Production and post-harvest activities for rice in Ghana

Backgrounder

Introduction 

Why is this subject important to listeners?

Because rice farmers in Ghana should know:

• How to prepare their lands for cultivating rice.
• The volume of seeds to sow when planting and how to space them.
• How to select land that is suitable for rice production.
• The ideal climate for rice production in central and northern Ghana.
• How to handle rice after harvesting to prevent post-harvest losses.
• How to select the best seed varieties to plant.
• How to manage growing rice.
• The diseases and pests that affect rice and how to manage them.

What are some key facts?

• If farmers are planting rice for the first time, they should select flat lowlands where they can construct water controls like drainage canals and bunds.
• Farmers should prioritize planting disease-tolerant rice varieties with suitable maturity periods to achieve stable yields. Most varieties mature in 115-130 days, but 150-day varieties are preferred in valleys in northern Ghana.
• The recommended ploughing depth is 20 centimetres.
• To test a seed variety for germination, plant 100 seedlings. If 80 germinate, that batch of seeds is viable and can be planted.
• Transplant seedlings from the nursery to the main field when they have four leaves.
• To grow rice in rain fed conditions or under puddle irrigation, apply 7-8 tonnes of cow dung or 4 tonnes of poultry manure per hectare before planting.
• Weed three weeks after direct planting in rain-fed farming or three weeks after transplanting seedlings into irrigated paddies.
• Harvest rice 80-130 and up to 150 days for late-maturing varieties after planting when:
  • grains turn brown or golden in colour,
  • grains are hard and dry when bitten, and
  • the panicle is yellow.
• After harvest, dry rice to 12-14% moisture content before storing.

What are the big challenges in rice production and post-harvest handling?

• Farmers lack access to high quality certified rice seeds as well as inputs like fertilizer.
• Pests and diseases that affect growing and stored rice.
• Farmers have problems with weed control.
• Low access to mechanization services, for example, tractors for ploughing, planters, and combine harvesters.
• Post-harvest losses due to poor handling of harvested rice.
• Farmers lack knowledge of rice varieties suited for their regions.
• Farmers lack knowledge of how to properly dry rice after harvest. This results in post-harvest-losses, declines in grain quality, and loss of aroma.
• Farmers lack knowledge on how to grow rice.
• Lack of access to enough water for growing rice, especially when rains are scarce and rice is grown in rain-fed conditions.

Gender aspects of rice production and post-harvest handling

• In Ghana, men dominate land preparation activities for rice farming, including ploughing, while women transplant, weed, thresh, scare birds, winnow, dry rice, parboil, and mill rice.
• Much of the rice in Ghana is marketed through small businesses dominated by women, who sell in smaller quantities.
• In Ghana’s Volta region, women dominate rice farming, while men concentrate on coffee and cocoa crops. In the Northern region, men product rice, while women grow vegetables.
• In Ashanti region, Ghanaian women prefer to cultivate traditional varieties that are stress-tolerant but yield less than other varieties.

For further information, please see documents 1, 3, and 10.

Predicted impact of climate change on rice production

• In Ghana’s Upper West region, rice growing conditions are difficult due to the unreliable weather, in particular the erratic rainfall pattern. In response, farmers have grown traditional, drought-tolerant varieties.
• Rice grown in Ghanaian lowlands is prone to low yields due to regular floods from heavy rain.
• In Ghana’s lowland rice farming regions, there are sporadic droughts and seasonal occurrences of low soil moisture because of climate change. As a result, farmers grow early-maturing varieties.

For further information, please see documents 1, 2, 3, and 13.

Key information about production and post-harvest activities

 

Rice-growing regions

In Ghana, much of the rice is grown in Ghana’s northern savannah zones. The three rice-growing ecologies are upland rain-fed zones, lowland rain-fed zones or inland valley bottom swamps, and paddy irrigation schemes.

Soils

Rice is best grown in soils that are fertile and well-drained but with good water retention capacity. They should contain some clay and be rich in organic matter like loam soils. Land used to grow rice should be exposed to sun and not prone to erosion. Soil clods should be the same size as rice grains so that they can make contact with seeds.

Land preparation

Adequate land preparation, including levelling, minimizes the need to replant seedlings when there are gaps. Such replanting delays maturity and causes harvested rice to have varying moisture levels.

