Watering & Fertilizer Application
Fertilizer Application in Tobacco Field:
An appropriate ratio of fertilizers of Nitrogen, Phosphorus, Potassium and Magnesium should be 2:2:2:1.
It is wise to avoid excess of Nitrogenous fertilizers for tobacco because it helps grow leaves larger and thick though it increases the level of Nicotine in the leaves, as a result, quality may deteriorate.
Excess of phosphorus will result in early maturity but it hampers the rate of combustibility. While selecting the Potassium fertilizer, few points should be taken into consideration for the sources.
Muriate of potash should not be used as a source for Potassium.
Presence of excess Chlorine in the leaves may slow down the rate of combustibility. Potassium Nitrate, Potassium Sulphate etc are the suitable sources of Potassium fertilizer for tobacco cultivation.
However, if the soil pH is lower than optimum, Potassium Sulphate should be avoided.
Recommended dose of fertilizers
For cultivation of tobacco recommended dosages are 120 kg, 100 kg and 100 kg for Urea, TSP and Potassium Sulphate respectively Half of the Urea (Nitrogen) and full of the TSP (Phosphorus) and Potassium Sulphate should be applied during the land preparation along with Farm Yard Manure (FYM) @ 7.5 tons per hactre.
The rest of the Nitrogen fertilizer should be applied after a month around the base of the plant 8-19 cm radius away the plant and incorporated with soil as well.
Recommended fertilizer dose based on soil fertility: low to medium soil nutrient content.
Tentative target of Yield- 2.5 tons/ha and 2.0 tons/ha
|Name of fertilizer||Amount of fertilizer ( kg/ha)||Name of fertilizer||Amount of fertilizer ( kg/ha)|
|Potassium Sulphate||70||Potassium Sulphate||60|
|Calcium oxide||1000-1200||Calcium oxide||800–1000|
|Zinc Sulphate||4-7||Zinc Sulphate||3-4|
Method of Fertilizer Application
⦁ All the fertilizers should be applied during the time of land preparation.
⦁ 2/3 of Urea should be used during the soil preparation and rest of the urea should be used after 30 days of transplantation.
Weed control and Soil Incorporation:
For tobacco cultivation weeding and loosening of soil is done to facilitate the air movement to the soil and also to the root system.
After 8-10 days of transplantation a hand hoe can be used to make loose the upper surface and break the crust in between two lines so that weed can’t grow and good aeration sustains.
Two weeding may be necessary for properly controlling weeds. During the last weeding, few soils can be given to the base of the plant helps in better anchorage and firmness of the stem to the soil.
It also helps the plants become strong and easy to growing, improve drainage facilities and irrigation
Before planting in the dry condition it is recommended to treat the soil with pre-emergent herbicide like Metribuzin 70 WG.for weed control @ 1kg per acre
Tobacco plant is day neutral in respect of showing flowering behavior. Around 50-70 days after sowing to protect the misuse of nutrients in production of flowers, fruit and seeds, and to divert the nutrients to use that in production of leaves, bud and terminal shoots are trimmed or broken.
The young leaves contain higher percentage of nicotine. The young shoot should be broken such that the remaining leaves can grow and mature as well. While starting for topping 3-4 lower leaves are removed and upper 15-16 leaves are kept to grow as well.
For topical dominance a plant hormone called Auxin that is produced in the tips of the shoot is responsible for elongation of the shoots and it protects the plant not to produce any side branching or sprouting of the buds.
Due to topping of the tobacco shoots, the production of Auxin plant hormone stops, as a result, side branching starts to develop, so all these sprouting buds should be removed every 7 days.
In USA, Canada and Australia etc countries various growth retardants are used to save the cost of labor in stopping the side branching or bud sprouts.
It has no side effect on restoring the quality and the yield of the leaves.
Maleic hydrazide is one of the chemicals used in this process that is composed of plant derived oil and fatty acids.
Irrigation and drainage
For achieving a bumper production and quality leaves, tobacco plants should be given 2-3 irrigation. Normally irrigation is not necessary until topping. In case the soil texture is of sandy type, irrigation may be required even before Topping.
To remember that excess of irrigation water should to be avoided. A good drainage system is always helpful when there’s huge rainfall or excess of irrigation water.
The soil should be kept moist but not soggy and should never be allowed to dry completely out. Care should be taken when watering freshly emerging tobacco seedlings because the force of the water can uproot the tiny seedlings causing them to die.
The best way to water seedlings is from the bottom, the way this is accomplished (if you are using a pot with holes in the bottom) sitting the container with the seedlings into a pan of water for only a few seconds or a bit longer, the potting mix will wick the water up into the seedling container allowing your seedlings to be water without getting the leaves wet.
Nutritional Deficiency Symptom:
In Tobacco macro-nutrients deficiency may express the exact symptom of Magnesium deficiency.
So, different micro and macro-nutrients deficiencies should be detected in the field timely and appropriate correction measures or amendments should be adopted.
Magnesium-deficient tobacco plants generally develop a mottled pale green or chlorotic pattern in the interveinal tissue of older leaves, often starting near the margin.
In severe cases, the chlorosis progresses to the middle of the leaf and the small veins also become affected. Reddish or brown spots appear on the leaf blade. Later on, the development of necrotic areas in the highly chlorotic tissue gives the leaves a rugged and deformed aspect.
Finally, the yellowing engulfs the whole leaf, eventually leading to premature death and early shedding. Root growth is inhibited, resulting in poor plant vigor.
To use foliar fertilizers containing magnesium complement is recommended. Magnesium oxide allows a slow release of the nutrient and is used in blends for an immediate supply of magnesium to tobacco plants.
Magnesium sulphate releases the magnesium over a period of weeks to the soil and is ideal for a quick release. An example of treatment could be the application of MgSO4 @ 10g/l of water twice at 10 days interval.