Sunflower

Crop Establishment

Guidelines Seed Treatment And Crop Uniformity Time Of Sowing Thinning Cropping System Advantage of taking Sunflower in High Intensity Cropping System

Guidelines

  • Deep ploughing is necessary to break up compacted layers and allow unrestricted root development.
  • Since sunflower seeds vary considerably in size, those used for mechanical planting should preferably be graded to produce an even sample.
  • This will ensure a free flow in the seeders with no blockages or crushed seeds to cause gappy stands.
  • Germination will also be more even, allowing more efficient weed and pest control
  • The achievement of optimum plant population is essential for profitable yield, since sunflower with its single head is less able to compensate for gross variation in plant number than, for instance, soya or rape Combine drills, maize or cotton planters with suitable sunflower seed plates can be used.
  • Uniform spacing ensures uniform growth, and thus ease of working for cultivators and harvesters. When using electronically controlled seeder units, depth of planting and seed rate are very even and grading of seed may be unnecessary.
  • Although seed grading is not essential, since large or small seeds of equal quality produce similar plants at maturity ,clean bold seeds should be selected since they germinate evenly and produce vigorous seedlings.
  • Whenever possible new seeds should be sown, Since sunflower seed rapidly loses viability when improperly stored.
  • As a field guide to final stand, most modern cultivars have 80-85 percent emergence 2-5 days after first seedlings appear.
  • Seed should be dressed with a fungicide; Captan, Carboxin, Quintozene and Thiram are suitable, and preferably an insecticide, or a combination may be used, i.e. a standard groundnut or maize seed dressing.
  • Dressing the seed some months before planting helps to retain viability and reduce fungal infection.
  • Seed should normally be planted 3-8 cm deep, depending mainly on the variety and moisture in the seed-bed.
  • Soil in the vicinity of the seed must remain moist throughout germination, and there should be no danger of frost.
  • On light soils a press wheel should be set to give a firm seed-bed, since this will ensure that the soil does not dry out too quickly and the small furrow made will stop soil blowing off the seed.
  • This technique should also be used in areas of low rainfall to assist moisture penetration and absorption.
  • Below 15 degrees C generally retards germination and below 10 degrees C inhibits many varieties.
  • High oil-content seed is more susceptible to low temperature damage than low oil-content seed especially when germination has commenced.
  • When using standard planters with 75 cm row-width, seed rates will vary from 3 to 8 kg/ha depending on seed size, to achieve a final spacing of approximately 30 cm between plants.

Seed rates can be calculated from the following formula

(a) Seed number/ha= desired population/ha X 100 / expected germination percentage

(b) Seed required, kg=seed number/ha X area to be sown (ha)/seed number/kg

(c) Number of seeds=seed number/ha X row-width (mm)/required/10 m of row 1,000,000

  • The practice of sowing sunflower on lands which remain unplanted to maize or wheat is economically unsound, since the yield tends to fall significantly and quickly outside the optimum period.
  • Correct time of planting affects not only yield, but also the kernel-husk ratio.
  • Seed weight tends to decrease with delay in sowing, and the greatest loss is in the kernel.
  • However, sowing outside the optimum period to obtain a high seed yield may be necessary in some areas to avoid flowering at periods of high temperature, in order to obtain a particular grade of oil
  • Within the optimum sowing period, plant population can vary within reasonable limits since plants tend to produce larger heads at wider spacing .
  • However, large heads also tend to have more pops, and yield of oil per hectare may be significantly reduced.
  • Seed size may also be affected, and thus the kernel-husk ratio.
  • Thus the optimum plant population must be determined in terms of the product required, oil or bold seed, and not solely by final seed yield.
  • Population in the range 30,000 - 40,000 plants/ha at harvest is acceptable for the tall varieties and 35,000 - 60,000 for hybrids in areas where annual rainfall of 500 mm or above is normal.
  • Population can be 25-50 percent higher under irrigation in the same area, but the possibility of increased loss form lodging must be considered.
  • Under dry-land farming conditions, the plant population which can be sustained is usually between 12,000 and 15,000 plants/ha, mainly dependent on the rainfall expected during crop growth.

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Seed Treatment And Crop Uniformity

  • The seed should be planted at 4 cm deep in the plough for getting highest percentage of germination.
  • Sunflower can stand a little deeper sowings than other oil seeds. Hence depth of sowing should be adjusted according to the soil moisture.
  • Dibbling of seed at proper distance and depth is also a common method of sowing sunflower seed. Initially 2-3 soaked (12 hours) seed per hill should be planted and with in 15-20 days of germination, the additional one to two weak plant should be thinned out.
  • Gap if any , should be filled at 10 days after sowing .
  • In heavy soils, the crop can be grown on ridges and furrows as to avoid water stagnation.

Seed dormancy and Viability

  • The sunflower seeds (achenes) remain dormant upto 40-45 days of harvesting however, the dehusked seeds may germinate from 10th day after harvest.
  • Exogenous application of ethrel, benzyl adenine and Gibberlic acid promotes germination of achenes.
  • Pre-soaking of dormant seeds with ethrel solution (25 ppm) equivalent to 40% by volume of seeds has been found to be optimum.
  • The soaking period may vary from 6 hours to 24 hours.
  • The achenes should be dried in shade and then may be sown directly.
  • Usually sunflower seeds remain viable for 10-12 months but under hot humid conditions the seeds lose viability quickly.
  • At 50 to 85% relative humidity, seeds lose viability within 40-60 days.
  • Pre-soaking seeds with water or protein (10-5 M concentration) before storing increases viability even under high humidity conditions.

