Wheat Value Chain
Description
Wheat, is the name given to several plants in the genus Triticum including Triticum aestivum, Triticum compactum, Triticum spelta and Triticum durum, which are annual or biennial grasses grown primarily for their grain. Wheat species possess an erect smooth stem with linear leaves that grow in two rows on either side of the stem with larger ‘flag’ leaves at the top of the stem. The stem terminates in a spike that is made up on individual spikelets, each possessing 3–9 florets. The wheat fruit develops within the spikelets, maturing to a seed (kernel). Wheat can reach 1.2 m (4 ft) in height and like other cereals, has been developed into different varieties that are adapted to planting at different times of the year. Spring wheat is planted for a late summer harvest, whereas Winter wheat is planted for harvesting in early to mid-summer. Overwintering varieties are more commonly grown in regions with mild winters. Wheat may be referred to by variety and these include durum or macaroni wheat (Triticum durum), club wheat (Triticum compactum), spelt wheat (Triticum spelta) and bread wheat (Triticum aestivum). Wheat originated in the Fertile Crescent of the Middle East. https://plantvillage.org/topics/wheat/infos
Land Preparation
Land Preparation Wheat crop requires a well pulverized but compact seed-bed for good and uniform seed germination. In irrigated areas, after the harvest of previous crop, the field should be ploughed with disc or mould board plough. Where tractor is available, one deep ploughing followed by two to three harrowings with disc or tines and 2 to 3 planking should be given to prepare a well pulverized seed-bed. But where bullocks are the source of power, deep ploughing followed by two to three harrowings or four to five intercross ploughing with local plough should be done. Planking should be done after each ploughing. In rainfed areas, the field preparation should be done with care as conservation of moisture is dependent on it. Fields are usually prepared by giving one deep ploughing followed by two to three ploughing with local plough and then planking. In these areas, ploughing should be done in the evening and furrows should be kept open whole night to absorb dew moisture. Planking should be done early in the morning. A buffer zone of 10-30 m width should be kept to avoid contamination from the non-organic field. www.matirkatha.net
Variety
Improve varieties
Northern Hills Zone (NHZ)
VL-832,VL-804, HS-365, HS-240 — Irrigated/Rainfed, Medium Fertility, Timely Sown
VL-829,HS-277 — Rainfed, Medium Fertility, Early Sown
HS-375(Himgiri),HS-207, HS-295, HS-420 (Shivalik) — Irrigated/Rainfed, Medium Fertility, Late Sown
HS375 (Himgiri), HPW42 — Very High Altitude
Noth Western Plains Zone (NWPZ)
HD2687,WH-147, WH-542, PBW-343, WH-896(d), PDW-233(d), UP-2338, PBW-502, Shresth (HD 2687), Aditya (HD 2781) — Irrigated, High Fertility,Timely Sown
PBW-435, UP-2425, PBW-373, Raj-3765 — Irrigated, Medium Fertility, Late Sown
North Eastern Plain Zone (NEPZ)
PBW-443, PBW-502, HD-2733, K-9107, HD-2824 (Poorva), HUW-468, NW-1012, HUW-468, HP-1731, Poorva (HD 2824) — Irrigated,High Fertility,Timely Sown
Raj-3765, HD-2643, NW-1014, NW-2036, HUW-234, HW-2045, HP-1744, DBW-14 — Irrigated, Medium Fertility, Late Sown
HDR77, K8027, K8962 — Rainfed, Low Fertility, Late Sown
HD-2888 — Rainfed, Timely Sown
Central Zone (CZ)
DL-803-3, GW-273, GW-190, Lok-1, Raj-1555, HI-8498(d), HI-8381(d) — Irrigated, High Fertility, Timely Sown
DL-788-2, GW-173, NI-5439, MP-4010, GW-322, Urja (HD 2864) — Irrigated, Medium Fertility, Late Sown
C-306, Sujata, HW-2004, HI-1500, HD-4672(d), JWS-17 — Rainfed, Low Fertility, Timely Sown
Peninsular Zone (PZ)
DWR-195, HD-2189,DWR-1006(d), MACS-2846(d), DWR-2001(di), Raj-4037, DDK-1009(di) — Irrigated, High Fertility,Timely Sown
HUW-510, NIAW-34, HD-2501, HI-1977, Pusa Tripti (HD-2833) — Irrigated, Medium Fertility, Late Sown
A9-30-1, K-9644,NIAW-15(d), HD-2380 — Rainfed, Low Fertility,Timely Sown
Southern Hills Zone (SHZ)
HW-2044, HW-1085, NP-200(di), HW-741– Rainfed, Low Fertility, Timely Sown
HUW-318, HW-741, HW-517, NP-200(di), HW-1085 — Irrigated, High Fertility, Timely Sown
National Capital Region Delhi (NCR)
HD-2851(Pusa Visesh), HD-4713(i)(d) — Irrigated, Timely Sown
Pusa Gold (WR-544) — Irrigated, Late Sown
Latest Release of wheat varieties
HD-2894 (2008) — High yielding variety for NCR Delhi, with an average yield of 5.2 t/ha having a protein content of 12.9%, high gluten score, and good chapati making. It is developed by IARI New Delhi
HD-4713 (durum) (2008) — High yielding durum variety for NCR Delhi, with an average yield of 4.71 t/ha having a protein content of 5.15%. It is resistant to brown rust under both natural and artificial conditions and is suitable for pasta products.
Pusa Gold (WR-544)(2005) — for late sown, irrigated conditions of Delhi region, released by IARI New Delhi.
