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Organic farming – composting and its mechanism




Organic Farming is a modern, sustaining & close to nature farming system, which maintains the long-term fertility of the soil and uses less of the Earth’s finite resources to produce high quality nutritious food grains/vegetables/fruits. Organic techniques have been developed from an understanding of and research into soil science, crop breeding, animal husbandry and ecology. The maintenance of soil fertility relies principally on the use of legumes, crop rotation, the application of composted animal manures and ground rock minerals. Weeds are controlled by mechanically methods, while pests & diseases tend not to be a problem due to the inherent bio-diversity in the system. Artificial fertilizers, pesticides, growth regulators and livestock feed additives are restricted/prohibited. Organic Farming implies that the farmers should use organically produced seed, which shows more strength & yield due to bio-diversity.

Organic farming - composting & its mechanismWhilst the sector is still in negligible ratio in Pakistan; however, it would expand dramatically and set to be the most exciting sector within agriculture industry.

No doubt, organic farming has to be understood as part of a sustainable farming system and a viable alternative to the more traditional approaches to agriculture. Thousands of farmers have been converted to this system, as a result of increased consumer awareness of, and demand for, organically grown products. Sustainable development in Organic Farming would encompass food production alongside conservation of finite resources and protection of the natural environment, so that the needs of people living today can be met without compromising the ability of future generations to meet their own needs. This objective requires farmers to consider the effect that their activities should have on the future of agriculture and how the systems, they employ shape the environment. As a consequence, farmers, consumers and policy makers are showing a renewed interest in organic farming.

a) Understanding how nature works instead of relying on chemicals A common misconception about organic farming is that it lacks sophistication, or “Science”. Some people think that organic farmers just put seeds in the ground and “let nature take its course”. Nothing could be farther from the truth.

Organic farmers rely heavily on a complex understanding of ecology and soil science. Modern organic farming techniques are used in concert with traditional methods of crop rotations to ensure fertility and weed/pest control. We know that when we farm, we interact intimately with many creatures and ecological micro-system _ from tiny bacteria and fungi in healthy soil, to larger soil organisms, beneficial insects, and other animals with whom we share the planet.

The methods, we use to farm organically tend to be more labour intensive and costly in the short run, but cost effective in long run. It is notable that groundwater pollution, soil erosion, loss of biodiversity, and human health problems caused by chemical residues are seriously effects of conventional agriculture.

Although organic produce may cost a bit more in the grocery store, because long term costs associated with these problems are factored in, the organic choice is the healthiest and, ultimately least costly option

b) Developing healthy, fertile soil – the natural way Organic matter means the part of the soil that is comprised of anything that once lived, including plants and soil organism. Field high in organic matter have less soil erosion, retain water better, and release nutrients more slowly into soil for natural, healthy plant growth.

Every time crops are harvested or weeds pulled, nutrients and organic matter are withdrawn from the soil. If they are not replaced, the soil is eventually depleted of the resources that plants need to flourish. Healthy soil, rich in organic matter, is “alive” with microorganisms. These vital organisms break down nutrients to make them available to plants and they not only make the soil more fertile but also kill plant pathogens in the soil. The natural way outs to meet the challenges are appended:

c) Introduction of Compost:

A quality compost recycle and some time animal waste materials, and turns them into nature’s best plant food, containing high quality organic matter and beneficial microorganisms. Microorganisms {Bacteria, fungi, nematodes, protozoa, earthworm} break down {Digest}, the raw components of compost.

This metabolic activity generates heat. Before compost applying to the field, it reaches & maintains an internal temperature of 120 to 130F for at least five days to kill any disease-causing bacteria and weed seeds.

Litter/Palletized chicken manure is also used for heat-steam process to kill unwanted bacteria. Mature compost is also containing minimal amounts of undigested carbonaceous {i.e. Woody/Saw dust} materials because these tend to immobilize nitrogen supplies in the soil and thereby starve plants of this critical nutrient.

