ORGANIC FARMING FOR SUSTAINABLE AGRICULTURE

by Manohari

INTRODUCTION:

Green revolution in India has witnessed a jump in agricultural production with the introduction of HYVs of various crops and by following intensive cultivation practices with the use of fertilizers, pesticides and other inputs. The intensive use of inputs has not only polluted the soil, water and the environment causing their slow degradation but also affected the human beings. With the increase in the country’s population, compulsion would be not only to mobilize the agricultural production but also to increase further in a sustainable manner. The scientists have realized that the green revolution with high input use has reached a plateau and is now sustained with diminishing return and falling dividend. Therefore, there is a need to study the past trends in inputs usage like fertilizers and pesticides which are the major components in crop production and future challenges and strategies for sustainable agriculture. This paper is an attempt in this direction.

The specific objectives of this paper are :

• To examine the trends of chemical fertilizers and pesticides used for agricultural production.
• To study the adverse effects of fertilizers and pesticides
• Strategies to overcome adverse effects of fertilizers and pesticides

TRENDS IN CHEMICAL FERTILIZERS AND PESTICIDES USAGE

Chemical Fertilizers:

Consumption of chemical fertilizers has increased tremendously in recent years. Nitrogen, phosphorous and potassium are the primary fertilizers nutrients which are widely used in our country.

Table-1 : Trends in Consumption of chemical fertilizers in India (in lakh tonnes)

 

          

The total consumption of chemical fertilizers is in increasing trends from 0.69 lakh tonnes in 1950-51 to 173.18 lakh tonnes in 1997-98. Decreasing trends in total fertilizers consumption is observed from 127.28 lakh tonnes in 1991-92 to 121.55 lakh tonnes in 1992-93. The same decreasing trend is observed in Phosphatic and Potassic fertilizer consumption during the same period. In case of nitrogenous fertilizers, continuous increasing trends is observed from 1950-51 to 1997-98. Fertilizer consumption per hectare was negligible (0.5 kg per hectare) in 1951-52 increased to 76.75 kgs per hectare during 1996-97.

 
 
Table-2A : Consumption of pesticides (technical grade material)

(in thousand tonnes)

Year	Pesticides
1950-51	2.35
1960-61	8.62
1970-71	24.32
1980-81	45.00
1988-89	75.89

 
The trend in consumption of pesticide is increasing from 2.35 thousand tonnes to 75.8 thousand tonnes from 1950-51 to 1988-89.

Table: 2B Trends in consumption pattern of different groups of pesticides

(Technical Grade Material, MT)

Year	Insecticides	Fungicides	Herbicides	Others	Total
1988	67692	16365	4160	1020	89237
1989	56424	17530	4730	925	79609
1990	47074	17770	5162	1075	71081
1991	49516	18465	5367	975	74323
1992	55166	18925	6695	1280	82066
1993	56239	17313	9975	1315	84842
1994	55209	16956	10798	1315	84278
1995	59487	19197	10557	1345	90586
1996	38111	20795	10651	1625	71182
1997	37602	21695	11869	1725	72891
Compound Growth Rates (%)
1998-95	-0.44	1.07	16.52	5.59	1.22
1995-97	-20.49	6.31	6.03	13.25	-10.30
1988-97	-3.88	2.31	13.70	6.71	-0.59

 
Source: Various issues of pesticides information (PAI)

Pesticide usage:

Herbicides:

The use of herbicides has gradually improved in the country. During the period 1988 to 1997 herbicides had an annual growth rate 13.70 percent. The share of herbicides in total pesticides consumption has increased from 4.7 percent in 1988 to 16.3 percent 1997. The used of herbicides is increasing in agriculturally in advanced regions of the country due to rising cost of labour and shift of labour from agriculture to other investors. Nearly, 85 percent of herbicides are used on rice, tea, bee and beans (BAMI – 1996).

