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Partially rotten farmyard manure should generally be applied to the soil about three to four weeks before the sowing of a crop. In case there is sufficient moisture in the soil, there sill be enough time for its decomposition and for improving the soil structure. Its application too long before sowing a crop will either cause a drying up of the rotted manure or too quick decomppostion, depending on the incidence of rains. But in each case, there will be a serious loss of ammonia and nitrogen. If the manure is already well rotted, it is advisable to apply it just before sowing to a crop. This procedure is perticularly essential in the case of light soils. In any case, after the manure is carted to the field, it should be evenly spread and worked into the soil soon to avoid the loss of nitrogen. The existing practice of leaving the manure in small heaps scattered in the field for several days, before spreading it in the field and incorporating it into the soil, results in the serious deterioration of its quality, particularly if strong winds blow. In vagitable and fruit cultivation, the application of well-rotten manure, in conjunction with fertilizers to young plants individually, has been founnd to give the best results. In Egypt, even the cotton crop, which is invariably grown on ridges, is given a top-dressing a handful of the rotten manure being applied to the soil at the base of each plant before an irrigation, and is worked into the soil with a hand hoe.
The practice of penning cattle, sheep and goats in the fields in summer is common in some parts of the country. Folding 7,000 sheep for one night is said to add the equivalent of 149.3 quintals(14.93 tonnes) of cattle dung. The fresh dung left in the field in such cases rapidly dries up. This drying checks ammonification and loss of nitrogen. With the first fall of rain, the dung is worked into the soil. It, therefore, does not lose much of its fertilizing value. Further more, its beneficia effects on the physical condition of the soil are undeniable. However, sheep-folding is said to make the land more weedy.
There must be adequate moisture in the soil for the proper decomposition of organic matter. Farmyard manure can, therefore, be applied to all crops grown in the rainy season or grown under irrigation. The quantity of manure to be applied to unirrigated crops varies from 1.5 to 2 cartloads per hectare in areas of heavier rainfall. If sufficient farmy manure is not available, it may be applied at the usual rate to a part of the land,say, to one-third or one-forth of the area, in rotation every year, so that all parts of the field receive the manure regularly once in three or four years. For irrigated field crops, the rate varies from 10 to 20 cartloads. Sugarcane, maize and garden crops, such as potatoes, turmeric, ginger, vegetables and fruits receive still higher doses, amounting sometimes to 15 to 25 cartloads. A cartload of manure, measuring 9 cubic metres, weighs about half a tonne.
It must be stressed that the value of farmyard manure in soil improvement is due to its content of principal nutritive elements and its ability to (i) improve the soil tilth and aeration, (ii) increase the water-holding capacity of the soil, And (iii) stimulate the activity of micro-organisms that make the plant-food elements in the soil readily available to crops. The supply of organic matter, which is later converted into humus is a property of farmyard manure.
One tonne of carttle dung can supply only 2.95 kg of nitrogen, 1,59 kg of phsophoric acid and 2,95 kg of potash.
The use of farmyard manure alone causes an imbalance in nutirtion owing to its relatively low content of phosphoric acid. Therefore, to keep the soils well supplied with all the essential elements of plant food in a readily available form, and also to keep them in good 'heart', it is advisable to use the bulky organic manures in conjuction with superphosphate and such other artificial fertilizers as contain the particular plant food or foods in which a soil may be deficient or which the crop to be grown may specially require.
(2) Composted manure
Another method of augmenting the supplies of organic is the preparation of compost from farmhouse, and cattle-shed wastes of all types. Composting has been advocated and adopted extensively during the past 25 years. Composting is the process of reducing vegetable and animal refuse(rural or urban) to a quickly utilizable condition for improving the maintaining soil fertility. Research conducted in India and abroad has shown that good organic manure similar in appearance and fertilizing value to cattle manure similar in appearance and fertilizing value to cattle manure can be produced from waste materials of various kinds, such as cereal straws, crop stubble, cotton stalks, groundnut husk, farm weed and grasses, leaves, leaf-mould, house refuse, wood ashes, litter, urine-soaked earth from cattle-sheds and other similar substances. These raw vegetables materials are rich in cellulose and other readily decomposable carbohydrates and have a carbon-nitrogen ratio of 40 or more to 1. The direct application of such undecomposed, low nitrogen organic matter as manure brings about a temporary deficiency of mineral nutrients(specially nitrates and ammonium compounds) in the soil by stimulating the growth of micro-organisms, which in turn, compete with crop plants for available nitrogen, phosphorous and other elements. Hence, before using them as manure, it is necessary to compost or partially decompose them. This process lowers the carbon-nitrogen ratio to about 10 or 12 to 1.
