Environmental Sciences CHY1003 PDF

Environmental Sciences CHY1003 Dr. Jayanta Parui, PhD Module 1 Syllabus Outline Syllabus for Module - 1 Environment and Natural Resources Definition, scope, importance need for public awareness on natural resources Forest resources use, exploitation, causes and conseque...

Environmental Sciences CHY1003 Dr. Jayanta Parui, PhD Module 1 Syllabus Outline Syllabus for Module - 1 Environment and Natural Resources Definition, scope, importance need for public awareness on natural resources Forest resources use, exploitation, causes and consequences of deforestation Water resources – use of surface and subsurface water; dams, effect of drought, water conflicts; Land resources - Land degradation, soil erosion and desertification Indian Case studies Food resources – Definition, world food problems, Traditional and modern agriculture and its impacts and remedies Environment Is the nature environment? The environment is everything around us. It includes all of the living and the nonliving things with which we interact. And it includes a complex web of relationships that connect us with one another and with the world we live in.  What is environment? Define Environment - encompasses everything that is around us or surroundings of an object Environment derived from French word Environner - encircle or surround. 4  Scope of environmental studies Environmental scientist – cleaner technology and sustainable environment Environmental engineers – green technology Pollution control technology, cleaning up of wastes Green advocacy, Green marketing Green media 5  Global Vs local problems of environment Global – global warming, depletion of ozone layer, deforestation, loss of global biodiversity. Local – river pollution, soil erosion, salinization of soil, arsenic pollution of ground water, mining or hydro-electric project in a area etc. Understand environment to live in - clean, healthy, beautiful, safe and secure environment. 6  Public awareness for environment Sustainable development – government and public participation – public awareness Littering of polyethene – can be stopped only by awareness 7  Contemporary Indian environment In 1991 SC – curricula environmental-oriented – PIL by M. C. Mehta Sh. Sunderlal Bahuguna – Chipko movement, Tehri movement Smt. Medha Patkar and Ms. Arundhati Roy – Naramada movement Sh. Rajender Singh – water conservation efforts Mrs. Maneka Gandhi – wild life protection 8  Concept of Eco-mark Eco-labelling of consumer products – ISO 14000. It is made, used or disposed off in a harmless manner. Eco-club – children, Eco-task force – army men Environment belongs to all – participation of masses – successful implementation environmental protection plans. Earth-oriented – self-oriented Create public awareness – environmental pollution and sustainability 9  Natural resources Water Air Soil Natural resources Minerals Coal Forests Crops Wildlife Renewable resources Non-renewable resources 10  Renewable resources Regenerated within a span of time Forest Wildlife Biomass Solar energy Wind energy Tidal energy Hydro power 11  Non-renewable resources Fossil fuels Coal Oil Natural gas Renewable can become non- renewable! We can stop use of natural resources? Judicious use of natural resources 12 Minerals  Major natural resources Forest Water Energy Land Mineral Food 13  Uses of forests Commercial Ecological uses uses fruits, spices, beverages etc. regulate hydrological cycle CO2 sink synthesis of oxygen fodd Earth’sabsorbs lung er pollutants pulpwood rubber, resins, non-edible oils habitat for Timber, fire wildlife wood etc. drugs, Conservation medicines of soil Other uses – agriculture, mining, grazing wind-breaks and recreation 14  Invaluable medicines from forest How ecological uses surpass commercial uses of forest? Ecological uses does not involve destruction of forest resources Only humans gain out of commercial uses, whereas, humans and all other living things gain out of ecological uses Economic value of ecological uses is greater than commercial uses Ecological uses maintains ecological balance 15  Invaluable medicines from forest Tax Taxol an anti-cancer drug - ol used for the treatment of breast, ovarian, lung, bladder, prostate. Isolated from bark of pacific yew, Taxus brevifolia 16  Forest source of invaluable medicines Quinine and Quinine – antimalarial drug Quinidine Quinidine – antiarrhythmic drug Isolated from bark of cinchona tree Quini Quinid 17  Exploitation of forests timber, pulp, firewood mining activities big hydropower projects and dams create more road construction agriculture land Only Costal Western Ghats and North East Indian forest left! We must stop over-exploitation of forest Joint Forest Management – community participation 18  