• Prepare the nursery seed bed and main field before the onset of rains.
• Well-tilled soils use fertilizer more effectively and are porous and well-aerated.
• If the planting field is flat, plough once and harrow twice to make the right tilth* for planting. But if the field is sloppy, plough and harrow once.
• Construct bunds around the field to suppress weeds, using hoes or animal-drawn ploughs. (See photo below)

• If the rainy season is brief, deep plough at the end of the previous planting season to a depth of 10-25 centimetres to manage weeds. Apply basal fertilizer before the final harrowing.
• Where soils are fragile and prone to erosion, use minimal or zero tillage and spray herbicides to kill emerging weeds. Emerging weeds will die off within 10 days after spraying, and can then be slashed or mowed.
• Divide fields that are prone to soil erosion into 50×50 m or 50×100 m plots, and construct bunds to harvest rainwater and allow drainage.
• Level fields to ensure a uniform depth of water over the entire season and uniform growth and maturity of rice.

For further information, please see documents 6, 7, 9, 11, 12 and offline documents

Seed preparation

Farmers should select certified rice seeds that grow robustly and are suited to the climate, then prepare them for planting. Seeds should not have been stored for more than11 months as they can lose their germination viability. During seed preparation, farmers must break seed dormancy, clean rice seeds, and conduct germination tests. Farmers can also do a float test before planting. The seeds that float on water should be discarded.

Varieties

Ghanaian farmers should buy rice seeds from credible input suppliers who stock tolerant, disease-free, and high-yielding varieties for upland and lowland ecologies. In Ghana, the rice varieties in the following table and their maturity periods are suitable for either upland and lowland areas, or both.

Breaking seed dormancy: Dry seeds for 1-2 days before planting. If using saved seeds, the best seeds for planting are those harvested last season.

Seed cleaning: Clean by first winnowing to remove chaff. Then soak in water and skim off floating seeds. Those that sink can be planted.

Germination test: This tests if the seed is viable and can germinate or not before planting. Pick 100 seeds from each bag and place them in shallow trenches. Cover with 3-5 centimetres of soil and water. Check germination after one week. If more than 80 seeds germinate, seed from the bag can be planted. If less than 60 germinate, don’t use the seeds. If 60-80 germinate, increase the recommended seeding rate by 20%.

Pre-germination: To increase the percentage of seedlings that successfully establish, farmers can soak a bag of seeds in water for 24 hours or until tiny shoots appear. Dry the seeds in the bag for 24 hours in the shade, ensuring that air can freely circulate around the bags. Ensure that the bags don’t exceed 42 degrees Celsius to avoid seed damage. Plant seeds before roots exceed five millimetres in length.

For further information, please see documents 6 and 11.

Planting: Rice can be planted by growing seedlings on a nursery and transplanting them into the field after 21 days. Or farmers can plant rice seeds or pre-germinated seedlings directly in the field. Water seedling nurseries regularly to keep soil moist. Maintain good drainage to prevent flooding. Seeds can be planted by broadcasting or in straight rows with uniform spacing.

If broadcasting, use 30 kilograms of seed per acre, or 80 to 100 kilograms per hectare.

The two planting methods for direct seeding in the main field are drilling and dibbling:

• Drill seeding: Manually plant seeds 2 centimetres apart at depths of 3-5 centimetres in rows 30 centimetres apart. The seeding rate per hectare is 60 kilograms or24 kilograms per acre. After seedlings establish, there will be 35 to 40 plants per row. With drill seeding, apply fertilizer in the planting hole. Drill seeding makes weeding easier.
• Dibble seeding: Space 3-4 rice seeds 20 centimetres apart in rows that are also 20 centimeters apart and at a depth of 3 to 5 centimeters. The seeding rate is 50 kilograms per hectare or 20 kilograms per acre.
  Farmers should weed 2 to 3 weeks after seeding.

Figure: Growth stages of rice plant

Crop establishment

Rice is planted at 20 cm between rows and 20 cm within rows. With this plant density, there are 25 plants in a square metre. Depending on the plant’s tillering ability and effective tillers, at this density, there will be about 300-400 panicles per square metre.

Farmers can improve crop establishment by practicing crop rotation, growing trap crops, bare fallowing, and dressing seeds with insecticides (see below a description of for these practices). To protect the stem and root, fumigate the soil or use organic pesticides.

Gap filling: When seedlings fail to germinate, grow, or are destroyed by pests, fill gaps one week after planting with new rice seedlings. In order to ensure uniform growth and maturity, do not wait longer than one week.

Thinning: Remove extra rice plants two weeks after sowing to reduce competition for nutrients, sunlight, and water.

Roguing: Remove irregular or non-standard rice varieties (off types) to ensure that the stand is of a uniform variety and ensure high productivity. Roguing maintains the quality of rice seed and minimizes the incidence of broken rice grains when milling due to lack of grain uniformity.