Insecticides:

India is predominantly an insecticides market. The most important crops with regard to insecticide usage are cotton and rice which account for about 70 percent of total pesticide consumption in India. During the last 10 year (1988-97), the consumption of insecticide has declined an annual compound growth rate of 3.88 percent. Organo phosphates dominate the Indian market with about 50 percent share followed by the synthetic pyrephroids(19 percent), organo chlorines (18 percent), carbamats (4 percent) and bio-pesticides(1 percent). While organo chlorine group of pesticides has been banned and phased out in advanced countries, India still uses some of this products with adverse impact on environmental and human health (BAMI – 1996).

Fungicides:

At present, fungicides most commonly used agro-chemicals for growing food crops and vegetables. In India the use of fungicides is most popular in fruits followed by potatoe, rice, tea and coffee. The use of fungicides has increased significantly (2.31 percent) during 1988-97 and its share in total pesticide consumption has increased from about 18 percent to about 30 percent.

PROBLEM POSED BY FERTILIZERS AND PESTICIDES

Fertilizers:

Continuous use of inorganic fertilizers mainly containing major nutrients NPK in large quantities and neglecting organic and bio-fertilizers paved the way for deterioration of soil health and in turn ill effects on plants, human being and cattle.

The adverse effects of using fertilizers are explained below.

I Nitrate pollution:

Nitrogen is applied to the soil as urea (Which is readily hydrolyzed to ammonium), ammonium nitrate or a combination of ammonium and nitrate. About 40-60 percent of applied nitrogen is lost by voltalization run off, de-nitrification and leaching. The nitrate that is leached causes a lot of visible and invisible hazardous effects.

Visible effects :

1. Plants become succulent and dark green colour thus becoming more susceptible to pests and diseases. Ex. BPH in paddy in most of the paddy growing regions.

2. It increases the growth, weakens the stem and brings lodging in crops like paddy. It reduces the quality of the seed

Invisible effects:

1. Pollution of ground water by nitrates : Excess nitrate moves below the root zone or into the ground water (once the ground water becoming polluted it remaining for extended periods of time) and draining of such water causes or disease called "Methemoglobinemia", where nitrite (reduced form of nitrate) interferes with oxygen carrying capacity of blood.

2. Japanese encephalitis (JE) : Excess use of urea in rice fields promotes the growth and spread of vectors causing of human disease called JE. Children between the age group between 4-14 years are mainly affected.

3. Nitrosomine illness is caused by the presence of secondary amines which causes cancer in human beings.

4. Feroxyl nitrates, alkyl nitrates, vapours of HNO₃ and nitrate aerosoles causes respiratory illness

5. HNO₃ in aerosols may lead to acid rains causing lot of damage to ecosystem and buildings

6. Nitrate oxide produced by de-nitrification damages the stratospheric ozone layer.

2. Eutrophication:


This refers to the process of enrichment of surface water bodies with nutrients, addition of plant nutrients particularly P&N to surface water bodies such as lakes, reservoirs and streams result in intense prolification and accumulation of algae and higher aquatic plants in excessive quantities which can result in detrimental changes in water quality and can significantly interfere with man’s use of the water resource.

3. Soil acidification and alkalization:


Development of soil acidification and alkalization due to continuos use of acidic (NH₄ Cl (NH₂ ) SO₄ etc.) and basic (NANO₃ ) (CAN basic slag etc.) fertilizers causing imbalance in nutrients availability to crops and effecting activities of beneficial micro organisms.

4. Iron, aluminium and manganese toxicities in acidic soil and sodium toxicity in alkali soils effect the availability of other nutrients and deteriorate fertility and productivity of soils.

5. The continuous application of ‘P’ fertilizers can result in the build up of trace metal contaminants such as arsenic and cadmium contained in the fertilize.

6. Excessive application of potassic fertilizers decrease vit "C" (ascorbic acid) and carotene content in vegetable and fruits.

