[MCN] Water/Ag: A level field doesn't make irrigation decisions easy

[Lance Olsen]

Study finds significant variability in soil moisture across leveled fields
December 10, 2015

https://dl.sciencesocieties.org/story/2015/dec/fri/study-finds-significant-variability-in-soil-moisture-across-leveled-fields

Scientists, extension personnel, and crop 
advisers often hear, "This farm field was 
laser-leveled, and has only one soil type. So 
there is hardly any variability to justify 
variable-rate irrigation."

In a study that published in September-October 
2015 issue of Soil Science Society of America 
Journal, a team of researchers from Colorado and 
China put these statements to the test.

Topography is the main driver of spatial patterns 
in soil water content across crop fields, the 
team explains. However, in leveled fields, 
factors such as soil texture, soil depth, and 
organic matter content, among others, can still 
influence the spatial pattern of soil water 
content.

Using a neutron probe, the researchers measured 
the soil water content of leveled fields at a 
high spatial density, at five depths, and over an 
entire season. Doing so enabled them to study 
changes in soil water content from one location 
of the field to another, as well as changes 
happening between superficial and deeper soil 
profiles, and with time.

They discovered two significant findings: Soil 
water content does vary across levelled fields, 
and the spatial patterns related to this 
variability themselves change over time and 
across depths.
These findings are eye-opening for farmers 
managing irrigation on leveled fields, and should 
encourage them to think twice about their current 
practices.
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"Booms have consequences."

James Grant. Money of the Mind : Borrowing and 
Lending in America from the Civil War to Michael 
Milken. Farrar Straus Giroux. 1992.

Introduction, p.5.
"Real estate speculation must be as old as the 
land - in the United States, it is certainly as 
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was no doubt made around the time of the opening 
of the first bank."

"Still, the boom of the 1980s was unique. Not 
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actively than it had ever done before to absorb 
the inevitable losses."

Afterword: End of the Line. Pp. 436-437
"In the early 1990s a number of long-running 
trends were apparently cresting Š. Tommy 
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returned home from camp in the summer of 1990 to 
find his name inscribed on a MasterCard complete 
with a $5,000 credit line.  ' I jumped up and 
down and said Wow - the hologram was cool,' 
Tommy told the Washington Post. 'But it sure made 
me wonder who was running that bank'."

James Grant. Money of the Mind: Borrowing and 
Lending in America from the Civil War to Micheal 
Milken. Farrar Straus Giroux. 1992.
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