WEED CONTROL & CLASSIFICATION OF HERBICIDES
Chemical Weed Control
Controlling of weed is very important in agriculture that has been discovered loss of yield by 20% – 30% due to competition of weeds. Also classification of weedicides are very important to know in agriculture. Before controlling of the weeds we should beware of below reasons.
- Distinguish between weeds and crop.
- Climate & soil, should good knowledge about them.
- We should know characteristics of weeds.
WEEDS CONTROLLING SYSTEMS
(01) MECHANICAL CONTROL
This is done by using manual, labour, animal or machines drawn implements (hoeing ,flooding,burring,tilling,mooring,smothering).
(02) AGRONOMIC CONTROL
- Weeds seeds free crop seeds.
- Proper land preparation.
- correct water management.
(03) BIOLOGICAL CONTROL
Using natural enemies of certain weeds.
(04) CHEMICAL CONTROL
Control weeds by chemicals. The most popular method of controlling weeds is using chemicals called Weedicids.
CLASSIFICATION OF HERBICIDES
Herbicides , also commonly known as weedkillers, are substances used to control unwanted plants. Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called total weedkillers in commercial products) can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact. Apart from selective/non-selective, other important distinctions include persistence (also known as residual action: how long the product stays in place and remains active), means of uptake (whether it is absorbed by above-ground foliage only, through the roots, or by other means), and mechanism of action (how it works). Historically, products such as common salt and other metal salts were used as herbicides, however these have gradually fallen out of favor and in some countries a number of these are banned due to their persistence in soil, and toxicity and groundwater contamination concerns. Herbicides have also been used in warfare and conflict.
Modern herbicides are often synthetic mimics of natural plant hormones which interfere with growth of the target plants. The term organic herbicide has come to mean herbicides intended for organic farming. Some plants also produce their own natural herbicides, such as the genus Juglans (walnuts), or the tree of heaven; such action of natural herbicides, and other related chemical interactions, is called allelopathy. Due to herbicide resistance – a major concern in agriculture – a number of products combine herbicides with different means of action. Integrated pest management may use herbicides alongside other pest control methods.
In the United States in 2012, about 91% of all herbicide usage, determined by weight applied, was in agriculture. In 2012, world pesticide expenditures totaled nearly $24.7 billion; herbicides were about 44% of those sales and constituted the biggest portion, followed by insecticides, fungicides, and fumigants. Herbicide is also used in forestry, where certain formulations have been found to suppress hardwood varieties in favor of conifers after clearcutting, as well as pasture systems, and management of areas set aside as wildlife habitat.
Credit : Wikipedia
|Selective Contact Foliar applicant||Di nitrophenol,KCN,Petroleum oil,H2So4,Propanil,3-4 Dichloro propinalide|
|Selective Translocated Foliar applicant||2-4 Dichloro propinalide acitic acid, 2-4 T, M.C.P.A|
|Selective Translocated Root||2-4 D, 2-4 T, M.C.P.M|
|Non-Selective Contact Foliar||ClO3– penta borate, Petrolium oil, Arganic Compounds, Ammonium Sulphate,Di-Nitrol, Gramexone|
|Non Selective Translocated Foliar||Amonium Sulphate, Chlorate Compounds,Roun up,Sodium Asanide, Yellow fiuid (rubberst).|
|Non Selective Translocated Root Applicant||S2O3 2-, N.C.R.C. (Borone Compounds),|