Doing some research the other day and ran into this topic. It intrigued me enough that I decided to research this topic further. Traditional farming involves tilling fields with a plow. This kills weeds and makes the soil more porous, making planting easier. The problem with this is that it uses a great deal of energy and also loosens the soil, leaving it vulerable to erosion. A more advanced method of farming is known as conservation tilling. This includes both no-till and minimum-till techniques. The advantages being that there is a lot less energy (fossil fuel) consumed and the soil is left intact, preventing erosion and sequestering carbon which helps fight global warming. The other main advantage is that if done right, it can be much cheaper giving the farmer greater profit margins and over time it can even increase yields. The point of explaining all this is to advocate for more incentives from our government to adopt these advanced farming practices.
Now maybe to some this topic can be somewhat boring but I find it fascinating. I've heard many say that agriculture uses up a lot of fossil fuel. So conservation tilling is an important part of a national energy policy. Not to mention that if crops are grown for biomass fuels such as ethanol, you want to use as little energy as possible to cultivate the crop so that you obtain a more positive energy ratio. Tilling the soil also releases carbon into the atmosphere. No-till agriculture sequesters carbon in the soil, helping to combat global warming.
So how do you deal with weeds and plant seeds and fertilize using conservation tilling? Well it appears there are varying methods. One is to use herbicides to get rid of weeds. This means you need crops that are resistant to herbicides. Herbicides will also add to the cost of cultivating crops. Seeds are planted by drilling a hole in the previous crop residue and dropping the seed in. There are other methods that don't require herbicides. It's really quite involved so I'm not up on the details of the various techniques yet. Fertilizer actually takes up a lot of the energy that goes into farming. The right rotation or even growing the right crops together can negate the need for fertilizer. A simple google search on conservation tilling will yield quite a bit of information.
I've only gone over a small bit on this topic but it's a start for anyone who wants to research more on it which I will. I have read that something like 40% of the acreage in the US uses some form of conservation tilling. Many farmers are reluctant to change their ways however. For one thing, you have to do things a different way which means getting educated on the new techniques. Second, farmers have already invested in the machinery that is used in traditional agriculture. They are reluctant to put aside the old machinery and invest in the new machinery that specializes in no-till agriculture. Another thing is the subidies that are given to farmers. With the subsidies they are given, there is little incentive to change the way they do things. This needs to change. I propose that more incentives be given to farmers to convert to conservation tilling. Also, federal grants should be given to these farmers to attend classes on the subject. Modern farming is really a science as much as nanotechnology and robotics and engineering, etc. Education is important.
Links of interest:
guy in Brazil does no-till
another guy in Brazil Brazil is really into this
world wildlife fund page on no-till which consequently mentions Brazil (OK, I get it, Brazil is really into this.)
No-Till Farmer website Can subscribe for a No-Till newsletter. There are some articles and a forum on the site though.
notill.org lots of stuff here
The Fukuoka Farming WebsiteMasanobu Fukuoka is a pioneer in sustainable agriculture. This is a website on his techniques