Pusa Visesh (HD-2851) (2005) & HD-4713(d)(i) (2006) — for timely sown, irrigated conditions of Delhi region, released by IARI New Delhi
Poorva (HD 2824) (2005) — timly sown irrigated for NEPZ region, released by IARI New Delhi
HD-2888 (2006) — timly sown, Rainfed conditions for NEPZ region, released by IARI New Delhi
Shresth (HD 2687)(2005), Aditya (HD 2781)(2005) — timly sown, irrigated conditions of NWPZ region, released by IARI New Delhi
Pusa Tripti (HD-2833)(2006) — Late sown & Irrigated conditions of PZ, released by IARI New Delhi
Urja (HD 2864) — for late sown, irrigated conditions for CZ region, released by IARI New Delhi
Amrta (HI 1500) — for timely sown unirrigated for central India, released by IARI Indore
Swarna (HI 1479) — for timely sown irrigated condition for central India, released by IARI Indore
PBW 502 — timly sown, irrigated conditions of NWPZ credited with Punjab Agriculture Univ.
DBW 14 — late sown,irrigated conditions of NEPZ credited with Directorate of Wheat Research
Planting
Soil treatment
Phosphetica culture 2.5 kg + azatobacter 2.5 kg + trycoderma powder 2.5 kg mix with 100-120 kg F.Y.M. and broadcast at the time of last ploughing.
Seed rate and its treatment
100kg/hact. (for normal condition)
120kg /hact. (for coarse size grain )
125 kg /hact. (for late sowing)
2.5 kg thiram or 2.5 kg carbendazim or 5 gram trycoderma spore @ 1kg seed.
Spacing and sowing time
Row to row spacing should be 22.5 to 23 cm
The late sown wheat should be sown in rows spaced 15-18 cm
Last Dates up to which sowing would be economical are:
up to 25th December – in North-West Plain Zone
up to 10th December – in North-East plain & Central Zone
up to 30th November – in Peninsular Zone
Soaking seeds in water overnight before sowing, using higher seed rate, closer spacing, shallow sowing (2-3 cm) and spreading thin covering of FYM soon after sowing, can reduce loss caused by late sowing, the dwarf wheat should be sown only at 5-6 cm depth as they have shorter coleoptiles. Seeding depth of 8-10 cm results in poor germination and reduced yield.
Irrigation
First at 20-25 day after sowing
Second at 40-45 day after sowing
Third at 60-65 day after sowing
Forth at 80-85 day after sowing
Fifth at 100-105 day after sowing
Sixth at 115-120 day after sowing
Pre-emergence
As pre-emergence, only Stomp 30EC (Pendimethalin) is available which can be applied @ 3300 ml/ha (1OOO g a.i/ha) at 0-3 days after sowing in 500 liters of water /ha. Care must be taken to have fine tilth for better performance of pendimethalin. It controls both grasses and broadleaved weeds.
Post-emergence
During the last 3-4 years a number of herbicides were found effective against even the resistant biotypes of Phalaris minor. Out of the four new herbicides found effective against Phalaris, two namely Sulfosulfuran and Metribuzin were effective against both grassy and non-grassy weeds, whereas clodinafop and fenoxaprop were specific to grassy weeds. Application of Metribuzin should be done carefully as this chemical is not safe at double the recommended dose. Also its application is risky if hot and windy weather prevails and rainfall occurs immediately after its spray / application.
The herbicides that are to be applied as post emergence after first irrigation at 3035 days of sowing or 2-3 leaf stage of Phalaris minor are;
Weed control
Both Grassy and Broad Leaved
Sulfosulfuran @ 25.0g a.i./ha in 250-300 liters of water /ha.
Metribuzin @ 175 g a.i./ha in at least 500 liters of water /ha.
A mixture of Sulfosulfuran at 25g/ha and metsulfuron methyl @ 4 g/ha in 250-300 liters water/ha.
Combination of 2,4-0 and isoproturon can also be used for the control of mixed weed population in resistance free area.
Only Grassy Weeds
Clodinafop @ 400 g/ha (60g a.i./ha) in 250-300 liters of water / ha.
Fenoxaprop-ethyl @ 80-120g a.i./ha in 250-300 liters of water / ha.
Only Broadleaf Weeds
2,4-0 @ 500 g a.i./ha in 250-300 liters of water /ha.
Metsulfuron methyl @ 4 g a.i. / ha 250-300 liters of water /ha.
Some Useful Hints
Do’s
Spray the herbicides, both pre and post emergence, when there is sufficient moisture in the soil.
Spray the post-emergence herbicides when Phalaris minor is at 2-3 leaf stage.
Spray on clear and sunny days only when the leaves are dry.
Use only flat fan nozzle especially for Fenoxaprop.
Remove Phalaris minor before seed setting and use as fodder.
Ensure complete coverage of the field.
Don’ts
Do not use Sulfosulfuran in mixed cropping system of wheat and mustard or other crops.
Never apply these post emergence herbicides by mixing with sand, urea or soil.
Do not mix Clodinafop and Fenoxaprop with 2,4-D
The major diseases of wheat in India are, three rusts – leaf, yellow and stem rust, Karnal bunt, foliar blights, powdery mildew and loose smut. Diseases of limited importance include head scab, foot rot and flag smut; these diseases though of lesser importance, may be important in certain pockets.
Pest and Disease Management
Leaf Rust /Brown Rust– Puccinia recondita tritici.
Distribution: Throughout wheat growing regions of India.
Development: Pathogen over-summers in low and mid altitudes of Himalayas and Nilgiris. Primary infections develop from wind deposited urediospores in eastern Indo-gangetic plains in middle of January where it multiplies and moves westwards by March. Temperatures of 20 :t 5° C with free moisture (rain or dew) cause epidemics. Severe infection causes upto 30 percent yield losses.
Management: The presently recommended varieties in most of the wheat growing zones are rust resistant.
Stripe Rust /Yellow Rust- Puccinia striiformis tritici
Distribution: Hills, foothills and plains of north western India and southern hills zone (Nilgiri hills of Tamilnadu).
Development: Spreads through air-borne urediospores, when temperature are 10¬20°C but the spread is checked above 25°c. Pathogen survives in the cool temperatures of hills (Himalayas and Nilgiris ) and the primary infection takes places by middle of January in the foot hills and sub mountainous parts of north western India. Also, infection comes from across the western border, hence the probability of evolution of new races increases in this area. Yellow rust from Nilgiri hills cannot come out of the zone due to high temperatures in the Peninsular and Central India.
