About the crop
Potatoes (Solanum tuberosum) are the world's most widely grown tuber crop.
The high ranges of Kerala are suitable for its cultivation. Presently, the crop
is being cultivated on a small scale in the rain shadow areas of Idukki district
throughout the year.
Climate & Soil
A day temperature of 20-30ºC is optimum for growth and tuberisation in potato.
Tuber formation is adversely affected, if the temperature goes above 30ºC.
Loose friable sandy loam or silt loam, rich in organic matter are ideal for potato.
Hard clay should be avoided. Optimum pH range is 5.2-7.0.
Propagation & Planting
Among the high yielding varieties Kufri Jyothi (early), Kufri Muthu (medium) and
Kufri Dewa (late) can be tried in the high ranges of Kerala.
Potato is propagated by planting tubers. Whole potato tuber or cut pieces (50-60
g size) longitudinally cut from bud end to stem end can be used for plating. For
planting 1 ha, 1000-2000 kg seed tubers are required. Seed tubers are treated with
1 ppm of GA3 for one hour and then dried in shade for getting uniform
sprouting. Tubers are filled in gunny bags after drying and kept in vertical position
in well ventilated dark room for 10 days for encouraging sprouting. Seed pieces
should be treated with mancozeb (@ 1 kg in 450 litres of water) before planting
to protect them from soil borne diseases. Tubers can be planted on ridges 50-60
cm wide at a spacing of 15-20 cm between the plants. Earthing up is needed during
the growing phase (30 days after planting) and 70 days after planting.
The shortage of quality seed tubers, high seed cost, difficulty in transportation
due to bulkiness of seed tubers, and virus infection in seed tubers are some of
the important problems associated with use of seed tubers as planting material.
To overcome these problems True Potato Seed (TPS) is used as planting material.
TPS is a botanical seed developed in the berry of the plant as a result of fertilization.
These seeds are raised for crops commercially. Only 100 g of TPS costing around
Rs. 3000/- is sufficient for cultivating in one hectare, as against 2.5t/ha seed
tubers, which cost Rs. 20,000-30,000/-, thus effecting a drastic reduction in cost
of cultivation. Potato crop can be raised from TPS using seedling transplants or
through seedling tubers produced in preceding crop season. In former method, the
TPS seedlings raised in nursery beds are transplanted in the field and grown to
maturity. While, in latter, the TPS seedlings are grown to maturity in nursery beds
to obtain seedling-tubers. These seedling tubers are used as a seed for raising
normal potato crop in next season.
A basal application of FYM (20 t/ha) is required during field preparation. Apply
60 kg N, 100 kg P2O5 and 120 kg K2O as basal. Topdressing
with 60 kg N, 30 days after planting at the time of first earthing up is essential.
Irrigation has a special significance in the potato production as the plant has
shallow and sparse root system. First irrigation should be light and given 5-7 days
after planting and subsequent irrigation are given at 7-15 days interval depending
upon the climatic condition and soil type. The drip system of irrigation is most
economical and also enables application of fertilizers through irrigation water.
The sprinkler system gives uniform distribution of water and reduces water losses
by percolation and is suitable for areas with undulating topography.
The potato crop develops canopy in about 4 weeks after planting and weeds must be
controlled by this time to gain competitive advantage for the crop. If the weeds
are large, they should be removed before the ridging operations begin. After earthing
up, the weeds between the growing plants and at the top of the ridge should be removed
by mechanical or herbicide application.
Earthing up helps to keep the soil loose and destroy weeds. Carry out two or three
earthing up at an interval of 15-20 days. The first earthing up should be done when
the plants are about 15-25 cm high. The second earthing up is often done to cover
up the tubers properly.
The potato crop can be grown in rotation with paddy, mung, okra, green manure, etc.
Early blight and late blight are the important fungal diseases. Spraying zineb (2
g/litre) is effective to control early blight. Copper fungicides can control late
blight. Cut worms, aphids and jassids are common pests of potato. Dusting with carbaryl
10 % DP immediately after planting can control cut worms. To control aphids and
jassids spraying dimethoate (1 ml/litre) is effective.
The time of harvest is very important in potato as the development of tuber continues
till vines die. The crop is ready for harvest within 75-120 days of planting, when
majority of the leaves turn yellow brown. At this stage, the tops are cut near the
ground level. The potatoes are dug out from the field by ploughing after 8-10 days.
These potatoes are manually picked from the field and stored in shade. Since manual
harvesting is labour intensive, time consuming and causes lot of damage to the tubers,
various low cost bullock drawn and tractor drawn potato diggers have been developed.