It is imperative to ready a new ground before plantation. It comprises the vital functions of clearing the land by ridding it off the plants in the area, regulating the shade, terracing, and preparing the pit during summer months.
Shade regulation is an essential practice for cardamom cultivation. It should be conducted in the plantation during summer and after the summer rainfall. Dense branches are chopped off to allow filtered light of 40 to 60 percent of the area. Alternate side branches of the tress are lopped in the lower one third or half portion of the total canopy height, to warrant a balanced umbrella shade. The shade trees should have small leaves, tap root system, and in summer should not shed their leaves. The South-Western parts should be abundantly provided with shade leaves than the North-Eastern slopes because of their vulnerability to sunlight. Open tract of land or area prone to tree fall should be abundantly supplanted by tree species like Karuna (Vernonia arborea), Corangati, Chandana Viambu, Njaval tree and so on, in order to protect the cardamom plantation from direct sunlight. Both forms of severe heat and intense shade can prove detrimental for the growth and produce of cardamom cultivation.
Soil preparation is the most important groundwork for cardamom cultivation. Varying field preparation practices are adapted for different slope types ranging from medium to steep to gentle slopes. Terrace planting is implemented to protect the soil from erosion after torrential rains. Terraces are prepared by leaving prescribed space and distance of 1.5-1.8 metres width across the slopes, before the onset of monsoon. Around 8-15 cm should be expunged from the top soil before preparing terraces and kept aside for pit filling. Pits of 90 x 90 x 45 cm area should be prepared and about 1/3 of the pit depth should be filled with a ratio of 1:3 blend of organic manure and top soil for boosting cardamom yield. However, in regions with lower rainfall, trenches of size 75 cm width and 30 cm depth should be dug. Plants should be planted extensively with a spacing of 1 to 1.5 m in order to fulfil the ideal field condition for cardamom cultivation.
It is important to analyse whether the nature and variety of planting material is suitable for the planting area. The plants should be protected from wind by staking. For Mysore and Vazukka breeds, approximate spacing of 3 x 3 m or 2.4 x 2.4 m should be maintained in highly irrigated and rainfall prone areas. In Karnataka, the distance of 1.8 x 1.8 m or 1.2 x 1.8 m is appropriate. The plant base should be thoroughly manured with dried leaves to ensure conservation of moisture and safeguard from soil erosion. Diagonal planting towards the angle of the slope facilitates soil rotection.
Weeds consume a lot of water and nutrients from the soil which may thwart the growth of cardamom plants. Initially, the weeds outgrow cardamom clump. During the months of May, September, December and January two three rounds of hand weeding at the base of the plants and slash weeding in the rest of the areas is highly recommended. It is important to avoid mammatty (spade) for weeding since it will loosen the soil and result in soil erosion. The weeds are important ingredients for fertilisation.
Skilful irrigation during summer proliferates cardamom produce by 50%. Channelization of irrigation is primarily dependent on the amount of rainfall. However, in areas like Tamil Nadu, where the South-West monsoon is not substantial, effective irrigation during March to August is necessary since during this period the growth and development of young tillers and panicles occur. Therefore, negligence during this stage can significantly reduce the yield. It is wise to store water during rainy season with the construction of dams, without impairing the environment. The excess water may be drawn from the storage used for irrigation as and when required. There are different methods of irrigation like pot irrigation and hose irrigation, sprinkler irrigation and drip irrigation based on the amenities available in the plantation. Pot irrigation and hose irrigation can be administered on a weekly basis at the rate of 20-30 L per clump and its size. Sprinkler irrigation demands water equivalent to 35 to 45 mm rainfall at fortnightly intervals, whereas in drip irrigation water should be provided at the rate of 4-6 L per cluster.
Soil and Water Conservation
Cardamom cropping is assisted by effective conservation of natural resources like soil and water. Agricultural cultivation on sloppy hills can loosen and intensify soil erosion due to exposure and water. The measures of planting trenches, fertilising soil, diagonal plantation, and digging rectangular silt pit (1.8 X 0.5 X 0.6 m) in between four plants substantially aids conservation of natural resources across gentle slopes. However, steep slopes need stone pitched walls at 10-20 m intervals and simultaneous collection of water in the trenches along the wall proves immensely beneficial.
Forking and Mulching
Augmentation and growth of plants may be enhanced by forking plant base to a distance of 90 cm and depth of 9-12 cm. The plantation and plant base should be kept under mulch to the extent possible, atleast 5-10 cm thick, barring the months from June to September, for reducing the impairing drought effects, for minimising evaporation, and sustaining the normal temperature.
The practice of elimination of old tillers, leaf sheaths, and dry leaves is known as trashing. This action is undertaken once a year in any month post final harvest.
When excess soil erosion occurs due to mismanagement, and the top soil layer of the plant base is debilitated due to abrasion and the rhizomes and roots get bare, repleting the top soil by earthing-up is necessary, specially during December and January. While ridging, one should ensure that the earth matter used is from the top soil and is evenly distributed at the base, blanketing only half the bulb part of the rhizome. Earthing-up, therefore helps to keep the top 10-15 cm of the soil lax and brittle so as to enable root penetration and water filtration.