Management: Most of the presently recommended varieties are resistant. Major emphasis is on host resistance and cultivation of resistant varieties is the main strategy of management.
Stem Rust /Black Rust- Puccinia graminis tritici
Distribution: Mainly in Peninsular and I Central India, may occur in traces in Northern India too’ were the infestation comes late.
Development: Develops from air-borne urediospores, needs free moisture and temperature above 20° C for spread. It can cause severe grain losses if infection is early. The pathogen perpetuates in Nilgiri hills during off season and becomes air¬borne. If Peninsular and Central India experience rainfall during November, then epidemics are severe. Late infections cause less damage in north India.
Management: The presently re¬commended varieties in most of the wheat growing zones are rust resistant, hence the old susceptible varieties be avoided.
Karnal Bunt- Tilletia indica (=Neovossia indica)
Distribution: Parts of Northern Plains, especially Punjab, parts of northern Haryana, foot hills of J&K and HP., tarai area of Uttranchal, in lesser severity in Rajasthan, Bihar and UP. The states of Gujarat, Maharashtra, Karnataka and several parts of M.P. are free of KB.
Development: Seed and soil-borne; infection occurs at flowering by means of soil-borne inoculum. The degree of disease development depends upon the weather conditions prevailing during spike emergence to grain filling stage of crop. If the rains occur during the month of February in north Indian plains (disease – prone areas), the disease is likely to come with higher severity.
Management: Among the present day varieties, PBW 502 is resistant while the others show various levels of susceptibility. For management of this disease, one spray of Propiconazole (Tilt 25EC@ 0.1 %) should be given at the time of anthesis. Integration of one spray of propiconazole with one spray of bioagent fungus, Trichoderma viride (0.4% suspension) gives almost cent per cent disease control. The bioagent spray should be done before earhead emergence (Crop growth stage 31- 39 on Zadoks scale), followed by the spray of chemical at start of earhead emergence (crop growth stage 41 -49 on Zadoks scale). Two sprays of T. viride, at these two critical growth stages also give non chemical control of the disease which is almost similar to one spray of propiconazole. Chemical control should be adopted mostly in seed production plots.
Black Point- Alternaria alternate
Development: Disease causes blackening of embryonic region of the seed (black point), discoloration of area beyond the embryonic region (black discoloration (Caused by Aalternata, Curvularia lunate, Epicoccum sp., Bipolaris sorokiniana, etc.) and eye-spot symptom (B. sorokiniana). The warm and humid weather at grain filling or near maturity favors this disease.
Management: This disease is of minor importance. Only when the disease percentage is high, it causes concern to the trader and the consumer. The discolored seeds are mostly shrivelled and they are separated out during processing.
Loose Smut- Ustilago segatum (U. tritici)
Distribution: North Indian plains and northern hills zone.
Development: It is a seed borne disease; infection occurs during Loose Smut
flowering through wind-borne spores. The infection remains dormant inside the otherwise healthy looking seed but the plants grown from such seeds bear infected inflorescence. Infection is favored by cool, humid conditions during flowering period of the host plant.
Management: Disease can be easily controlled through seed treatment with systemic fungicides hence resistance breeding has not attracted much attention. Treat the seed with fungicides like carboxin (Vitavax 75WP @ 2.5g / kg seed), carbendazim (Bavistin 50WP @ 2.5g / kg seed), tebuconazole (Raxil 2DS @ 1.25g / kg seed) if the disease level in the seed lot is high. If it is low to moderate, treat the seed with a combination of Trichoderma viride (@4 g/ kg seed) and half the recommended dose of carboxin (Vitavax 75WP @ 1.25g / kg seed).
Foliar Blights- Bipolaris sorokiniana (Spot blotch), Pyrenophora tritici repentis (leaf blotch or tan spot), Alternaria triticina (Alternaria leaf blight)
Distribution: Mainly in eastern India but also occurs in Peninsular and Central Foliar blights India. This disease complex is emerging as a problem in the north western India too.
Development: The disease requires high temperature and high humidity. This disease is more severe in late sown crop and causes substantial yield losses through formation of shrivelled grains. Most of the varieties are susceptible or moderately susceptible. The disease can be controlled through one spray of propiconazole (Tilt 25EC @ 0.1 %).
Powdery Mildew- Erysiphe graminis tritici
Distribution: Mainly in the cooler areas and hilly region; foot hills and plains of north – western India and the southern hills (Nilgiris).
Development: Powdery mildew can easily be diagnosed by the white, powdery patches that form on the upper surface of leaves and stem. With age, the patches turn dull dirty white and may have small black specks embedded. This disease can spread to all aboveground
parts of the plant, including earhead and awns. The disease infects plants during periods of high humidity (not necessarily rain) and cool to moderate temperatures. Low light intensity, which accompanies dry weather and a dense crop canopy favours this disease.
Management: Present day varieties are not resistant to powdery mildew. Hence, the disease severity is more in some pockets. Avoid excessively dense, stands by using adequate seed. For chemical control, one spray of propi-conazole (Tilt 25EC@ 0.1 %) on disease appearance (which usually occurs during early March in northern plains) is highly effective.
Head Scab- Fusarium graminearum
Distribution: Parts of Punjab, especially in the sub mountainous regions. Bread wheat suffers lesser damage than the durum. It was first recorded in severe proportion in some parts of Punjab during 1995-96 crop season and again during 2004-05 crop season.
Development: Disease development is favoured by cool, moist weather with high humidity. Spores are produced on crop debris and reach the leaves through rain splash or wind. Apart from ear head infection, it can cause seedling blight and foot rot leading to lodging. In severe cases, it can cause shriveling of grains and low-test weights. At present, it is a disease of limited importance but has the potential to emerge as a major problem due to the production of toxins.