Deforestation in world Total forest area of the World According to Food and Agriculture Organization (FAO,1983) decline in forest area is only 0.04% annually in India. Lowest among tropical countries! Far behind National Forest Policy – 33% forest!. Each day 32,300 ha disappear from Earth! Tropical deforestation increased by 8.5% compare to 1990 deforestation rate. Loss of primary forest increased by 25% Primary forest replaced by plantation with much less biodiversity 19  Joint Forest Management (JFM) JFM state forest department + local communities (FPC) FPC – safeguard illegal logging, grazing and fire in the forest Profit state forest department (75%) + local communities (FPC) 20 (25%) Major causes for deforestation Shift cultivation Fuel requirements 21 Major causes for deforestation Timber Development projects 22  Major causes for deforestation Expansion of agriculture land Over grazing Forest fire 23  Soil erosion Loss of biodiversity – genetics biodiversity Hydrological cycle- affect rainfall Major effects of deforestation Land slide Loss of wild life species- Loss of natural habitat 24 Global warming  Case studies Desertification of hilly regions of the Himalayas Deforestation - monoculture - upset ecosystem, poor nutrient cycle, loss of germplasm and fertility. Meghalaya, Ladakh, Kumaon and Garhwal - desertification. Waning rainfall in Udhagamandalam (Ooty) Deforestation - decrease in rainfall Disappearing tea gardens in Chhota Nagpur Deforestation – rainfall decline - disappearance of tea garden. 25 Desertification of hilly regions of the Himalayas Desertification of West Khasi hill district of Meghalaya in North-east Himalaya, Ladakh and parts of Kumaon. 26  Desertification of hilly regions of the Himalayas Natural forest cleared and planted with monoculture tress (i.e) plant of much less biodiversity Pinus Roxburghii Eucalyptus Upsets ecosystem by change soil nature, biological properties, poor nutrient cycle, 27 germplasm and fertility is lost Disappearing tea gardens in Chota Nagpur Hilly region receives fairly frequent rainfall favor tea plantation. Deforestation lead to decline in rainfall to such an extent that tea garden also disappeared! 28 Disappearing tea gardens in Chhota Nagpur Sub-normal rainfall due to deforestation. Rainfall pattern fluctuate with wooded land area in the hills. 29 Major activities in forest-logging for timber Logging teak, sandalwood and mahogany etc. for various commercial purposes. Road construction etc. 30  Major activities in forest-mining Surface mining - shallow deposit Mining of minerals Sub-surface mining and coals - deep deposit Destruction of vegetation, soil mantle & rock mass 31  Major activities in forest Mussorie and Dehradun - large scale deforestation due to indiscriminate mining of minerals over 40 km. Forest area decreases at an average rate of 33% due to mining - lead to land slide 32  Deforestation activities Mining of forest in Goa destroy – 50,000 ha. Coal mining in Jharia, Raniganj and Singrauli – deforestation. Mining magnesite and soap-stones destroy 14 ha in Kosi valley, Almora. Mining radioactive minerals – Kerela, Tamilnadu and Karnataka to lead deforestation. Extraction of copper, chromite, bauxite and magnetite in Western Ghats lead to deforestation. 33  Effect of dams on forest and people Big dams “Temples of modern India” Loss of medicinal Biodiversity loss Deforestation Drought value plants Land slide Flood 34  Effect of dams on forest and people India has more than 1550 dams Maharashtra - more than 600 Gujarat - more than 250 MP – 130 Tallest dam – Tehri on river Bhagirathi in Uttarakhand Biggest dam - Bhakranangal on river Satluj in H.P Big dams – breaks eco-logical balance deforestation, evacuation of tribal peoples, loss of biodiversity. 35  Case study Sardar Sarovar Dam (uprooted forests and tribals) Sardar Sarovar dam across Narmada river - Medha Patkar 36 Sardar Sarovar Dam (uprooted forests and tribals) Sardar Sarovar dam – Narmada river spread over three states Gujarat, Maharashtra, and M.P. 1,44,731 ha land submerged by dam, out of which 56,547 ha is forest land. A total of 573 villages are submerged by the dam. 37 Protest against Sardar Sarovar dam Submerged area is rich is wildlife. Thus a massive loss of these wildlife! More than 1 million people displaced for this project, uprooting of tribals. 38  Steps towards sustainability in Fashion Industry https://www.fibre2fashion.com/industry-article/9788/eco-innovation-in-fashion-revolutionising-the-industry  WATER RESOURCES 1. About 97% of the earth's surface is covered by water and most of the animals and plants have 60-65% water in their body. 2. It has the highest specific heat, due to which it warms up and cools down very slowly without causing shocks of temperature jerks to the aquatic life. 3. It is an excellent solvent for several nutrients. Thus, it can serve as a very good carrier of nutrients, including oxygen, which are essential for life. But, it can also easily dissolve various pollutants and become a carrier of pathogenic microorganisms. 