UPLAND AND LOWLAND RICE PRODUCTION IN TROPICAL
REGION OF NIGERIA
Rice (Ory/a saliva L.) is one of the leading food crops of the world. Demand for rice is rapidly increasing in West Africa. Nigeria imports more than 80% of its rice requirement. Local production is low and efforts to increase production are hindered by high input costs, low prices for rice, and low yields, especially in the uplands. This is true in most West African nations. There is an urgent need tor cultivars and production technologies in the both the upland and lowland ecosystems that will help increase yields at lower monetary costs. Upland rice is mainly grown under a shifting cultivation system. This involves slashing and burning of virgin forest to acquire new and more fertile lands. Environmental concerns and increasing human density are discouraging this practice and research on permanent cropping of the land is being promoted. One strategy to facilitate cultivation of the same piece of upland rice field withoul yield loss and without high input of human labor, fossil energy, feriili/er, and herbicide is the use of low input rice varieties. These varieties present a major challenge for research because upland rice often needs a higher level of fertilization than does lowland rice. The West Africa Rice Development Association (VVARDA) is developing low input varieties primarily from selections among African varieties and exotic varieties. In a 3 - year varietal screening exercise, conducted in the Nigeria, cu WAR 377 B 16 LB LB and WABs6 125, bred by WARDA were found to be higher yielding and more stable than the commonly used Asian variety (Peking) aL low fertilizer application rates. The low - input varieties were also found to have higher NUE than the Asian variety (Peking). In lowland rice farming, water control is the most important management practice that determines the efficacy of other production inputs.
Poor drainage that keeps soil saturated is detrimental to crops and degrades soil quality. In many rice irrigation systems in Nigeria, water control is highly inefficient. Drainage mechanisms are dysfunctional or inadequate because farmers believe that rice grows best when water is supplied in abundance. Poor drainage mechanisms makes it necessary for farmers to transplant tall, very old seedlings, usually 4 ~ 6 weeks old, and 3 - 4 seedlings per hill. Rice fields are kept continuously flooded and are flood - free only at time of harvest. This practice is not only wasteful in terms of water use efficiency, but also leads to leaching of soluble nutrients, blocks aerobic soil microbial activities and biological nitrogen fixation as well as slows minerali/ation and nutrient release from the soil complexes. New management practices that address lowland rice production constraints in Nigeria are needed. The System of Rice Intensification (SRI), used in Madagascar, proposes a methodology that has the potential to increase rice productivity without a high investment in external inputs or introduction of new cultivars. SRI changes the ways in which plant, soil, water and nutrients arc managed. In 2000, 2001, and 2002, SRI experiments were conducted in Nigeria. The SRI water management practices of repeated soil wetting and drying were found to be beneficial to rice plant growth probably through increased biological nitrogen fixation, more nutrient availability, profuse root development, increased tillering, and a high panicle setting ratio leading to higher grain yields. Grain yields of rice under SRI management are 2 - 3 times higher than the national average in Nigeria.
UPLAND RICE PRODUCTION
Growing Upland Rice in Nigeria
Choice of Land
i. Select site in ecological zones where rice is grown traditionally.
ii. Choose fertile land with good water retention capacity (contain some clay and/or organic matter i.e. loamy soil),
iii. If you have to grow rice for one or more consecutive year on the same piece of land, seek the advice of Soil Survey and Testing Service of the Institute of Agricultural Research and Training (JAR&T) or any other reputable soil-testing unit.
iv. Grow legumes after rice, and plough rice residues into the soil as organic matter.
1) MECHANISATION: (Forest Area) For newly cleared areas, stump big trees before the rains preferably from November to February and remove all stumps, roots and trees before ploughing. Plough once and disc harrow twice with the first rains from late February to early March to make good tilt if land is flat. Plough twice and disc harrow once if land is sloppy. Apply basal fertilizer before final harrowing. Divide the field into plots of 50 or loom2. Construct bunds depending upon the slope, to accumulate rain water. Level the land to reduce erosion. For consecutive cropping, take necessary soil conservation measures in land preparation.
