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IT potential in agriculture – A GIS implementation in evaluating cardamom potential in Sikkim Himalayas

Saurabh Gupta, Syed Taha Owais

It is believed that ancient Indian merchants conquered the world with their large varieties of species. One of the major spices is cardamom. It has been a part of Indian food for time immemorial. Cardamom is an important cash crop. Cardamom production in the country during the recent years has fallen to about 25-30 per cent. Though the production in the country has increased in last 30 years there has been no major breakthrough in its productivity. Besides this, in order to boost its cultivation, import has been banned, but there are instances of illegal import into this country in order to meet the domestic requirements (refer to Financial Times, Oct. 1998). Thus it is very essential to properly investigate into the causes and factors, which led to loss of our past glory in this field. Implementation of IT can be a boon in analyzing and generating models in various fields of agriculture. This paper presents a case study of GIS implementation in finding large cardamom cultivation potential model in Sikkim Himalayas. To make a sample of our study we have selected a watershed named RateChhu situated between East and North districts.

Large Cardamom is grown in forest loamy soils having soil depth a few inches to several feet. Colour of large cardamom dry soil ranges from brownish yellow to dark brown; most of the soil colour varies from dark yellowish brown to very dark grayish brown. Texture varies from sandy, sandy loam, silty loam and clay. In general Large Cardamom soil is acidic and majority of soils have pH ranges from 5.0 to 5.5 and more than 1% organic carbon (Biswas et al 1986). On an average, these soils have high in available Nitrogen and medium in available Phosphorous and Potassium. Because of steepness of the terrain, chance of water logging is less, however water logged conditions are not suitable for the plants and adequate drainage is quite essential for better stand of the crop.

In general cardamom is cultivated on hill slopes. It is also seen that the crop is cultivated in terrace land (earlier under paddy cultivation), after raising shade trees. In case of land under gentle slope, large cardamom can be planted on the slopes and in case of medium and steep slopes, the slopes are cut into terraces and then cardamom is planted. Large cardamom is a shade-loving crop. It is seen to grow under dense shade (60-70% of full day light interception) to light shade (26% full day light interception) condition. The day light intensity required for optimum growth of cardamom is 5000-20000 lux. Therefore in virgin forest it is necessary to clean the under growth, over head shade regulation is essential in such a way that at least 50 percent shade is maintained in the area. In case of a bare field having irrigation facility or an area having scarcity of shade trees, planting shade tree saplings of species commonly found in a particular area and suitable for cardamom cultivation may be done in June-July (Table showing suitable shade tree species). The most common shade trees are Utis (Alnus nepalensis), (600-2000 m above mean sea level), Chilaune (Schima wallichi), (550-1515m amsl), Panisaj (Terminalia myriocarpa), (400-1000m amsl), Malato Macaranga denticulata, (67001515m amsl), Asarey (Colebrookianum), (850-2000m amsl), Gogun (Saurauvia nepalensis), (1400-2000m amsl), Bilaune (Maesa chesia), 670-15615m amsl). Planting more than one species of shade tree commonly grown in a particular locality is encouraged. In case of bare land, Utis is of first choice, with other species, depending on the altitude of the area, because of its fast growing nature and is an actinorhizal tree capable of fixing atmospheric nitrogen and it has faster rates of nutrient cycling (Sharma 1984). Planting of shade tree sapling (Utis) at a row distance of 5m in a row and row to row distance of 10m is beneficial. While planting the trees the course and direction of the sun movement and the slope of the hill are generally considered. Usually the tree rows are run along the south-west direction inside the plantation (Karibassavapa 1997).

Major Varieties of Cardamom
There are mainly five varieties of large cardamom; Ramsey, Swaney, Golsey, Varlangey(Bharlangey) and Bebo. Other sub-varieties are Ramnag, Madhusey, Ramla, Mongney etc. are cultivated in small areas.

Ramsey: This name is derived from two Bhtia words – ‘Ram’ meaning mother and ‘Sey’ meaning Gold (yellow). This variety is well suited for higher altitude above 5500 on steep slopes.