4. The water we use keeps on cycling endlessly through the environment, which we call as Hydrological Cycle.  WATER USE AND OVER-EXPLOITATION 1. Uptake of nutrients, their distribution in the body, regulation of temperature, and removal of wastes are all mediated through water. 2. Water is used for drinking, irrigation, transportation, washing and waste disposal for industries and used as a coolant for thermal power plants. 3. Water use by humans is of two types: water withdrawal: taking water from groundwater or surface water resource Water consumption: the water which is taken up but not returned for reuse. Globally, only about 60 percent of the water withdrawn is consumed due to loss through evaporation. 4. Out of the total water reserves of the world, about 97% is salty water(marine) and only 3% is fresh water. Even this small fraction of fresh water is not available to us as most of it is locked up in polar ice caps and just 0.003% is readily available to us in the form of groundwater and surface water.  WATER USE AND OVER-EXPLOITATION 5. Overuse of groundwater for drinking, irrigation and domestic purposes has resulted in rapid depletion of groundwater in various regions leading to lowering of water table and drying of wells. Pollution of many of the groundwater aquifers has made many of these wells unfit for consumption. 6. Rivers and streams have long been used for discharging the wastes. Most of the civilizations have grown and flourished on the banks of rivers, but unfortunately, growth in turn, has been responsible for pollution of the rivers.  WATER USE AND OVER-EXPLOITATION Causes: Example 1: 2. Unsustainable resource use: If renewable resources are exploited in such a way that Colorado there is no time for regeneration, it will be converted to River: non-renewable. Source: Rocky Mountain USA Mouth: Gulf of California Tamed: 14 major dams Provides: Power distribution of water Supplies to hottest & driest cities Much withdrawal: Very little reaches to the sea. Increasing population Limited resource.  WATER USE AND OVER-EXPLOITATION Causes: Example 1: 2. Unsustainable resource use: If renewable resources are exploited in such a way that Colorado there is no time for regeneration, it will be converted to River: non-renewable. Source: Rocky Mountain USA Mouth: Gulf of California Tamed: 14 major dams Provides: Power distribution of water Supplies to hottest & driest cities Much withdrawal: Very little reaches to the sea. Increasing population Limited resource.  WATER USE AND OVER-EXPLOITATION Causes: Example 1 (continued): Over tapped Colorado River Basin: Amount of water flowing to the mouth of Colorado is decreased It threatens the survival of species that spawn in the river and that live in its estuary i.e. near its mouth. In 2008 water scientists warned that the current withdrawal of water from the Colorado River is not sustainable. Lake Mead reservoir behind Hoover Dam could run dry by 2021. The political and legal battle between the water rich and poor are expected. Diminished water level likely to desert Arizona, Las Vegas, Phoenix & Nevada. Changes on geographical locations alter the environment and change climates Water from rich to poor region through canal & pipe lines addition to it  WATER USE AND OVER-EXPLOITATION Causes: Example 2: Aral Sea Aral Sea Syr Darya Amu Darya  WATER USE AND OVER-EXPLOITATION Causes: Example 2: Aral Sea Aral Sea Syr Darya Amu Darya  WATER USE AND OVER-EXPLOITATION Causes: Example 2: Aral Sea Aral Sea Syr Darya Amu Darya  WATER USE AND OVER-EXPLOITATION Causes: Example 2 (Continued): Over tapped River & Aral Sea Disaster:  WATER USE AND OVER-EXPLOITATION Causes: Example 2 (Continued): Reasons: Over tapping of two feeder rivers for irrigation To achieve world’s largest irrigation land To raise thirsty cotton and rice from very dry area. Consequences: Since 1961 salinity of water increased 7 times and average level dropped by 22 m nearly at the degree of 6 – storied building. Single sea divided into two major parts exposing large area salt desert. About 85% of wetland almost eliminated around the sea. About 50% of local mammals and birds disappeared. Increased salinity made extinction of 26 of the native 32 fish species. Devastate fishing industry once provided work for more than 60,000 people  WATER USE AND OVER-EXPLOITATION Causes: Example 2 (Continued): Consequences: Salt & sand picked by wind affect vegetation, wild life and pollute water blown onto the fields as far as 500 kms away. Aral Sea dust settling on glaciers in the Himalayas causing them faster melting. Altered climate; thermal buffer by the sea destroyed providing extreme hot at summer and extreme cold at winter growing seasons shorter. Combination of climate change and salinization reduced crops yield by 20 – 50% Use of herbicide, insecticide and fertilizer for better crops yield polluting ground water by percolation. Dependence on ground water based drinking water increases health problems like anaemia, respiratory illness, liver and kidney disease, eye problems and various cancers from the combinatorial effect toxic dust and contaminated water.  