Weeding: Apply suitable herbicides to ensure a clean field two weeks after transplanting rice seedlings or direct seeding. At first weeding, apply NPK fertilizer by broadcasting as basal. Conduct a second weeding 7-8 weeks after planting, depending on the maturity of the rice crop. After the second weeding, farmers should apply urea or sulphate of ammonia as topdressing when the soil is moist so that the nitrogen fertilizer can dissolve. Farmers should consult extension officers on how to use safely and effectively use herbicides.

Farmers who do not wish to use herbicides can weed with a hoe or a weeding machine.

Seed dressing: This involves applying protective pesticides to rice seeds before planting to stop pest and disease attacking.

Trap crops: These are crops that draw plant pests away from the main crops.

Bare fallowing: The farm is left without crops for a season and free of vegetation by either cultivation or herbicides. It helps improve soil organic matter and water intake and retention and increase plants nutrients availability.

Nutrition

To produce optimal and even yields, rice farmers should ensure that fertilizer and manure are applied uniformly. Uneven crop nutrition leads to uneven grain maturity.

Manure: In rain fed conditions, farmers should apply 7-8 tonnes of cow dung or 4 tonnes of poultry manure per hectare before planting and work it into the soil. For irrigated rice, farmers should apply 7-8 tonnes of cow dung or 4 tonnes of poultry manure per hectare two weeks before planting and work it into the soil.

Fertilizer: Two to three weeks after transplanting or direct seeding, rice farmers should apply 250 kilograms of NPK*15-15-15 as basal. Farmers should top-dress with 125 kilograms of urea or 250 kilograms of sulphate of ammonia per hectare 7-8 weeks after planting.

Each season 1-7 days after transplanting, farmers should incorporate 1-3 grams of urea granules 7-10 centimetres deep in the soil near the plants’ rooting system. The granules make nitrogen available to the growing rice.

• Scout for common pests and diseases as shown below.

Pest management

Stem borers: These pests bore through the stem and base during the vegetative stage and cause young tillers to die. They leave a whitish colouration on the panicles, causing whiteheads. * In older rice plants, stem borers bore into the upper nodes and feed on them.

Stem borers can be managed by:

• Hand picking and destroying caterpillars and eggs
• Early planting
• Applying a pinch of neem powder on the funnels* of young rice plants
• Spraying pesticides
• Planting varieties that are resistant to stem borers
• Crop rotation with short-term crops that are, unlike rice, not in the grass family
• Burning rice stubble after harvesting
• Installing light traps (five per hectare)
• Deep ploughing crop residues into the soil also destroys stem borers
• Cutting off mature rice plants at the base to remove the majority of stem borers attached to the plants

Africa rice gall midge: This insect attacks lowland rice varieties. Its larvae attack the growing tips of the apical bud* at the node, causing the leaf sheath to curve like a tube. The pest can be managed through early planting or growing rice varieties that are tolerant to it.

Rice leaf folder: A yellow or red moth whose larvae scrape plant leaves and cause them to fold around it and then feed from inside it. Feeding results in transparent leaves. It causes the most damage during tillering, which results in low rice yields. The pest can be managed by:

• Moderating fertilizer applications, since too much fertilizer attracts females.
• Maintaining a grassy habitat around the field that hosts natural enemies such as crickets that feed on leaf folder eggs.
• Planting rice varieties resistant to rice leaf folder.
• Spraying insecticides when infestations are high at tillering and maturity.

Termites: These white ants attack upland and rain-fed wetland rice varieties. They become lodged on growing stems, stunt the plant, and muddy the stems. They can be managed by:

• Spraying with recommended pesticides
• Burying dry stalk residues after harvests.
• Not mulching fields infested with termites
• Destroying termite nests and colonies before planting
• Maintaining soil moisture in dry seasons to stop termite activities
• Inter-planting rice with termite-repellent plants like basil
• Treating seedlings with insecticides at planting or applying granular insecticides on seed furrows or hills.

Rice mealybugs: These whitish, wooly insects secrete and cover themselves with a white wax. They infest the leaf sheath and stunt the plant by sucking sap from the stem, resulting in abnormal tillering and smaller, yellowing leaves. With heavy infestations, panicles don’t form and plants can dry up. Since rice mealy bugs are highly immobile, they damage rice crops in patches. They can be managed by removing and destroying infested rice plants when first detected and spraying foliar feed at high pressure at the base of plants to dislodge mealybugs.

Rice weevil: These two-millimetre brown or black snouted insects feed on stored dry rice grains in granaries. They can be managed by treating stored rice with insecticides. Alternatively, farmers can apply 5 ml of neem oil per kilogram of stored rice to manage the rice weevil.