The most immediate and dramatic effect of the regular additions of compost is an increase in the water holding capacity of sandy soil, increased oxygen content and drainage in clay soils, and significantly healthier and more production of crops. Less obvious, however, are the environmental and human health benefits of using compost such as recycling, otherwise unused “Waste” products (e.g. surplus farm manure, food waste, leaves, grass clippings etc.) and avoiding & minimizing the use of harmful synthetic fertilizers and pesticides.

While compost is being used as a “ nutritive-mulch” throughout the growing season, incorporating compost into the soil prior to planting is the quickest and most efficient way to improve soil fertility. Specific compost application rates are determined by an evaluation of exiting organic matter and nutrient levels. A good rule of thumb is to apply at least one inch but not more than four inches per year.

d) Horse Manure and its Composting:

Horse Manure Composting is a microbial process that has long been used to manage a wide variety (i.e. Carbon-Containing) waste. Horse owners are increasingly taking advantage of many environmental and economic benefits of this practice. The horse manure contains nutrients and pathogens that can pollute surface and ground water, if managed properly. For example, phosphorus rich runoff from stock piled manure can cause uncontrolled growth of aquatic plants in streams, ponds, and lakes. These algae “blooms” kill fish and other aquatic organisms by using up the dis-solved oxygen supplies in water. Runoff and leachate from manure piles also contain nitrates and bacteria, which can make surface and groundwater un-safe for drinking and recreational use. Through a combination of composting and proper environmental controls, pathogens can be destroyed and local water resources protected.

Horse manure commonly contains the larvae or eggs of equine parasites. While spreading untreated manure on pasture increases the risk of exposure to horses that graze there, the heat generated in properly managed compost pile (120 to 155 F) has shown to effectively kill these harmful pests.

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BENEFITS OF COMPOSTING / WHY MAKE COMPOST:

Compost has several advantages over using un-composted organic matter and synthetic fertilizers. To begin with, composting makes plant nutrients available over a longer period of time. Most agronomic and soil fertility research has focused on nitrogen, phosphorus and potash (NPK) as plant nutrients. Studies have shown that only a small percentage of these nutrients will ever be taken up by plants, when readily available form, and the remaining N, P, or K will either leach, volatilize or become immobilized. The advantage of compost is most apparent with nitrogen.

Composting mineralizes complex nitrogen, slowly putting it into a form that is available to higher plants. Mineralized nitrogen is released as nitrate more slowly compared to soluble and volatile forms. Soluble nitrate, whether contained in nitrate-salt fertilizers or raw manure, is more likely to leach to the ground water. A significant portion of ammonia is lost to the atmosphere, when it is applied as raw manure or ammonia-based fertilizers, such as urea or anhydrous. Other nutrients, such as phosphorus, potassium and calcium, are usually present in sufficient quantities, but in a form un-available to plants. Research has shown that compost can activate minerals that are ordinarily un-available – such as rock phosphorus – can be activated by composting. This may be accomplished by the microbial action of a compost pile, or by acidification by humic acid. Humus consists mostly of organic carbon groups that form exchange sites for available essential plant nutrients. The importance of humus and organic matter is a matter of debate in soil science. The role in plant nutrient cycling played by organic matter decomposition into humus and humic acid is not well understood.

Compost also conditions the soil and builds soil structure. Organic matter in compost lightens and aerates heavy clay soils, while it improves soil moisture holding capacity in sandy soils. In irrigate systems, compost serves to improve water penetration, stores & releases water, and , with humic acid, neutralizes alkalinity of saline water.

More over, the composting process can decompose many contaminants found in agriculture wastes. For example, the heat of composting process kills most plants and human pathogens. Plant pathogens seldom survive temperature above 50 C degree (122F). In addition composting also decomposes many pesticides. For this reason, cotton gin trash, cottonseed meal, sugar beet, lime and mushroom compost must either be composted or prove by testing that they have no detected pesticide residues.