7. . Excessive application of chemical fertilizers lead to malnutrition due to degradation of carbohydrates and proteins both qualitatively and quantitatively.

8. . Excessive application of chemical fertilizers effects physical properties of soil such as infiltration, soil aeration, soil structure and bulk density etc.

Pesticides:

Pesticides enter environment mainly by air, water and soil. Pesticides enter air by sprayed drift or voltalization from soil or water. The entry of pesticides in water is mainly by surface runoff, sediment transport from treated soil, industrial wastes and direct application of pesticides to control acquatic pests. Soil receives pesticides when the pesticides are directly applied besides runoff from plants, rains and dumping of empty containers of pesticides. The challenges posed by pesticide usage are explained below:

2. Indiscriminate and defective handling of the pesticides causes environmental pollution and leads to health hazardous.

3. Pesticides resistance: Consistent use of pesticide to control pests had led to development of resistance among pests and vectors and adverse effect on non target organisms.

4. Destruction of beneficial organisms: Continuous use of pesticides had an adverse effect on beneficial organisms like honeybees, pollinators, parasites and predators. At the height of the American boll worm problem in Guntur and Prakasham districts in Andhra Pradesh in 1986 almost all the predaceous bird fauna were totally exterminated. The crisis in cotton cultivation posed by boll worms, white flies etc. leading to total crop loss and eventual frustration and suicides of many farmers in A.P.

5. Pesticides poisoning:

a. Manufacturing Level: Persons engaged in manufacturing of insecticides are subjected to insecticider exposure. This results in chronic poisoning. The poisoning symptoms of aldrin, dialdrin and endrine are headache, fatigue, loss of appetite, loss of weight and memory.

2. Operating level: The majority of cases occur in hot and humid field conditions. The reason is that the operators or farmers do not wear protective clothing.

3. Consumer level: Chlorinated hydro carbons can accumulate in the adipose tissues of man. It is very difficult to ascertain the extent of safety of residue in human beings. However, there are a number of evidences that some forms of wild life are suffering due to bio-magnification of these residues.

     VI. Pesticide residues:

The widespread use of pesticides provides many possible sources of pesticides in the environment and living organism. Pesticides after application are known to persist on crop produce, soil, water and air with harmful effects on human health and the environment. In India problem of pesticide residue in food has been studied by Indian Council of Medical Research (ICMR), Indian Council of Agricultural Research (ICAR) and other institutions in an isolated manner.

 

PESTICIDES RESIDUES IN WATER
 

	SAMPLING AREA	PESTICIDE	RESIDUE LEVEL
1	Ponds in coffee plantations, Chikmagalore, Karnataka	HCH	0.02 – 0.2 ppm
2	Yamuna, Delhi	DDT	2.9 – 21.8 ppm
3	Srinagar, J & K	HCH	2.5 – 73.5 ppm
4	River Khan, near Indore, M.P.	Total HCH	0.05 – 0.39 ppm
5	River Chambal, near Kota, Rajasthan	Total HCH	0.06 – 1.49 ppm
6	Drinking water source around Bhopal	Total HCH	1.58-15.88 ppm
			3.15-34.77 ppm

 
Source : Handa and Walia (1996)
 
 
DDT CONTAMINATION IN MILK
 

STATE	TOTAL SAMPLES	INCIDENCE(%)	SAMPLE ABOVE TOLERANCE LEVEL(%)	RANGE(ppm)
Punjab	263	97.7	50.6	ND-1.11
Haryana	120	93.7	05.0	ND-0.33
Himachal Pradesh	120	100.0	55.8	0.006-0.75
Uttar Pradesh	240	57.1	10.8	ND-0.652
Madhya Pradesh	240	95.8	21.7	ND-0.36
Maharashtra	299	100.0	74.2	0.02-0.965
Gujarat	120	100.0	70.0	0.015-0.20
Andhra Pradesh	240	96.7	57.1	ND-2.224
Karnataka	203	22.2	17.7	ND-1.079
Kerala	120	95.8	09.2	ND-0.08
Bihar	120	95.8	19.2	ND-0.08
West Bengal	120	35.8	12.5	ND-2.82
All states of India	2205	81.1	36.0	ND-2.224