Mole crickets: These are crickets with mole-like digging front legs. Their chewing severs roots and stems and causes rice plants to wilt. Mole crickets can be managed by:

• Spraying them with neem or other insecticides once a month.
• Irrigating and applying recommended amounts of manure and fertilizer to ensure crop health and allow crops to recover from mole cricket injuries.
• Destroying mole cricket nymphs and adults during land preparation.

Weaver birds: These birds attack rice at the milk and grain-filling stage and feed on grains from the panicles. Weaver birds can be managed by using scarecrows or scaring birds away and destroying their nests.

Diseases

Rice yellow mottle virus (RYMV): This viral disease reduces tiller*numbers and stunts and kills plants. Symptoms include yellow or orange leaf colouration and empty spikelets (male and female flowering organs). Infected plants are susceptible to other diseases like brown spot. RYMV can be prevented by:

• Not planting rice in areas where RYMV is present.
• Direct seeding instead of transplanting minimizes RYMV.
• Managing weeds growing around rice fields.
• Planting rice varieties that are resistant or tolerant to RYMV.
• Roguing rice plants infected by RYMV.
• Preventing injury to rice seedlings when transplanting or weeding.
• Washing hands after contacting infected rice plants to avoid transmitting RYMV to healthy rice plants.
• Destroying insects that vector* the disease, including leafhoppers.
• Ploughing infected rice stalks, ratoons*, weeds, and waste under the soil after harvest.
• Inhibiting growth of secondary rice plants which are sources of RYMV. (Secondary rice plants grow from the still-living shoots of remaining rice plants after harvest.)

Rice blast: This seed-and airborne disease causes up to 100 percent yield loss in some rice varieties. It infects rice from the seedling to maturity stages. The disease causes whitish to grey-green and brown or reddish diamond-shaped lesions and darkened borders on rice leaves.

It also causes the collar and dark purple or blue-gray nodes and neck to shrivel, rot. and break off. Panicles turn a straw colour starting from the nodes.

Management

• Plant certified varieties that are tolerant or resistant to rice blast.
• Treat rice seeds with fungicides before planting.
• Destroy crop residues that can propagate rice blast.
• Minimize the use of nitrogen fertilizer. Excess nitrogen fertilizer increases the risk of rice blast.
• Stress from drought and water shortages increases the risk of rice blast.
• Remove leaves or stems affected by rice blast if damage is minimal.

Brown leaf spot: Symptoms include reddish-brown spots on leaf surfaces. Sheaths have small, circular dark-brown and purple lesions.

Management

• Buy high quality, certified seed.
• Transplant only healthy and disease-free seedlings.
• Burn infected crop residues after each harvest.
• Weed rice fields both in and out of season.
• Remove diseased rice plants from nurseries or fields and burn.
• Treat soils with calcium silicate to boost plant resistance to brown leaf spot.
• Apply fungicides that fight brown leaf spot.

Sheath blight: This fungal disease leaves brown spots on leaf sheathes. High temperatures and humidity increase the severity of sheath blight. Infected leaves die and rice yields can be reduced by 20-25%.

Management

• Sheath blight can be managed by moderating nitrogen application.
• Fungicides can also be used to manage the disease.

Brown spot: This fungal disease is common in rice fields with low-nutrient and poorly-drained soils. It’s transmitted through infected seeds and lowers rice grain quality and weight at harvest. Infected rice grains and leaves have brown spots on them.

Management

• Grow rice in good soils that are adequately fertilized.
• Grow rice varieties resistant to brown spot.
• Treat rice seeds with fungicides or hot water before planting.

Leaf scald: A fungal disease that diminishes rice grain quality and inhibits growth. It creates brown lesions on leaves starting from the leaf tip. Leaf scald fungus feeds on rice straws. Flooding in rice fields can cause the disease to be severe.

Management

• Avoid excess nitrogen fertilizer application.

Summary

• In case of attack by pests and diseases, use the crop protection method recommended by your extension agent/community-based advisor.
• Regularly scout for common pests and diseases in rice plantations.

Harvesting and post-harvest activities

Rice varieties mature and are ready to be harvested in 80 to 130 days. At maturity, 85-90%of rice panicles turn yellowish-brown and grains have 18-20% moisture content. Rice can be harvested manually by cutting panicles with a sickle or by using a mechanized harvester. The panicles are placed in clusters in the field, then threshed after harvesting is complete.

Threshing

Threshing separates rice grains from panicles and should be conducted on clean and dry surfaces like plastic sheets or canvas. The panicles are either beaten on special wooden frames, by rubbing panicles by hand, or by being trampled by humans, animals, or tractors.