MECHANICS OF COMPOSTING:

For most growers, aerobic composting is the easiest and most reliable method. Aerobic methods rely on organisms that require oxygen to digest organic matter. The following steps are recommended for compost making:

a) Collection and Preparation of Feedstock:

Raw organic matter that is being turned into compost is called the feedstock. It is important to use a variety of materials, since nutrient content of compost made from a single material is unlikely to be balanced or have a carbon to nitrogen (C: N) ratio favourable to decomposing organisms.

The single most important ingredient in composts is animal manure. The nutrient contents of different animal manures vary from species to species, and analysis can vary widely within animal type depending on diet and handling. Proper handing of manure ensures that the most unstable major nutrient, nitrogen, does not volatilize or leach. Collection, handling and disposal of manure has been further complicated by the increased concentration of the livestock industry.

Ingredients such as straw, cotton gin trash, sawdust and even wood chips provide a substrate for cellulolytic (cellulose eating) micro-organisms to function. It is important to decrease particle size, so that the surface area for microorganisms to consume and accelerate decomposition is increased. However, particle size should not be so fine that it makes the material more prone to go anaerobic. Cellulolytic and non-cellulolytic microorganisms appear to have a symbiotic relationship with one another, given that mixed communities of microorganisms in the lab decompose faster than single organism communities. Finally, minerals can be added to the pile to balance essential plant nutrients in the compost and make relatively immobile nutrients available.

NUTRIENT COMPOSITION OF COPOSTABLE MATERIALS IN %
Feed Stock              Nitrogen      Phosphate      Potash
Blood Meal              15.00         1.30                0.70
Bone Meal               4.00          21.00               0.20
Brewer’s Grain (Wet) 0.90         0.50                 0.05
Cotton Seed Meal     7.00         2.50                 1.50
Cotton Gin Trash       1.32        0.45                  0.36
Egg Shells                1.19        0.38                 0.14
Fish Waste               6.50        3.75                   —
Leaves (Apple)          1.00        0.15                  0.35
Leaves (Grape)        0.45         0.10                  0.35
Leaves (Oak)           0.65         0.13                  0.52
Lemon Culls            0.15         0.06                  0.26
Manure (Cattle)       0.29          0.17                 0.10
Manure (Horse)       0.44          0.17                 0.35
Manure (Poultry)    1.63           1.54                 0.85
Manure (Sheep)     0.55           0.31                 0.15
Milk                      0.50           0.30                 0.18
Orange Culls         0.20           0.13                 0.21
Phosphate Rock    —              28.00                  —
Sugar Beet Residue 2.56       0.24                  0.45
Straw (Corn)           1.11        0.18                  1.33
Straw (Oat)            0.63         0.16                 1.65
Straw (Rice)           0.60        0.09                  1.16
Straw (Wheat)       0.67         0.07                  0.97
Wood Ash            —            1.50                   7.00

b) Forming Piles:

Aerobic Composting Methods require that the feedstock receive adequate air and moisture, be able to absorb adequate moisture, and shed excessive moisture. Different feedstocks are layered to alternate dry and moist materials. Dry materials should be on bottom, top and outer parts of pile.

As the pile is turned, the compost becomes more homogeneous and the different layers less distinct. Most commonly used by commercial scale operations is the windrow, which is a long, trapezoidal or semi-circular pile of between four and six feet height and six to ten feet across. Height is important, since a too shallow windrow will rapidly lose heat, while one that higher will become compressed by its own weight and create anaerobic conditions.

c) Compost Site Selection:

Any pile of organic matter will eventually rot, but a well-chosen site can speed up the process. Look for a level, well-drained area. If you plan to add kitchen scraps, keep it accessible to the back door. Don’t put it so far away you’ll neglect the pile. In cooler latitudes, keep the pile in a sunny spot to trap solar heat. Look for some shelter to protect the pile from freezing cold winds which could slow down the decaying process. In warm, dry latitudes, shelter the pile in a shadier spot so it doesn’t dry out too quickly.