WATER USE AND OVER-EXPLOITATION Groundwater About 9.86% of the total fresh water resources is in the form of groundwater and it is about 35-50 times that of surface water supplies. layer of sediment or rock that is highly permeable and contains water is called an aquifer. Layers of sand and gravel are good aquifers while clay and crystalline rocks (like granite) are not since they have low permeability. Aquifers may be of two types: Unconfined aquifers which are overlaid by permeable earth materials and they are recharged by water seeping down from above in the form of rainfall and snow melt Confined aquifers which are sandwiched between two impermeable layers of rock or sediments and are recharged only in those areas where the aquifer intersects the land surface. Sometimes the recharged area is hundreds of kilometers away from the location of the well.  WATER USE AND OVER-EXPLOITATION https://www.ngwa.org/what-is-groundwater/About-groundwater/unconfined-or-water-table-aquifers  WATER USE AND OVER-EXPLOITATION Surface Water The water coming through precipitation (rainfall, snow) when does not percolate down into the ground or does not return to the atmosphere as evaporation or transpiration loss, assumes the form of streams, lakes, ponds, wetlands or artificial reservoirs known as surface water The surface water is largely used for irrigation, industrial use, public water supply, navigation etc. A country's economy is largely dependent upon its rivers. FLOODS Heavy rainfall often causes floods in the low-lying coastal areas. Prolonged downpour can also cause the over-flowing of lakes and rivers resulting into floods. Deforestation, overgrazing, mining, rapid industrialization, global warming etc. have also contributed largely to a sharp rise in the incidence of floods, which otherwise is a natural disaster. WATER USE AND OVER-EXPLOITATION WATER USE AND OVER-EXPLOITATION WATER USE AND OVER-EXPLOITATION  WATER USE AND OVER-EXPLOITATION DROUGHTS When annual rainfall is below normal and less than evaporation, drought conditions are created. Ironically, these drought-hit areas are often having a high population growth which leads to poor land use and makes the situation worse Anthropogenic causes: Due to several anthropogenic causes like over grazing, deforestation, mining etc. there is spreading of the deserts tending to convert more areas to drought affected areas. In the last twenty years, India has experienced more and more desertification, thereby increasing the vulnerability of larger parts of the country to droughts. Erroneous and intensive cropping pattern and increased exploitation of scarce water resources through well or canal irrigation to get high productivity has converted drought - prone areas into deserts. State like Maharashtra is finding difficulty to get recovery from drought due to over-exploitation of water by sugarcane crop which has high water demands.  WATER USE AND OVER-EXPLOITATION DROUGHTS Remedial measures: Carefully selected mixed cropping help optimize production and minimize the risks of crop failures. Social Forestry and Wasteland development can prove quite effective to fight the problem, but it should be based on proper understanding of ecological requirements and natural process, otherwise it may even boomerang. The Kolar district of Karnataka is one of the leaders in Social Forestry with World Bank Aid, but all its 11 talukas suffer from drought. It is because the tree used for plantation here was Eucalyptus which is now known to lower the water table because of its very high transpiration rate.  WATER USE AND OVER-EXPLOITATION CONFLICTS OVER WATER Indispensability of water and its unequal distribution has often led to inter-state or international disputes. Issues related to sharing of river water have been largely affecting our farmers and also shaking our governments. Some major water conflicts are discussed here. Water conflict in the Middle East: Three river basins, namely the Jordan, the Tigris- Euphrates and the Nile are the shared water resources for Middle East countries. Ethiopia controls the head waters of 80% of Niles flow and plans to increase it. Sudan too is trying to divert more water. This would badly affect Egypt, which is a desert, except for a thin strip of irrigated cropland along the river Nile and its delta. The population of Egypt is likely to increase, thereby increasing its water crisis. Likewise there is a fierce battle for water among Jordan, Syria and Israel for the Jordan River water share.  