Weeds are plants that grow in an area where their growth is not desired by a farmer because they either limit or completely disrupt the growth or production of crops. They do this by competing with crops for limited resources like water, nutrients, and sunlight. Weeds are characterized by their ability to swiftly populate large areas through rapid reproduction and dispersal.
Weed control in agriculture is the means of limiting the growth and spread of weeds in agricultural lands using several techniques, either alone or in combinations so as to remove the harmful impacts of weed invasion on the productivity of the land under consideration.
Why is it important?
Weed control is considered to be one of the most significant factors causing a massive economic loss in the farmland productivity of several countries. If unmanaged and appropriate control measures are not applied, the hardy and invasive weeds, either native or exotic, can lead to huge economic loss in the long run.
Although weeds are a part of the agro-ecosystem and can help in nutrient-recycling as well as soil texture improvement, the benefits are only realized if their drawbacks are properly checked. So control of weeds in agriculture is a vital part of any successful agricultural farmland.
Weed control has been practiced ever since the first agricultural revolution by hand but the ways of managing weeds have evolved with time and the advent of technology. Herbicides were being used extensively and vigorously in the recent past because of their easy application, effectiveness, and inexpensive quality. However, as the negative environmental and health impacts of herbicides came to light, more focus is being directed towards biological weed control and eco-friendly control of weeds in agriculture.
Weed control techniques
But studies show that the best way of managing weeds in your land is the coordinated application of a range of techniques. Some of the weed-management techniques are briefly explained below:
Biologically controlling weeds depends on the simple fact that weeds have a natural enemy which if introduced into the system can naturally reduce and limit the growth of the weed population and the size of the seed pool of the weeds. The agent that is introduced can be either insects, mites, or even some specific diseases which kill the weeds.
The biological-control measure can use bio-herbicides as the control agents, which are compounds and secondary metabolites that are obtained from microorganisms like bacteria and fungi. However, this method is not considered a long-term approach since its effects are often limited in their application duration. As a result, biological-control agents like insects and mites are more preferred if the goal is to place them as a long-term part of the agro-ecosystem so that the weed-controlling effect of the agents can be realized over long durations.
Besides the elimination of negative environmental effects, another prominent advantage of biological control is that it can be applied in remote, inaccessible, and sensitive areas where other methods are rendered ineffective or infeasible.
But special care should be taken in selecting the control agent for a weed-infested area based on geographical location and ecosystem type. This is because if the introduced agent acts as an invasive alien species, its population can explode and can even harm the agricultural crops. So, although biological control offers an environment-friendly approach to weed control, proper selection and monitoring are essential when choosing biological control which should be based on research and technical advice.
Flaming can be a highly effective weed control technique, but its usage is limited to certain special circumstances since fire is a dangerous element in itself and in the wrong hands, can do more harm than good. Flaming is famously used to control weeds growing in non-agricultural areas like roadside weeds, railway tracks weeds, etc. However, in agricultural lands, flaming must be used so as not to damage the crops. So, it is used to control pre-emergent weeds when crops aren’t present in the land. Flaming can also be recommended if the crops are considerably heated and tolerant. Advanced flaming techniques used specialized flame-throwers that adjust the flame so that it only produces enough fire to affect the desired plants and the effect often includes causing the leaves of the weeds to only wilt which subsequently causes death.
Although not used on large scales, steaming as a weed-management technique can be a promising method with further research and development. The process is carried out by the application of heated water in pressure to weeds that makes the waxy-coating of the plant deteriorate which increases moisture removal and subsequently dehydration and death.
Although goats are renowned for their roles in literally chewing off the weeds from your lands, they can be mixed with other animals like bovines and sheep to sustainably remove weeds from agricultural lands and pastures. Some of the common weed species that are preferred by goats are thistles, scotch-broom, blackberry, etc.
Goats and other animals can be highly useful in agricultural farms extended over vast areas in difficult topography and thus can be highly economic, especially since they have livestock economic value in themselves. One of the best ways to integrate goats into your weed control system of a large agricultural land is to divide your land into blocks to implement a rotational cycle for grazing which ensures uniformity over the entire area.