Seed treatment

  • Seeds must be treated with a fungicides to control the seed borne disease.
  • For this , the seed should be treated with Captan or Thiram or Mancozeb 75 W.P @ 3 gm. per kg of seed before sowing.
  • For getting good result, the sunflower seed should be soaked in water twelve hours and shade dried before sowing.
  • This will avoid ill filled grains and for quick and uniform-germination.
  • After fungicide treatment, the seed can be treated with Azospirillum which helps in N-fixation (or) apply one kg or Azospirillum to soil after mixing with powdered FYM.

Seed rate

  • Straight varieties - Rainfed 8-10 Kg/ha/ ID 6-8 Kg/ha
  • Hybrids - Rainfed 6-7 Kg/ha/ ID 5-6 Kg/ha

Spacing

  • The seed should be sown in lines 60 cm. apart (row to row) and in rows with a plant spacing of 30 cm.
  • For a good crop, row to row spacing of 80 cm, and plant to plant spacing of 20 cm must be kept .
  • Root development is affected in Narrow spaced plantings.
  • Development of numerous small roots and spreading of root system into deeper layers is more in wide spaced plantings.

Spacing in different soils

Soils Spacing(cm) Optimum population/ha
Light 45 x 20 1,11,000
Medium 45 x 30 74,000
Heavy 60 x 30 55,000

  • Usually for long duration varieties or hybrids adopt a spacing of 60 x 30cm.
  • In regions where the amount and distribution of rainfall is good adopt a spacing of 45 x 30cm.
  • For short duration straight varieties like Mordern adopt a spacing of 45 x 20 cm.
  • For rainfed sunflower keep more spacing between the rows and less spacing within the row which facilitates better root development.
  • In fertile heavy soils adopt closer spacing while in light red soil adopt wider spacing.
  • Under I.D conditions maintain more population which control weeds, avoids lodging and give higher yields.
  • Immediately after seeding cover the seed with soil by running a blade harrow.
  • Care should be exercised upto 7-10 days after sowing against bird, rat and squirrel damage.

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Time Of Sowing

  • Time of planting affects not only yield, but also the kernel-husk ratio.
  • Seed weight tends to decrease with delay in sowing, and the greatest loss is in the kernel.
  • Sowing outside the optimum period to obtain a high seed yield may be necessary in some areas to avoid flowering at periods of high temperature, in order to obtain a particular grade of oil.
  • Within the optimum sowing period, plant population can vary within reasonable limits since plants tend to produce larger heads at wider spacing .

Recommended sowing dates

Season Sowing Period
Rainfed 
Kharif July 15th to August 15th
Kharif(Late) August 16th to August 31st
Rabi September 15th to September 30th
Rabi(Late) October 1st to October 15th
Irrigated 
Rabi October
Summer January

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Thinning

  • The sunflower seed is planted at the rate of 2-3 seeds per hill.
  • Thinning is done to keep one healthy plant per hill as excess plant population adversely affects the growth and yield of the crop.
  • Thinning should be done with 15-20 days of germination seeds
  • The early thinning will facilitate good establishment of plant and proper utilization of space, light and plant nutrients.

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Cropping System

  • Sunflower is not season bound crop.
  • Its short growing period of 90-125 days makes it an ideal catch crop.
  • It can follow potato, sugarcane or even early wheat.
  • Sunflower is the best crop for contingency planning under unfavourable weather condition.
  • Sunflower also fit well in most multiple cropping programme. It can also serve as a companion crop to a long duration crop like sugarcane.

Sunflower is grown in rotation with several crops as follows

  • ¬†Sunflower + Redgram (2:1)
  • Paddy-Sunflower
  • Maize-Potato-Sunflower
  • Maize-Sunflower
  • Maize-Mustard-Sunflower
  • Arhar-Sunflower
  • It is grown on a small scale in the rice fallows in the saline coastal areas in West Bengal.

The following intercropping systems are recommended for different states:

Sl.No State Suggested intercropping Ratio of base crop to inter crop (i.e. Sunflower)
1. Andhra Pradesh and Telangana Hybrid Jowar + Sunflower 4:2
2. Gujarat Groundnut + Sunflower 1:1
3. Karnataka Ragi + Sunflower Groundnut + Sunflower Cowpea/Horsegram + Sunflower 6:3 4:2 4:1
4. Maharashtra Soyabean+ Sunflower Groundnut + Sunflower 3:3 6:2
5. Tamilnadu Groundnut + Sunflower Blackgram + Sunflower Cotton + Sunflower 6:2 6:2 4:2

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Advantage of taking Sunflower in High Intensity Cropping System

  • Being a short duration, it can be well suited as catch crop.
  • It is a drought, frost and salt tolerant crop.
  • There is very slow degeneration in seed quality hence the same seed can be used for sowing upto 4-5 years.
  • Being thermo and photo insensitive it can be grown any time in the age, year, in any part of the country and under any type of cropping system.
  • Sunflower is a useful crop for apiculture (bee keeping) at it attracts the bees and provides them nectar.
  • The rainy season sunflower is mostly grown as rainfed crop in which few crops like groundnut (2 : 6); Ragi (2 : 5); Cowpea or Blackgram (2 : 3) may be successfully intercropped.

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Andhra pradesh