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Better agronomy, better wheat yield
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The optimum water quantity must be applied to
wheat for reducing water losses
By Dr. Shamsuddin Tunio
Nov 27 - Dec 03, 2000
To increase and improve food grains for the largest
growing population of Pakistan is the job of Today's Agriculturists
and growers. Wheat contributes about at least 80% in the food needs of
people of Pakistan except rice and maize. The current record explores
the scenario of the target of the area and production, which was 8mha
and 20 mTons for the year 1998-99, against wheat production target of
22 mTons for 2000-2001. This was a quite big jump in last two decades
and also more than 50 years' history of Pakistan. How and why this
quantum jump in production has occurred?. The answer of this question
is evolution of high yield varieties of wheat by the plant breeders
and use of high inputs and better weed control measures. The high
yielding quality of wheat varieties is not due to resistant to
diseases only, but also the dwarf and semi dwarf height characters of
such promising wheat varieties. However, adaptation of improved crop
production technologies including better seed quality, proper land
preparation i.e. fine seed bed, precise land levelling and dividing
field into small plots for making proper use of inputs and control of
weeds in wheat, have been the main reason for yield increase.
Basic concept: The concept of better agronomy,
better wheat yields may properly be exploited by the agriculture
scientists and growers, which must depend upon a set of technologies
developed for the growers to enhance wheat production in Pakistan.
In broad sense, agronomy is field of crop
production and management of soil as well as management of rest of the
inputs. Whereas, agronomist is the crop management expert who provide
expertise to the single crop growers and multiple crop growers within
the agro-economic system of the country. Plant breeders evolve crop
varieties and agronomists adopt that newly introduced variety under
different agro-ecological zones for its better performance.
Wheat crop needs better agronomic practices right
from time of the sowing upto harvest of the crop. The improved
agronomic technologies include pure seed, proper land preparation,
timely sowing, enhanced seed rate, balanced fertilizer use, proper
irrigation scheduling, timely control of weeds, harvesting and
threshing of wheat. However, modern farm machinery and proper use of
agriculture credit may also help in boosting wheat yields.
Pure seed use: Farmers always come across the
pure seed supply problems at their door steps. Seed of thigh purity
and germinability is the need of time and it may be considered as high
quality input by the growers. The pure seed of high yielding wheat
varieties may produce vigorous and healthy plants that would
ultimately increase crop yield. Pakistan has well organized seed
production system including National Seed Council, provincial seed
councils, seed corporations, such as Punjab seed corporation and Sindh
seed corporation, Federal Seed Registration Department, Federal Seed
Certification Department etc., but even then, pure seed production and
its supply is one of the main problems of the growers. There is
admixtures in the seed and selling wheat with fake names of the
varieties. Whereas, enhanced rate of seed from 40 upto 50 kg/acre (125
kg/ha) during normal sowing and from 50 upto 60 kg/acre (150 kg/ha)
for late crop of wheat may be suggested for higher yields. However,
the sowing of clean and graded seed may give better germination. But,
local Seed Corporation like Sindh Seed Corporation at Sakrand and
wheat research oriented institutes such as, Wheat Research Institute
at Sakrand and Nuclear Institute of Agriculture Tandjam as well as
Wheat Research Station at Tandojam would supply reliable seed to the
growers in the Province of Sindh.
Proper land preparation:
The precision land
leveling is one of the important agronomic practice to remove ups and
downs of the soil and to achieve better seed bed conditions for the
uniform distribution of irrigation water and better supply of other
inputs to the growing wheat crop. Wheat requires fertile loam to clay
loam soils with good drainage for better yields. The crop growing
areas should be divided into small plots of half an acre or 10 ghuntas
alongwith channels in the middle to separate each plot and to make
proper use of irrigation water according to crop needs.