2) MANUAL CULTIVATION: Clear and pack bush between November and February, and use hoe to remove bush and weeds. In the Savannah, land preparation can start in February, depending on the rain.
Faro 38 (IRAT 133), FARO 39 (IRAT 144), FARO 45 (ITA 257), FARO 46 (ITA 150).
FARO n(OS 6), FARO 48 (ita 128), FARO 47 (ITA 117), FARO 48 (ITA 301), FARO 49 (ITA 315)
Time of Planting
(i) In the forest area, plant in mid-March to mid-April, after 2 to 3 good rains.
(ii) In the savannah, plant rice in mid-May to Mid-June, depending on the rains.
60 kg/ha by dibbling; 50-55 kg/ha by drilling in rows spaced 30 cm apart; and 80 00 kg/ha by broadcasting.
In dibbling or direct seeding, sow seeds 25 x 25 cm to give 160,000 stands/ha. Use a "pinch" or 4 to 5 seeds paddy per hole. Plant about 3-5cm deep, cover lightly and press. In drilling method, drill in rows 15-20 cm apart.
Fertilizer Rate and Time of Application
Undertake soil test before any fertilizer application. Do not apply any fertilizer on newly cleared land in the first year.
(i) BASAL FERTILIZER OR FIRST APPLICATION: Where basal fertilizer is applied, use phosphate and potash fertilizer in deficient soils at final harrowing before seeding. After bush burning, no phosphate and potash fertilizer are needed. Apply 100kg of 15-15-15 per hectare (2 bags/ha) as basal fertili/.er or just at the lime of first weeding (2-3 weeks after emergence) to facilitate incorporation of fertilizer into the soil.
(ii) SECOND APPLICATION OF TOP DRESSING: Apply 50 kg (one bag) of Urea per hectare—5 weeks after sowing. In areas where acidity is high, do NOT use Sulphate of Ammonia but use other sources of nitrogen e.g. urea.
METHOD OF APPLICATION
By drilling or broadcasting, ensuring incorporation into the soil. Apply fertilizer at 10 cm from base of plant (hill application) immediately after a sufficient rain.
(i) Iron Deficiency: When the soil is deficient in organic matter and iron, the seedlings turn yellow then white a week after germination. They later die.
• Spray 1% ferrous sulphate with 0.2% citric acid or lemon at 500 liters/ha once or twice depending on the recovery of plants.
• Apply iron chelates and urea in between rows at 25 kg/ha.
(ii) Zinc Deficiency
• Apply 25 kg/ha /inc sulphate (20% zinc) or
• Spray 1% /inc sulphate with 0.5% lime at 500 Itr/ha to the base as symptoms are seen.
First weeding should be thorough and should be done within 2 to 3 weeks after emergence, using hoe instead of cutlass (The earlier the first weeding is done the better).
Second weeding should be done 6 to 7 weeks after emergence. Weed a third time, if necessary.
1) Pre-emergence: Apply RonstarTM 25(EC) 2-3 days after sowing or just after seeding at the rate of 4-6 litres/ha. Spray GramoxcTM at 2 Itr/ha when weeds have grown in the field. DO NOT spray GramoxcTM after the germination of paddy seeds.
2) Post-emergence: Apply RonstarTM (PL) 14 to 21 days after planting at the rate of 5-6 litres/ha. Use Propanil (Stan 1734), Tamarice or Propanil-Bentzon (Basagram) 14 to 21 days after planting at the rate of 3 kg a.i. (10 liter tin) per hectare. With a knapsack sprayer, use 220 ec of Propanil or Tamarice, except Basagram which should be used at the rate of 150 cc, in 10 liters of water. Any resistant weed species or newly germinating weeds like corn grass Rottboellia cochinchinensis should be roguecl. A weed-free seed-bed at planting also contributes to the effectiveness of the herbicides.
i. Preventive: Destroy all dead woods and plant residues by burning. Locate termite mounds in surrounding bush and destroy.
ii. Control: Spray Nogos 50 at the rate of 30 ml per 4.51 (one gallon) of water. Nine litres (two gallons) of solution are sufficient to destroy a termite mound.