Winnowing

Winnowing separates threshed rice grains from impurities like dust, immature grains, chaff, rice straw, sand, small stones, and other substances, protecting milled grains from contamination. Winnowing can be conducted manually by pouring rice grains from a tray held in front of the body to a container below, and allowing the wind to blow away impurities.

Drying

After harvesting, drying is the most critical process to minimize rice post-harvest losses since it affects storage, transportation, and processing quality. Drying lowers the moisture content to 12-14% so that rice can be milled and stored without the growth of toxic fungi. Most farmers sundry their rice for a few days until it reaches the desired moisture content.

For further information, please see documents 4, 5, 6, 7, 8, 9, 11, 12, 14 and offline documents

Definitions

Bunds: Embankments that separate rice fields and manage the depth of water in a rice paddy. Bunds are at least 20 centimetres in height and 15-150 centimetres wide. Their shape depends on the topography of the rice paddy. Bunds have a spillway about five centimetres wide that controls the depth of water in a rice paddy.

Tillering: Tillers or side shoots appear as secondary shoots to the main shoot. Each tiller can be removed and become an independent plant. The tillering stage of growth marks the end of the seedling stage and it’s when the fourth true leaf emerges.

Tilth: The condition of the soil and its suitability for planting and growing crops. A soil with good tilth is loose with fine and easy-to-crumble particles, granular and not compacted.

Where can I find other resources on this topic?

 

1. Addison, M. et al, 2014. Gender Constraints and Rice Varietal Characteristics Preferences in Lowland Rice Ecosystem in Ghana, Developing Country Studies, volume 4, No. 15, pp. 92-98. https://core.ac.uk/download/pdf/234681844.pdf (275 KB).
2. Al-hassan, S., 2008. Technical Efficiency of Rice Farmers in Northern Ghana. https://media.africaportal.org/documents/RP178.pdf (155 KB).
3. Coronel, C., and Lançon, F., 2008. Study and training on the Ghanaian rice commodity chain. https://agritrop.cirad.fr/553282/1/document_553282.pdf (1.537 MB).
4. Government of Papua New Guinea, 2015. Handbook On Rice Post-Harvest Techniques. https://www.jica.go.jp/png/english/activities/c8h0vm00008t2xqj-att/activity10_04.pdf (2.703 MB).
5. Hodges, R., and Stathers, T., 2012. Training Manual for Improving Grain Postharvest Handling and Storage. https://documents.wfp.org/stellent/groups/public/documents/reports/wfp250916.pdf (15.446 MB).
6. International Rice Research Institute, 2015. Steps to successful rice production. http://knowledgebank.irri.org/images/docs/12-Steps-Required-for-Successful-Rice-Production.pdf (1.21 MB).
7. Japan International Research Center for Agricultural Sciences(JIRCAS), 2012. Manual for Improving Rice Production in Africa. https://www.jircas.go.jp/sites/default/files/publication/manual_guideline/manual_guideline-_-_9.pdf Research (6.157 MB).
8. Lantin, R., 2012. Rice Post Harvest Operations. In FAO INpho, 2012, Post-Harvest Compendium. http://www.fao.org/fileadmin/user_upload/inpho/docs/Post_Harvest_Compendium_-_RICE.pdf (623 KB).
9. Oikeh, S.O., et al, undated. Growing upland rice: a production handbook. http://www.fao.org/fileadmin/user_upload/ivc/docs/uplandrice.pdf (766 KB).
10. Overseas Development Institute, 2000. National Workshop On Rice Production In Ghana. https://cdn.odi.org/media/documents/4130.pdf (197 KB).
11. Phiri, N. A et al, 2011. Quality Rice Seed. Production Manual. https://www.cabi.org/Uploads/projectsdb/documents/45948/Quality%20rice%20production%20manual.pdf (4.826 MB).
12. Ssebunya, B., 2011. Rice. Chapter 9-1 in African Organic Agriculture Training Manual: A Resource Manual for Trainers. https://www.organic-africa.net/fileadmin/organic-africa/documents/training-manual/chapter-09/Africa_Manual_M09-1.pdf (2.198 MB).
13. Sustainable Rice Development Project in Sierra Leone, 2014. Technical Package on Rice Production. https://openjicareport.jica.go.jp/pdf/1000022265.pdf (1.8 MB).
14. World Bank, 2011. Missing Food: The Case of Postharvest Grain Losses in Sub-Saharan Africa. http://www.fao.org/3/at454e/at454e.pdf (1.668 MB).