Two methods of composting waste organic materials are usually recommended. One depends on aerobic and other one unaerobic decomposition. In both cases, the farm wastes have to be used as a bedding for cattle in order to absorb a large of the animal urine. In the aerobic process, the used bedding, the sweepings from cattle sheds and some urine-soaked earth from the stable floar are removed everyday, mixed with a little cattle dung and 2 or 3 handfuls of wood ashes are deposited on a well drained site to gradually builed up a lowpile about 30 or 45 cm in height, about 5 m in width and of any convenient length. The pile is built up before to start of rainy season. After the first heavy shower, the waited material in 1.2 strip on each side of the long heap is turn with a rake on to 2.4 m wide stripe in the middle, so raising the height of the heap to nearly 1 m. This process prevents loss of misture and ensures a quick start of decomposition. When the heap sinks appreciably and such a sinking takes about 3 to 4 weeks, it is given a turning and made into fresh heap, thus mixing the outside material with that from inside. After about a month or more, depending on incidence of rains the heap is given a final turning on a cloudy or moderately rainy day and rebuilt the vacant part of the original position. The composed becomes ready for use in about 4 months. This method is eminently suited for composting in the rainy season. The following proposition of raw materials is considered suitable for compost making:
| Parts by weight |
| Mixed farm residues and cattle-shed | 400 |
| Urine-soaked earth | 56 |
| Fresh cattle dung | 60 |
| Wood ashes | 6 |
In Tamil Nadu, the application of 90 kg of partially fermented dung in the form of a thin suspension, with 22.50 kg of bone-meal per tonne of dry material to be composted is recommended.
If urine-soaked earth and cattle-dung are not available, the raw organic materials can still be composted, provided more than one-third of the residues is soft and finely broken, such as fallen leaves, leaf-mould, kitchen wastes, grass clippings, green and succulent weeds, plant trimming and clopped wheat, barley and soft cereal straw. The use of ordinary soil and wood ashes or lime is, however, essential.
In the anaerobic process, the mixed farm residues are collected in pits of a convenient size, say, 4.5 m*1.5 m*1 m. Each day's collection is spread in a thin layer, sprinkled with a mixture of fresh cowdung(4.5 kg), ashes(140 to 170 g) and water (18 to 22 litres) and compacted. The pit is filled till the raw material stands 38 to 46 cm above its edge, and then is then plastered with a 2-5 cm layer of a mixture of mud cowdung. Under such conditions, decompostion is anaerobic and high temperatures do not develop. Insoluble nitrogen compunds gradually become soluble and the carbonaceous matter is broken down into carbon dioxide and water. The loss of ammonia is negligible, because in high concentrations of carbon dioxide, ammonium carbonate is stable. The plastered pit also prevents the fly nuisance. The well-made compost contains 0.8 to 1 per cent of nitrogen and has all the good properties of farmyard manure. It can be used in the same way as the latter. The anaerobic process is particularly suited for use by gardeners in or near cities and towns.
COMPOSTING METHODS
Raw Materials
The materials are needed are
mixed plant residues, animal dung and urine,earth, wood ash and water. All vegetables
wastes available on a farm like weeds,stalks,stems,fallen purnings,chaff,fodder remnants,green matter and so on, are collected and
stacked in a pile. Hard woody material like cotton or pigeon-pad stalks and stubble are first spread on the farm road and crushed
under Vehicles viz. tractors or bullock carts before being piled. Such hard materials should in any case not exceed 10 percent of the
total plants residues. Green material which are soft and sufficient and allowed to wilt for 2 or 3 days to remove access moistures before stacking; they tend to pack closely, if they are stacked in the fresh state. While stacking, each material is spread in layers of
about 15cm thickness until the heap is about 1m and 50cm high. The mixture of different kinds of vegetable residuesensures a more efficient decomposition.
The heap is then cut into vertical slices and about 20-25 kg is put under the feet of cattle in the shed as bedding for the night. The next morning the bedding, along with the dung and the urine, and urine earth, is taken to the pits where the composting is to be done.
PIT METHOD
This method includes following steps :
Site and size of pit
The site selected for the compost pit should be near to cattle shed and water source at high level so that no rain water gets in during the mansoon season. A temporary shed amy be constructed over it to protect the compost from heavy raifall. The pit should be about 1 m deep * 1.5-2.0 m wide and of any suitable length.
