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Field Preparation and Sowing

Field Preparation and Sowing : 

Large Cardamom is mainly grown in highly steep terrain. The topography and climatic condition permits soil erosion to a considerable extent. Intensive operations, which loosen and expose soil will increase soil erosion and therefore only minimum tillage operations should be followed. As far as possible contour terraces may be made well before taking up planting operations. This helps in reducing soil erosion and soil moisture conservation. Though contour terrace making is expensive and requires high initial investment, the long term benefit will be more to compensate the initial extra expenditure.

The plantation site should be preferably near a perennial water source. Planting is done during June-July when there is enough moisture in the soil. The land selected for planting is cleared of all under growth, weeds etc. for new planting or if it is replanting, old plants may be removed. A layout for foot-paths, irrigation channels or for drainage is to be carried out. A permanent place for curing should be planned preferably at the entrance while compost pits are located on rear side of the plantations. Pits of size 30 x 30 cm are prepared on contour at a spacing of 1.5 x 1.5 m after the onset of monsoon showers. Wider spacing of 1.8 x 1.8 m is recommended for robust cultivars like Sawney, Varlangey, Ramsey etc. The pits are left for weathering for a fortnight and then filled with topsoil mixed with cow-dung or compost @ 1-3 kg per pit. Seedlings/Suckers are planted in the centre of the pits. Care should be taken not to plant the seedling/rhizome very deep in the pit. After planting the seedling/suckers may be staked and the base of the plant is mulched with dried leaves. 

Canopy Requirement 

It is necessary to establish shade prior to planting of cardamom so as to save the plant from direct sun shine. However, excessive thick canopy adversely affect as it may not allow light to pass through and may compete for nutrition. Leaf shading trees at the time of cardamom flowering are not good for shade trees as the leaves cover up the short stalked inflorescence causing rotting of the flower and as a result less fruit setting is found. Hence planning and planting of shade tree saplings should be made well in advance by at least 2 years. Keep only appropriate shade by thinning out excess branches so that only 35% of the sunlight is infiltrated down to its canopy.

Large cardamom grows well in forest loamy soils with gentle to medium slopes. Water logged condition is detrimental to the growth of the plants. It performs well under shade. Utis or Himalayan alder (Alnus nepalensis) is the most common and preferred shade tree for large cardamom. The other species of shade trees are Panisaj (Termalia myriocarpa), Pipli (Bucklandia sp.), Malito (Macaranga denticulate), Argeli (Edgeworthes gardneri) , Asare (Viburnus eruberens), Bilaune (Maesa chesia), Kharane (Symplocos sp.), Siris (Albizzia lebbeck), Dhurpis and Khasi Cherry, Katuse, Faledo (Erythrina indica), Jhingani (Eurja tapanica), Chillowne (Schima wallichi) etc. The shade trees are plated within alternate rows or mixed intermittently in the same row with a spacing of 7-10 m between plants for uniform shade on plantations. A few progressive planters for believe that a mixture of utis-siris-gurpis, utis-argeli-bilaune, utis-asare-chuletro etc., would be beneficial. Roots of A. nepalensis are nodulated with Frankia as an endophyte, and rates of biological N2-fixation are high (Sharma and Ambasht, 1984, 1988). New plantations and large patches of Amomum subulatum-based systems have recently incorporated Alnus nepalensis as a shade tree (Sharma et al., 1994). The potential increase in productivity of plants growing near N2-fixing species has long been recognized. The effects of N2-fixing trees on inter-planted non-N2-fixing trees have most often been characterized in terms of tree dimensions (Newton et al., 1968; Cole and Newton, 1986; Heilman, 1990). Intensive research over the past few decades has provided a relatively solid foundation for understanding many of the major ecological interactions that occur in mixed stands of N2-fixing and non-N2-fixing trees (Binkley, 1992). 

Propagation 

Propagation of large cardamom is done through seeds and suckers. The Propagation through seeds enables production of large number of seedlings. Virus diseases are not transmitted through seeds and therefore the seedlings are free from viral diseases, if adequate care is taken to isolate and protect the nursery from fresh infection. Hants raised from seeds need not necessarily be high yielders even if they are collected from very productive plants due to cross-pollination. The major pollinator is bumble bees, even though honey bees also play a role in pollination'. On the other hand, planting through suckers ensures true to the parents with a high productivity if they are collected from high yielding, disease free plants.

In Sikkim large cardamom is generally propagated through rhizomes due to unavailability of seedling raising technology in the nurseries. With the functions of Cardamom Board since 1979 scientific technology has been made available for plantation in large scale. The nurseries located at Gyalshing, Kabi, Marchak and Kalimpong distributed about one lakh seedlings raised scientifically for the first time in 1980.