Golsey: This name is derived from Hindi and Bhutia word ‘Gol’ meaning round and ‘Sey’ meaning Gold. They are generally cultivated in lower altitudes; below 4500 ft, especially in Dzongu area in North Sikkim. These are tolerant to common diseases like Chirke and Foorkey.

Varlangey: Cultivated in low, medium, high altitude areas of South regu (East Sikkim). Its yields are exceptionally high at higher altitudes. But these are susceptible to Foorkey and Chirkey. Seed propagation, rhizomes (sucker multiplication) and tissue culture can do plant Propagation of cardamom.

Thus from above discussion we can conclude that cardamom is altitude friendly with certain aspect and soil requirement, which makes it ideal in its cultivation in this Himalayan mystic state of Sikkim. We have made an attempt to determine the cardamom cultivation potential at micro watershed level, RateChhu watershed.

Description Of Study Area
Sikkim is situated between 27004′ N to 28007’N latitude and 88001′ E and 88055′ E londitude. The state is almost rectangular in shape and covers an area of 7096 sq. kms. Nepal bound state in west by vast stretches of Tibetan plateau in the north, in east by Bhutan and Chumbi valley of Tibet and Darjeeling district of West Bengal stretches along its southern boundary. Administratively state has been divided into four districts namely East, West, North and South and the districts have been further divided into nine sub-divisions.

The sample study has been made on RateChhu watershed, which is located in Gangtok subdivision and Mangan subdivision under East and North districts respectively in the Himalayan State of Sikkim.

Location and Extent of Study Area
Name of study area RateChhu Watershed
Toposheet source 78/11, 78/15
Geographical Location 27° 20’30’’ and 27° 30’30″ North
88° 33’57″ and 88° 45’50″ East
Total Area Covered 87.34 sq. km. (Spans calculated)
Spatial Information Watershed map, contour map, forest density map (1988), land use map (1963), roads, settlement, river and drains and soil maps and streams maps.




Demographic Description
In Rate Chhu watershed we have taken into account blocks Tintek, Tshalumthang, Tirkatum and Pangthang Forest Block in East district and Zimchung and Upper Mangshila (part of it only) and Reserve forests for the purpose of analysis because they form full panchayat blocks.

This watershed consists of drains and prennial kholas which drain to Bakcha Chhu. Major streams are Rate Chhu and Bhi Khola. The altitude varies from 1000 metres to above 4800 mts above sea level. According to 1991 census total population of the watershed is 5134 in total households of 958. Population of Schedule Casre and Tribes are 326 and 739 respectively and there are 1241 cultivators and 1805 total workers. Agriculture is the major occupation along with other economic activities. There are in total 11 primary schools, 01 middle school. There is only one PHC, facilities like post and telegraph and market are not available, but lie within a radius of 15 kms. Footpath, unmatteled and mattled roads are available.

Block Map of RateChhu WaterShed

Contour Map

Slope Map

Illumination Map

Aspect Map

Soil Cover Map

Soil Depth Map

Land use 1988


Parameters For Development of Cardamom Cultivation Potential
Sikkim grows 90% of the total country’s cardamom, which is a cash crop. Government is also encouraging cardamom cultivation and has setup Species Board to help farmers and do research work. Here, an attempt is made to find the suitability for cultivation of cardamom.

Requirement for cardamom cultivation: –

Soil requirement: pH value should be 5 to 5.5 i.e., soil should be acidic having organic carbon 23.8 mg/gm and nitrate about 3.30 mg/gm and phosphorus about 0.75 mg/gm. Soil depth should be greater than 9 inches.

Altitude requirement: Cardamom can be cultivated from 900 mts. to 2000 mts. above sea level. 900-1200 is best suited for Golsey variety, 1200-1600 is best suited for Sawney type and above 1600 is best suited for Ramsey variety and Varlangeo variety.