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Build the pile over soil or lawn rather than concrete or asphalt, to take advantage of the earthworms, beneficial microbes, and other decomposers, which will migrate up and down as the seasons change. Uncovered soil also allows for drainage. If tree roots are extending their roots into the pile, turn it frequently so they can’t make headway.

Look for a spot that allows you to compost discretely, especially if you have neighboring yards in close proximity. Aim for distance and visual barriers between the pile and the neighbors.

d) Maintain Optimum Conditions:

The conditions most critical to compost are air, moisture and temperature. Aerobic methods require that the pile be turned regularly to improve air circulation. Microorganisms require moisture in order to thrive and reproduce rapidly.

Most feedstocks contain some decomposition organism. Introducing microorganisms can accelerate decomposition process. Adding soil can introduce most organisms necessary to initiate the compost process, but can reduce both carbon and nitrogen. Cultured microorganisms are also commercially available. The compost must be moist, but not waterlogged.

During rainy season, compost piles may need to be covered to keep them from becoming waterlogged. Some composters also cover their piles during the dry season to maintain moisture. The more often a pile is turned, the faster will be decomposition. Some methods turn the compost in14 to 21 days.

Turning every week to ten days will usually produce finished compost in four to six weeks, depending on temperature.

e) Finished Compost:

Finished compost should cool back down to ambient air temperatures. It should be dark and moist, with rich, earthy smell. The texture should be fairly loose and homogeneous, with the ingredients thoroughly decomposed.

After the pile has “Cooked” or “Roasted”, the compost can be spread in the cropping area. Loading rates depend on existing soil nutrient levels, soil structure being grown, and previous crop grown. Unlike with synthetic fertilizers or raw manure, there is little chance that compost will burn crops.

Compost is indispensable to most organic soil building programs, offering growers a source of balanced nutrients, organic matter and soil conditioner.

Organic growers, who do not now use this nature soil amendment should examine the benefits of compost and consider introducing it to their program. It is possible to tell, if compost is finished without any more any complicated equipment than one’s senses.

SENSE COMPOST NOT COMPOST
Look Dark, Uniformly, Decomposed Light, un-even, with un-decomposed pieces. Smell Earthy Ammonia (un-finished), Putrid and rotten (Anaerobic un-finished) Feel Cool, Moist Warm (still decomposing), Dry (un-finished, or past its prime) or wet (anaerobic) Vermi-Composting / Composting with Worms: Vermi-composting, or worm composting, is different than traditional composting.

Worm composting is a process that uses red earthworms, also commonly called red worms, to consume organic waste, producing castings (an odor-free compost product for use as mulch), soil conditioner, and topsoil additive. Naturally occurring organisms, such as bacteria and millipedes, also assist in the aerobic degradation of the organic material.

Using Compost:

Finished compost is dark brown, crumbly, and earthy-smells. Small pieces of leaves or other ingredients may be visible. If the compost contains many materials, which are not broken down, it is only partly decomposed.

This product can be used as mulch, but adding partly decomposed compost to the soil can reduce the amount of nitrogen available to the plants. The microorganisms will continue to do the work of decomposing, but will use soil nitrogen for their own growth, restricting the nitrogen’s availability to plants growing nearby.

Allow partly decomposed compost particles to break down further or separate them out before using compost on growing plants. Or add extra nitrogen such as manure, to ensure that growing plants will not suffer from a nitrogen deficiency.

Compost serves primarily as a soil conditioner, whether it’s spread in a layer on the soil surface or is dug in. A garden soil regularly amended with compost is better able to hold air and water, drains more efficiently, and contains a nutrient reserve that plants can draw on. The amended soil also tends to produce plants with fewer insect and disease problems. The compost encourages a larger population of beneficial soil microorganisms, which control harmful microorganisms. It also fosters healthy plant growth, and healthy plants are better able to resist pests. One inch thick is enough to spread on farm beds. Compost continues to decompose, so eventually the percentage of organic matter in the soil begins to decline.

