3 – Role of Earthworm in Sustainable Agriculture
- Introduction. Human beings always equate their well-being with consumption. …
- Earthworm as Ecosystem Engineers. Earthworms are one of the most important soil animals that have the capability to maintain soil fertility, thus playing a key role in sustainability.
- Composting Versus Vermicomposting. …
- Composting Earthworms. …
- Interaction of Earthworm With Soil. …
What is the purpose of an earthworm’s crop?
Earthworms are an important part of the soil ecosystem. They help improve soil structure and soil chemical and biological properties . They are especially important in no-till, helping to stimulate air and water movement in soil. Earthworms tend to thrive most without tillage, if sufficient crop residue is left on the soil surface.
What is the reproductive system of an earthworm?
The female reproductive system of earthworm comprises ovaries, oviduct and spermatheca. One pair of ovaries, present at 13th segment. Each ovary consists of several finger-like projections. In these projections, developing ova are present in a row, which looks like a series of beads.
What is the crop for an earthworm?
Earthworms thrive in grasslands and alfalfa. In one grassland study, 70 earthworms were counted per square foot (more than 3 million earthworms per acre). Crop residue. If crop residue is removed, earthworms lose their food source. Use of a cover crop that is left in the field or removal of only part of the crop are ways to feed earthworms. Manure
What is the function of coelom in an earthworm?
Under the skin is a layer of nerve tissue, and two layers of muscles—a thin outer layer of circular muscle, and a much thicker inner layer of longitudinal muscle. Interior to the muscle layer is a fluid-filled chamber called a coelom that by its pressurization provides structure to the worm’s boneless body.
Why are earthworms important to agriculture?
Emphasis was placed on physical and chemical aspects of plant growth while biological aspects were neglected . We are now realizing how interactions between crops, climate, soil, and living organisms play important roles in sustaining our agriculture. Earthworms are among the most visible of soil organisms and have received considerable attention. They play a pivotal role in maintaining the productivity of our soils. This makes understanding these lowly animals and finding ways to make them thrive very important.
Why are earthworms important?
Earthworms are an important part of the soil ecosystem. They help improve soil structure and soil chemical and biological properties. They are especially important in no-till, helping to stimulate air and water movement in soil. Earthworms tend to thrive most without tillage, if sufficient crop residue is left on the soil surface. Crop rotations, cover crops, manure, fertilizer and lime applications all affect earthworm populations. Some pesticides, especially organophosphates and carbamates, are toxic to earthworms. Most herbicides do not pose a threat to earthworms.
How does tillage affect earthworms?
In long-term clean-tilled fields, nightcrawlers are scarce. Tillage also stimulates drying the surface soil and wide day/night temperature fluctuations. This is another reason earthworms are less numerous in clean-tilled fields compared to no-tilled fields. Tillage brings earthworms to the surface where they are subject to predators such as birds. Total earthworm populations in long-term no-tilled fields are typically at least twice those of clean-tilled fields.
How do earthworms reproduce?
Earthworms are invertebrates composed of many segments (Fig. 1). They don’t have bones and move by contracting and relaxing the body segments in sequence. They also have little bristlelike organs that help them cling to slippery surfaces. Most earthworms have both male and female organs. Typically, however, they still need a partner to reproduce. When earthworms mate, they lay side by side in reverse position. At that moment they exchange sperm. The sperm of the partner is stored in little chambers called spermathecal apertures. These are positioned in front of the egg-producing organs. After mating, the swollen external gland, called clitellum, produces egg cases called cocoons. A cocoon case slides slowly forward, picking up eggs and sperm as it moves over the head of the earthworm. From 3 to 1,000 cocoons can be produced per year, depending on species and environmental conditions. Typically, an earthworm will produce 20 to 30 cocoons per year, with each cocoon containing 1 to 10 eggs. Peak cocoon production is in the spring or early summer. The eggs in the cocoons hatch when conditions are right. Under ideal conditions, it may take from 1 to 5 months for the eggs to hatch. It may then take from 3 to 12 months before these worms are sexually mature. Worms typically live only a few months because of the many environmental threats they face. They have been observed to live for 10 years in a protected environment. In a favorable environment previously without earthworms, earthworm populations increased 80-fold in 4 years after introduction.
How much dry matter do earthworms eat?
Typical earthworm populations can easily consume 2 tons of dry matter per acre per year, partly digesting and mixing it with soil. The importance of earthworms to mix surface residue with soil becomes very clear in soils that do not have any earthworms.
Why are earthworms tied up in a knot?
Earthworms in diapause are tied up in a knot in a little hole that is lined with a slimy substance to avoid moisture loss. Eggs in cocoons survive prolonged drought, allowing earthworm populations to survive drought periods. Because of dry conditions, earthworm populations in Pennsylvania are low in the summer.