Tree shade requirement: Cardamom requires shades so that it gets diffused light as direct rays are harmful. Common shade trees are Alnus nepalensis,Schima wallichi, Bucklandia populnea.

Rainfall requirement: Rainfall should be between 3000-3500 mm. for 200 days. During dry seasons (winter and summer) irrigation can be arranged through sprinkler or hoses preceded by heavy mulching the plant base with dry leaves and trashes or weed material.

Land topography: Cardamom can be grown at any slope but the aspect of slope should be north or north east or south or south east as temperature buildup in these areas are minimum.


Potential for cardamom cultivation is calculated by using altitude, forest type, aspect, soil depth and soil type.

Development of Model

Altitude Weight Forest Type Weight Incidence Weight
1000 4 Agriculture 1 0 5
1500 4 Alpine Barren 1 30 4
2000 3 Alpine Scrub 2 45 3
2500 3 Degraded 4 60 2
3000 2 Dense Forest 5  
3500 2 Forest Blank 3
4000 1 Open Forest 5
4500 1 Rock 1
  Scrub Forest 1
Soil Depth Weight Assigned Soil Type Weight Assigned
Deep 5 Coarse Loamy 5
Moderate Shallow 3 Fine 4
Moderate Deep 4 Fine Loamy 4
Shallow 2 Loamy Skeletal 4

Result of potential for cardamom cultivation

Sl. No Potential Area(%) Cumm Area Area(sq km)
1 Very Good 3.39 3.39 2.8214
2 Good 55.21 58.59 46.0128
3 Satisfactory 20.75 79.34 17.2960
4 Not Recommended 20.66 100.00 17.2185
5 Total 100.00   83.3487

Result of potential for cardamom cultivation at Non Reserve

Sl. no Cardamom Potential Area(%) Cumm Area % Area(sq km)
1 Very Good 7.61 7.61 1.7261
2 Good 82.34 89.95 18.6713
3 Satisfactory 10.05 99.99 2.2779
4 Not Recommended 0.01 100.00 0.0016
  Total 100.00   22.6770

Distribution of Potential Along Altitudes in Non Reserve Forest

Altitude/ Cardamom 
Very Good Good Satisfactory Not Recommended Total
1000 0.4480 9.9138 1.2188 0.0016 11.5822
1.98 43.72 5.37 0.01 51.07
3.87 85.59 10.52 0.01  
25.95 53.10 53.51 100.00  
1500 0.8894 5.2723 1.0294 0.0000 7.1911
3.92 23.25 4.54 0.00 31.71
12.37 73.32 14.32 0.00  
51.53 28.24 45.19 0.00  
2000 0.3311 3.0109 0.0296 0.0000 3.3716
1.46 13.28 0.13 0.00 14.87
9.82 89.30 0.88 0.00  
19.18 16.13 1.30 0.00  
2500 0.0576 0.4744 0.0000 0.0000 0.5320
0.25 2.09 0.00 0.00 2.35
10.84 89.16 0.00 0.00  
3.34 2.54 0.00 0.00  
  1.7261 18.6713 2.2779 0.0016 22.6770
7.61 82.34 10.05 0.01  


Potential At Watershed Level

Potential In Non Reserve Forest

Thus from the above analysis we can conclude that the potential for cardamom cultivation is fairly high at around 80% both at whole watershed level and non-reserve forest level. As a matter of fact the cultivation of cardamom is limited to non-reserve forest. For improvement of cardamom production and proper marketing following measures are suggested,

  • As Ramsey and Varlangey varieties are very susceptible to fookey and chirke diseases proper management like pest control, use of modern seeding techniques should be used and the potential cultivators need to be properly educated in this regard.
  • As this watershed is located very near to Gangtok, capital of Sikkim, the product can be marketed easily. For this communication facilities must be upgraded.
  • Using IT like remote sensing and GIS based studies to properly monitor the cardamom cultivation.
  • The cardamom suffers from major diseases like Chirkey and Foorkey which should be properly dealt and further study can be made on this issue.