Management: Bread wheat are more resistant than durum. However, no resistant varieties are available. Hence, vigil is needed for this disease.
Cereal Cyst Nematode- Heterodera avenae
Distribution: This nematode is found In most of the cereal growing regions of the country, especially, the dry and warmer areas of Rajasthan, Haryana and Punjab, but incidence is less in cooler climates.
Development: Larvae enter the roots near the growing point especially, at the seedling stage. Roots of infected plants become predisposed to various soil borne disease like root rots. In infected fields, the losses can be considerably enough.
Management: Most of the wheat cultivars are susceptible but some resist cyst formation. Chemical pesticides, some natural plant products and botanicals, coupled with improved cultural practices help in management of the CCN. For Rajasthan, one CCN resistant variety, CCNRV – 1 is available for the disease prone areas.
Seed Gall Nematode /Ear Cockle- Anguina tritici
Distribution: It is found mainly in some parts of northern India especially the states of Bihar, Jharkhand, eastern UP and Chhatisgarh.
Development: These nematodes are spread through seed galls in the seed lots during planting and harvesting. Wet weather favors larval movement and infestation. The nematode invades the crown and basal stem area, finally penetrating floral primordia. This leads to formation of nematode galls in ear heads.
Management: Use of clean seed (free of galls) is the only method to prevent this disease. For removal of galls, the seed lots are floated in 2 – 5 per cent brine solution. The galls, which float on the surface, can be easily separated and destroyed away from the fields. The seed thus cleaned should be washed with fresh water and used for planting.
Aphids- Sitobion avenae, Rhopalosiphum padi and various other species
Distribution: All wheat growing areas, especially in NWPZ and Peninsular India.
Development: The aphids exist in different stages, viz., winged (alates), wingless (apterous) sexual and asexual forms. The rapid spread takes place through asexual reproduction where females give rise directly to nymphs rather than eggs. Infestation usually occurs during second fortnight of January till crop maturity.
Management: When feeding in sufficient numbers, they can cause considerable damage, but under normal conditions, losses are not much. Chemical pesticides are recommended for this pest in wheat if the level of aphids per tiller crosses 10 during vegetative phase and 5 during reproductive phase. However, there is need to keep watch on this pest. The spray of imidacloprid @ 20 g a.i. per ha initially on border rows and if infestation is severe then in entire field will give good protection against this pest. Generally, natural enemies present in the field help in controlling the population of this pest.
Brown Wheat Mite- Petrobia lateens
Distribution: In most of the wheat growing areas, under rainfed conditions, especially in the states of Rajasthan, Haryana and M.P. Sometimes, it is a pest in humid and warm conditions of irrigated areas also.
Development: They Brown wheat cause damage through mite infestation
sucking mouth parts. When present in large numbers, mites cause a silvery flecking on leaves. Individual mites are too small to be visible with naked eye without ‘effort. These can be seen by shaking the infested leaves on a white paper.
Management: Most of the times, mites do not cause any production constraint in wheat so no management practices are required. However, there is a need to keep vigil on this pest so that it may not become important in changing cropping sequence of future.
Army Worm- Mythimna separate
Distribution: Mostly in the warmer climates of central India and to some extent in northern plains.
Development & Management: The larvae are found in the cracks of soil and hide during the day but feed during night or early morning. In wet and humid weather, they may feed during day time also. They survive during summer on the subsequent crops like rice and also continue to exist in rice stubbles before wheat crop comes in the field. Recently, this pest is catching attention in the northern India under Rice-Wheat rotation and where rice stubbles / straw remain in the fields.
Legume Pod-borer- Helicoverpa armigera (= Heliothis armigera)
Importance: This is a polyphagous insect that attacks various legumes as a pod border. It is seen damaging wheat ear heads at grain development stage when major hosts are not available. However, the damage is below economic threshold level.
Distribution: It is found mostly in northern and central parts of India. Wheat can serve as a bridge host for carry-over of this polyphagous pest.
Termites- Odontotermis obesus, Microtermis obesi
Distribution: Mainly in the northern and central India, but also in some pockets of peninsular India.
Early Symptoms of Damage: Termites attack the crop at various growth stages,
from seedlings to maturity. The severely damaged plants can be easily uprooted and look wilted and dried. In case roots are partially damaged, the plants show yellowing.
Management: For effective management, chemicals like endosulfan, chlorpyriphos and carbosulfan can be used both for seed treatment and for broadcast of treated soil in standing crop.
http://agropedia.iitk.ac.in/content/cultivation-wheat
Harvesting and Post-Harvest Handling
Harvesting
A major proportion of the crop in Asia is harvested manually using sickles (over 70 percentages in Pakistan, India and Bangladesh – Figure 2) or with types of knives leaving 3-6 cm wheat straw above the ground level. Methods and timing of harvesting are important factors to total crop yield. In South Asia wheat is harvested in the dry summer months from March to May. Farmers are conscious of the fact that the harvested wheat should be dry enough for threshing and storage. Artificial drying is uncommon. The manually harvested wheat crop is tied into small bundles and stacked in bunches of 10 – 15 bundles, which are left in the field for one to three days to dry (Figure 3). Combine or mechanical harvesters (Figure 4) yield a higher proportion of immature grains and pose a moisture hazard, leaving no time for the grain to dry.
Figure 2: Woman harvesting wheat manually
Figure 3: Manually harvested crop left to dry on the field
Figure 4: Mechanical harvester
Transport
Labour-intensive systems of grain movement serve to minimise capital investment in countries where the cost of labour is low. Most wheat is manually loaded and unloaded from wagons, trucks, railroad cars, and barges between farm and mill. The greater the grain loss the higher the cost. In some situations, bagged wheat may be loaded on and off vehicles ten times manually before it is milled.