What are the nutrients in earthworm casts?
Earthworm casts have higher available nitrogen, phosphorus, potassium, and calcium contents than surrounding soil, as well as a higher cation-exchange capacity. Some micronutrients, such as zinc and boron, are more available in the excrement of earthworms through chelation of the micronutrients.
Which family of earthworms is most important in enhancing agricultural soil?
The family of earthworms that is most important in enhancing agricultural soil is Lumbricidae, which includes the genuses Lumbricus, Aporrectodea, and several others. Lumbricids originated in Europe and have been transported by human activities to many parts of the world. The United States has only one or two known native species of lumbricids. Others were brought to this country by settlers (probably in potted plants from Europe), and were distributed down the waterways.
How do earthworms affect soil?
Earthworms dramatically alter soil structure, water movement , nutrient dynamics, and plant growth. They are not essential to all healthy soil systems, but their presence is usually an indicator of a healthy system. Earthworms perform several beneficial functions. Stimulate microbial activity.
How to find earthworms in soil?
It is easy to determine whether you have an adequate population of earthworms in your soil. Look for their casts in the forms of little piles of soil, mineral particles, or organic matter at the soil surface. They can be seen moving over the soil surface or even breeding, particularly on warm, damp nights. Dump a spade full of moist soil into a bucket or onto a sheet of plastic, and sort through for earthworms. Can you identify different species? To find the deep burrowing species, pour a dilute mustard solution onto the soil. Many will quickly come to the soil surface in response to this irritant.
What are deep burrowing earthworms?
Deep-burrowing species – Anecic species. These earthworms, which are typified by the “night crawler,” Lumbricus terrestris, inhabit more or less permanent burrow systems that may extend several meters into the soil. They feed mainly on surface litter that they pull into their burrows. They may leave plugs, organic matter, or cast (excreted soil and mineral particles) blocking the mouth of their burrows.
What are the casts on soil?
Casts at the soil surface are evidence that earthworms are shredding, mixing, and burying surface residue.
How many species of earthworms are there?
They are divided into 23 families, more than 700 genera, and more than 7,000 species. They range from an inch to two yards in length and are found seasonally at all depths in the soil. In terms of biomass and overall activity, earthworms dominate the world of soil invertebrates, including arthropods. Earthworms.
How many earthworms are there in a square yard of soil?
The majority of temperate and many tropical soils support significant earthworm populations. A square yard of cropland in the United States can contain from 50-300 earthworms, or even larger populations in highly organic soils.
How do earthworms help humans?
Earthworms provide these ecosystem services to humans: 1 Increasing pastoral productivity: Once lumbricid earthworms become established, pastoral productivity increases by 25–30%. This is equivalent to 2.5 stock units per hectare. Earthworms remove the surface thatch material that can block water from entering the soil, as the thatch can cause it (and soluble nutrients) to run off. 2 Facilitating and accelerating mine restoration: By increasing soil fertility, recycling waste products and providing food resources for predators, earthworms help to restore functioning ecosystems#N#20#N#both above and below the ground.
Why are earthworms considered ecosystem engineers?
Earthworms are sometimes known as ‘ecosystem engineers’ because they significantly modify the physical, chemical and biological properties of the soil profile. These modifications can influence the habitat#N#5#N#and activities of other organisms within the soil ecosystem.
How do lumbricid earthworms increase pastoral productivity?
Increasing pastoral productivity: Once lumbricid earthworms become established, pastoral productivit y increases by 25–30%. This is equivalent to 2.5 stock units per hectare. Earthworms remove the surface thatch material that can block water from entering the soil, as the thatch can cause it (and soluble nutrients) to run off.
What is an earthworm cast?
Earthworm casts. Earthworm casts are digested material that earthworms excrete. Their digestion unlocks nutrients like nitrogen and phosphorus, making them more available to plants. Earthworms may lack the charm or excitement of more familiar animals, but their contribution to our world is significant.
How do worms increase the availability of nutrients?
Increasing nutrient availability: This happens in two ways: by incorporating organic materials into the soil and by unlocking the nutrients held within dead organisms and plant matter. Nutrients like phosphorus and nitrogen become more readily available to plants after digestion by earthworms and being excreted in earthworm casts. Scientists have measured up to five fold increases in nitrogen availability in earthworm casts compared to undigested soil. Earthworms also take nutrients down through the soil profile, bringing them into closer contact with plant roots.
How do earthworms affect pastoral lands?
Earthworms provide these ecosystem services to humans: Increasing pastoral productivity: Once lumbricid earthworms become established, pastoral productivity increases by 25–30%.
How much organic matter do earthworms produce?
8. material. Most people know about earthworms and compost, but earthworms do the same in pasture soils, decomposing dung and plant litter and processing 2–20 tonnes of organic matter per hectare each year, and recycling leaf litter under orchards and in other forested areas.