In case of an attack, spray Gammalin 20 or Carbaryl (Vetox 85) at the rate of 1.68 kg in 225 liters gallons) of water per hectare (i.e. six levels of empty large match box in 9 liters (2 gallons) of water.
Keep 2 to 3 metre border round the field free from grass, weed and burn thrash to control rodents. Build bamboo or palm frond fence (if possible), around the field immediately after planting. Create openings at. short intervals and place traps in the openings. If rats and grass cutters become troublesome, kill them with snap traps. Use scaring devices to control birds. Employ human scarcrs to drive birds from farms from 6 am to 7 pm first two weeks after planting, and from heading to harvesting. Use traditional means where it is effective or plant contiguous fields.
Harvest when 80 percent of the grains have turned straw colour to avoid shattering.
Thresh immediately after harvest to avoid losses. Use wacking frames or mechanical devices, but avoid threshing on bare floor. Thresh on a mat or tarpaulin over concrete floor by Hailing (i.e. beating rice against the floor, or against a stick or drum). Thresh carefully and avoid dehusking the grains. Damaged grains become stained and coloured after parboiling and milling.
If above recommendations are followed, and rainfall is adequate, an average yield of 1.5-2.0 t/ha could be obtained.
Dry paddy properly to a safe moisture content of 13-14 percent, by spreading on clean concrete floor, mat or tarpaulin. Sun-dry slowly for 2-3 DAYS Lo reduce breakage during milling. On a clear bright day, sun- dry for one day only by spreading paddy thinly on clean concrete floor, mat or tarpaulin. Use mechanical drier if possible.
Store in cool, dry rodent-proof conditions. Infested paddy should be fumigated with phostoxin in air-tight containers at the rate of one tablet per jute bag (100 kg paddy) or 10-15 tablets per ton of paddy.
i. Parboiling: Soak paddy in hot water at yooC for 5 to 6 hours. Discard all floating empty grains. Parboil rice by steaming soaked paddy put in a jute bag for 10 to 16 minutes by suspending the bag over steaming water in a drum. Stop parboiling when rice husks start to split open. Chalky grains or white centers indicate incomplete parboiling, which may cause breakage of grains during milling.
ii. Milling: Mill rice in a two-storage milling machine. Always mill one pure variety at a time.
LOWLAND RICE PRODUCTION
Major lowland production constraints
- Africanrice gallmidge (AfRGM)
- Stem borers
- Rice yellow mottle virus (RYMV)
- Sheath rot
• Low soil fertility (P and N deficiencies)
• Iron toxicity.
• Salinity/alkalinity problems in the irrigated lowland production
Choice of land
• Choose fertile land with good water retention capacity (contain some clay and/or organic matter, i.e. loamy soil); clayed soils arc most desirable.
• Heavy soils of valleys andfadamas are preferred.
• Consult Soil Survey and Testing Service of the Institute of Agricultural Research and Training (IAR&T), Ibadan or any other reputable soil-testing unit if growing rice for one or more consecutive years on the same piece of land.
Recommended lowland varieties
• Early maturing (<9O-ioo days): FARO 44 (SIPI) and 'etumbe' (local).
• Mediummaturing (100-120 days): FARO21, 26, 29, 52 (WITA 4), 57TOX 4004-43-1-2-1, and others.
• SUAKOKO 8 and FARO 15: Suitable for iron toxic areas.
• Late maturing (>12O days): FARO 10, 12, 13, 16, 17, 19, 24, 28, and others.
• Gall midge-affected areas: Cisadane (FARO 51).
Choice of seed
• Use good quality seeds with no insect damage and no contaminants (weed seeds, stones, other seed types) with high percentage of viability (>8()%).
Sources to contact for good quality seed
• State Agricultural Development Project (ADP) that includes rice in its production programs.
• River Basin Development Authority.
• Branch office of the National Agricultural Seed Council.
• Seed company.
• Other rice farmers.
