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Friday, April 8, 2011

Movement against Chemical usage in Agriculture


Many inorganic fertilizers do not replace trace mineral elements in the soil which become gradually depleted by crops. This depletion has been linked to studies which have shown a marked fall (up to 75%) in the quantities of such minerals present in fruit and vegetables.
However, a recent review of 55 scientific studies concluded "there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs" Conversely, a major long-term study funded by the European Union found that organically-produced milk and produce were significantly higher in antioxidants (such as carotenoids and alpha-linoleic acids) than their conventionally grown counterparts.

In Western Australia deficiencies of zinc, copper, manganese, iron and molybdenum were identified as limiting the growth of broad-acre crops and pastures in the 1940s and 1950s . Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements. Since this time these trace elements are routinely added to inorganic fertilizers used in agriculture in this state

Effects of fertilizer use

1. Eutrophication
The nitrogen-rich compounds found in fertilizer run-off is the primary cause of a serious depletion of oxygen in many parts of the ocean, especially in coastal zones; the resulting lack of dissolved oxygen is greatly reducing the ability of these areas to sustain oceanic fauna Visually, water may become cloudy and discolored (green, yellow, brown, or red).
About half of all the lakes in the United States are now eutrophic, while the number of oceanic dead zones near inhabited coastlines are increasing. As of 2006, the application of nitrogen fertilizer is being increasingly controlled in Britain and the United States If eutrophication can be reversed, it may take decades before the accumulated nitrates in groundwater can be broken down by natural processes.
High application rates of inorganic nitrogen fertilizers in order to maximize crop yields combined with the high solubilities of these fertilizers leads to increased runoff into surface water as well as leaching into groundwater. The use of ammonium nitrate in inorganic fertilizers is particularly damaging, as plants absorb ammonium ions preferentially over nitrate ions, while excess nitrate ions which are not absorbed dissolve (by rain or irrigation) into runoff or groundwater.

2. Blue Baby Syndrome
Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause 'blue baby syndrome' (acquired methemoglobinemia), leading to hypoxia (which can lead to coma and death if not treated)
3. Soil acidification

Nitrogen-containing inorganic and organic fertilizers can cause soil acidification when added. This may lead to decreases in nutrient availability which may be offset by liming.

4. Persistent organic pollutants
Toxic persistent organic pollutants ("POPs"), such as Dioxins, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) have been detected in agricultural fertilizers and soil amendments

5. Heavy metal accumulation

The concentration of up to 100 mg/kg of cadmium in phosphate minerals (for example, minerals from Nauru and the Christmas islands increases the contamination of soil with cadmium, for example in New Zealand. Uranium is another example of a contaminant often found in phosphate fertilizers (at levels from 7 to 100 pCi/g) Eventually these heavy metals can build up to unacceptable levels and build up in vegetable produce. Average annual intake of uranium by adults is estimated to be about 0.5 mg (500 μg) from ingestion of food and water and 0.6 μg from breathing air. Steel industry wastes, recycled into fertilizers for their high levels of zinc (essential to plant growth), wastes can include the following toxic metals: lead arsenic, cadmium chromium, and nickel. The most common toxic elements in this type of fertilizer are mercury, lead, and arsenic. Concerns have been raised concerning fish meal mercury content by at least one source in Spain Also, highly-radioactive Polonium-210 contained in phosphate fertilizers is absorbed by the roots of plants and stored in its tissues; tobacco derived from plants fertilized by rock phosphates contains Polonium-210 which emits alpha radiation estimated to cause about 11,700 lung cancer deaths each year worldwide. For these reasons, it is recommended that nutrient budgeting, through careful observation and monitoring of crops, take place to mitigate the effects of excess fertilizer application.

Benefits of organic fertilizer

In addition to increasing yield and fertilizing plants directly, organic fertilizers can improve the biodiversity (soil life) and long-term productivity of soil, and may prove a large depository for excess carbon dioxide
Organic nutrients increase the abundance of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhiza, (which aid plants in absorbing nutrients), and can drastically reduce external inputs of pesticides, energy and fertilizer, at the cost of decreased yield

Alternatives for chemicals...

1. Vermiwash
Take 10 lit of mudpot or plastic container for preparation of vermiwash. Arrange a tap for it at the bottom. Then place 10 cm gravel or broken bricks at the bottom. Spread coconut husk upto 4 cm. on this. Place partially decomposed agricultural waste material and dung and moisten the material with water. After wetting the material for 2 days, release ………….earthworms. in 2 weeks the wastes get transformed into black compost. At this stage pour 3 litres of water. After 24 hrs 2 lit vermiwash can be collected through the tap. Continue this method for one week, remove the compost from the container and it can be used as manure. Again refill the container as explained above and prepare vermiwash.

2. Chilli-Garlic solution

1. Grind the chillies after removing the petioles and add 10lts of water to it. Keep this solution throughout the night.
2. Grind the 1/2 kg garlic and add 250 ml kerosene keep it for a night
3. Next day morning filter the chilli solution through a thin cloth
4. Do the same for garlic solution
5. Mix chilli solution, garlic solution and surf powder thoroughly and make a mixture
6. Add 100 lts of water to the above solution. This can be applied for
one acre

3. 5% Neem seed kernel extract

• 5 Kgs of Neem seeds dried under shade with good quality can be Powdered
• This powder canbe packed in cloth and keep in 10lts of water for 10-12 hrs
• Extract the decoction by pressing the cloth pack for 10-15mints
• Filter this solution through a thin cloth
• Add 100grs of surf to the filtered solution
• Add 100lts of water to the solution and spray it in 1acre during evening time

4. Dry chilli –Garlic solution

Take 1 kg dry chillies & soak in 10ltrs of water throughout the night. Grind 1/2 kg garlic and keep it in 250 ml of kerosine over night. Filter the dry chillies mixer
Filter the garlic solution through a thin cloth. Add chilli
solution and garlic solution and 75 gms detergent to make a mixture After 4 hrs this solution is ready to spray in one acre

5. Vermicompost
Cover the bottom of the cement ring with a layer of tiles or coconut husk or polythene sheet, Spread 15–20 cm layer of organic waste material on the polythene sheet. Sprinkle rock Phosphate powder if available (it helps in improving nutritional quality of compost) on the waste material and then sprinkle cow dung slurry. Fill the ring completely in layers as described. Paste the top of the ring with soil or cow dung. Allow the material to decompose for 15 to 20 days. When the heat evolved during the decomposition of the materials has subsided (15–20 days after heaping), release selected earthworms (one Kg) through the cracks developed. Cover the ring with wire mesh or gunny bag to prevent birds from picking the earthworms. Sprinkle water every three days to maintain adequate moisture and body temperature of the earthworms. The vermicompost is ready in about 2 months if agricultural waste is used and about 4 weeks if sericulture waste is used as substrate. The processed vermicompost is black, light in weight and free from bad odor. When the compost is ready, do not water for 2–3 days to make compost easy for sifting. Pile the compost in small heaps and leave under ambient conditions for a couple of hours when all the worms move down the heap in the bed. Separate upper portion of the manure and sieve the lower portion to separate the earthworms from the manure. The culture in the bed contains different stages of the earthworm’s life cycle, namely, cocoons, juveniles and adults. Transfer this culture to fresh half decomposed feed material. The excess as well as big earthworms can be used for feeding fish or poultry. Pack the compost in bags and store the bags in a cool place. Prepare another pile about 20 days before removing the compost.

1 comment:

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