Nepal

This report was compiled and last updated on 11 May 2005 by Binod P. Sharma
in association with the MENRIS Division of the International Centre for
Integrated Mountain Development (ICIMOD), Kathmandu, Nepal

1.   Country overview

1.1  Geography and administrative units

1.2  Socio-economic features

1.3  Climate

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1.1  Geography and administrative units

Nepal is located between 80° 04’ and 88° 12’ East longitudes and between 26° 22’ and 30° 27’ North latitudes. It is a landlocked country bounded in the East, West, and South by India and in the North by the Tibetan autonomous region of the People’s Republic of China.

Kathmandu is the capital of Nepal. The country is divided into five Development Regions and 75 districts.

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1.2  Socio-economic features

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1.3  Climate

In a global context, Nepal is considered to lie within the subtropical climatic belt. However, local climates range from humid subtropical in the southern Terai to alpine in the north. Distinct wet and dry seasons alternate over the year. The wet season lasts from June to September and is due to the south-west monsoon. October through May is mostly dry, occasionally interrupted by a few showers in winter and spring. Thus the main rainy season is confined to the monsoon season followed by a cool to cold, dry, post-monsoon season and a hot, dry pre-monsoon season.

The highest mean monthly temperatures occur in April or May, just before the monsoon breaks. The mean monthly maximum temperatures during this period range from 35 - 40° C in the Terai to about 16° C at 3000 m. altitude. December and January are the coldest months, during which period the mean monthly temperatures drop down to 14 - 16° C in the Terai, 6 - 8° C at 2000 m altitudes, and about 2° C at 3000 m. Above 3000 meters, they fall below zero. Winter temperatures in the Kathmandu valley are lower than would be expected from the altitude, as the valley is a depression surrounded by hills, and cold night air accumulates in it. The mean monthly January temperature at Kathmandu (1300 m) is 9.5° C (Jackson, 1987).

In general, annual rainfall amount decreases slightly from east to west and increases with elevation from south to north on windward slopes. Increase in rainfall with elevation appears to be maximum between 1800 and 2400 m. on the windward sides. The northward increase of precipitation appears to be maximum at around 3000 m. on suitably exposed slopes. Thereafter, it tends to decrease with further increase in elevation.

The distribution of annual rainfall over time and space can be considered to be of the following three types:

1. Main rainy season occurs during the four months of monsoon from June to September. About 80 percent of the annual rainfall occurs during this season and the rainfall regime covers the whole country except the northern Himalayan region.

2. Westerly weather systems bring occasional rains during winter and early spring. But occurring occasionally, they affect isolated hilly areas, often in the western part of the country.

3. During the pre-monsoon season from March to May, local orographic or convective rains may occur mostly over the hills and inner Terai areas. But they affect isolated areas, mostly in the form of brief thundershowers.

The rainfalls of latter two types are rather unreliable and account for only about 20 percent of the annual total precipitation.

Annual rainfall varies from about 250 mm in the rain-shadow areas of north-west Dolpa and Mustang to about 5000 mm on the windward slopes of Kaski district. Western parts receive less rainfall in the monsoon compared to central and eastern parts. During the winter, however, rainfall is more reliable in the west than in the east. More rainfall occurs on the south-eastern slopes which act as windward side to monsoon winds during the summer. The hilly areas of western and north-western slopes as well as those behind the high mountains receive little rainfall. Isohyets of 1500 to 2500 mm cover most of the eastern and central hilly regions while those in the western region are between 1000 to 1500 mm. This difference in annual rainfall distribution may be due to topography, continentality and partly to late onset and early retreat of summer monsoon in the west (APROSC, 1995). 

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2.   Land resources

2.1  Physiography

2.2  Soils

2.3  Agroecological systems

2.4  Wetlands, mangroves and inland valley bottoms

2.5  Inundation Land Types

2.6  Natural hazards

2.7  Land cover

2.8  Land use

2.9  Land use change

2.10  Land Productivity

2.11  Environmental Impact of land uses

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It is believed that 190 species of water fowl - including resident species, migratory species and uncommon and rare resident species - inhabit these wetlands. In addition to this, numerous other mammals, fishes, reptiles, and birds are found in these habitats. At least two crocodile species found in the wetlands of Nepal have now become threatened.