• Dormancy is the failure of good quality mature seeds to germinate under favorable conditions. Dormancy of freshly harvested seed should be broken by using heat treatment at 5O°C in an oven if available or by placing the seeds on a plastic sheet and covering with itself or another under direct sunlight for i or 2 days. Acid treatment may also be used.
• Acid treatment: soak seeds for 16 to 24 hours in 6 ml of concentrated nitric acid (69% HNOs) per liter of water for every i kg of newly-harvested seeds. After soaking, drain acid solution off and sun-dry the seeds for 3 to 5 days to a moisture content of 14%. Store in dry conditions for sowing.
• Conduct germination test on seeds to establish rates to use based on seed viability.
Seed viability testing and seed requirement
i. Use only filled grains of quality for sowing: add water to seeds and discard all empty grains that float in water.
ii. When the seed viability is not known, carry out a simple seed viability test to guide the actual seeds required for sowing,
iii. Place moistened tissue paper (preferably filter paper, if available in a dish with lid (use Petri-dish if available) and put in 100 ramdomly selected filled seeds. Cover and keep the dish at room temperature for 4-5 days to allow germination.
iv. Then count the number of sprouting seeds (only those with shoots >i cm). If 75 germinating seeds are counted, it means the viability rate is 75%(%germinat:on).
v. If the seed rate is 80 kg/ha, the actual quantity of seeds to be used for sowing is calculated thus:
Seed required (kg/ha) = X % filled grain
= X 1 (assuming 100% filled grains) = 107 kg/ha
iv. To estimate percentage filled grains, select at random 100 seeds from the seed lots to be sown and count the number of filled grains. If 100, it means 100% filled grains.
• First, treat selected seeds with a mixture of insecticide and fungicide. For example, Apron StarTM 42 WS (thiamethoxam 20 g/1 + difenocona/olc 2 g/1 + metalaxyl-m 20 g/1) at the rate of one sachet per 4 kg seeds or any available seed dressing chemical before sowing.
• Other products can be used:
- PROCOT 4oWS (carbosulfan + carbenda/im + metalaxyl-m.
- CALTH1O C 50WS (Lhirain + ehlorpyriphos-ethyl).
• In areas with termite and nematode problems, incorporate carbofuran (FuradanTM) at the rate of 2.5 kg a.i. per hectare into planting row. To ensure uniform application, mix Furadan with sand at a ratio of 1:4.
• Soak seeds in water for 24 hours and incubate for 48 hours before sowing to ensure uniform seedling emergence and good establishment.
Establishment of nursery
Dry bed nursery
• The nursery bed should be watered regularly to keep the soil moist but not puddled. Good drainage should be provided to ensure that the nursery is never flooded.
Wet bed nursery
v Select a good site with well-drained fertile soil exposed to full sunlight, and conveniently located in an area close to the main field and to facilities for efficient watering when needed.
v Prepare seed bed at least 7 days but preferably 14 days before the seeds arc sown.
v Seed bed should be i to i.smwide, 10 m long, 4 to 6 cm above the ground surface and well leveled.
v Soak the seeds in water for 24 hours. Spread seeds on the floor. Incubate seeds by covering with polyethylene bags or raffia palms for another 48 hours for seeds to sprout.
v Spread the sprouted seeds uniformly on a puddled nursery bed (wet bed nursery) or on a leveled surface for dry bed nursery. Use seed rate of 80-100 kg/ha depending on percentage seed viability and grain filling percentage for the actual requirement.
v Drain the excess water from the nursery bed for about a week. Then flood to 2-3 cm depth if using wet bed nursery.
v Apply 50 g/m2 of NPK 15-15-15 fertilizer or apply 5 t/ha of rice husk + bran as mulch/manure. A combination of the two, where available, will give better seedlings.
v About 5 days after sowing seeds, the nursery beds should be kept flooded to a depth of 2-3 em. To prevent weeds and also ensure easy pulling of seedlings, water depth should gradually be increased to a depth of about 5 cm.
v Avoid bird damage during germination by scaring the birds.
v In areas prone to gall midge, apply carbofuran at i kg a.i./ha in the nursery beds a week before uprooting.
