Soil
Sunflower grows well
in soils ranging in texture from sand to clay. It does not require as high
fertility as other crops like corn, wheat to produce satisfactory seed yield.
But grows best on well drained soils. Sunflower grows best at near neutral soil
pH (6.5 to 7.5) but also can be grown on acid soil that have been limed. Soil
Fertility and water holding capacity influence sunflower growth. However, the
more sandy, saline and water logged soils are not suitable for its cultivation.
Seed bed preparation
Seed bed should be
prepared so that moist environment is available for seed germination and
growth. Excessive break down of soil surface and structure should be avoided
because it causes reduced nutrient uptake and thus reduced yield.
Conventional systems
of seed bed preparation consist of one deep ploughings with mould board plough
followed by cultivator and planker to plain the field and conserve the moisture
for longer period. Both germination percentage and lodging have been shown to
increase in ridge-till systems as compared to level (flat) planting.
Method of
planting
Sunflower should be
sown in rows for better weed control. Sunflower row spacing is determined by
the method of planting and availability of machinery. A planting depth of 1 to
3.5 inches allows sunflower to reach available soil moisture and gives
satisfactory plant stand. However, it depends upon the soil type and panting
method. Deeper plantings have resulted in reduced stands and yields. If crusting
or packing of the soil is expected, shallower planting is recommended.
Placement of seed one to two inches deep give better emergence results.
Sunflower is planted
by different methods, i.e., Planters, multi-crop drills, mannual (Dibbling and
broad cast). In case of drill planting and manual, plant population is more
than optimum, therefore, after emergence at 3-5 leaves stage thinning is
recommended to maintain optimum population.
Seed Treatment
At present all the
commercial sunflower crop is grown in the county from exotic hybrids, the seed
of which is already treated. In case of locally produced , seed should be
properly treated with fungicides to prevent seed borne diseases and get optimum
plant stand. For this purpose vitavex and Benlate are very effective.
Seed Rate
Generally 2-3 Kg/acre
seed is recommended depending on hybrid, soil type, availability of water and
method of sowing. The seed rate of hybrids with large seed size should be more
as compared to small size seeds. For soils with good structure, texture and
fertility as compared to other soils. In irrigated areas more seed should be
used compared to rainfed areas. Seed rate is reduced to 50 % if planted with
new planters.
Direction of
Rows
Sunflower is
phototropic from emergence to flowering. Its head and leaves face east in the
morning and west in the evening. Sunflower grown in East-West (EW) and
North-South (NS) did not differ in yield, oil content, seed weight, but
significantly more lodging occurs in EW rows.
Depth of
Planting
Ideal planting depth
for sunflower is 3-5 cm. Seed should be placed into moisture but not deeper
than 7 cm. Shallow plantings are best when planting small seeds, cold, fine
textured soils. Planting in silt loam soil should not be done more than 3-5 cm,
because heavy rains pack the soil and reduce the emergence. On sandy soil or in
environments where the top soil dries quickly planting should be done slightly
deeper than on fine textured soils.
Temperature
Sunflower is well
adapted to both cold and higher temperature but more tolerant to low
temperatures. Sunflower seeds germinate at 4°C, but temperatures of 8-10°C are more suitable for the satisfactory
emergence. Young plants resist frost. This resistance declines gradually in
later stages, specially at flowering time frost and low temperatures affect
crop and pollinators.
The optimum range for
better seed set is 25-35 C.
Water
requirements
Water is a
prerequisite for better yield in sunflower. The water requirements of the crop
depends on soil type, climate, (i.e., temperature, spread of rain fall)
Variety/hybrids. Sunflower has tolerance to some extent against low moisture,
but the extended period of drought affects adversely and poor yields are
obtained. Sunflower in Pakistan is mostly grown in irrigated areas. The
irrigation schedule for the sunflower crop is given below.
