Tropical and subtropical vegetables (2+1)

Preparation of field

• The field is first ploughed with soil turning plough followed by 4-5 ploughings with country plough or harrow. Leveling should be done after ploughing and bring the soil into fine tilth and also provide better drainage facilities. At the time of soil preparation, raising the planting bed above ground level facilitates drainage during rainy season.

Transplanting
Seedlings should be hardened before transplanting by withholding watering for 4-5 days so as to reduce the available moisture to 20 per cent Hardening can also be achieved by adding 4000 ppm NaCl to the irrigation water or by spray of 200 ppm cycocel+ZnSO4 (0.25%) + 25 mm proline at time of transplanting. The tomato seedlings are transplanted on flat beds or on side of ridges. In the initial stage, seedlings are transplanted at the side of the ridge and later earthing up is done to keep plant in the middle of the ridge.

Spacing
In tomato, plant spacing is dicided on the basis of growth habit of the variety and purpose such as fresh marketing or processing. The closer the spacing, the higher is the yield but this reduces fruit quality. There is especially reduction in the size and more incidence of insect pests and diseases. Different spacings are followed such as 60cmx45cm, 75cmx60cm and 75cmx75cm on flat and raised beds. In some areas 100cmx60cm spacing is also followed. The plant population of 35,000/ ha is considered to be optimum for producing fruit yield of 40 tonnes/ha.

Nutrition
The quantity of nutrient applied in the field depends upon several factors such as cultivar, soil and growing condition, irrigation and season. A crop grown in spring summer will require more nitrogen as compared to crop of winter season. Early maturing varieties will require less nitrogen as compared to long duration ones. Adequate supply of nitrogen increases, fruit size, fruit quality, keeping quality, colour and taste. Acidity is also increased by excess nitrogen. High level of phosphorous throughout root zone area is essential for rapid root development and for better utilization of water and other nutrients. Adequate amount of potassium is required for growth, yield and quality. Removal of primary nutrients from the soil is 0.33 kg N, 0.11 kg P and 0.44 kg K per 100 kg yield.

Recommended dose of fertilizers for varieties are given below

Sl. No.	Place	Nitrogen (kg/ha)	Phosphorous(kg/ha)	Potassium(kg/ha)	FYM (t/ha)
1	New Delhi	60	60	0	25
2	Coimbatore	100	80	50	25
3	Bangalore	115	104	64	25
4	Chaubatia	100	90	-	-

• Well rotten 38 tons of FYM and 250 kg of each NPK per hectare is the recommended dose for hybrids .Half dose of nitrogen and full dose of phosphorus and potassium should be applied as basal while half dose of nitrogen may be applied as top dressing after 25-30 days of transplanting. The application of Zn, Cu and B significantly increased the number of fruits per plant, yield and quality. Application of 20-30kg of Borax and 0.5% Zn is beneficial for yield and good quality of fruit.

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Irrigation
Tomato plants require adequate moisture throughout their growth period. First irrigation is required soon after transplanting. Too much of water at the time of transplanting and before fruit set have been found detrimental causing blossoms off. Irrigate the crops at an interval of 3-4 days during summer and 10-15 days during winter to maintain the soil moderately wet. During winter, the plants are not irrigated at the time of ripening of fruit. A long spell of drought followed by sudden heavy irrigation may cause cracking of fruits. Furrow irrigation is most widely used to irrigate tomato crop in India. Drip irrigation of tomato crop increases the yield by 50 per cent and saved water by 30 per cent as compared to furrow method. Nowadays sprinkler irrigation is also being popularized which is found to be more economical. Irrigation following a period of moisture stress during fruit development leads to blossom end rot. Development of moisture stress in foliage results different physiological consequences. Viz. (1) Decrease in stomata opening (2) Reduction in photosynthesis and transpiration. (3) Dehydration of protoplasm (4) Reduction of cell division and cell enlargement. (6) Decrease in total dry matter production and growth.

Weed control
The normal method of weed control is to give two hand hoeing in the first and third fortnight after transplanting and an earthing up operation during the seasonal fortnight. The application of pre emergence herbicides like metribuzin at 0.35kg/ha, fluchloraline 1.25kg/ha controls the weed population and increases the yield of tomato. Recently the use of pendimethalin @1.0kg/ha as pre emergence application at three days after transplanting was found very effective in suppressing the weeds.

Staking
In case of indeterminate varieties, the yield and quality of fruit is improved by staking the plants with wooden sticks/polythene threads. Staking not only increases the yield and improve its quality but also reduces the infection by fungal diseases.

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