WATER USE AND OVER-EXPLOITATION CONFLICTS OVER WATER Water conflict in the Middle East: Turkey has abundant water and plans to build 22 dams on Tigris-Euphrates for Hydroelectric power generation. But, it would drastically reduce the flow of water to Syria and Iraq, lying downstream. Turkey dreams to become the region's water Super power. It plans to transport and sell water to starved Saudi Arabia, Kuwait, Syria, Israel and Jordan.  WATER USE AND OVER-EXPLOITATION CONFLICTS OVER WATER The Indus Water Treaty: The Indus, one of the mightiest rivers is dying a slow death due to dams and barrages that have been built higher up on the river. The Sukkur barrage (1932), Ghulam Mohamad Barrage at Kotri (1958) and Tarbela and Chasma Dams on Jhelum, a tributary of Indus have resulted in severe shrinking of the Indus delta. In 1960, the Indus water treaty was established vide which Indus, the Jhelum and the Chenab were allocated to Pakistan and the Satluj, the Ravi and the Beas were allocated to India. Being the riparian state, India has pre-emptive right to construct barrages across all these rivers in Indian territory. However, the treaty requires that the three rivers allocated to Pakistan may be used for non-consumptive purposes by India i.e. without changing its flow and quality.  WATER USE AND OVER-EXPLOITATION CONFLICTS OVER WATER The Cauvery water dispute: Out of India's 18 major rivers, 17 are shared between different states. In all these cases, there are intense conflicts over these resources which hardly seem to resolve. The Cauvery river water is a bone of Contention between Tamilnadu and Karnataka and the fighting is almost hundred years old. Tamilnadu, occupying downstream region of the river wants water-use regulated in the upstream. the upstream state Karnataka refuses to do so, claims its primacy over the river as upstream user. In 1995, the situation turned into a crisis due to delayed rains and an expert Committee was set up to look into the matter which found that there was a complex cropping pattern in Cauvery basin. Proper selection of crop varieties, optimum use of water, better rationing, sharing patterns, pricing of water brought some measures to solve the problem.  WATER USE AND OVER-EXPLOITATION CONFLICTS OVER WATER The Satluj-Yamuna link (SYL) canal dispute: The issue of sharing the Ravi-Beas waters and SYL issue between Punjab and Haryana is being discussed several times and the case is in the Supreme Court. The conflict is that Punjab being the riparian state for Beas, Ravi and Satluj stakes its claim, Haryana has faced acute shortage of water after it became a state in 1966 and has been trying to help it out by signing an MOU (Memorandum of understanding) with UP, Rajasthan and Delhi for allocation of Yamuna waters. The Yamuna basin covers the state of Haryana while the Indus basin covers Punjab. The conflict revolving around sharing of river water needs to be tackled with greater understanding and objectivity. https://jalshakti-dowr.gov.in/sutlej-yamuna-link-canal/  LAND RESOURCES Land is a finite and valuable resource upon which we depend for our food, fibre and fuel wood, the basic amenities of life. Soil, especially the top soil, is classified as a renewable resource because it is continuously regenerated by natural process though at a very slow rate. About 200-1000 years are needed for the formation of one inch or 2.5 cm soil, depending upon the climate and the soil type. But, when rate of erosion is faster than rate of renewal, then the soil becomes a non- renewable resource LAND DEGRADATION With increasing population growth the demands for arable land for producing food, fibre and fuel wood is also increasing. Hence there is pressure of demand on stipulated resource Instead of demand of forest resources, the soil erosion is an added problem Land is being degraded mainly by Soil erosion, water logging, salinization, dumping industrial waste like fly ash, heavy metals and pressed mud.  LAND RESOURCES SOIL EROSION The literal meaning of soil erosion is the wearing away of soil, but it is defined as the movement of soil components, especially surface litter and top soil from one place to another. The major concern of soil erosion as it diminish the soil fertility. Types of soil erosion: i. Normal erosion or geologic erosion: It is a natural process of top soil removal keeping the equilibrium between physical, biological and hydrological process which are also responsible for renewal of top soil. ii. Accelerated erosion: This is due man-made (anthropogenic) activities like overgrazing, deforestation, and mining by which the top soil erosion is higher than its renewal.  