Awareness on this important ecosystem has developed considerably in the recent years and many researchers are now engaged in wetlands research in Nepal. Several projects related to wetland management have either been implemented or are in the process of being implemented through various organizations. IUCN, in collaboration with UNDP, is taking a special interest in the wetlands management and is at present engaged in the formulation of a project for conservation and sustainable use of the wetlands of Nepal. Several NGOs, e.g., Wetlands Nepal, are also currently working in the Wetland habitats of the country. 

Nepal is signatory to a number of international conventions and treaties to protect the environment and biodiversity. Three of these are of special importance in relation to the conservation of the wetlands: 1) Convention on Wetlands of International Importance, especially Waterfowl Habitat (Ramsar Convention), signed on 17 December 1987, 2) Agreement on the Network of Aquaculture Centres in Asia and the Pacific, signed on 8 January 1988, and 3) Convention on Biological Diversity, signed on 15 June 1992. This shows the commitment of Nepal to conserve the wetland habitats. Several national acts, rules and regulations have also been enacted for the protection of environment and biodiversity, which also includes the wetlands, but their enforcement remains weak.

The Koshi Tappu Wildlife Reserve is the largest protected wetland and the only Ramsar site in Nepal.

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2.5  Inundation Land Types

Not relevant

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Some of the most common and frequent natural hazards that occur in Nepal are:

Landslides

Earthquakes

Windstorms, hailstorms, thunderbolts

Forest fire

Glacial lake outbursts flood events

Landslides:

Among the natural hazards that occur regularly in Nepal, floods and landslides are by far the most serious ones. They claim many human lives every year and cause other damages such as destruction and blockages of highways, losses of livestock, crops, and agricultural land. Based on a reconnaissance study, Laban (1979) estimated that at least 75 percent of all landslides in Nepal were natural. Brundsen et al. (1981), working in the Middle Mountains of Nepal, conclude that landslides should be considered normal rather than exceptional in the study area.

Earthquakes:

Geologically, Nepal is considered to lie on a seismic zone which experiences frequent earthquakes. As a result, earthquakes of various magnitudes occur almost every year and have caused heavy losses of lives on several occasions. Based on the data available from the Department of Mines and Geology, CBS (1998) concludes that earthquakes of more than or equal to 5.0 on the Richter scale have occurred at least once every year in Nepal since 1987, with the exception of 1989 and 1992 when no such events were recorded.

Scientists attribute the occurrence of frequent earthquakes in Nepal to the disturbances occurring due to the continuous encroachment of the Indian subcontinental plate into the main Asian plate. At the same time, two major parallel fault systems called the Main Boundary Thrust (MBT) and Central Boundary Thrust (CBT) cross Nepal longitudinally. Constant adjustments and readjustments taking place in these fault systems are known to trigger earthquakes in the country as well.

Windstorms, hailstorms, thunderbolts:

Windstorms, hailstorms and thunderbolts (lightening strikes) also occur frequently in Nepal and affect many areas of the country on a regular basis. Although not as serious as floods, landslides, and earthquakes these events, nevertheless, cause loss of human lives and damages to properties. Analyzing the available data (DPTC, 1997), CBS (1998) concludes that in 1995, forty-five districts of Nepal were affected by hailstorms, windstorms and thunderbolts. These events, particularly the hailstorms, cause considerable damages to the standing crops in the fields.

Forest Fire

Every year forest fires occur in many places of the country and cause heavy loss of property as well as loss of many species of wildlife. Nepal has no statistics on the occurrence of forest fires, and no assessment of impact on the economy or on the environment of the country is available. Though there are no records, forest fire is mainly caused by ignorance and illiteracy of local people, or personal interest such as interest of illegal wood cutters, poachers, charcoal traders, or persons encroaching on forest land. There is no record of forest fires caused by natural events like thunderbolts. About 45 percent of forest fires with known causes are due to burning for new grass to graze cattle and to smokers. About 64 percent of forest fires are set intentionally by local people. The share of accidental cause of forest fire is only 32 percent. The Department of Forest is the main responsible government organization to control forest fire. But progress on this field is yet to be achieved due because of lack of resources, lack of specific fire control rules and regulations, etc.

