Kiriala: Xanthosoma sagittifolium

The Xanthosoma species are plants of the tropical rain forest and, although in their natural habitat they grow under the forest canopy, under cultivation they are usually sown with full exposure to sunlight. They require well-drained soils and do not tolerate the permanent presence of water. The mean temperature for their optimum growth must exceed 20 C.

Xanthoxoma is one of domestic traditional crop. Today it has high demand and high income earning crop.

It is not a seasonal crop. Thus it can be cultivated any time under availability of water.

Botanical description

A herbaceous perennial, Xanthosoma sagittifolium has a corm or main underground stem in the form of a rhizome from which swollen secondary shoots, or cormels, sprout. Several large leaves also sprout from the main stem, which are sagittate and erect with long, ribbed petioles; inflorescences sprout between the leaves in a spadix, with a white 12 to 15 cm spathe which closes at its base in the form of a spherical chamber and opens at the top into a concave lamina; the spadix is cylindrical, slightly longer than the spathe, with female flowers on the lower portion, male flowers on the upper portion and sterile flowers in the middle portion. The spadices are rarely fertile and produce few viable seeds. The growth cycle lasts from nine to 11 months: during the first six months the corms and leaves develop; in the last four months, the foliage remains stable and, when it begins to dry, the plants are ready for the cormels to be harvested.

Climatic condition

Xanthosoma is a shade loving plant. However, it can be cultivated as a main crop in paddy fields in dry and intermediate zones as well as sloppy and open lands in wet zone.

Also it can be cultivated under coconut and banana cultivation in wet and intermediate zones. It is low risk as well as low in pest and disease attack.

Recommended varieties
Isuru

It produces high quality corms with good market demand. It can be suited for any cultivating method. Xanthoxoma can be harvested within 8-10 months with low attention too.

Planting materials

Mother corms obtain after the harvesting, can be used as planting materials. About 15 good quality plantlets can be obtained out of well grown mother corm. Good quality high yielding mother corms must be obtained as a mother corms.
The planting material most commonly used are 2-2.5 thickness mother corm slices. They give greater yields than the cormels which are also same times used.

Spacing

4000 seed corms per Acer.
Spacing can be varied with the cultivating method.
Sole cropping 1X1m
Mixed cropping 1.2X1.2m

Planting
On set of rain in the most suitable time period to planting. A coconut husk layer can be used to retain moisture in dry areas. In the mixed cropping drying out will be reduced due to perennial main crops. It reduces the drying out of soil.

Fertilizer Management
The use of chemical and organic fertilizers is widespread both in small and commercial plantations. In the latter, several dressings of fertilizer are applied.

Time of Application	Urea Kg/ha	Triple super phosphate Kg/ha	Muriate of potash Kg/ha
Basal dressing	30	120	60
Top dressing 1 11/2-2month after planting	60	-	60
Top dressing 1 3-31/2months after planting	60	-	60

In the heavy rain season split application must be done as a top dressing.

The inorganic fertilizer must be applied only with the availability of water. Thus, after the rain or watering. Therefore, time of application of fertilizer determine by the soil water availability. However recommended dosage must be applied.

The recommended dosage must be applied according to the age of the plant. Otherwise, yield and quality of the cormels will be reduced.

Weed Management
The first six months is a critical period for weed control. Backed up by the application of pre-emergence herbicides, preparation of the ground for planting (ploughing and raking) helps considerably in controlling weeds. As the plants need to be earthed up several times, this contributes to keeping the soil clean.

Earthing up
Cormel growth will be started from 4 - 4  months of age. It continuous up to 8 - 10 of months in the earth.

Earthing up can be done with the application of fertilizer as well as weeding.

Pest and disease management
In santhosoma varieties pest and disease attacks rarely occur.

But with the water logging condition and clay soil, root rot disease can be occurred. Leaves get yellowish and dried off.

Apart of that Aphids and hoppers damage to leaves. Nematode disease also can be seen with the cultivation of same crop in same field continuously.

Good cultural practices avoid all those hazardous conditions.

Harvesting period
Leafs growth rate will be reduced with the cormels get matured. At that time leaf size and petiole length get reduced. Same time cormel growth occurs on top of the earth.

This is the time to harvesting with out damage to cormels.

Harvesting
In commercial plantations harvesting is carried out ten to 12 months after planting, when the leaves have turned yellow and are beginning to dry. The crop is harvested by hand or by a semi-mechanized method.

The commercial product is washed, dried and disinfected carefully before being placed in boxes in cold-storage rooms.

In small plantations, harvesting of the cormels begins 4-6 months after planting and is done without uprooting the plant 16-18 tons of yield per hectare can be obtained in well managed cultivation.

Post harvest handling
Harvested corms can be storage long tine with out destroying the quality. Store the cleaned corms with 3-4 layers under good ventilation.