How do earthworms help the soil?
Plants can then reuse mineral nutrients released after digestion. Earthworms play a vital role in nitrogen mineralization through the release of metabolic products such as mucus, casts, and urine , which contain urea, uric acid, and dead tissue. Nitrogen mineralization can also be enhanced indirectly through the fragmentation of organic matter and alteration of the soil’s physical properties. The process of nitrogen mineralization, however, depends on the species of earthworm present in the ground.
What are the services that earthworms provide?
Additionally, earthworms provide cultural services by burying archeological artifacts and providing bait for fishing.
How do worms affect soil?
Earthworms affect soil water regulation by modifying soil porosity , which occurs through the production of microporosity, mesoporosity, and macroporosity. The specific configuration of pore shapes and sizes may allow the soil to store or transfer water in various ways. Several studies have shown that some species of earthworms increase the rate of water infiltration. In Mediterranean soils, the amount of biomass, particularly earthworms, significantly affects water percolation through the ground. Experts estimate that an increase in percolation due to worms can decrease soil erosion by up to 50%. Endogeic de-compacting species in the tropics increase the porosity of the soil and water infiltration, thereby reducing run-off.
What are the physical forces that affect soil structure?
It is a function of interacting physical forces including water, actions of biota including earthworms and plant roots, the presence of organic matter, and soil tillage. Worms help in making soil both compact and at times, lose. For example, R. omodei, an endogeic earthworm species, decreases soil porosity leading to compaction, whereas Eudrilidae earthworms increase porosity, leading to loosening of the soil. In general, worms have a positive effect on soil structure.
What are the three categories of earthworms?
Ecological Classification. Earthworms are divided into three categories that contribute in various distinctive ways to ecosystem processes, and by extension, ecosystem services. Epigeic earthworm species produce casts on the soil surface that affect the distribution of macropores and the soil’s roughness. Anecic species can be found in vertical …
What are endogeic worms?
Endogeic species are known to form horizontal and randomly oriented holes within the mineral soil. The tunnels of endogeic species are temporary, as they are rarely reused. Based on the terms of the Millennium Ecosystem Assessment, earthworms act as a catalyst for supporting services that include soil formation and nutrient cycling.
Why are earthworms considered an engineer?
Earthworms are regarded as typical ecosystem engineers due to their impact on various aspects of the ecosystem, including soil structure.
How do earthworms help the agroecosystem?
Their feeding and burrowing activities incorporate organic residues and amendments into the soil, enhancing decomposition, humus formation, nutrient cycling, and soil structural development (Mackay and Kladivko, 1985; Kladivko et al., 1986). Earthworm burrows persist as macropores which provide low resistance channels for root growth, water infiltration, and gas exchange (Kladivko and Timmenga, 1990; Zachmann and Linden, 1989). Quality, quantity and placement of organic matter is a main determinant of earthworm abundance and activity in agricultural soils (Edwards, 1983; Lofs-Holmin, 1983), as are disturbances of the soil by tillage, cultivation, and the use of pesticides (Doran and Werner, 1990).
What are earthworms used for?
Earthworm casts are sources of nutrients for plants. Lumbricids in a pasture soil produced casts that contained 73 percent of the nitrogen found in the ingested litter; indicating both the importance of earthworms in incorporating litter nitrogen into the soil and the inefficiency of nitrogen digestion by earthworms (Syers et al., 1979). Earthworms increase the amount of nitrogen mineralized from organic matter in soil. Because nitrification is enhanced in earthworm casts, the ratio of nitrate-N to ammonium-N tends to increase when earthworms are present (Ruz Jerez et al., 1988). Nitrogen-fixing bacteria are found in the gut of earthworms and in earthworm casts, and higher nitrogenase activity, meaning greater rates of N-fixation, are found in casts when compared with soil (Simek and Pizl, 1989).
What is the red worm?
Red wriggler or red marsh worm (Lumbricus rubellus) is an epigeic detritivorous earthworm that is common in apple orchards with permanent cover crops. Photographs by Suzanne Paisley.
What are the worms that live in California?
The earthworm fauna in California includes some native species, lumbricid immigrants, as well as immigrants from Asia and South America. From limited personal observations, the lumbricids found in California agricultural soils tend to have small populations that are active for relatively short periods during the wet season. This may reflect agricultural management practices as well as climate effects. There may be species that are adapted to seasonally-dry climates that would flourish in California agricultural soils, if provided the proper conditions.
How to introduce earthworms to a farm?