To bolster poor soil with little organic matter, spread 2 to 3 inches of compost over a newly dug surface. Then work the compost into the top 6 inches of earth. A farm soil that has been well mulched and amended periodically requires only about a ½ inch layer of compost yearly to maintain its quality.

Some people recommend late fall as a good time to spread compost over a garden bed, and cover it with winter mulch, such as chopped leaves. By spring, soil organisms will have worked the compost into the soil. Others recommend spreading compost two weeks before planting time in the spring. There is really no wrong time to spread it. The benefits remain the same.

If your supply of compost is really limited, consider side dressing, a way to use compost sparingly by strategically placing it around certain plants or along certain rows. This is best done in late spring and early summer so that the rapidly growing plants can derive the maximum benefit from the compost.

To side-dress a plant, work the compost into the soil around the plant, starting about an inch from the stem, out to the drip line, taking care not to disturb the roots. For shallow rooted plants, leave the compost on the soil surface.

Compost mulch can benefit trees and shrubs just as it does other plants. Spread a ½” to 1″ layer of compost on the bare soil under the tree as far as the drip line. Then cover with a 2-3″ layer of some other kind of organic mulch, such as chopped leaves or pine needles. The mulch will hold the compost in place and keep it from drying out.

Adding compost to the planting hole of small perennial plants is valuable, particularly perennial food plants. Annuals will also benefit from a dose of compost at planting time.

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Compost is the ultimate farm fertilizer. It contains virtually all the nutrients a living plant needs and delivers them in a slow-release manner over a period of years. Compost made with a wide variety of ingredients will provide an even more nutritious meal to your growing plants. Compost is the best material available to enliven your soil no matter where you live.

Farmers around the world will testify that healthier soil grows healthier plants that naturally resist disease, insects, and other environmental pressures. Adding compost to your farm is a long-term investment – it becomes a permanent part of the soil structure, helping to feed future plantings in years to come.

Warm Castings and Worm Juice:
Compost Worms produce a safe, organic alternative to expensive chemical fertilizers. These will not burn the most sensitive plants and being full of richness only needs to be sparingly.

Worm Castings contain approximately:
• Five times more available…………………………………… Nitrogen
• Seven time more available………………………………….. Phosphorous
• Three times more available…………………………………. Potassium
• One & Half time more available……………………………. Calcium
…….………………………………………………….than ordinary top soil.

Worm Casting also……………. Promotes…………….. Strong root growth…………….. Better water penetration…………..Improved soil stability

Recommended Feeding To Plant:
a. Sprinkle 1-2 teaspoons around plants every two weeks and water well. For larger area apply 250-litres per hectare.

b. 5 liters Worm Juice Concentrate, a rich liquid fertilizer may be used per hectare.
Worm Juice Contains:

Nitrate-Phosphorous-Potassium-Magnesium-Calcium-Manganese-Zinc-Boron-Copper-Sulpher-Sodium.

COMPOST TEA:

Compost Tea describes many different preparations made using compost as a starting material and producing a liquid extract or in some cases a “liquid Version” of the original compost. There are probably many recipes for compost tea and a focus on its use for more specific applications. For instance, when making compost tea to combat plant pathogens, the trend is to have as much microbial diversity as possible. When making a tea to supplement plant nutrients, many producers are fortifying the tea with supplements either during production or as a post-production addition.

Optimism about compost tea is high, but understanding its limitations and having realistic expectations are necessary. With all of the variations in compost tea production, there are some applicable basic guidelines independent of recipe or equipment differences.

I) Quality – From Maturity to Microorganism Content:

Compost tea is a readily available form of compost that will impact the plant more quickly than compost mixed into the soil. Compost quality issues, including maturity and microorganism content, become very important for making effective compost tea. The transformation of compost into compost tea cannot improve on the original quality of the compost.