Herbicides are essentially chemicals that kill plants by altering their physiology. Most often, they are the easiest and cheapest options for weed removal, control, or management on agricultural farms. However, herbicides have a harmful impact on the crops, soil microorganisms, and as result on the livestock and humans that depend on the land. Moreover, it causes a range of environmental problems like water resource contamination and loss of soil fertility.
So if you intend to use herbicides to manage weeds on your agricultural farm, you should always make sure to follow the appropriate legal and technical guidelines. Only approved herbicides and pesticides should be used in prescribed quantities.
Cultivation is an age-old practice for the management of weeds in cropland. Cultivation can be used at different times of a crop rotation cycle. For example, the weeds are allowed to germinate before the crop rotation period starts and in fact, even be induced through irrigation. When the weeds grow, the new young weeds are cultivated. The process can be repeated after cultivation; new weeds can emerge from the remaining weed seed bank that was exposed to the soil because of previous cultivation. Finally, after harvesting the crop, additional weed cultivation can be done to further reduce the growth of new weeds in the next cycle.
Cultivation is performed by using heavy machinery like large tractors or using simple hand tools like mattocks and hoes. These tools are used to either cut down the shoots or to dig up the root altogether and bury the shoots. Cultivation, if used correctly and in a timely manner can be a great addition to the integrated weed control system of agricultural land.
A handheld brush cutter is still used to slash weeds on agricultural farms, but a slasher often fitted on tractors is much faster and more effective in slashing large areas covered with weeds and grasses. Slashing is better than cultivation in some regards since it keeps the soil intact, which can be worked on later according to the needs of the crops, and also it is cheaper than the latter. One of the most important aspects of slashing is that it helps to maintain a ground cover and allows for zero tillage farming. As a result, it also drastically reduces soil erosion and further adds nutrients to the soil, increasing its productive potential.
However, slashing cannot be used alone to completely eradicate weeds from your land. In fact, it is best used to control the growth of weeds temporarily to allow for the growth of pasture species that are beneficial for your agricultural productivity.
Mulching can be defined as adding a layer of protection to the soil for a number of reasons like conserving moisture, adding nutrients, making land more aesthetic and in this case, lowering the chances of weeds germinating in the area. Mulches help to block sunlight from reaching the weed seeds and restrict their germination potential.
Materials used for mulching are often organic in nature like timber chips, manures, saw-dust, fallen leaves, etc. But inorganic materials like plastic, often black, are also widely used in large-scale agricultural farms like strawberry cultivation. The effectiveness of mulching on weed control can be undermined if the mulching material used itself contains weed seeds in it and if the material is penetrable by seeds or sunlight. So these two factors should be considered while using mulching as a weed control option.
Fire is distinct from the flaming technique we discussed earlier in that flaming refers to the use of a flame through a muzzle to cause wilting in the weeds while fire is the actual burning of weeds by spreading it across the infested land. Fire is a bad master but a good servant. This means that uncontrolled fire like wildfire can potentially cost massive economic and ecological damage but controlled fire, applied under supervision can prove to be a highly cost-effective and easy method of weed control and even eradication. Special considerations like the season of introducing the fire, the weather condition, amount of fuel, the direction of weed, and the plant and animal diversity need to be evaluated before using fire for weed control. One of the most practical approaches is to establish fire lines and use the back burning technique to control the fire. Fire is often used to eliminate really hardy varieties of weeds. Fire helps to add nutrients and minerals into the soil and increases soil fertility.
While weeds are natural occurrences in almost all types of lands, weeds become problematic in agricultural lands when the land is not managed properly in the first place. Proper management of farmland is the best way to reduce the need for weed control. This directly aligns with the principle that prevention is better than cure. There are certain specific land management activities one can perform to reduce or manage weeds. Some of them include controlled grazing systems, promotion of weed-suppressing plants, the introduction of a system to quickly identify weeds in the initial stages of infestation, soil management, management of good pasture species, and so on.
Although all weed control techniques are highly effective for different needs and circumstances of weed infestations in agricultural land, every agriculture system should have a system of weed control in place that acts to prevent, reduce and control weeds from the lands. The system should ideally be an integrated system with several appropriate techniques combined so that weeds can be managed in the most environmentally friendly way and with the use of the least amount of resources and capital so as to increase the profitability of the agricultural system in the long run.Whats