Better time and method of sowing:
Time and
method of sowing may be the major cause of low yield in wheat. In
normal course, the sowing of wheat must be completed in the month of
November. But in some cases, wheat grown after Cotton, Rice, Sugarcane
and fodder crops in rotation may be delayed upto December. The zero
tillage technology may be adopted in rice-wheat growing area, where
wheat is grown as Dubari crop on residual moisture after rice, without
initial tillage practices. The seeds may be drilled directly using
zero tillage drill in rice areas, after soil comes in condition. This
method would show better yield performance. The delay in sowing of
wheat in different crop zones may be hazardous to crop yields, due to
poor crop growth and low tillering during delayed periods, which might
show negative effects on yield contributing parameters. The method of
sowing is also important feature in wheat production technologies to
enhance crop yields. Drilling method has far better qualities such as
to keep proper space between rows, which would help to reduce crop
competition, make easiness in controlling weeds and removing hard pan
of soil by weeding and interculturing practices during initial growth
period. This also helps in to dressing of fertilizers and spraying of
crop. Harvesting become much easier by local method using sickle and
combine harvesters. But, wheat can also be grown by broadcasting
method, which do not encourage inputs to be utilized properly and
there is no way out to provide better environment to the crop for its
vigorous growth and yield increase.
Balanced fertilizer use:
Wheat crop needs
balanced use of chemical fertilizer, which is applied at the time of
sowing and it must be completed upto first and/or second irrigation.
Full dose of phosphorous should be given at the time of sowing and
nitrogen should be applied in split doses i.e. half at the time of
sowing and half at first or second irrigation. But, the fertilizer
dose must be selected after soil test with regard to its quality and
crop needs. Wheat requires adequate amount of nitrogen and phosphorous
during early growth period for vigorous growth that ultimately enhance
crop yield.
Proper irrigation scheduling:
The optimum water
quantity must be applied to wheat for reducing water losses. The
excess water may cause lodging problem in wheat. However, wheat crop
needs 5 to 6 irrigations from sowing to maturity periods. First
irrigation should be given after 21 days of sowing and it must not be
delayed beyond 21 days, which may cause poor root development.
Whereas, subsequent irrigations should be given according to three
weeks interval or critical growth stages such as crown root
initiation, tillering, flowering and anthesis, grain filling, Milky
and grain maturity or dough stages etc. These critical stages needs
special attention for yield increase with the timely supply of
irrigation water needed in proper growth, development and maturity of
the crop. The drought condition during different growth stages may
decrease tiller number, which can survive to produce grains and may
also decrease number of seeds and seed weight per ear that contributes
to low yields.
Timely weed control: Weeds cause great losses
in crops especially cereal grains. In wheat some broad and narrow
leaved species of weeds, such as Jhil, Sinjh, Naro, Kanderi, Kandero,
Dhank, Jhangli Jai, Drubh, Kabah, Chabber etc are found, which crease
serious problem of competition with crop in food nutrients, water,
sunlight, air and space; make crop weak and poor in growth and also
cause decrease in yield. In fact, farmers give little or no attention
to the weeds, which are considered as crop pests and cause yield
losses in wheat. Therefore, weeds must be uprooted and controlled
before first irrigation and/or after first watering to the crop. The
effective methods are cultural and chemical control. The cultural
method is laborious and time consign one. Whereas, chemical method is
easy, cheap and less time consuming. However, yield may be increased
from 15 to 25 per cent by the control of weeds.
Crop harvest technology:
Crop harvest, its time
and method are important features to reduce yield losses in cereal
grain crops. The wheat crop must be harvested after maturity, keeping
in view the golden colour of ears and straw and also solid condition
of the grain. Threshing of wheat must be done by a machine such as
wheat thresher, which reduces grain losses from 5 to 10 per cent as
compared to threshing of wheat by the use of bullocks. Seed cleaning
and grading is limiting factor for quality maintenance in wheat. For
pure seed production, the mixtures of other varieties should be rouged
out before crop harvest. The weeds of wheat should be removed off
before mature their seeds.
Seed quality maintenance:
The harvested
materials of any particular variety should be kept separately in a
bulk to avoid mixtures of seed. The precautionary measures must be
taken during threshing, winnowing and cleaning of wheat seeds to avoid
mixtures. The seed graders and sieves may be used to clean and screen
out inert matter and small or undersize seeds for maintaining seed
quality. The proper storage of seeds under hygienic condition is also
a measure for quality control. This whole scenario of production
technology leads to obtain higher wheat yields, which might solve food
grain shortage problem in the country. Pakistan is very near to the
door steps of self sufficiency in wheat production and it is hoped
that we would emerge as wheat exporter in the world.
The author is Associate Professor Department of
Agronomy Sindh Agriculture University, Tandojam.
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