Propagation through seeds 
Seeds are collected from high yielding and well-maintained plantation free from diseases. Well matured capsules from bottom and middle position of the spikes are selected for extraction of seeds. After de-husking^ seeds are mixed and rubbed with sand and then washed with water to remove the mucilage completely. Once the water is completely drained, the seeds are mixed with wood ash, dried in shade and sown in the primary nursery. 

In another method, seeds are treated with 25% Nitric acid (HN03) after removing the mucilage (25 ml of concentrated Nitric acid is mixed with 75 ml of water to make 25% Nitric acid). Seeds may completely be immersed in the acid and stirred well for 10 minutes. Excess acid is drained out. Seeds are then washed thoroughly in running water to make it free from acid. Normally, germination percentage is only 20-30%. However seeds treated with Nitric acid (25%) and soaked in GA3 (GibbereUic acid, 10 ppm) gives 60% germination even after 60 days of extraction of seeds. 


Primary nursery 
Seeds are generally sown in September - October. Seed beds are prepared in well drained soil dug to a depth of 30 cm and left for weathering. Raised beds with 15 to 20 cm height, 1 m width and convenient length, preferably 6m, are prepared. Well decomposed cattle manure is mixed with the soil and the surface of the bed is made to fine tilth. About 80-100 g of seeds per bed is sown in lines across the bed at a distance of 10 cm. Seeds are covered with fine soil and mulch with paddy straw/dry grass (10-15 cm thick). Watering is done at regular intervals to keep the surface of the bed moist. Germination of acid treated seeds commences after 25 to 30 days of sowing. When average germination is noticed the mulch materials are removed. The inter space between rows is then re-mulched with chopped paddy straw. Shade pandals are immediately erected by using bamboo mats/reed mats or agro-shade nets. The beds are watered regularly and weeding is done as and when required. When the seedlings attain 3 to 4 leaf stage, they are transplanted to secondary beds/nursery.

Secondary Nursery 
Secondary nurseries can be prepared in poly bags or in raised, secondary beds. For Poly bag nursery, polythene bags of size 15 x 15 cm with perforations at the base are used for planting the seedlings from the primary nursery beds. The bags are filled with potting mixture of soil, sand and cow dung in the ratio of 4:1:1. The bags filled with the mixture are arranged in row of one meter width and in convenient length under shade. Seedlings with 3-4 leaves are planted in the poly bags in April - May and watered regularly. They become ready for field planting in 10 to 12 months. In the case of raised secondary beds, beds of size 15 cm in height and 10 cm width with convenient length are prepared and well decomposed cattle manure is mixed with the soil and an even surface is formed. Seedlings with 3 - 4 leaves are transplanted to the beds in May - June at spacing of 15 cm. The inter space is mulched with chopped paddy straw or dry leaves. Over head pandal is erected for providing shade and the soil is kept moist with, irrigation. The seedlings once attained a growth of 45 - 60 cm height with 2 - 3 tillers are planted in the main field during June - July of the subsequent year.

PROPAGATION THROUGH SUCKERS 

Selection of planting material 

  • High yielding disease free plantations to be selected.
  • The plantation should have high yield record i.e. more than 800 kg / ha for at least 3 consecutive years.
  • One mature tiller with two immature tiller or vegetative buds is used as planting units.

Site of nursery

  • The nursery should be about 500 meters away from the main plantation to avoid occurrence of pests and diseases.
  • The irrigation facility should be available in the nursery.
  • It should be easily accessible by road.

Preparation of trenches

  • The trenches should be of 45 cm (1 '/2ft) width and 30 cm (1 ft) depth with convenient length & may be made across the slopes of the field.
  • Top soil 15 cm ('Aft) to be kept separately from the trench in the upside.
  • Below side 15cm soil to be forked thoroughly.
  • Dried leaves to be applied as layer in the trench first.
  • Then the trench to be filled by top soil mixed with cow dung compost.
  • Spacing of 30 cm is required in between two trenches
  • The planting units to be planted at a spacing of 45 cm (l'/i ft) in between with proper staking

Planting season 

  • Last week of May to June.


Maintenance 

  • Thick mulching with dry leaf / grass may be applied at the base of plant and watering may be done during November to March depending on the soil moisture condition.
  • Well decomposed cattle manure may be applied
  • The plot may be maintained with 50% shade under shade trees or using agro shade net.
  • The disease and pest incidence to be observed from time to time. Disease affected plants to be uprooted and to be destroyed outside the sucker nursery.
  • With proper management, a minimum of 5 planting units could be obtained from a single plant