Highly efficient bulk handling systems exist in developed countries to load loose wheat into trucks. Using an auger, wheat is moved to the grain-processing centre in a single trip, dumped into a receiving bin, carried by a mechanical conveyor through the cleaning and drying processes and into storage. Next, it is moved out of storage into the flour mill at the same location, where the finished flour is mechanically bagged, loaded into trucks by elevator, and taken to a commercial bakery or retail market without once being handled manually. National policy regarding the appropriate degree of mechanical wheat handling is often based on the need to maximise employment for unskilled labour.
In South Asia post-harvest handling, transport and storage of grains at the farm level is done partially in bulk. The transportation of grain to primary markets by the farmers is also done in bulk using bullock carts, tractor trolleys or lorries. At the market yard, the grain is displayed in bulk, auctioned, cleaned, bagged, weighed and delivered to consumers in bags. The food grain trade depends upon labour. Therefore, handling, transport and storage of marketed grains in bags is common. Availability of cheaper jute bags in these countries also encourages handling, storage and marketing of grain in bags. Large quantities of food grain have to be moved through rail or road transport, another major factor promoting use of bags.
From farms in Pakistan, wheat is mainly transported in animal driven carts or carried on camelback. Large farmers use tractor driven trolleys and trucks. In each case bags are used for transportation. Problems arise when old torn bags are used which spill grain, causing loss. Mostly 100-kg bags are used which are cumbersome to carry. Other hazards for bags are hooks which tear the bags, the rough surface of the carts and trolleys and nails, which damage sacks when they are pulled. Transportation occurs from farm to market, market to consumer, market to temporary storage, temporary storage to long term storage and long term storage to consumers.
Threshing
The sheaves of wheat are carried to the threshing floor manually or on the backs of animals like camel donkeys and bullock (Figure 5). Tractor trolleys and bullock carts are mostly used for transporting harvested wheat crop to the threshing floor where they are spread out to dry in the sun and wind for a few days. The threshing and separation of the grain from the straw is done in a variety of ways. The wheat crop may be beaten with sticks or trampled by a bunch of animals. Animals may be used to draw a wheat bundle/stone roller over the thick layer of harvested wheat crop. Or, an implement consisting of a series of steel disks may be used. In some locales, a tractor may be repeatedly driven over the wheat stack spread on the threshing floor.
Figure 5: Animal transport to threshing floor
The tractor-drawn thresher (Figure 6) and self-propelled harvester combine causes the least grain contamination, but are capital intensive solutions. Farmers, who cultivate only one or two hectares a season, hire small threshers, which are, light enough to be carried from one field to another by two people. Pedal or motor-driven mechanical threshers have been devised. One type has a revolving drum with projecting teeth that strip off the grain when a sheaf of wheat is held against the moving surface.
Figure 6: Tractor-drawn thresher
After threshing, the straw (bhoosa) is stacked around the threshing floor (Figure 7), and used as animal feed, bedding, cooking fuel, to make sun-dried bricks, or compost. The wheat grain will be contaminated with pieces of straw chaff, broken grains, stones, and dirt when it is spread on the threshing floor for further drying.
Figure 7: Straw stacks around the threshing floor
Labour saving schemes are employed in some farming communities. An old and simple improvement in threshing is to beat a sheaf of wheat and the grain heads against a low wall, an oil drum, or a wagon bed. This method is more efficient than trampling as the grains fall into a container or onto a woven mat. Small quantities are threshed but are less likely to become contaminated.
In many developing countries manpower is shifting from cereal production to cash crops or to industry causing a dearth of manpower in the urban areas. However, by tradition, the whole family participates in the harvesting and threshing process together with borrowed or hired labour. Women also join in these activities. In places where mechanical harvesters are used women do not participate. Labour prefers to be paid in kind than in cash. In typical communities, the farmers share resources of the village. Manpower reciprocates labour in the harvesting and threshing schedule. Whenever threshing is by bullocks, the community shares the threshing floor and animals.
Threshing is mainly mechanical (60-80 percentage) in Pakistan. Tractor-driven threshers and at times combine harvesters are used. The design and maintenance of the thresher are central to reducing the broken grain percentage. Threshing using animals is also common in many areas of Pakistan. Several animals continuously walk around a pole to crush the wheat straw and heads to separate the grains and convert the straw to bhoosa.
Drying
The most critical decision in harvesting is not the degree of mechanisation but the timing of the harvest. If the harvest starts late, the grain becomes too dry and rate of grain shattering is high. The longer a ripe crop is left in the field or on the threshing floor, the higher will be the loss from natural calamities including hailstorm, fire, birds, or rodents. The moisture content of the grain will be high, making drying difficult if the harvest starts too early.
The moisture content of wheat grain is a crucial factor from harvest until milling. Moisture content of 25 percentages is not uncommon in newly harvested grain in humid areas but it must be dried immediately to protect it against mould. At 14 percentage moisture grain can be safely stored for 2 to 3 months. For longer periods of storage from 4-12 months, the moisture content must be reduced to 13 percentage or below.
Drying in many wheat-growing countries of Asia, Africa, and Latin America is done by spreading a thin layer of grain in the sun, on the threshing floor or on rooftops. Mechanical drying of wheat grain is not practised in most of the developing countries. It is mostly sun dried. Sun drying is risky because it depends on weather conditions leading to dirty grain, spillage loss and bird attack.
Each small farmer cannot afford mechanical equipment for cleaning and drying, but as a co-operative they could own such equipment. Some commercial grain buyers or government warehouses offer to accumulate the grain of small farmers, bulk, clean, and dry it with modern equipment. Unfortunately, these services are rare in developing countries.
As the weather is quite warm at harvest, the moisture content of the grain (Pakistan) is below 10 percentages. During the rainy season moisture content slowly increases to 15 percentages. Deterioration of grain is closely related to the moisture content which is key to safe storage. Temperature and relative humidity influence moisture content of a stored product. The moisture content of wheat in Pakistan when first stored is usually low. In areas where there is heavy rainfall during summer, the relative humidity and grain moisture content increases.
