MEDICINAL AND AROMATIC CROPS (2+1)

Cultivation

Soil

Cinchona prefers a light, well drained, virgin forest soil, rich in organic matter with no possibility of subsoil water-logging and with a high moisture holding capacity. It prefers acidic soil (pH 4-6 to 6.5). The calcium requirement of this crop is high.

Climate
C. ledgeriana grows best in tropical climates at altitudes of 1800 m (6000 ft). However, the other species grow well in areas with an average minimum temperature of 13.50C and a maximum of 210C with a mean relative humidity of 83%. The growth is very poor at temperatures below 70C or above 260C. It grows well in places where the annual rainfall is a little less than 200 mm and is well distributed over at least eight months of the year. Cinchona is susceptible to frost and hence, is not grown on very high hill ranges.

Land preparation
For raising cinchona plantations, virgin forest soils are best suited. The forest is cleared and the ground is leveled and dug to a depth of 1½ ft to improve the soil structure and to remove stones, if any. About a fortnight prior to planting, pits of 60 x 60 cm are dug and filled up with top soil and well decomposed organic matter.

Propagation
Cinchona is propagated both by seeds as well as vegetative by cutting, stooling, layering and cleft-grafting, veneer or side-grafting and patch-budding. As most of the species of cinchona are highly heterozygous, vegetative propagation is preferred. But, in India, cinchona is propagated by seeds as it is comparatively less expensive.

Seeds propagation
Cinchona seeds are small and light and loose viability on storage. The seeds are generally sown during April in sloping beds, 12x4 ft, and covered with a thatched roof.
While sowing, the fresh seeds are scattered thickly on the surface and covered with a thin layer of fine sand. The beds are then lightly watered using a spray can. The seed germination is noticed, out of which only about 10% of the seedlings will be suitable for transplanting after eliminating all the weak, lean and lanky seedlings. Seedlings are transplanted when they are about four months old, with two pairs of leaves. The seedlings will be ready for planting in the main field during mid-May of the succeeding year when they are about 14-18 months old and 30-60 cm in height.

Vegetative propagation
Among vegetative methods of propagation, patch-budding, soft terminal cuttings and layering have recorded the best results. A high percentage (85%) of success is obtained in patch-budding in the period from March to the middle of June. Patch-budding is usually done in the nurseries or plantations, in situ on plants which are one to two years old. Even the budding on coppices has given a better growth of budded plants. The cuttings are made to root by cincturing and etiolating. During May-June, the shoots are treated, from which cuttings are taken after 50-65 days and planted in the nursery.

Transplanting
Planting is done before the onset of heavy rains. The soil should be sufficiently moist at the time of planting. The planting is done in open pits at a spacing of 120x120 cm or 150x150 cm or dense planting of about 8000 plants per hectare is done. The plants are gradually harvested from 3-5 years, until about 800 plants remain in one hectare after 25 years. Young cinchona plants need shade which is provided by planting shade plants like Alnus nepalensis, Erythrina indica, Albizzia stipulata and Grivellea robusta, 20 ft apart.

Manures and fertilizers
Application of a fertilizer mixture containing N, P and K gives marked results. Liming (dolomite or limestone) is done for the soil if the pH is 5 or lower. Nutrients are supplied @ 115 kg N, 105 kg P2O5 and 115 kg K2O/ha in the form of triple super phosphate, muriate of potash and ammonium sulphate. The quinine content in cinchona is known to increase with the age of the trees, under favourable nutritional conditions.

Weeding
Weeds have to be removed at regular intervals, particularly in young plantations.

Cover cropping
Besides the native cover, Crotalaria usaramoenis or Leucaena glauca are grown as cover crops in cinchona plantations. When the plantation becomes older, the ground is shaded more heavily, hence the original cover crop must be replaced with shade-tolerant species. The plants should be staked properly in the first three years to prevent their swaying or leaning.