Source: CBS, 1998

Glacial lake outburst flood events:

Apart from landslides and river erosion, the high mountains or Himalayas of Nepal, covering about 15 prcent of the country, are quite susceptible to land degradation caused by glacial lake outburst floods (GLOF). These mountains, with an average elevation of 4 500 m. on, are mostly covered with snow and ice throughout the year. Since the second half of the twentieth century, the large glaciers of the high mountains have been experiencing rapid melting, resulting in the formation of a large number of glacial lakes. This may well be a result of global warming. Almost all the glacial lakes of the Himalayas are formed by a glacier terminus dammed by moraine. These moraine dams are not geologically consolidated enough and a slight disturbance can break the balance of the structure, resulting in an abrupt release of a great amount of water and generating floods. These floods can cause serious damage to infrastructure, houses, and the environment along the flood path downstream. This phenomenon is called a ‘glacial lake outburst flood’ (GLOF).

In Nepal, GLOF events have been occurring for many decades, but this catastrophic glacier phenomenon came into the limelight only after 1985, when the Dig Tsho glacier outburst took place. Investigations into the nature of glacial lakes began in the country. In 1996, the Water and Energy Commission Secretariat (WECS) of Nepal reported that five lakes were potentially dangerous, namely, Dig Tsho, Imja, Lower Barun, Tsho Rolpa, and Thulagi, all lying above 4100m. Their extent ranges from 0.6 to 1.39 sq. km. The maximum depth ranges from 81 to 131m, with ages above 30 years. A recent study done by ICIMOD and UNEP (UNEP, 2001) reported 27 potentially dangerous lakes in Nepal. In ten of them GLOF events have occurred in the past few years and some have been regenerating after the event. This means activities have to be planned carefully in order to avoid human-instigated triggering factors creating an outburst. A monitoring system for lakes with outburst risk should be established to avoid flood hazards.

Source: UNEP, 2001

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Information on land use is available from different sources such as the Cadastral Survey, Central Bureau of Statistics (CBS), Department of Forestry (DoF), Ministry of Agriculture (MoA), etc. The data from these sources were collected  for different purposes, using different methodologies and at different points in time, and thus do not agree with  each other.  Data based on the interpretation of aerial photographs taken in 1977/78 were prepared by the Land Resource Mapping Project (LRMP) and published in 1986. Although the data are old, the information is the most systematic set available and provides a framework for analyzing and comparing land  uses at regional and district levels.

3.   Water Resources (AQUASTAT)

3.1  Hydrography

3.2  Irrigation and drainage

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Information on water resources in Nepal is available at AQUASTAT:Nepal.

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4.   Plant nutrient resources

4.1  Plant nutrient use and nutrient balance

4.2  Fertilizer production and costs

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4.1  Plant nutrient use and nutrient balance

Soil Fertility Status

pH:

The pH of Nepalese soils ranges from a low of 4.0 for a cryorthod in an Abies forest to a high of 8.0 for a calcareous ustifluvent in a riverine Acacia forest. Calcareous soils are common on the Terai, especially on active alluvial plains. Throughout the hills, calcareous rocks lead to higher pH soils and granitic rocks produce acidic soils. The most acid soils in Nepal were found on coarse textured granitic, morainal material between 2500 and 3500 m elevation in the higher-rainfall areas of the High Mountains. Ericaeous plants, expecially of the Rhododendron genus, are particularly well represented there.

Organic matter:

The organic matter content of the soil is highly dependent on the ecological zone, as well as the landuse and management of the soil. Newly opened forested areas on the Terai may have 4 or 5 percent organic matter on initial clearing, and after a few years the levels have dropped to less than 2 percent. Organic matter contents in cultivated soils below 2 000 m range from 0.5 to 3 percent, and average around 1.5 percent. Forest soils tend to be 1 or 2 percentage points higher. Above 2 000 m climatic and vegetation changes are quite dramatic, and the organic matter increases by 2 to 3 percent for both agricultural and the forest soils. This is because decomposition rates are lower and litter production is higher in conifer forests at high elevations.