 
Source : ICAR PROJECT 1986 - 1999

VALUES FOR DDT AND BHC IN HUMAN MILK

COUNTRY	YEAR	BHC	DDT
Japan	1977	250	1900
USA	1977-78	NA	NA
Canada	1987	34	840
Great Britain	1979-80	220	1900
Germany	1979-81	450	1900
Italy	1985	7	47
Israel	1985	390	2800
Kenya	1983-85	110	6900
China	1982	6600	6200
India	1988-89	750	3700

 
Figure by which overall intake exceeds the acceptable daily in take (ADI), based on 2 % fat 0.8 litres of milk per day.

Source : Ho1. E.H.1995 Down to Earth. 4(10). 27-31

6. Destruction of soil microbes spoiling the soil health.

• Minor pests become major ones
• Increase in investment for crop production
• Severe imbalance in ecology

Herbicides:

1. Persistence in soil: The herbicide applied to one crop may persist in the soil at concentration high enough to damage subsequent sensitive crops.

2. Residues in crops: At coimbatore, the sorghum grain & stalk showed detectable amount of residues when atrazine was applied at 0.5 and 1.0 Kg / ha which was well below the MRL.

3. Toxicity: Herbicides like trifluralin were found associated with nitrosamines which are potent carcinogens. However, at 1.12 kg/ha of trifluralin, the top soil layer (15 cm) would contain only 0.006 ppb of nitrosamine and this is too small amount to cause cancer (Witter, 1980).
   

Fungicides:

• Emergence of resistant strains: Improper use of systematic fungicides like (carbendazium) resulted into development of resistant stains of different plant pathogens.

• Health Hazards: Maneb and Streptocycline caused dermititis and some people working with captan or in fields treated with it showed symptoms of skin irritation and rashes (Sharma Kaur 1990).

• Fungicide residues: If the fungicides are used judiciously they may pose serious residue problems.

• Non-target effects: Copper fungicides used for the control of coffee rust resulted in increased occurrence of coffee leaf miner and of spider mites (Panlam et al 1976)

Beever et al (1984) reported that the residues of captan when used as spray against Botrytis storage of kiwi fruit were within the acceptable limits when used as per recommended dose. However, the increased number of sprays resulted in more than acceptable limit of residue levels.

STRATEGIES TO OVERCOME THE CHALLENGES OF PRESENT SITUATION:

After seeing the deleterious effects arising with the use of agro chemicals coupled with the degradation of cultivable land and increasing agricultural pollution has created an unhealthy situation in the country. In order to balance this situation, organic farming, which aims at cultivating the land and raising crops in such a way as to keep the soil alive and in good health may be an alternative to the present system of farming solely depending on chemicals.

It is a method of farming which avoids or largely excludes the use of compound chemicals such as chemical fertilizers, pesticides and herbicides. Instead of that natural resources such as organic matters, minerals and microbes are used. It gives an idea to use all sources which are natural so that soil health is maintained.

Organic farming systems rely on large scale application of animal or FYM, compost, crop rotations, cooperative residues, green manuring, vermicompost, bio-fertilizers, bio-pesticides and biological control.

Key characteristics:

• Protecting the long-term fertility of soils by maintaining organic matter levels, fostering soil biological activity and careful mechanical intervention;

• Providing crop nutrients indirectly by using relatively insoluble nutrient sources which are made available to the plant by the action of soil microorganisms;

• Nitrogen self-sufficiency through the use of legumes and biological nitrogen fixation, as well as effective recycling of organic materials including crop residues and livestock wastes;

• Weed, disease and pest control relying primarily on crop rotations, natural predators, diversity, organic manuring, resistant varieties and limited (preferably minimal) thermal, biological and chemical intervention;

• The extensive management of livestock, paying full regard to their evolutionary adaptations, behavioural needs and animal welfare issues with respect to nutrition, housing, health, breeding and rearing;

• Careful attention to the impact of the farming system on the wider environment and the conservation of wildlife and natural habitats.

