, India.​

It takes nature between 100 and 1,000 years to produce 1 cm of soil, and if poorly maintained it can be lost in a single rainfall, or high wind, Vargas said. "It is almost impossible to bring back that soil loss. So what you can do is try to avoid losing more," he said. A study in India shows how growing pigeon peas reduced soil runoff and erosion by up to 59 percent, according to the report. Healthy soil acts like a sponge, absorbing even very heavy rainfall, and filtering it. If the soil is compacted by overuse of agricultural machinery, or walking, the rain is not absorbed, and instead washes the soil away and may cause flooding.

A layer of healthy soil also reduces harmful greenhouse gases. The first metre of soil contains as much carbon as exists in the atmosphere and all vegetation combined. If it is poorly managed, carbon is released into the atmosphere, Vargas said. The consequences of not managing soil better are serious, Vargas said. "We will be facing poverty, we will have more issues of food security ... we will not be able to deal with ... floods and drought. So we will compromise our future," he said.

UN: Lentils, Chickpeas Can Help Reverse Dangerous Trend of Soil Erosion
 

Forum List

Back
Top