Wednesday, February 1, 2012

Texas vs US Soybean Yields

I was curious how the 2011 drought in Texas translated into crop yield statistics.  I happened to pick on soybeans to start with, and generated the graph above, which shows whole-US and Texas soybean yields.  Sure enough the drought has caused a 30% or so drop in Texas yield in 2011 versus  the 2000-2010 average.  However, for the US as a whole, 2011 is well within the normal range of variation.

However, the graph raises a larger question: over the last sixty years, US yields have been generally increasing (consistent with the usual technologically driven yield improvements in most crops in most places).  However, Texas yields have been basically flat the entire time.  What's up with that?

Theories are solicited in comments.

FWIW, here's the USDA's county level yield map for soybeans in 2010 - clearly Texas is well outside the sweet spot for growing soybeans, but there is production along the Gulf coast.

And here's the acreage planted:


Joe said...

I would want to know how many acres were being planted in Texas, and whether they were the same acres.
The flat yield could be the result of other factors:
1) Texas soil which is favorable for high yields from soybeans is more favorable for increased yields from cotton, afalfa, or suburban McMansions;
2) Texas farmers are using soybeans for a different purpose than other, Midwest farmers, causing them to fertilize less, or use lower yielding strains;
3) The new strains of soybeans which produce increased yields are more heat-sensitive than the old strains; and
4) Texas farmers are bringing on line more low yield soils, or Midwest farmers are concentrating on high yielding soils (or are better able to use new things, such as GPS for fertilizing and yield management).

The immediate conclusion, based upon your drought series, is that it is the heat and lack of moisture that is hurting yields, and that is the horse I would bet on. But those other factors could probably be teased out of the data, and subject to a pretty simple regression analysis, to rule out or in.


Stuki said...

I'd also want to look at production cost per bushel in Texas, vs. the higher yielding areas. Geography, infrastructural and organizational peculiarities could well mean optimum profitability in Texas occur at lower yields/area than in some other places. And while access to water is likely one such issue, there could well be others as well.

Som said...

This paper suggests a large impact on yield of crossing a 30-degree threshold in un-irrigated counties:

I don't know if the temperature trend in Texas matches.

Mr. Sunshine said...

Soybeans don't seem to be the big crop in Texas, for one thing. AG there depends heavily on the depleting Ogallala Aquifer, for another.

"In 1974 there were 8.5 million acres in Texas under irrigation ... In 1991 the total irrigated acres in the state had decreased to six million. The southern High Plains still accounted for the largest portion—68 percent."

"Cotton, grain sorghum, wheat, and corn are the major agricultural crops produced in the Texas High Plains. Of fourteen million acres irrigated in areas where ground water aquifers are declining four million are located in Texas (National Research Council, 1996). The majority of this Texas acreage is located in the Texas High Plains (THP), where the Ogallala Aquifer is the main source of irrigation water."

"West Texas cotton farmers likely will maintain or increase acreage this year, but many will adjust production routines to take better advantage of diminishing water supplies and to increase efficiency."