according to philip callahan in the book "paramagnetism..." weeds are critical for soil health. they perform three key functions -

1. they "fiberize" the soil. by this he means they break down hardened soil and create nutrient roadways. the crops roots then follow along those roadways.

2. their root systems penetrate deep into the soil, bringing up minerals and nutrients that the top soil if depleted of. if you then pull up the weed, and compost it, and add that compost back to your soil, you have completed the cycle of regenerating the soil.

3. the water from deep underground actually travels along the outside of the weeds roots, up to the topsoil. thus the correct amount of weeds (not too many, not too few) actually HELP to keep your soil moist. they don't compete with your crops for water as is the popular notion.

he talks a lot about fire weed and how valuable it is and how animals love it. its a member of the evening primrose family and can be eaten by humans. its roots go way way deep into the soil, and its very very hearty. he believes cultivating this plant could do a world of good for our soils.

i will post some more thoughts from the book as i read along, both to help me understand it better and to give others who won't read the book the cliff note version of some of his main points.