• In areas with lots of perennial weeds, disc plow the field immediately after harvest in November/December to expose the rhi/omes (roots) to the sun.
• Plow and harrow field Flood the field for about 2 weeks to kill weeds.
• Remove water after 2 weeks and mark out field into basins (e.g. 5111 x 5111) with hand hoes.
• Construct bunds around the field to retain water and suppress weeds using animal traction, hand hoe, etc.
• Irrigate or allow rain into the basins and level properly (hand puddling or with animal traction).
Time of sowing
• Forest zone - March to April.
• Derived savannah - May to June.
• Guinea savannah - June to July.
• Sahel savannah - seed at any time of the year depending on water availability.
• In all eases, seeding should he done when rains arc well established.
Transplanting and spacing
• Transplant seedlings to the well-puddled and leveled main field between 14 and 21 days after sowing.
• Transplant at a rate of 2-3 seedlings per hill, to a depth of 3-4 cm, and at a spaeing of 30 001x30 cm (best for late-maturing eultivars), or 20 x 2Ocm when soil is fertile or sufficient fertilizer is available.
• Direct seeding can be done in hydromorphic areas of the toposcquence.
• Divide the field into plots of 50 or loom2 and construct bunds.
• Apply herbicides to controlweeds as they can be a problem.
• Sowsecds at a spacingof20cmbetween rows andi5-2O cm within rows (between hills) by dibbling.
• Direct seeding can be done using pregerminated seeds on wet soils.
Gap fill the empty spaces with seedlings within 7-10 days after transplanting using leftover seedlings from the nursery.
• Fertilizers supply nutrients essential for growth, nutrition and health of the rice plant.
• Fertilizers can be applied in the form of organic or inorganic (mineral) or both.
• Organic fertilizer can be in the form of manure, compost or crop residues.
• Mineral fertilizers are manufactured. It is important to apply the right quantity and at the right time to obtain optimum yields and for environmental protection.
Types of fertilizers
• Straight (single) fertilizers: These supply only one primary nutrient (e.g. N, P or K) to the crop.
- Nitrogen: urea, ammoniumsulphate, ammonium nitrate, calcium ammonium nitrate (CAN), and others.
- Phosphorus: single super-phosphate (SSP), triple superphosphate (TSP), and others.
- Potassium: muriate of potash (MOP; KCl)
• Compound fertilizers: these supply more than one nutrient (e.g. N, P and K) to the crop.
- NPK 15-15-15 (15%N; i5%P2Os; 15%K2O);
- NPK 20-LO-io (20% N; 10% P2Os; io%K2O);
- NPK 30-10-0 (30%N; 10% P2C>5; o% K2O);
- Ammonium phosphate nitrate (APN).
• Fertilizer should be applied based on the residual nutrients found after soil testing, the expected yield and the type of fertilizer materials available.
• The farmer should strive to obtain fertilizer recommendations based on the analyses of soil samples. Table 2 can serve as a guide.
• In situations where it is not possible to conduct a soil test due to high cost and unavailability of analytical services, or when the fanner is running out of time because the crop is subnormal in growth, the general recommendations in this handbook should serve as a guide.
General fertilizer recommendation based on Agroeeology
• Humid forest:
Apply 60 kg N, 30-60 kg P2O5 and 30 kg of K2O per hectare
Apply 60-80 kg N, 30-60 kg P2O5 and 30 kg KaO per hectare
• Sudan/Sahcl (under irrigation):
Apply 100-120 kg N, 60 kg P2Os and 60 kg K2O perhectare
Time of application
Basal Application of Phosphorus and Potassium
• Apply P and K within one week before transplanting and work the ferlili/er well into the soil.
Topdressing of N fertilizer (e.g. urea)
• Apply in three equal doses:
- Deep placement (2-3 cm) at transplanting.
- Broadcast at aboiitmid-tillering (3-5 weeks after transplanting [WAT]).
- Panicle initiation (i.e. when the plants are about 'pregnant'; 8 WAT for late maturing cultivars > iso-days or ealier, (6 WAT) for medium maturing cultivars).
