Hello friend, do you know what is Herbicide ? we are going learn about “What is herbicide ? definition and classification with example” in this blog.
what is herbicide ? definition and classification with Example
Definition
Which chemical substance that destroy herb/ weed or Affects herb/weed growth and reproduction It is called Herbicide.
Herbicide is derived from Greek word first herb and second Cide.
Herb means plant and Cide means kill It’s meaning “to kill weed/plant/herb”
Classification of Herbicide
(1) Base on time of application
Herbicides are divided into four types on the basis of time of application.
(i) Pre sowing herbicide
Herbicides which is use in before sowing to kill the herb/plant/weed, is called pre-sowing herbicide or pre-planting herbicide.
Ex- Fluchloralin , etc.
(ii) Pre-Emergence herbicide
Herbicides which is use in after sowing to kill the herb/plant/weed, is called pre-emergence herbicide.
Note– (a) There should be sufficient moisture in the soil to apply this herbicide.
(b) This herbicide is mostly applied 1-2 day after planting.
(c) It is used before germination.
Ex- Pendimethalin, Atrazine, simazine, Butachlor, pretilachlor, Nitrofen etc..
(iii) Post-Emergence Herbicide
Post Emergence herbicide is used after germination. it kill weed/herb after germination. it is mostly used 30-35 day after sowing.
Ex- 2-4 D, 2-4-5 D, Isoproturon etc..
(iv) Lay by Application Herbicide
Lay by application is used as herbicide after first irrigation (CRI) in wheat.
Ex- 2-4D
(2) Base on selectivity / Mode of Action
(i) Selective Herbicide
The herbicide that are selected destroy the plants or stop their growth and the herbicides and those who was not selected have a little or no impact, It kills few plant/species/Group of plant.
Ex- 2-4D (broad leaf killer ), etc.
(ii) Non selective Herbicide
It kills all plant/species/Group of plant. It is can not use any particular plant/species/groups. wherever herbicide is applied it kills all the plants, It is not selective herbicide.
Ex – paraquat, glyphosate etc.
(3) Base on site of Application
(i) Soil Application
Soil Application is used directly on the soil. It is deepened by the root and stems of the plants and mostly commonly used in pre- planting or pre- emergence of plant.
(a) Surface Application
In this herbicide goes down with the moisture of soil and after than weeds than germinate die. These herbicide are generally used in pre-emergent or pre- planting.
(b) Sub-surface Application
Herbicide is injected at one or two feet of surface. There have special equipment to apply herbicide because its seed bank is at below 1 or 2 feet and kill the seed bank
Ex- Carbamate ( It control generally Cyperus Rotundus ), EPTC etc.
Band application
The herbicides are used in the seed zone area and the weed in the remaining area is controlled through physical methods. This type of farming is done in rows and a distance of a few feet is left between each rows. Its objective is to save the amount of herbicide.
(d) Fumigation
These type herbicide is mainly used during nursery development, some weeds grow and they are controlled.
EX- Methyl bromide
(e) Herbigation
Herbigation is composed two term first term is herbicide and second term is irrigation Its means herbicide is applied along with irrigation. before applying herbicides, It should be ensure that irrigation is done evenly in the entire field. This dry land agriculture can not be used of agriculture because irrigation is not done properly.
Ex- pretilachlor, pendimethalin, etc.
(ii) Foliar Application
Spaying herbicide in the fields is called foliar Application ,when plants wither, it is batter to spray instead of using soil application because it works fast than soil application.
(a) Blanket Application
In blanket Application we apply herbicide to the entire field without any space. In this condition, It is verry important for the herbicide to be selective. It given moisture to the weed and does not cause any harm to the crop.
Ex- Endothall, etc.
(b) Directed Spray
In direct spray, herbicide is not sprayed in the entire crop, the difference is that herbicide is sprayed only in the Inter row and the crop row is left.
Ex- glyphosate etc.
(c) Protective Spray
Protective spray is generally like direct spray but in protective spray we protect the crop with some physical method. generally not selective herbicide are used in the field.
Ex- glyphosate etc.
(d) Spot Application
In Spot Application, we apply herbicide at the place where weed growth is increasing. Its can not used every where, generally not selective herbicide are used in the field
Ex- paraquat, glyphosate, etc.
(4) Base on chemistry of Herbicide
(5) Base on spectrum
(i) Narrow spectrum Herbicide
Herbicide which destroy narrow leaf weeds are called Narrow spectrum Herbicide.
Ex- Penicillin etc.
(ii) Broad spectrum Herbicide
Herbicide which destroy broad leaf weeds are called Broad spectrum Herbicide.
Ex- 2,4,d,
(6) Base on mobility
(i) Contact herbicide
When these herbicide come in contact with weed, they kill that weed, It has no mobility. It herbicides kill the part of the weed on which it fall. therefor it is called none translocated herbicides.
Ex- Bromoxynil, Endothall, Diquat, paraquat, etc.
Systemic herbicide
Systemic herbicide are mobile in weeds and when they come in contact with any part of the weed, they destroy the entire part of the weed.
Ex- Glyphosate, 2,4D , atrazine, etc.
Base on chemical nature herbicide
(i) Organic herbicide
Organic herbicide contain carbon and are in the form of oil.
Ex- Diesel oil, etc.
(ii) Inorganic herbicide
carbon is not found in Inorganic herbicide and they are not in oil form, they are in the form liquid or powder.
Ex- 2,4D, atrazine , glyphosate, endothall, etc.
Two type of inorganic herbicide are found :-
(i) Acid Nature
(ii) Salt Nature
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