The Eleventh Regional Wheat Workshop For Eastern ... - Cimmyt

Reducing mechanical harvesting losses ofwheat - Dawelbeit
ranging from 6.3 to 8.4 hectares.
Wheat is one of the crop rotation crops. It is preceded by cotton and followed by groundnut and
sorghum. About 168 thousand hectares are cultivated annually with wheat. Wheat production is
fully mechanized (Dawlbeit, 1996). Disc harrows and ridgers are used for seedbed preparation
while seed drills and wide level disc harrows equipped with seeder boxes are used for seeding.
Land preparation starts usually during the rainy season in September while seeding is during
November. Private service companies and individuals execute the mechanized operations of
seedbed preparation and seeding. There are about three large service companies, about ten
medium companies and a large number of individually owned machines. Wheat yields are low
with a mean of 1.26 tlha (Faki and Ismail, 1994).
Harvesting is usually during March and April. About 300 combine harvesters are involved in
wheat harvesting. Almost all of these machines are privately owned. The most common type is
the self-propelled combine harvester equipped with 4.5m wide grain header.
One of the most serious problems of using combine harvesters is high harvesting losses. It is
estimated that about 18-20% of the produced crop is·lost during harvesting.
Previous Research
A study was conducted at Gezira Research Station at Wad Medani for two seasons (1991/92­
1992/93) to estimate the effect of time of harvesting on wheat harvesting losses (Dawelbeit,
1996). Results, as depicted in Table 1, showed that the average total losses amounted to 2.6% in
the first season and 2.3% in the second season. Results also showed that delayed harvesting
could result in very high losses since the rain showers start as early as May. The table also shows
that in 1992/93 season the last harvest date (May 29) which occurred after a rain shower resulted
in very high grain losses.
Wheat Harvesting System in Gezira
Due to the importance of wheat harvesting, a special system was developed to manage wheat
harvesting in the Gezira Scheme. A high committee for wheat harvesting at the headquarters
assisted by committees on the group level is responsible for management of harvesting. This
committee sets wheat harvesting regulations and prices, contracts combines, secures inputs,
follows up harvesting operations, delivers wheat to flour mills and collects loans and taxes from
the tenants. The committee usually starts its activities in January and ends its activities in June of
every year.
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All the area is harvested by harvesting contractors. For those contractors, wheat harvesting is a
special season. A combine harvester usually works about 18 hours per day in two shifts. Every
shift has six laborers. These include a driver, an assistant in addition to four laborers responsible
for sack stitching and handling: all combine harvesters in the Sudan are equipped with a special
handling system that uses j ute sacks rather than bulk handling. Those laborers are temporary
employed for the harvesting period only. They are paid by the area they harvest. Most of the
combine operators are not trained and have a very low standard of education.
Usually, at mid wheat production season (December), a survey is made to estimate the number of
available harvesting machines in the area. The number of combine harvesters that is required to
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