The wheat delivered from the farm at harvest to the village market or to a government food corporation presents different challenges. Since mills need to be able to hold sufficient grain for 30 to 60 days of milling this wheat may be kept in sheds, large steel bins, concrete silos, or in the holding bins of a flour mill. Wheat may be temporarily stored in railroad cars or in open piles in market towns where protection is little better than on a village-threshing floor.
Cleaning
After threshing, the straw, chaff, immature grains, sand, stones, and other substances are separated from the grain by sieving, winnowing or hand picking. In traditional manual winnowing, a shallow basket containing grain is held overhead, and the grain is tossed during periods of fast winds. Lighter weight broken grain, straw, and weed seed are carried by the wind to one side, as the whole grain falls to the bottom of the winnowing device. The winnowing device may stand on a stool to give the falling grain longer exposure to the wind. Manual winnowing requires a continuous brisk wind and several repetitions. Even then, the results are erratic producing grain, which is far from satisfactory. Wheat cleaning is most often done manually by women, occasionally by professionals.
Simple, low-cost appliances that use hand-driven or motorised blowers have been developed that are more efficient and less time consuming than hand winnowing. A FAO publication on processing and storage of food grains by rural families describes grain mills, flourmills and sophisticated grain cleaners. Lending agencies that finance grain storage facilities can provide advice on appropriate cleaning equipment.
Storage
In South Asia and most of the developing countries, farmers for their own use for food, cattle feed and seed retain about 50-80 percentage of the grain produced. The farmers generally store their grain in simple granaries constructed from locally available materials like paddy straw, split bamboo, reeds, mud and bricks. A majority of wheat is stored in bags in a room, bin, drum or container for family consumption or is piled in farm buildings lacking proper flooring, closed doors and windows. Wheat is lost to moulds, birds, rodents, and insects. Storage varies in size and type including indoor, outdoor, above-ground, under-ground or airtight structures. Some conventional storage structures used by the farmers in Asia are:
1.Mud structures mostly bins or pots
2.Wood or Bamboo structures
3.Metallic drums, bins or containers
4.Kothis (small rooms)
5.Bokharies (straw structures)
It has been estimated that in Pakistan about 70 percentage of wheat is stored at farms in bags. The balance is stocked in the market and public sector storage partially in bulk. Wheat storage is primarily assigned to the public sector for food security. http://www.fastonline.org/CD3WD_40/INPHO/COMPEND/TEXT/EN/CH06_01.HTM
Processing
After a seed crop has been harvested, the seed, if necessary, has to be dried and cleaned, i.e. removal of inert matter, seed of weeds, other crops and other varieties, and seeds that are diseased, damaged and deteriorated. Cleaning can be done because wheat seeds differ in length, width, thickness, density, weight and shape.
For wheat seed cleaning, mainly screens, indented cylinders and air are used. Screens separate based on the width and thickness; a width (or diameter) separation is obtained by round screens, while for thickness separation oblong screens are used (Plate 76). Indented cylinders carry out length separation; the indents (cells or pockets) in the cylinder will, depending on their size, lift the seeds, which fit in the indents. Air separates seeds according to their behaviour in an air stream. The most important characteristic is the weight; light particles (dust, chaff, glumes or empty or partly filled seeds) will be lifted, whereas the heavier seed will fall down through the air stream. Each crop requires a different set of machines.
The raw (unprocessed) wheat seed is received from growers in bags or bulk and sampled to evaluate the need for fumigation, drying and cleaning, as well as to guide and monitor processing operations. If seed moisture is too high, the seed is first (pre-cleaned and) dried. If insects are present, the seed should be fumigated. After the raw seed has been received and where necessary fumigated, processing operations (and sequence) are as outlined below (Figure 28.2).
FIGURE 28.2
Flow diagrams of wheat seed processing
Pre-cleaner
Wheat seed often contains considerable plant material trash, and it is often pre-cleaned. A typical pre-cleaner is similar to an air-screen cleaner, except that it has only one air channel to remove light material, one top scalping screen to remove large particles and one bottom grading screen to remove small particles.
Dryer
If wheat seed is above 11 to 12 percent moisture, it is dried before it goes into bulk storage or processing.
Air-screen cleaner
This is the basic cleaner, usually with two air channels and, preferably, four screens. The first air channel (head aspiration) removes dust and light materials as the seed falls from the feed hopper. The second air channel (tail aspiration) removes light seed and materials after the seed passes through the last screen. Although screen configurations vary considerably, one or two top or scalping screens remove particles larger than the good seed, and one or two bottom or grading screens remove particles smaller than the good seed. Because the average size of wheat seed varies according to the growing conditions, standard screen sizes cannot be recommended. Hand testing screens should be used to determine the exact screen perforations.
Length separator
A length separator is almost always used to clean wheat seed. By using the proper machine configuration, shorter or longer undesirable materials (such as broken grains, weed seeds, oat, barley, etc.) are removed. Broken grains and weed seeds, which are shorter than the good seed, are removed by using cylinders with smaller indents. Larger impurities can be removed by using a cylinder with indents that lift all good seed, but contaminants (wild oats, oats or barley grains and unthreshed glumes) remain in the cylinder.
Gravity separator
After the seed is cleaned by the air-screen cleaner and indented cylinder, it may be necessary to use a gravity separator. The gravity separator classifies a seed mixture mainly according to density or specific gravity. It can be used to remove unthreshed glumes and soil particles, which have similar sizes to wheat but different weights. Another application is the removal of weevil-infested grains from the seed lot and upgrading seed (in order to improve germination). Furthermore, wild oats and some barley may be removed from the wheat seed lots, but at the expense of substantial amounts of good seed and only after recycling the material a number of times on the gravity separator.
Treater
Wheat seed should, if necessary, be treated with the appropriate fungicide to protect the seed and seedling after planting. Insecticides are sometimes applied to protect seed in storage and in the soil. Treatments may be applied to protect the seedlings or adult plants against pathogens carried on or in the seed.