Filling the pit
The material brought from the cattle shed is spread and on each layer is spread a slurry of dung made with 4.5 kg urine earth and 4.5 kg of inoculum taken from a 15-day-old composting pit. A sufficient quantity of water (nearly 90%) is sprinkled over the material in the pit to the wet it. The pit is filled in this way layer-by-layer and it should not take longer than 1 week to fill. Care should be taken to avoid compacting the material in any way.
Turning
The material is turned 3 times during the whole period of composting (i) after 15 days from filling the pit, (ii) another 15 days , (iii) after another 30 days. At each turning the material is mixed throughly, moistened with water and replaced with the pit.
HEAP METHOD
During rainy seasons or in regions with heavy rainfall the compost may be prepared in heaps above ground. when sufficient nitrogeneous material is not available a green manure or leguminous crop like sunhemp is grown on the fermenting heap by sowing seeds after the first turning. The green mater is then turned in at the second mixing.
Dimensions
The basic Indore pile is about 2 m wide at the base, 1.5 m high 2 m long. The sides are tapered so that the top is about 0.5 m narrower in width than the base. A small bund is sometimes built around the pile to protect it from wind which tends to dry the heap.
Forming the heap
The heap isusually commenced with a 20 cm layer of carbonceous material such as leaves, hay-straw, sawdust, wood chips and chopped corn stalks. This is then covered with the 10 cm of nitrogeneous material such as fresh grass, weeds or garden plant residues, garbage, fresh or dry manure or digested sewage sludge. The pattern of 20 cm carbonaceous material and 10 cm nitrogeneous material is followed until the pile is 1.5 m high and they are normally wetted so that they feel damp but not soggy. The pile is sometimes covered with soil or hay to retain heat and is turned at 6- and 12-weeks-interval. In the republic of korea, heaps are covered with thin plasic sheets to retain heat and it has also resulted in the death of insects.
If materials are limited, the alternate layres can be added as they become available. Also, all materials may be mixed together in the pile, if one is careful to maintain the proper proportions. Shredding the material speeds up deconposition considerably; most materials can be shredded by running over it several times with a rotary-mower.
Advantages and limitations
Preparation on a large scale can be done through community composting. there is lack of protection from rain and wind. A considerable amount of water is needed ans so the heap method is not suitale in near areas of scanty rainfall.
The intense aerobic decomposition to which the material is subjected no doubt shortens the period of composting but it leads to heavy losses of organic matter and nitrogen. Therefore the C:N ratio should be maintained between 30 and 40 to reduce such losses.
BANGALORE METHOD
Preparation of the pit
Trenches or pits 1m deep are dug; the breadth and length of the trenches can be made depending on the availability of land and the type of material to be composted. The selection of site for 1 pit is made as mentioned in the Indore method. The trenches should preferably have sloping walls and a floor of 90 cm slope to prevent waterlogging.
Filling the pit
Organic residues and night soil are put in alternate layers and after filling, the pit is covered with a 15-20 cm thick layer of refuse. the materials are allowed to remain in the pit without turning and watering for 90 days. during this period the material settles down due to reduction in volume of the biomass and additional nightsoil and refuse in alternate layers are placed on top and plastered or covered with mud or earth to prevent loss of moisture and breeding of files. the material undergoes anaerobic decomposition at a vey slow rate and it takes about 180-240 days to abtain the finished product.
Advantages and limitations
The recovery of the finished product is greater as compared to aerobic composting but loss of nitrogen is negligible. Labour requirements is less than for the Indore method as turning of material is not done; labour is needed only for digging and filling the pits.
The methods requires along time to produce a finished compost and so takes up more land use. A uniform high temperature is not assured in the biomass. Problems of odour and fly breeding need to be attended too.
SYNTHETIC COMPOST
In the preparation of synthetic compost, the organic nitrogen as dung, required by micro-organism, can be completely substituted by inorganic nitrogen compounds like ammonium sulphate and urea which are utilized equally effectively for decomposition of carbonaceous materials into compost. The Adco process of preparations of synthetic compost developed by Hutuchinson and richards is based on this principle.
This facilitates the utilization of large quantities of various organic waste material where supplies of dung are either short of the requirement or not available at all, as on mechanized farms.
The basic principle of C:N ratio in manure preparation can be applied to add nitrogenous fertilizers in sufficient quantity to decompose. The material to be composted is moistened. This is sprinkled with the fertilizer solution and then with lime. Superphosphate may be added to fortify the phosphorous content of the manure. The treatment is continued layer-wise until the heap or pit is filled to the size and allowed to ferment. The manure becomes ready for application in about 120-180 days and resembles with farmyard manure in its action on soil and plant growth.
