Machine/equipment that completely removes the unwanted grass with roots from any crop fields

[srkvemula]

I agree with you about type of crops and environment were entirely different from your area. Mechanical application can be done with small sized equipments which were in market but not meeting my complete requirement.Coming to the chemicals plese clarufy the following questions,

1.Is chemical application causes any problem to the soil in future.

2.Will chemical application effect the productivity of the crop.

3.How many times we need to apply chemicals to remove the weed for a particular crop period of 6-8months.

[Nebrfarmr]

It will be very difficult, to get one machine, that will work in all those crops.

I forgot to ask, about how big your fields are, that will matter as well.    I have a friend who used to work in the Phillipines, and most of the farmers there, had a small 'tractor' that was maybe 20 HP, maybe a little less, that could pull everything from a rotary tiller, small cultivator, or even a small wagon.   They used it for everything from preparing the soil for planting, to cultivating out weeds, to hauling in a crop.   From what I could gather, it worked very well but was only suited to fields of a few hectares.   

[mike se il]

As I said, I can't really offer much advice for your specific location, environment, or crops.  I will discuss it in reference to what we do.

Pesticides are highly regulated in the US. To be used a pesticide must have an approved ...  we just use the term "label".  The "label" discloses what the active ingredients are (the chemicals that do the work) as well as the concentration in a standardized format.  It will list personal protection equipment and procedures, pests controlled, the rate of use, limitations like soil types or timing of application, how long it must be between when the pesticide is applied and when you may harvest it, crop rotation restrictions, on and on and on.   The federal government's Environmental Protection Agency must approve the label.

Some pesticides are "restricted", meaning the user must have a special license to purchase or apply them.

Because of all this any information needs to be considered just an intersting fact for US use.  You must follow your country's rules and regulations. For an example of a label for atrazine, one of our most common herbicides, see http://pest.ca.uky.edu/PSEP/Private/Drexel%20Atrazine%204L.pdf

On to your specific questions:

1.Is chemical application causes any problem to the soil in future.

That is a very debatable question with what some consider a clear answer and others saying it is just hype with no facts to back it up. I have a friend who is strongly anti-chemicals and considers them the downfall of American society. From my end-user standpoint the problems I see are carryover past the growing season. 

2.Will chemical application effect the productivity of the crop.

Another debatable question. It should improve it.

3.How many times we need to apply chemicals to remove the weed for a particular crop period of 6-8months

That is an answer I can't give.  For corn we generally make  appplcation early and a late one if needed

[srkvemula]

Mechanically my problem won't solve as i come across with some answers from experts.I need look for alternate solution like applying chemicals to the weeds.If you know any inforamtion about this please share.

[srkvemula]

Thankful for the valuable information provided by you.Actually in India we do not have the provision/facility or knowledge of applying chemicals to remove weeds.As of now with the help of labor only formers are overcoming this.But due to the globalization, getting labor is not easy and became expensive also.I want to encourage these kind of techniques in our area to get better productivity with less investment.If you have further information about this pls share it.

Another question from me,

Is there any technique to improve the soil quality for better yielding.My area is full of black cotton soil and can be used for certain type of crops as I mentioned early.Some areas we have plenty of water near to river basin and some areas depending only on rain/bore water only.

[Nebrfarmr]

Here are a couple links that I have used, to compare various herbicides.   You can also google a particular herbicide you are thinking of using, and get all sorts of info that way, as well.

http://www.ianrpubs.unl.edu/epublic/pages/index.jsp?what=subjectAreasD&subjectAreasId=37

http://www.msuweeds.com/publications/weed-control-guide/

[mike se il]

"Is there any technique to improve the soil quality for better yielding"?

Many books have been and can be written on that subject. The first place to start in the US is soil pH and calcium (we call it lime, but do not confuse ag lime with the fruit lime.) If the pH is not right and there is not the right balance of calcium nothing will work well.

Most commercial farms in the US have soil testing performed professionally, but that may not be a possibility for you.  There are several do it yourself kits available.  Most times they are designed for the home gardener but some are more professional. I'm going to refer you to Gempler's catalog (http://www.gemplers.com/soil-test-kits) just because it shows many of the possibilities.

Part of the difficulty answering is I don't know your environment.  For example, where I live it is currently just over 0 C (34 degrees F). It is not uncommon to get as cold as -20 C (-4F) and -25 C or even -30C (-13 and -22F) is not unheard of.  Several days of -10 C (14F) is normal.  This summer we had several days with the temperature over 38 C (100F).

One of the current ... I hesitate to use the word "fads" because it is good science ... is cover crops.  But the cover crops that might be recommended in the environment are different than one farther south where the winter temperatures are not normally so extreme.  And it is different from farther north where they might normally expect extended periods of -30C temperatures.

Having said all that let me give you a few resources to study without giving so many it overwhelms you. You will have to adapt all this to your situation.  We have learned from painful experience just importing plants from other places can be a disaster.  The big example in the southern US is Kudzu (see http://www.maxshores.com/kudzu/)

These 2 resources are oriented for the eastern US

http://www.hort.cornell.edu/bjorkman/lab/covercrops/

http://ohioline.osu.edu/agf-fact/0142.html

This one is more for the south, where winters are not as harsh

http://www.clemson.edu/sustainableag/IP024_covercrop.pdf

And the "organic" versus "chemical" debate can go on forever, but there are some good resources from the organic folks.  And many of their ideas may be more suited to your use.

http://www.organicgardening.com/learn-and-grow/cover-crop-basics

http://www.motherearthnews.com/organic-gardening/cover-cropping-zm0z10zsto.aspx

I've given you a lot to consider with just those references.  And they are written for American English generally with a farmer slant to them so you may find terms and phrases unfamiliar to you.    More later.