Dryer
In humid and hot climates, seeds may be sealed in vapourtight plastic bags to maintain viability over longer periods. In such cases, wheat seed moisture content must be below 9 percent, preferably not over 8.5 percent. Usually, a dehumidified, closed-circuit dryer is used after the seed treatment is applied.
Bagger-weigher
The final step is to weigh the proper amount of seed into the proper kind of bag. Wheat seed bags should be of a size that fits local farmer needs (seed rates and field size).
During processing, strict attention should be paid to the cleanliness of the processing machines and any admixture should be avoided. Every processing plant should have a complete set of hand screens, a small air-screen cleaner and an indented cylinder to help determine the proper processing requirements. It is also essential to have an internal quality control laboratory attached to each seed plant with a small seed testing facility. This laboratory unit should constantly monitor the quality of the seed and the efficiency of processing operations. http://www.fao.org/docrep/006/Y4011E/y4011e0v.htm#TopOfPage
Export
Wheat Exports by Country
Prairie wheat field
Wheat exports by country totaled US$36.3 billion in 2016, down by an overall -25.7% for all wheat shippers over the five-year period starting in 2012 when global wheat exports were valued at $48.8 billion. Similarly, the value of global wheat exports dipped by -6.4% from 2015 to 2016.
Among continents, European countries accounted for the highest dollar value worth of wheat exports during 2016 with shipments amounting to $19.3 billion or 53.3% of global wheat exports. Home to the two leading wheat-shipping nations (United States and Canada), North America accounted for 28.3%.
Representing Oceania, Australia was responsible for 10% of international wheat exports. Latin America (excluding Mexico) and the Caribbean provided 6.2%. Asian countries supplied 2.2% while African exporters trailed badly at 0.1% of worldwide wheat sales.
The 4-digit Harmonized Tariff System code prefix for wheat is 1001.
Wheat Exports by Country
Below are the 15 countries that exported the highest dollar value worth of wheat during 2016:
United States: US$5.4 billion (14.8% of total wheat exports)
Canada: $4.5 billion (12.4%)
Russia: $4.2 billion (11.6%)
Australia: $3.6 billion (9.9%)
France: $3.4 billion (9.3%)
Ukraine: $2.6 billion (7.2%)
Germany: $1.9 billion (5.3%)
Argentina: $1.9 billion (5.1%)
Romania: $1.3 billion (3.5%)
Poland: $806.9 million (2.2%)
Bulgaria: $767.7 million (2.1%)
Kazakhstan: $685.1 million (1.9%)
Lithuania: $594.4 million (1.6%)
United Kingdom: $526 million (1.4%)
Czech Republic: $494.4 million (1.4%)
The listed 15 countries shipped 89.9% of all wheat exports in 2016 (by value).
Among the above countries, the fastest-growing wheat exporters since 2012 were: Poland (up 158.1%), Romania (up 82.3%), United Kingdom (up 22.7%) and Czech Republic (up 15.7%).
Those countries that posted declines in their exported wheat sales were led by: Kazakhstan (down -57.2%), Australia (down -46.9%), Argentina (down -36.7%), United States (down -34.4%) and France (down -33.3%). http://www.worldstopexports.com/wheat-exports-country/
Top Wheat Exporting Countries
Wheat is traded in the international market between several countries. The European Union exports the largest quantity of wheat, flour, and wheat products. In the year 2015/2016, the European Union exported goods worth 33 million metric tons. Russia is the single largest exporter of wheat in the world. The country exported wheat, flour, and wheat products amounting to 24.5 million metric tons in 2015/2016. Only four decades ago, Russia depended on the US to import wheat and corn to offset shortfalls in its own harvests. However, over the past decade, the country has managed to emerge as the biggest single source of wheat in the world. Large proportions of Russia’s wheat and wheat product exports goes to Egypt, the world’s biggest buyer of these products. Russian wheat export to other countries like Nigeria, Indonesia, and Bangladesh is also increasing. The boom in Russia is triggered by factors such as government support, rich soil, and proximity to ports in the Black Sea. Canada, the US, and Australia are the three next top exporters of wheat, flour, and wheat products in the world.
Top Wheat Importing Countries
Egypt is the world’s leading importer of wheat in the world. In 2015/2016, the country imported wheat, flour, and wheat products amounting to 11.5 metric tons. What makes Egypt the world’s largest wheat buyer? Bread has been the most heavily subsidized good in the country since the 1952 revolution. The Egyptian cuisine is heavily dependent on wheat and wheat products. Egypt is not only the largest importer of wheat but also the largest wheat consumer, and bread eater per capita in the world. The heavy dependency on wheat has some negative effects on the country’s economy as it strains the national reserves required to import wheat from foreign nations. Also, excessive reliance on wheat triggers problems of obesity and provides a less than ideal nutrition despite high caloric intake. However, attempts to reduce the subsidies on wheat have been met with vehement rebellions by the people of the country, and thus Egypt continues to exports massive quantities of wheat annually. Indonesia, Algeria, and Turkey follow next with imports of wheat, flour, and wheat products amounting to 9.1, 8.1 and 7.1 million metric tons, respectively.