LEAF COMPOST
Leaf composting, can be achieved by heap or ditch composting or by windrow composting. windrow are preferred as they allow efficient handling of materials Provide good aeration, allow sufficient of water and are easy to be performed.
It is suggested the formation of uniform-shaped windrow from 2.40 m-3.60 m at the base and 2.40m-3.00m high and of any convenient lenght. Windrow built too high will have excessive compaction at the base resulting in anaerobic conditions. Windrows built too low will not allow sufficient insulation to sustain thermophilic temperatures during cold weather. To ensure proper aeration, it is important to break apart tightly compacted leaves.
Though reduction in size may aid in rapid decomposition, it is not desirable in leaves because it increases the compaction making more frequent aeration necessary. When the incoming leaves are not adequately moist, it is desirable to add water to maintain a proper moisture regime of 40 to 60%.
The C:N ratio of leaves is relatively high. It can be as high as 80, and needs to be amended with nitrogen. Sewage sludge, urea and grass clippings are good sources of nitrogen. If a nitrogen source is to be added, caution should be exercised to distribute it uniformly throughtout the windrow, lest it may result in undesirable anaerobic conditions and uneven decomposition. Proper aeration can be maintained by periodical mixing of the material.
Under optimum environmental composting conditions, leaf compost will be ready between 180 and 270 days. Leaf mould will have final PH range of 6-7.
It is suggested the use of finished compost (leaf mould) as converting material (10-15cm) in the subsequent preparation of leaf compost to supply a heavy inoculum of micro-organisms.
ENRICHMENT WITH PHOSPHOROUS
Phosphorous enriched compost is prepared by adding 5% superphosphate at the filling of the compost pits. Other sources of phosphorous for this purpose are powered rock phosphate, preferably of low grade (less than 11% P), can be used with profit. Besides, phosphorous it is a source of calcium and micronutrients. Bonemeal will provide nitrogen as well as phosphorous; it contain 9-11% P and 2-4% N. Steamed bonemeal is more easily ground than the fresh material. It contains a little less nitrogen but more phosphorous than the raw material. Basic slag provides calcium, magnesium and trace nutrients and small amount of phosphorous. Banana residues contains about 1-1.5% phosphorous on an ash basis.
ENRICHMENT WITH POTASSIUM
Granite dust of powdered potassium-containing minerals like feldspars can be added to enrich compost. Potassium and other deficient elements can be added to compost by including plant materials which contain apperciable amounts of those elements. Water hyacinth for example, is a rich source of potassium and of many other elements required by plants. Banana skin and stalks contain 34-42% potassiumon an ash basis, seaweeds are rich in iodine, boron, copper, magnesium, calcium and phosphorous. Leaves are also a good source of trace elements and should form a parta part of every compost heap. Potato peel is rich in trace elements and dry potato vines contain 1% potassium, 4% calcium and 1% magnesium.
VERMI COMPOSTING
VERMI-COMPOSTING is the use of earthworms for composting of organic residues. Earthworms can consume practically all kinds of organic matter. One worm, weighs about 0.5 to 0.6 g, eates wastes as their own body weight perday and produces cast of the same weight per day. It is estimated that 1000 tonnes of moist organic matter can be converted by earthworms into 300 tonnes of compost. Organnic materials undergo comples biochemical changes in the intestines and vermi-composting is an appropriate technique for disposal of non-toxicsolid and liquid organic wastes. It helps in cost effective and efficient recyclicing of animal wastes (poultry, equine,piggery excreta and cattle dung) agriculture residue and industrial wastes using low energy, excreta together with their cocoons and undigested feed make up vermicasting. The castings of earthworms are rich in nutrients (N, P, K, Ca and Mg), and also in bacterial and actinomycetes population. The actinomycetes population in worm cast is over 6 times more than in the original soil (Gaur 1982). A mosist compost heap (30-40% moisture level) of 2.4 m * 1.2 m * 0.6 m high, can support a population of mare than 50,000 worms. The temperature is the culture bed should be within the range of 200-300C. The introduction of worms into compost heap has been found to mix the materials, aerate the heaps and hasten decomposition. turning the heaps is not necessary, if earthworms are present to do the mixing and aeration. Besides rural and urban wastes, effluents from agro-industries viz dairies, tanneries, pulp and paper mills, distilleres etc.can be treated by using earthworms.
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