Re: weed control

>Dear Kelly,
>While nutrient balance can certainly affect plant ecology and community
compostion (e.g.  low K   may favor grasses over legumes, and visa verse; or
high N may favor grasses, etc.), I see no reason to believe weeds , as a
class of plants,  will be affected positively by imbalances that hurt crops,
or inibited by balanced nutrition that helps crops.  After all, a weed is
simply a plant we didn't ask for. Many are very close relatives of our crop
plants, and will repsond to nutrient balance much like the crop. That is, a
well balanced, fertile field will grow an excellent crop...and crop of
weeds, too.  There are a few special cases, though. For example, one could
use 3 to 4 lbs/acre of boron on a tolerant crop such as alfalfa, and create
soil boron levels that would kill off many less tolerant "weed" species.
>Hope this helps.
>At 07:06 AM 4/17/97 cdt, you wrote:
>>     I have had one of the county specialist contact me for information and 
>>     was hoping this group may be able to help me with an answer.  Below is 
>>     the specific request from the specialist:
>>     "Weed control by balanced soil nutrients is a request by a producer 
>>     interested in a sustainable agriculture approach to weed control.  He 
>>     feels that braodleaf weeds and grasses will thrive on soils that are 
>>     lacking nutrients in the correct amount and proportions.  In my 
>>     opinion, this concept may or may not be the direction to reduced grass 
>>     and broadleaf weeds in our crops.  Also, I am at a loss in finding 
>>     demonstrations that would support the idea.  Your assistance with 
>>     literature about this topic will be appreciated."
>>     If anyone has any comments I can pass along, I would appreciate it.
>>     Thanks,
>>     Debi Kelly, Project Manager
>>     Missouri Alternatives Center
>>     628 Clark Hall
>>     Columbia, MO 65211
>>     573-882-1905
>>     kellyd@ext.missouri.edu
Ray R. Weil
Professor of Soil Science
Dept. of Natural Resource Sciences & LA
1103 H.J. Patterson Hall
University of Maryland
College Park, MD 20742

telephone: 301 405 1314
FAX:            301 314 9041
e-mail:  rw17@umail.umd.edu