Medicinal and Aromatic Crops

Cultivation

Soil

Pyrethrum thrives best on well-drained, sandy soil. Red laterite loams and light and medium loam soils are also suitable. The yields are considerably lower in poorly-drained soils. It can grow on mountain slopes and wastelands, but too rich soils and water-logged conditions are unfavourable for its growth.

Climate
Pyrethrum is a temperate crop. It grows best in areas which have a mild, cool, dry climate with a short, mild winter and a cool summer. A period of chilling, in which the temperature falls below 17° C, for about six weeks, is necessary for flower-bud initiation. In places where the winters are long (November to March) and the summers are warm, there is only one flush of flowering in May and June. It grows well in places where the annual average rainfall is about 1000 mm and the elevation between 1500 to 2400 m.

Season
Nurseries are raised either in spring (April-may) or in autumn (October-November) and, in irrigated areas, from March to November. The ideal time for planting is spring (March-April) or autumn (October-November). However the seedlings can be planted during any time of the year, if irrigation facilities are available.

Land preparation
The land is prepared well by 2 to 3 ploughing followed by leveling, harrowing and clearing of weeds and stubble. Organic manure, if available may be applied at the time of the last ploughing. It is desirable to make rides 45-50 cm apart if the land is flat. In undulating land, the area should be terraced.

Propagation
Pyrethrum is propagated by seeds. However, it can also be raised vegetative by splits. The seeds required for sowing should be gathered from selected plants when the flowers are fully mature and the seeds are about to be shed. The seeds tend to lose viability on storage. In case of vegetative propagation, healthy plants are pulled up from the ground, the splits of which are used for planting. In certain areas it is better to plant the splits in nurseries before they are planted in the main field.

Nursery raising
Seed-beds of convenient length and breadth and 15-18 cm in height are made in well-prepared land. FYM or poultry manure is added in the top 10 cm of the soil. The seeds are sown in rows 10 cm apart, and covered with a layer of rice-straw, wheat-straw or dried grass. The beds are watered frequently. The seeds germinate in 5-10 days. The mulch is removed after the seeds have sprouted. The seed-beds should be kept weed-free by frequent irrigation. The seedlings will be ready for planting after 8-12 weeks.

Planting
The seedlings are planted at a distance of 27-45 cm in rows and 45-60 cm apart. Ridge-planting is preferred to flat-planting as it facilitates inter culture and irrigation and avoids water-logging.

Manures and fertilizers
Application of 40-60 kg N, 40-50 kg/ha P and 50-80 kg/ha K is optimum for the good growth of pyrethrum in the first year. The entire quantity of P and K should be applied as a basal dose with 50% of the N at the time of planting and the remaining 50% of N is applied in split doses. The fertilizer application should be repeated every year. P and K are generally applied in spring at the time of the first harvest, while N is applied in two split doses in the months of March and April
Experiments conducted at the CIMAP field station in Kodaikanal have established that the application of liquid phosphorus (3-% P) @ 120 kg/ha increased the flower-yield by 28%. Liming the soil @ 1 t/ha and foliar application of P, resulted in 20% increase in the flower-yield over the control.

Interculture
Proper weeding and hoeing are necessary to obtain a good yield. Both can be done by a tractor-drawn cultivator, and hand-hoes can be used in small terraces. The first hoeing can be done in autumn after the last crop is harvested, followed by two weedings and hoeings in spring.

Irrigation
Pyrethrum does not need irrigation if the rainfall is well distributed. However, under irrigated conditions, weekly irrigation during the peak season gives better results. Under irrigated conditions, it is observed that the pyrethrum plants start flowering after 1 year instead of 2 years under un-irrigated conditions. The crop should be irrigated frequently during the dry months. The crop should also be irrigated after the fertilizer application.