LAND RESOURCES There are two types of soil erosion agents and they are i. Climatic Agents and ii. Biotic Agents i. Climatic Agents: water and wind are the climatic agents of soil erosion. Water affects soil erosion in the form of torrential rains, rapid flow of water along slopes, run-off, wave action and melting and movement of snow. Water induced soil erosion is of the following types: Sheet erosion: when there is uniform removal of a thin layer of soil from a large surface area, it is called sheet erosion. This is usually due to run-off water. Rill erosion: When there is rainfall and rapidly running water produces finger-shaped grooves or rills over the area, it is called rill erosion.  LAND RESOURCES Gully erosion: It is a more prominent type of soil erosion. When the rainfall is very heavy, deeper cavities or gullies are formed, which may be U or V shaped. Slip erosion: This occurs due to heavy rainfall on slopes of hills and mountains. Stream bank erosion: During the rainy season, when fast running streams take a turn in some other direction, they cut the soil and make caves in the banks.  LAND RESOURCES Wind erosion is responsible for the following three types of soil movements: Saltation: This occurs under the influence of direct pressure of stormy wind and the soil particles of 1-1.5 mm diameter move up in vertical direction. Suspension: Here fine soil particles (less than 1 mm dia) which are suspended in the air are kicked up and taken away to distant places. Surface creep: Here larger particles (5-10 mm diameter) creep over the soil surface along with wind.  LAND RESOURCES (ii) Biotic agents: Excessive grazing, mining and deforestation are the major biotic agents responsible for soil erosion. Due to these processes the top soil is disturbed or rendered devoid of vegetation cover. So the land is directly exposed to the action of various physical forces facilitating erosion. Deforestation without reforestation, overgrazing by cattle, Surface mining without land reclamation, irrigation techniques that lead to salt build-up, water-logged soil, farming on land with unsuitable terrain, soil compaction by agricultural machinery etc make the top soil vulnerable to erosion.  LAND RESOURCES DESERTIFICATION: Desertification is a process whereby the productive potential of arid or semiarid lands falls by ten percent or more. Moderate desertification is 10-25% drop in productivity, severe desertification causes 25- 50% drop while very severe desertification results in more than 50% drop in productivity and usually creates huge gullies and sand dunes. Desertification is characterized by de-vegetation and loss of vegetal over, depletion of groundwater, salinization and severe soil erosion. Causes of Desertification: Formation of deserts may take place due to natural phenomena like climate change or may be due to abusive use of land. Even the climate change is linked in many ways to human activities. The major anthropogenic activities responsible for desertification are as follows: Deforestation: Since there is no vegetation to hold back the surface run-off, water drains off quickly before it can soak into the soil to nourish the plants or to replenish the groundwater. This increases soil erosion, loss of fertility and loss of water.  LAND RESOURCES Overgrazing: This is because the increasing cattle population heavily graze in grasslands or forests and as a result denude the land area. When the earth is denuded, the microclimate near the ground becomes inhospitable to seed germination. The dry barren land becomes loose and more prone to soil erosion. The top fertile layer is also lost and thus plant growth is badly hampered in such soils. Mining and quarrying: These activities are also responsible for loss of vegetal cover and denudation of extensive land areas leading to desertification. Deserts are found to occur in the arid and semi-arid areas of all the continents. Amongst the most badly affected areas are the sub Saharan Africa, the Middle East, Western Asia, parts of Central and South America, Australia and the Western half of the United States.  