Good compost has the potential to make good compost tea, if made properly; poor compost will always make poor compost tea. Many imperfections in the starting compost, such as high salt concentrations, high levels of anaerobic microorganisms and the presence of pathogens may actually be amplified in the final compost tea. It is critical, therefore, to use only the highest quality compost available. It is recommended that save the lesser quality compost for soil applications and use only the best for compost tea production.

II) Microbial Numbers & Diversity:

Compost that is rich in microbial numbers and diversity can result in compost tea with these same qualities. Even so, the typical representation of microorganisms in compost tea differs from the original compost. Some types of microorganisms like to live attached to particulate matter and a compost tea made using a fine mesh strainer popular for tea destined for drip irrigation, does not let a sufficient amount of particulate matter through to support these microorganisms. The beneficial fungi and antinomycetes prominent in good compost may be poorly represented in the compost tea simply due to the necessity of straining out the material to which they would attach due to the demands of the irrigation system equipment. It is imperative to note that compost tea microbiology is most impacted by oxygen availability, nutrient availability and initial microbiology of the compost used to make the tea.

Compost tea is analyzed for the same microbiological parameters as compost. This includes beneficial microorganisms including aerobic and anaerobic bacteria, fungi, actinomycetes, pseudomonads and nitrogen fixing bacteria, as well as pathogens such E. coli and Samonella. There is no gain to saying that compost tea microbiology is most influenced by oxygen availability, nutrient availability, and the initial microbiology of the compost used to make the tea.

III) Storage and Application Methods:

Compost Tea does not typically improve with time. For best results, it should be used as soon as possible and should store in shaded area with agitation and ventilation to the tank. Long storage times will negatively impact the diversity of microorganisms as well as the nutrients carried by the tea for plant use.

Compost Teas are applied either to the soil or to the plant foliage. Those applied to the soil will move into the root zone and affect the rhizosphere of the plant. The plant as well as the microorganisms in the soil will use nutrients carried in the tea area. The microbes in the compost tea may have a lot of competition with other soil microorganisms, but have the opportunity to become a part of the soil and rhizosphere microbial ecology.

Alternatively, compost tea applied to the plant foliage will immediately impact the plant and there is very little room for forgiveness from the plant, if a tea with toxic qualities is used. A good quality compost will provided beneficial microorganisms and nutrients to the surface of the plant to assist the plant in disease suppression and nutrient availability. Poor quality compost may be supplying the plant surface with unwanted component, such as salts and problem microorganisms. Compost tea destined for foliar applications in particular should only be made with the highest quality of pathogens in critical areas of the plant.

References:

1. Canadian Council of Ministers of the Environment, 1996, Guidelines for Compost Quality.

2. B.C. Ministry of Agriculture, Fisheries and Food, 1996, B.C. Agriculture Composting Handbook.

3. Northeast Regional Agricultural Engineering Service, 1992, On-Farm Composting Handbook.

4. H.A. Hoitink, D.Y. Yan, A.G. Stone, M.S. Krause, W. Zhang, W.A. Dick, Natural Suppression American Nurseryman, October 1997.

5. Chany, David E., Laurie E. Drinkwater and G. stuart Pettygrove {Organic Soil Amendments and Fertilizers, Okland: University of California, USA.

6. Gasser, J.K.R. Composting & other Wastes. New York, Elsevier Applied Science Publishers, 1985

7. Vicki H. Bess, BBC Laboratories, Inc. Tempe, Arizona.

About Saad Ur Rehman Malik

My name's Saad ur Rehman. I am Studying for M.Sc (Hons) in Agronomy. I am editor at Agrihunt and CEO at Hum Pakistan, President at Al Rehman Rural Development Organization and working as Secretary Information at Society for Human Rights. I've also done masters in Journalism and worked as columnist in "Daily Jang". My agriculture coursework and journalism background helps me how to communicate about issues that affect a farmer's everyday lives. I’ve been awarded the gold medal & shield of honor in order to recognize my community and literary services.

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