One management idea for introducing desired species is to set aside a small area of land on a farm to be managed exclusively as an earthworm reservoir. If needed, the soil could be limed to bring it near pH 7, fertilized, and a cover crop established and cut periodically to provide an organic mulch as food and physical cover. In this area a community of the desired species could be established and built up. From this reservoir blocks could periodically be taken and introduced into the field. Rate of spread would vary with species and conditions in the field. Lumbricus terrestris is capable of travelling at least 19 meters on the soil surface in the course of one evening foray (Mather and Christensen, 1988). This is a long term process for establishing earthworms, and would only be successful if ample organic matter was supplied to the soil where earthworms were being introduced, and if physical and chemical disturbances of the soil were minimized. Organically managed perennial crops would be ideal for this method.
How to manage earthworms?
There are many creative ways in which a farmer can manage for earthworms. A first step might be to determine what earthworm ecotypes are present , and how abundant they are. Endogeic species are most commonly found. These are useful, but a mixed community including anecic species as well would be even more beneficial, especially for incorporation of surface matter. Direct inoculation is one possible method, but transferring blocks of soil (one cubic foot each) from an area with a large earthworm population into a farm soil might work better. It is also important to consider what species should be introduced, and this is where research specific to seasonally-dry climates in California is needed. Much of our knowledge about earthworms concerns species of one family, the Lumbricidae, which are native to moist temperate areas of Europe. The spread of these earthworms has paralleled European colonialism around the world. They are the only earthworms present in the northeastern US and Canada, where glaciation killed the native fauna. In areas that have a native earthworm fauna, lumbricids often dominate in disturbed habitats. Morphologically, lumbricids are more muscular than any other family of earthworms, suggesting a greater capacity for burrowing (Hartenstein, 1986).
How does mulch help earthworms?
Organic mulches enhance earthworm habitat by moderating microclimate and supplying a food source. In corn plots in Pennsylvania, earthworms were most abundant in the fall in treatments that were not plowed before winter and where corn residues had been chopped and left as a mulch, regardless of whether the plots were organically or conventionally managed (Werner and Dindal, 1990).
How do earthworms help the ecosystem?
Earthworms play a key role in soil natural ecosystem. As they improve soil structure, microbial communities, and nutrient cycling. As a result, these activities of earthworms positively influence plant growth and reproduction.
Why are earthworms important to soil health?
Earthworms are the savior of soil health due to their unique abilities. They perform nitrogen mineralization and water infiltration due to their burrowing and feeding habits. Besides these, earthworms also build a home for other organisms. As they build different structures in the soil such as tunnels, middens, and casts. These structures serve as habitats for other soil organisms, which establish them as physical engineers.
How do earthworms affect soil microbiota?
Epigeic earthworms can ingest 3–50 mg of litter per day. But they do not have any effect on soil microbiota. However, the endogeic greatly affect the biomass of soil microbiota. Endogeic mainly affects the soil’s fungal and bacterial organisms. With the increase of endogeic biomass, there is a decrease in soil microbial biomass. In the case of endogeic earthworms, the biomass of soil microorganisms decreases with the soil depth. The anecic group of earthworms builds permanent vertical tunnels in the soil and, these are termed soil horizons. Unlike the other two groups of earthworms, the anecic greatly impact soil structures and their microbiota. This group of earthworms positively influence the soil microorganism communities. During their feeding of soil litter, they positively build up the soil microbiota. The feeding behavior of all three groups influences soil in terms of nutrients, soil texture, and water content.
What is the drilosphere of earthworms?
The image is consists of the drilosphere — the soil area consists of earthworm secretions and burrowing. This area represents a valuable niche of soil beneficial animals where they carry out litter decomposition. In this area, they also process nutrient mineralization and promote plant growth and development.
What are endogeic earthworms?
Endogeic earthworms: They live in soil and live on mineral soil. While living in soil, they build horizontal tunnels and cause the decomposition of soil material.
What are the organisms that live in S oil?
It includes microbial communities (fungi, bacteria), worm-like organisms ( nematodes ), and terrestrial invertebrates (earthworm). Collectively, these organisms maintain soil health and play their role autonomously. Soil physical properties also rely on the activities of its inhabitants. These communities also determine the production potential of the agriculture system. Such as soil microbial communities accumulate beneficial microbes at plant rhizosphere. In addition to these microbial communities, there are terrestrial invertebrates — Earthworms.
Do earthworms have microbial communities?
These energy-rich secretions also awake the soil dormant microorganisms. These microbial communities assist earthworms in the digestion of soil organic matter. Even earthworms feed on soil microorganisms, especially fungi. Such preference of soil microbial communities by earthworms could decrease the fungal biomass. And they may enrich the soil with bacterial microorganisms. Particularly those bacterial taxa that facilitate the feeding of earthworms.
Earthworms improve water infiltration and water holding capacity because their shredding, mixing, and defecating enhances soil structure. In addition, burrows provide quick entry for water into and through soil. High infiltration rates help prevent pollution by minimizing runoff, erosion, and chemical transport to surface waters. Although there is …