FOOD RESOURCES The main food resources include wheat, rice, maize, potato, barley, oats, cassava, sweet potato, sugarcane, pulses, sorghum, millet, about twenty or so common fruits and vegetables, milk, meat, fish and seafood. Amongst these rice, wheat and maize are the major grains, about 1500 million metric tons of which are grown each year, which is about half of all the agricultural crops. The Food and Agriculture Organization (FAO) of United Nations estimated that on an average the minimum caloric intake on a global scale is 2,500 calories/day. People receiving less than 90% of these minimum dietary calories are called undernourished and if it is less than 80% they are said to be seriously undernourished. Deficiency or lack of nutrition often leads to malnutrition resulting in several diseases as shown in Table  WORLD FOOD PROBLEMS During the last 50 years world grain production has increased almost three times, thereby increasing per capita production by about 50%. At the same time population growth increased at such a rate in LDCs (Less developed countries) that it outstripped food production. Every year 40 million people (fifty percent of which are young children between 1 to 5 years) die of undernourishment and malnutrition. This means that every year our food problem is killing as many people as were killed by the atomic bomb dropped on Hiroshima during World War II. These startling statistical figures demand the need to increase our food production, equal distribution and control on population growth Indian scenario: Though India is the third largest producer of staple crops, almost 300 million Indians are undernourished. Our food problem is also related to the population.  AGRICULTURE Some 10,000 to 12,000 years ago mankind took to agriculture by cultivating plants of its own choice. They used the practice of Slash and burn cultivation or shifting cultivation, which is still prevalent in many tribal areas, as in the North East Hills of India. The type of agriculture practiced these days is very different from the traditional ones and their outputs in terms of yield as well as their impacts on the environment show lots of differences. Traditional agriculture and its impacts: It usually involves a small plot, simple tools, naturally available water, organic fertilizer and a mix of crops. It is more near to natural conditions and usually it results in low production. It is still practiced by about half the global population. The main impacts of this type of agriculture are as follows: (i) Deforestation: The slash and burn of trees in forests to clear the land for cultivation and frequent shifting result in loss of forest cover. (ii) Soil erosion: Clearing of forest cover exposes the soil to wind, rain and storms, thereby resulting in loss of top fertile layer of soil.  AGRICULTURE (iii) Depletion of nutrients: During slash and burn the organic matter in the soil gets destroyed and most of the nutrients are taken up by the crops within a short period, thus making the Modern Agriculture and its impacts It makes use of hybrid seeds of selected and single crop variety, high-tech equipment and lots of energy subsidies in the form of fertilizers, pesticides and irrigation water. The food production has increased tremendously, evidenced by“green revolution”. However, it also gave rise to several problematic off-shoots as discussed below: (i) Impacts related to high yielding varieties (HYV): The uses of HYVs encourage monoculture i.e. the same genotype is grown over vast areas. In case of an attack by some pathogen, there is total devastation of the crop by the disease due to exactly uniform conditions, which help in rapid spread of the disease. (ii) Fertilizer related problems:  AGRICULTURE (ii)Fertilizer related problems: (a) Micronutrient imbalance: Most of the chemical fertilizers used in modern agriculture have nitrogen, phosphorus and potassium (N, P, K) which are essential macronutrients. Farmers usually use these fertilizers indiscriminately to boost up crop growth. Excessive use of fertilizers cause micronutrient imbalance. For example, excessive fertilizer use in Punjab and Haryana has caused deficiency of the micronutrient zinc in the soils, which is affecting productivity of the soil. (b) Nitrate Pollution: Nitrogenous fertilizers applied in the fields often leach deep into the soil and ultimately contaminate the ground water. The nitrates get concentrated in the water and when their concentration exceeds 25 mg/L, they become the cause of a serious health hazard called “Blue Baby Syndrome”or methaemoglobinemia. Blue Baby Syndrome can be the cause of death. Though the more problem is being faced by Denmark, England, France, Germany and Netherlands, the problem also exists in India  AGRICULTURE (c) Eutrophication: Excessive use of N and P fertilizers in the agricultural fields leads to another problem, which is not related to the soil, but relates to water bodies like lakes. A large proportion of nitrogen and phosphorus used in crop fields is washed off and along with runoff water reach the water bodies causing over nourishment of the lakes, a process known