GroveStudies present Agronomy Important Topics for Mid Semester 2 Weed Managements
GroveStudies Production
Agronomy :-
Contents ;-
Weeds classification
Loss and gain of weeds
Weed Contents
Water use efficiency
Herbicides
Advantages and disadvantage
Irrigation
And different methods
Drip and Sprinkler
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What is Weed?
Weeds may be defined as the unwanted and undesirable plant which interfere with the utilisation of land and water resources and adversely affect human welfare the term Veda was firstly used by Jethro Tull.
According to their economic importance of weeds :-
Relative weeds :-
unwanted plant which has some economic importance but called weeds because these are grown out of their places.
Example:- cynodon dactylon.
Absolute weeds :-
unwanted plant which has no economic value and growing out of their proper place.
Ex :- euphorbia hirta.
Losses caused by weeds :-
Weeds compete with the crop for their growth factors :-
The greatest loss caused by the wheat resulted from their competition with crop for growth factors namely nutrients soil moisture light and space etc.
Weeds increase the cost of cultivation of crop.
Poor quality produce weed reduce quality of farm livestock and wool produce.
Some of the ways serve as an alternate host for insect and diseases which prove more destructive and difficult to control.
GroveStudies Production:
Classification of Weeds According to Life Cycle:
Annual Weeds:
They complete their life cycle within one year or one season.
Biennial Weeds:
They take at least two years or two seasons to complete their life cycle. They complete their vegetative growth in first year or season and produce flowers and seeds in the next year or season. E.g Wild carrot- ( Daucas carota), wild onion
Perennial Weeds:
They continue or grow for more than two years or several years.
Importance of Weeds or Benefits or Advantages Derived from Weeds :-
Weeds Add Organic Matter and Nutrients to the Soil: ...
Weeds Check Wind, Water and Soil Erosion.
Some of the Weeds are used as Fodder for Animal.
Some of the Weeds are used as Leafy Vegetables.
Some of the Weeds have Medicinal Value.
Methods of weed control ;-
Weed control methods are group into cultural ,physical ,chemical and biological.
We use the prevent of weeds seeds by using the the adaptation of following techniques are :-
Use of clean seed
use of well rotten farmyard manure
uprooting weeds before flowering
keep clean field boundaries and irrigation channels
use of clean farm machinery
nursery sampling.
Mechanical method of removing weeds physically or tools implement is called mechanical methods.
Tillage , hand pulling, intercultural, flooding ,mowing.
Cultural methods following agronomic manipulations !-
Planting methods :-
sowing of clean crop seed without wheat seeds should be done.
Sowing are taken up 1 or 3 days after rainfall or irrigation depending on soil type weeds starting present in in soil start germinating within 2-3 days.
Sewing operation with c drills remove some of the germinating weeds.
2. Varieties
Weeds continue germinating for long time dwarf varities resulting in high weed growth.
3. Planting density :-
Plants of one type do not generally allow germinating of other plants near their vicinity.
wider planting should be avoided
4. Fertilizer applications :-
Plant differ in their capacity to respond to fertilizer applications.
crops like sorghum made pearl millet and rice grow at faster rate when nitrogen fertilizers are applied.
5. Irrigation and drainage:-
Depending on the method of irrigation weed infestation maybe increase or decrease.
Chemical methods :-
Chemical methods are used to control weeds with the use of chemical called herbicides.
That are toxic to certain categories of plant is called chemical weed or control method.
Advantage of chemical methods :-
Eliminate early crop weed competition
morphologically similar weeds to crop can be effectively controlled.
Sure method of controlling weeds
problematic weeds can be effectively control
Tillage can be minimised.
Limitation of chemical methods :-
The use of chemical herbicides required technical knowledge about choosing herbicides time of herbicide and the method of herbicides.
Herbicides use may cause environmental pollution.
Herbicides drifts may be harm the neighbouring crops.
Weed resistance chemical crop war
cost of few herbicides is high
no antidote is available.
Biological control of weeds:-
The biological control of weeds involve the use of living organisms such as insect herbivorous fees other animals disease organisms and competitive plants to limit their infestation.
Kinds of classical bioagents used for successful in controlling weeds both terrestrial and aquatic :-
Insect
Fish
Fungi
Competative plants
Integrated weed management :-
Integrated weed management means integrated multiple weed control statistics into a single weed management program optimising control of particular weed problems.
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