Dear Roland,

Your question is a complex one and I would say that there is no best method. First of all the approach should be controlling the weed population rather than aiming at total eradication. As for methods as you may learn in any textbook of weed science there are: physical, chemical and biological. The chemical methods are the most adopted because they can yield some results in a short time however, these chemicals are expensive and pose risks to human and environmental health. Therefore, before making any decision about the method of control I would consider learning as much as possible the biology of the weed population that is infesting the field. Is this an annual, biennial, or perennial species? What is its phenology? Secondly, weeds are overall opportunistic species and will thrive in an environment that is highly disturbed (tilled). Therefore reducing tillage and employing cover cropping and crop rotation may compete strongly against weeds. Weeds may also be looked at as indicators of soil quality/soil characteristics. Check out Ehrenfried Pfeiffer's book (Weeds and what they tell) to learn more about this topic, which suggests that effective control can be exerted by amending the soil, or correcting its pH and more. There is no rule that can be generalized and used by all. Employing browsers like goats in the rotation of crops can be another valuable methods to consider. In conclusion, it depends by the type of weed, type of soil, agronomic management, and resources available.

check this links maybe help you

http://weedscience.okstate.edu/Lecture%206%20Methods%20of%20Weed%20Control.pdf/

https://www.ipm.iastate.edu/files/11%20Managing%20Weeds.pdf

https://www.invasive.org/gist/products/handbook/methods-handbook.pdf

For wide farm, chemical method of weed control is the best option. But as you said, in long run, development of resistance is major concern. But now a days in market we can get herbicide mixture, which is having synergistic effect on weed control, broad spectrum weed control, lower herbicides dose requirement, and minimize the chance of herbicide resistance development.

Secondly if herbicide mixture is not available, then you can go for herbicidal rotation, which will also reduce the chances of resistance development and weed flora shift.

In addition prevention measure along with good agronomy practice will be most effective method for weed control in wide farm.

I think best method is mechanically control of weeds through tillage machinery. We can go for rotavator, rotary plough, cultivator. As if we go for chemically solution of this problem, herbicides harms the environment and human health. There is a tool named weed wiper used for wiping of weeds using herbicides. It is used in that crop where selective herbicides are not there. So, u can use these type of tools also.

Dear Roland,

Being an ecologist I am against chemical method of weed control because it not only enables the weeds to develop resistance, but also deteriorates the quality of environment. In such circumstances the physical and cultural methods of weed control are the best options.

Article Integrating physical and cultural methods of weed control: E...

Good luck!

Mechanical weeding

My opinion is for mechanical mode of control as plentiful good machinery is available to manage it.This will minimize chemical usage besides no issue of developing herbicide resistance in future.

Most weeds are not harmful, and there is no need to be fully controlled. But we must avoid resistance to herbicides. The use of rotation in herbicide application can be a good way to reduce herbicide resistance.

Eventually, the use of herbicides is a cheap and easy way to control weeds in wide farms.

The control of weeds in the large fields depends firstly on the type of crop grown and secondly on the nature of the growth of these weeds in terms of being annual or perennial and how to reproduce. For example, in the case of grain fields, especially infested by the broad-leaves weeds here we can use chemical control, whether using aircraft or machinery. In the normal fields, the mechanical control of the annual weeds can be used, and per-emergence herbicides can be used to fight the seeds of the weeds after they germinate. Systematic herbicides such as Glyphosate are used in order to control perennial weeds that have multi propagation methods .

Besides chemicals, cover cropping, mulching, and crop rotation would help!

Thanks.

Timing the intervention, no matter the method (Biological, chemical, mechanical, other) is also very important and this requires some sound biological knowledge of the weed to be controlled.

for large farms chemical application can be effective

How to reduce herbicide rate in large forms: consult with my publication

Article Large-scale farming operations are win-win for grain product...

IWM approach as long term can help.

One way is plant root zone watering and using plastic sheet to cover the rest of soil to avoid weed growth.

Another way is mechanical weeding. I am not in favour of using weedicides.

I think it is important also to consider weed prevention strategies in this discussion, and these can be achieved through:

1. Improving soil tilth, aeration, water infiltration and fertility to optimize crop growth and minimize weed pressure.

2. Cleaning equipment before moving it from farm to farm to avoid spreading weed seed.

2. Avoiding to allow weeds to form seed heads in the cultivated field.

3. Composting well all imported animal manure to insure destruction of weed seed.

4. Filtering surface irrigation water to avoid access to fields by weed seed.

5. Working with neighbors to reduce the potential of spreading weeds.

6. Understanding that eradication is an unattainable pursuit and therefore, learn as much as possible about weeds biology in order to keep their populations size below threshold levels that could affect the economic viability of growing crops.

Drip Irrigation also reduces the growth of weeds substantially.

It seems to me, that chemical control isn't a good deсision from many points of view. Much more preferable machinery methods (different types of tillage) plus biological control. The last one depends from climatic conditions, soils, water regime and so on. For our conditions one of simple and cheap methods - rye cultivation before the main culture. It permits to made a good weed control and to enrich the soil with nutrients.

As mentioned by Bruno Borsari it is really complex. Therefore, the best way is Integrated weed management (IWM).

IWM is the control of weeds through a long-term management approach, using several weed management techniques. As Physical, Chemical, Biological, Chemical, Cultural etc.

Since lWM cover several techniques to control weeds, you reduce the chance that weed species will adapt/resistance to the control techniques ( herbicide, mechanic etc).

A IWM plan or strategy for a specific area/farm should focus on the most economical and effective control of the weeds and on ecological considerations as well.

Interesting answers ! Learned something !