as Eutrophication (eu=more, trophic=nutrition). Due to eutrophication the lakes get invaded by algal blooms. These algal species grow very fast by rapidly using up the nutrients. They are often toxic and badly affect the food chain. The algal species quickly complete their life cycle and die thereby adding a lot of dead organic matter. The fishes are also killed and there is a lot of dead matter that starts getting decomposed. Oxygen is consumed in the process of decomposition and very soon the water gets depleted of dissolved oxygen. This further affects aquatic fauna and ultimately anaerobic conditions are created where only pathogenic anaerobic bacteria can survive. Thus, due to excessive use of fertilizers in the agricultural fields the lake ecosystem gets degraded.  AGRICULTURE (iii) Pesticide related problems: The first generation pesticides include chemicals like sulphur, arsenic, lead or mercury to kill the pests. DDT (Dichlorodiphenyl trichloroethane) whose insecticidal properties were discovered by Paul Mueller in 1939 belongs to the second generation pesticides. After 1940, a large number of synthetic pesticides came into use. Although these pesticides have gone a long way in protecting our crops from huge losses occurring due to pests, yet they have a number of side-effects, as discussed below: (a) Creating resistance in pests and producing new pests: Some individuals of the pest species usually survive even after pesticide spray. The survivors give rise to highly resistant generations. About 20 species of pests are now known which have become immune to all types of pesticides and are known as “Super pests”. (b) Death of non-target organisms: Many insecticides are broad spectrum poisons which not only kill the target species but also several non-target species that are useful to us.  AGRICULTURE (c) Biological magnification: Many of the pesticides are nonbiodegradable and keep on accumulating in the food chain, a process called biological magnification. Since human beings occupy a high trophic level in the food chain, hence they get the pesticides in a bio-magnified form which is very harmful. (iv) Water Logging: Over irrigation of croplands by farmers for good growth of their crop usually leads to waterlogging. Inadequate drainage causes excess water to accumulate underground and gradually forms a continuous column with the water table. Under water-logged conditions, pore-spaces in the soil get fully drenched with water and the soil-air gets depleted. The water table rises while the roots of plants do not get adequate air for respiration. Mechanical strength of the soil declines, the crop plants get lodged and crop yield falls. In Punjab and Haryana, extensive areas have become water-logged where adequate canal water supply or tube-well water encouraged the farmers to use it over- enthusiastically leading to water-logging problem. Preventing excessive irrigation, sub-surface drainage technology and bio-drainage with trees like Eucalyptus are some of the remedial measures to prevent water-logging  AGRICULTURE (v) Salinity problem: At present one third of the total cultivable land area of the world is affected by salts. In India about seven million hectares of land are estimated to be salt—affected which may be saline or sodic. Saline soils are characterized by the accumulation of soluble salts like sodium chloride, sodium sulphate, calcium chloride, magnesium chloride etc. in the soil profile. Their electrical conductivity is more than 4 dS/m. Sodic soils have carbonates and bicarbonates of sodium, the pH usually exceeds 8.0 and the exchangeable sodium percentage (ESP) is more than 15%. Causes: A Major cause of salinization of soil is excessive irrigation. About 20% of the worlds' croplands receive irrigation with canal water or ground water which unlike rainwater often contains dissolved salts. Under dry climates, the water evaporates leaving behind salts in the upper soil profile. Thousands of hectares of land area in Haryana and Punjab are affected by soil salinity and alkalinity. Salinity causes stunted plant growth and lowers crop yield. Most of the crops cannot tolerate high salinity.  AGRICULTURE Remedy: The most common method for getting rid of salts is to flush them out by applying more good quality water to such soils. Another method is laying underground network of perforated drainage pipes for flushing out the salts slowly. This sub-surface drainage system has been tried in the experimental station of CSSRI at Sampla, Haryana. The Central Soil Salinity Research Institute (CSSRI) located in Karnal, Haryana has to its achievement the success story of converting Zarifa Viran village to Zarifa Abad i.e. ‘from the barren land to productive land’through its research applications.