View Single Post
  #3   Report Post  
Old 20-09-2003, 05:20 AM
Dean Hoffman
 
Posts: n/a
Default Nitrogen-fixing crops.

On 9/19/03 9:38 AM, in article ,
"Phred" wrote:


When I shouted myself a trip around the US a few decades ago, I learnt
that soyabeans are typically "parasitic" on soil N in spite of their
ability to fix atmospheric N through their root nodule bacteria. In
other words, the yield of N in a crop was greater than the amount
fixed. I have to say I was a bit surprised by this outcome too,
because I had been well indoctrinated with the "legume/rhizobium
symbiosis" as an undergraduate.


For whatever it's worth, here's a chart showing the contributions of
legumes to the next year's corn crop. The chart is about 1/2 way down on
the right side.

http://www.ianr.unl.edu/pubs/fieldcrops/g174.htm

The research is from the University of Nebraska at Lincoln. The
Nebguides are recommendations to farmers for crop production.


Some cut.

Another aspect relating to your "makes a mess of the soil" is that
legume crops typically involve more cultivation and chemical
treatments than many broadacre gramineous crops. Their root system is
also inferior to the fibrous roots of grasses in preserving
soil structure (at least that's what I was taught many years ago .


No till and roundup ready soybeans are really changing farming practices.
Beans are sometimes drilled directly into the previous year's crop residue.
They're sprayed for weed control. Farmers in my area of Nebraska, USA are
really cutting back on the tillage. It's just too expensive to cultivate
unless absolutely necessary.
Some farmers here plant the corn, cultivate maybe once, and then spray to
control the weeds.

Cut rest.

Dean



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----