Total calcium carbonate (CaCO3):

High CaCO3 contents are associated with a number of recent floodplains on  the Terai, but do not appear detrimental to crop growth at present yields. With higher yields, zinc and boron deficiencies may be expected. High CaCO3 contents were found most commonly in active alluvial deposits throughout the country, and also in the upper piedmont in the Far Western and Mid Western Development Regions.

Exchangeable cations:

With several exceptions on ancient terraces, calcium always dominated the exchange capacity and sodium was not found anywhere in detrimental amounts. 

Cation Exchange Capacity (CEC):

The CEC values of the Nepalese soils range from a low of 2.4 meq/100g (for an Ah with 1.0 percent O.M. and 4 percent clay, of an eroded Ustochrept developed on old alluvium of the upper Terai Piedmont under scrub vegetation) to 32.9 meq/100g (for an Ah with 14.3 percent O.M. and 37 percent clay, of a Lithic Dystrochrept developed on quartzitic colluvium in the High Mountains at 2860m under a blue pine forest). The average CEC for all A and B horizons sampled is around 10 meq/100 grams of soil, indicating a moderately low cation exchange capacity. 

Nitrogen (N):

Except of recently cleared forest land with high organic matter levels and low C/N ratios, virtually all cultivated fields in Nepal experience nitrogen deficiencies. Under present nitrogen management, the topsoils of cultivated fields usually contain around 0.12 percent nitrogen (Kjeldahl method), although levels ranged from 0.05 to 0.40 percent.

Phosphorus (P):

Phosphorus is the second most important soil nutrient limiting crop production in Nepal. Most cultivated soils exhibit moderately low to low levels of available phosphorus, but under existing management, deficiency signs are not obvious.

Potassium (K):

On average 0.2 meq of exchangeable potassium was found per 100 grams of soil, and this seems to supply the plant with adequate potassium at present crop yields. 

Micronutrients:

None of the soil samples analysed for micronutrient contents have shown any indication of either deficiency or toxicity of any micronutrient element. Certain plantation crops however have shown distinct micronutrient deficiencies, and some have responded dramatically to boron application. If micronutrient problems occur, they are most likely to be with perennial crops such as oranges, lemons, apples, and exotic plantation forestry crops on very acid or highly calcareous soils. The results of soil micronutrient analyses carried out on topsoils representing the major parent materials occurring in Nepal are presented in Table 4.1.1.

Although comprehensive information on the micronutriet status at the national level is not available, researchers working in some specific areas report widespread deficiencies. A recent research carried out under the NUFU (Norwegian Committee for Development Research and Education) programme in the Arun valley in Eastern Nepal reports serious deficiencies of boron and zinc and to a lesser extent of selenium, molybdenum, and iodine. An interesting feature of this research is an attempt to identify and document the effects of soil micronutrient contents on crop porduction, animal health, and ultimately on human nutritiuon and health. According to the author, Peter Anderson, "the explanations are complex, and the causal links from ’soil-to-health’ are complicated by farming systems, socio-economic and cultural factors. Howeve r, the chains of explanation are plausible, and the main purpose of the paper is to demonstrate how models and methods commonly applied by geographers can contribute to micronutrient research." GIS is used to demonstrate spatial variation of micronutrients in the Arun valley and the author emphasizes the need to create maps showing such variations to enable spatial analysis of micronutrient distribution. Anderson asserts that metalevel discussions of the Green Revolution show how HYV crops lead to ’empty calories’.

[Text 4.1.1: Geographical approaches to micronutrient deficiencies in Himalaya]

Use of Plant Macro Nutrients

All the three macronutrient elements - nitrogen, phosphorus, and potassium - are recommended for various crops in Nepal. But nitrogen is the most popular nutrient amongst the farmers as it give a quick and visible response. Phosphorus is used to a certain extent, whereas potassium is used in almost negligible quantities. Urea is the most common source of nitrogen and is the fertilizer of choice of the farmers. After urea, the complex fertilizer with 20:20:0 : P2O5:K2O formulation is the preferred fertilizer of the farmers. In recent years, however, the government has discouraged the use of this complex fertiliser, as it was found to be less suitable for lowland rice due to the nitrate form of nitrogen it contains. Diammonium phosphate (DAP) has been promoted as an alternative to it, but the farmers still prefer complex, because of its wider N:P ratio and favourable price. Muriate of potassium (KCl) is the only form of potassium fertilizer used.

