What is a weed?
A weed is a plant which is not at its’ place.
This is genarally the opinion of a cultivator; when he has a plant in his mind, he has eyes only to it, even if it is not dominent in the field. A sort of facial discrimination for a plant.
For example : a cultivator can panic at the idea of having his field of wheat invaded by popies. In fact plant sociology teaches us that the ennemy for a plant is its own brother. Wheat produces enzimes by its roots, exsudates which wil hinder the growth of the neighbouring wheat… and the poppy just loves this exsudate, which it uses as fertilizer. And when the high heats comes the poppy will finish flowering and will gently lay down and protect the wheat from dryingto quickly, while purvaying some extra organic matter. Nature is well thought.
A bigger problem is monoculture. In fact to do well, one should plant clover with wheat (always a leguminous with a graminee) and so soil is covered and the wheat will get the azote fixed by the clover. One should alternate one row (the side you need) of wheat and one row of poppy and harvest the poppy seeds as well.which will absorb the roots exsudates. Here we cannot speak of weed anymore, can we? everything gets back in order.
On an ecologic and botanic point of view the invasive plants are many :
First the one planted by man : after thinking it twice one is not sure if it is the plant that dominated man or the reverse, after seducing it by its’ taste and special effects… to the extend of convincing him to grow it in the caves of Amssterdam.
Other plant are invading because they are foreign to the place and have no predators on the site. But beware! most of the time it is caused by a broken balance due to man. The bank of the Rhone riverhave been prohibitted to the public all summer 2008 because of the proliferation of Ambrosia artemisifolia, a plant from the Afghan desert ; there as in Tibet, this plant is a highly considerated medicine; here it is a bio indicator of soil destructuration provoqued by ploughing or chemical pollution which is the case of the Rhone banks…
The solution to get rid of it? Dont use organo chloride chemicals which will worsen the situation… just sow rie-grass, just another solution learned through observation and plant sociology.
In Argentina, South of Salta, the invasive plantis Galega officinalis. It is originated from Europe, where it is a good medicine against diabetis. Back in Argentina, after many proves and tests, we saw that it spreads where it has been poughed and later sprayed with glyphosate… In Europe the cattle eats it there nedoes not touch it as if it were poisonous, which it is not. it has no use and takes the space of good native forrage. Therefore it becomes a weed.
The solution? The galega is a leguminous which crosses itself genetically even with soybean to become resistant to glyphosate… whosays leguminous says a plant which fixes the azote of the air in the ground… It becomes a fantastic green fertilizer. So you need to sow clover and forrage by throwing it in the air and cover it with the Galega crushed on which you can spray from time to time soe oil containing a mix of spores which will boost the growth while assuming micro-irrigation…
The punch line : in agriculture you can almost always do good with bad. Life is stronger, it our business to find the good side of it.