The Top Wheat Exporting and Importing Countries in The World
| Rank | Country | Export of wheat, flour, and wheat products in 2015/2016, (in 1,000 metric tons) | Country | Import of wheat, flour, and wheat products in 2015/2016, (in 1,000 metric tons) |
| 1 | European Union | 33,000 | Egypt | 11,500 |
| 2 | Russia | 24,500 | Indonesia | 9,100 |
| 3 | Canada | 22,500 | Algeria | 8,100 |
| 4 | United States | 21,200 | Turkey | 7,300 |
| 5 | Australia | 16,300 | European Union | 6,700 |
| 6 | Ukraine | 15,800 | Brazil | 5,800 |
| 7 | Argentina | 8,800 | Japan | 5,700 |
| 8 | Kazakhstan | 7,500 | Iran | 5,500 |
| 9 | Turkey | 5,500 | Mexico | 4,500 |
| 10 | Mexico | 1,300 | Nigeria | 4,300 |
http://www.worldatlas.com/articles/the-top-wheat-exporting-and-importing-countries-in-the-world.html
Wheat Specifications
Milling Wheat Grade 1
Origin: India
Protein: 11% Min
Moisture Content: 12% Max
Damaged Kernels: 3% Max
Foreign Material: 2% Max
Gluten: 9.5% Min
Wet Gluten: 24% Min
Falling Number / Sec: 300 – 400 Min
Other Food Grains: 2% Max
Bored Grains: 2% Max
Hard Red Wheat Grade 2
Origin: USA/South America/Canada/Australia
1000 Kernel Weight: 30-32
Protein: 11% – 13%
Moisture Content: 12% Max
Damaged Kernels: 0.5% Max
Foreign Material: 0.5% Max
Imperfect Grains: 0.5% Max
Wet Gluten: 26% Min
Dry Gluten: 10% Min
Dockage: 1-3% Max
Radiation: Normal
Water Absorption: 76% Min
Hard Red Wheat Grade 3
Origin: USA
1000 Kernel Weight: 30-32
Protein: 11% – 13%
Moisture Content: 12% Max
Damaged Kernels: 0.5% Max
Foreign Material: 2.5% Max
Imperfect Grains: 0.5% Max
Wet Gluten: 26% Min
Dry Gluten: 10% Min
Dockage: 1-3% Max
Radiation: Normal
Water Absorption: 76% Min
Durum Wheat
Origin: USA/South America/Canada/Australia
Protein: 12.5% Min
Moisture: 13.5% Max
Falling Number: 300 Min
Heat Damaged Kernels: 0.2% Max
Total Damaged Kernel: 4.0% Max
Shrunken & Broken Kernels: 5.0% Max
Total Defects: 5.0% Max
Total other classes: 2.0% Max
Foreign Material: 0.7% Max
Dockage: 1.5% Max
Test Weight: 58 lbs per bushel
Vitreous Amber Kernels: 80% Min
Soft White Grade 2
Origin: USA
Protein: 8% – 10% Max
Moisture: 13% Max
Falling Numbers: 150-250
Damaged Kernels: 4% Max
Foreign Matter: 0.8% – 1% Max
Dockage: 1% – 3% Max
Wet Gluten: 25% Min
Dry Gluten: 10% Min
Test Weight: 76 Kg HT Min
Soft White Or Red Wheat Grade 3 & 4
Origin: USA
Protein: 12% Min
Moisture: 13% Max
Falling Numbers: 150-250
Damaged Kernels: 0.5% Max
Foreign Matter: 2.5% Max
Dockage: 10% Max
Wet Gluten: 24% Min
Dry Gluten: 10% Min
Test Weight: 74 Kg HT Min
Feed Wheat- Grade 1
Protein: 11.5% Min
Moisture: 14% Max
Test weight: 79 kg/hl, Min
Foreign matter: 0.75% Max
Broken kernels: 1.5% Max
Heat damaged kernels: 0.5% Max
Total damaged kernels: 1.0% Max
Smutty kernels: 0.1% Max
Weevil kernels: 0.5% Max
White belly: 15% Max
Melilotus indicus L: 8 sds
Gluten: 2.7% Max
Water absorption: 75% Min
Radiation: none
Feed Wheat- Grade 2
Protein: 10.5% Min
Moisture: 14% Max
Foreign matter: 1.5% Max
Heat damaged kernels: 1.0% Max
Total damaged kernels: 2.0% Max
Smutty kernels: 0.2% Max
Weevil kernels: 0.5% Max
White belly: 40% Max
Melilotus indicus L: 8 sds
Water absorption: 75% Min
Radiation: none
Feed Wheat- Grade 3
Protein: 9.5% Min
Moisture: 14% Max
Test weight: 73 kg/hl, Min
Foreign matter: 3.0% Max
Heat damaged kernels: 1.5% Max
Total damaged kernels: 3.0% Max
Smutty kernels: 0.3% Max
Weevil kernels: 0.5% Max
White belly: 40% Max
Melilotus indicus L: 8 sds
Gluten: 2.7% Max
Water absorption: 75% Min
Radiation: none absorption
Red Hard Winter Wheat-Grade 2
South America / Canada / Australia
Specifications:
Test Weight: 58 lb per bu Min. Damaged Kernels: 0.5 % Max.
1000 Kernel Wt: 30-32 Grams Foreign Matter: 0.5 % Max.
Protein Cont: 11 % – 13 % Min. Imperfect Grains: 0.5 % Max
Moisture Content: 12 % Max. Water Absorption: 76 % Min.
Wet Gluten: 26 % Min. Radiation: Normal
Dry Gluten: 10 % Min. Falling Number: 300 Min.
Dockage: 1-3 % Max. Crop Year: Latest Crop
All Prices valid for 14 days only and subject to change and Sellers approval.
Feed Wheat Grade 3
Specifications
Test Weight: 73 Kg/HL Min. Total Damaged Kernel: 3.0 % Max.
Foreign Matter: 3 % Max. Water absorption: 75 % Min.
Protein Content: 9.5% Min. Heat Dam. Kernels: 1.5 % Max.
Moisture Content: 14 % Max. Radiation: Normal
Wet Gluten: 2.7 % Max. Wheat of Other Classes: 5.0 % Max.
Falling Number: 250-275 sec/g activity Crop Year: Latest Crop
Feed Barley Grade 2
Origin: USA / South America /Canada / Australia /Sellers Option
Specifications
Moisture: 13 % Max. Weight: Min.63 pct kg/hl
Crude Protein: 10 % Min
Radiation: Normal Grain Impurities: 3% Max.
Damaged grains: 2% Max.
Crude Fat: 2 % Min. Foreign Matters: 1 % Max.
Crude Fiber: 8 % Min. Crop Year: Latest Crop