ALTERNATIVES FOR CHEMICAL FERTILIZERS

In India the use of organic manures in subsistence forming is an age old practice. Organic manures improve physical, chemical and biological properties of the soil. Addition of organic manure improves structure aeration, water holding capacity of soils, reduces phosphorous fixation in acidic soil forms chilates with metallic ions and reduces their toxicity in crops. For substituting the chemical fertilizers various forms of organic manures and bio-fertilizers are explained below:    

1. FYM cow dung is an important source of pl. nutrients. FYM is composed of drug, urine, bedding and straw. FYM contains approximately 5-6 Kg N, 1.5-2 Kg phosphorus and 5-6 Kg potash/ ton. It builds up soil health considerably.

2. Green Manuring: It is considered a good source of ‘N’ and it increases the availability of P, K and secondary and trace elements to the soil.

3. Coir Pith: The annual production of coir pith in India is about 7.5 million tonnes. Preferably bio-degraded and amended coir pith can serve as a substitute for FYM or similar organic manure, plenrotus sojorcaju. As per gillus and Trechoderma are found to be potent degrading of coir pith.  

4. Vermicompost: is 5 times richer in N, 7 times in P, 11 times in K, 2 times in Mg, 2 times in Ca & 7 times in actinomy and than ordinary soil. It is a rich source of vitamins and growth hormones like gibberling which regulate the growth of plant and microbes. The compost prepared by using earth wiring is called vermi-compost.

5. Biofertilizers: These are living cells of different types of micro organisms which have an ability to mobilize nutritionally important elements from non usable to usable form. They influence the avalability of major nutrients like nitrogen, phosphorus, potassium and sulphur to the plants. Rhizobium, Azotobacter, Azospirillum, Blue green algae, Azolla, Mycorrhizae, phosphate solubilizing bacteria can be used as biofertilizers to increase the crop production. These micro organisms require organic matter for their growth and activity in the soil and provide valuable nutrients to the plants in the soil.

Pesticides:

Many of the pesticide applications may be unnecessary and are economically unsound. A range of alternative methods of pest control to be used inorganic farming are detailed below:

1. Deep ploughing the fields during summer season help in killing pests, larval & eggs.
2. Clean cultivation by destruction of weeds and other alternate hosts breaks the carry over of the pest in succession which considerably reduces the pest numbers.
3. Adopting crop rotations to avoid carry over of pests from one season to next season.
4. Change in time of sowing
5. Draining of water out of fields at times of pests growing in number
6. Use of resistant varieties
7. Growing of trap crops
8. Release of parasites and predators
9. Use of pheromone traps and light traps
10. Use of biological insecticides
11. Use of mechanical weed control
12. Cover cropping to control weed-seed germination

CONCLUSION:

Organic agriculture is a viable alternative because it enlivens the soil, strengthens the natural resource base and sustains biological production at levels to commensurate the carrying capacity of the managed agro eco-system. In addition to this export market can also be tapped by group initiatives in organic farming. In a country like India, food production has to grow steadily. A sudden switch over to organic farming is not feasible. The minimum food requirement for the year 2001 is 240 million tonnes. The stage will be set in due course for a smooth transition to organic farming without causing any decline in production. The efforts from extension, research, supply of inputs, development of market channels, for disposal of organic foods are needed to facilitate the successful adoption of organic farming by the farmers. The approach shall be farmer centred and the programmes developed shall create conditions for the conservation and efficient use of locally available resources as inputs in agriculture. The role of MANAGE will be taking up specialized programmes in organic farming for training of extension personnels.

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