The fertilizer consumption in Nepal is quite low. The maximum national average consumption of total nutrients was recorded at 35 kg per hectare per year in 1994/95, which is the lowest after Bhutan in the SAARC (South Asian Association for Regional Cooperation) countries (MOPE, 2000). The consumption decreased further to about 27 kg per hectare per year in 1995/96. The reason for the sudden drop in consumption after 1994/95 is the removal of subsidy and privatization of the fertilizer trade in the country. After the initial adjustment period, the rate of consumption is again picking up but has not yet reached the 1994/95 level.

Source: Pandey and Joshi, 2000

The peak nutrient consumption of 35 kg/ha/yr in 1994/95 constituted 24.8 kg N, 8.1 kg P2O5, and 0.6 kg K2O. The average application rates of fertilizers for particular crops are far below the recommended rates. No primary data are available on crop-wise use of fertilizers, but calculations based on fertilizer sales data indicate that the wheat crop receives the maximum share of 40% of the fertilizers applied, followed by rice (35%). 

Source: Pandey and Joshi, 2000

Although comprehensive information on the micronutriet status at the national level is not available, researchers working in some specific areas report widespread deficiencies. A recent research carried out under the NUFU (Norwegian Committee for Development Research and Education) programme in the Arun valley in Eastern Nepal reports serious deficiencies of boron and zinc and to a lesser extent of selenium, molybdenum, and iodine. An interesting feature of this research is an attempt to identify and document the effects of soil micronutrient contents on crop porduction, animal health, and ultimately on human nutritiuon and health. According to the author, Peter Anderson, "the explanations are complex, and the causal links from ’soil-to-health’ are complicated by farming systems, socio-economic and cultural factors. Howeve r, the chains of explanation are plausible, and the main purpose of the paper is to demonstrate how models and methods commonly applied by geographers can contribute to micronutrient research." GIS is used to demonstrate spatial variation of micronutrients in the Arun valley and the author emphasizes the need to create maps showing such variations to enable spatial analysis of micronutrient distribution. Anderson asserts that metalevel discussions of the Green Revolution show how HYV crops lead to ’empty calories’.

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4.2  Fertilizer production and costs

Mineral fertilizers were first introduced into Nepal in 1952. In 1954 fertilizer consumption was 10 tons, and by 1965 it had increased to about 1 500 tons. It was only in 1965/66, with the establishment of the Agriculture Inputs Corporation (AIC), then known as Agriculture Inputs Supply Corporation, that organized supply of fertilizers actually began in Nepal. AIC began its fertilizer trade operation with 3 196 tons of fertilizers received as aid from India (2 169 tons) and the former Soviet Union (1 000 tons). Most of this was in the form of ammonium sulphate (21% N). In FY 1965/66, the amount of fertilizers sold was 2 069 tons. Sale of fertilizers at that time was confined to the Central Development Region, mostly around Kathmandu Valley and the surrounding hills, the Birgunj area of Bara, and Parsa districts in the Terai region. The consumption of mineral fertilizers increased from a mere 2 069 tons (451 tons of nutrients) in 1965/66 to 185 797 tons (90 277 tons of nutrients) in 1994/95 (MOPE, 2000).

No fertilizer manufacturing industry exists in Nepal. All fertilizer requirements are met through imports. Until recently (1996/97), AIC had a monopoly over fertilizer imports, including fertilizers received as aid, grant, or purchases under loan. Now, HMG has introduced a policy to involve the private sector in supplying fertilizer. HMG has also issued a Fertilizer Order in order to ensure the supply of quality fertilizers to the farmers (MOPE, 2000). As a consequence of this shift in policy, there was a temporary drop in import and consumption of fertilizers in the following couple of years. During this period, AIC drastically reduced the amount of its imports and the private sector had not yet come forward in the fertilizer trade. But now, as the private traders have started importing fertilizers, the total amount imported is again rising but has not yet reached the all time high level of 1994/95.

Source: Economic Survey, 2000

The following Table provides a comparative analysis of the estimated costs of supply of different fertilizers by AIC and private traders after liberalization of the import and sales of fertilizers.