• Maintain water level on the field to 3-5 cm at the time of fertilizer application to ensure efficient use of the applied fertilizer.
Methods of fertilizer application
The fertiliser can be applied in two ways:
• For small areas: in irrigated system, close the irrigation inlet and drainage outlet. Then apply the fertilizer between rows.
• Irrigate and close the canals for about 10 days to facilitate nutrient absorption.
• Drain the field and apply the fertilizer by broadcasting. The fertilizer should be flooded immediately to prevent dentrifieation.
Topdressing N from straight fertilizers (e.g. urea)
• Use 15 to 20 kg N for every tonne of target (expcetcd) yield.
• Apply in 2-3 splits for > 60 kg N/ha (>2y2 bags urea); use more splits for late-maturing cultivars (>12O DAS).
• Do not apply more than 35 kg N/ha (iVa bags urea) in a single dose (split) to minimize losses.
• Use 1RRI Leaf Color Chart (LCC) when available, to guide in topdressing.
• When it is required to apply two or more elements and the desired compound fertilizer is not available but the straight fertilizers are available (Annex i), you may weigh and mix the fertilizers before application. This is particularly important for large mechanized rice farms.
• However, note that not all fertilizers are compatible when mixed. For example, if basal N is necessary and you need to apply N and P as basal, do not mix ammonium sulphate with rock phosphate, or urea with super-phosphate. The elements will react with one another and become less effective. The chart in Annex 2 can serve as a guide for mixing fertilizers for application to various crops, not only rice.
• Plant tolerant varieties such as Suakoko 8, FARO 15, ITA 247, 1TA 249.
• Eliminalc excess iron through good water management by draining the field.
• Use balanced nutrients such as N, P, K, and Zn.
• Cultural practices such as ridging, organic manure application, among others.
• Maintain the water level in the field up to 5cm from one week alter transplanting until grain matures.
• Drain the water a week before harvesting
• Cracks should not be seen on the field
WEED CONTROL Hand weeding
• Drain water from the field
• Hand weed 14-20 days alter transplanting
• Hand weed again around 30-40 days after transplanting
Chemical weed control
For pre-emergence in direct-seeded fields
• Rice Force and Gramoxone (paraquat) at isoml each in 20 liters of water per hectare sprayed not later than 24 hours after seeding.
Post-emergence application in both transplanted and direct-seeded fields
• Delmin Forte (2,4-0 amine salt) or Amine Force (2,4-0 amine) plus Propan 360 (propanil) at 200-250 ml (depending on seedling age) or propanil mixed with 50 ml of the 2, 4-D in 20 liters of water per hectare.
Disease control (RYMV, blast, brown spot, grain discoloration)
• Use disease resistant/tolerant varieties to RYMV and Blast.
• Use good cultural practices to limit infection of blast and RYMV.
- High nitrogen associated with low potassium can increase blast damage.
- Split application of nitrogen is better than one application to reduce blast damage.
- Removing surrounding weeds to destroy the alternate host of RYMV can reduce the virus infection.
• Use clean healthy seeds.
• Treat the seeds 1-2 days before sowing to control seed-borne Pathogens
• In case (and only in case) of being in an area conducive to fungal diseases, spray DithaneTM M-45 (80% of mancozeb) at i.o kg or BenlateTM (50% of benomyl) at 1.5 kg a.i/ha, in 500 liters of water to control rice blast, brown spot and grain discoloration. If the damage is severe, spray again after 15 days.
Insect control Diopsis species
• Cultural practices such as early sowing, narrow spacing of plants and maintaining weed-free fields should be observed to minimize Diopsis infestation.
• Synchronize planting over a large area to allow the most; susceptible stage of rice to escape from Diopsis damage.
• Use of variety such as WAB 1159-2-12-1.1-6-9-1-2 with highly hairy leaves can trap Diopsis tlioracica larvae.
African rice gall midge control
• Early and synchronized planting of rice fields can minimize damage than late planting.
• Destroy alternative host plants such as rice ratoons, volunteers and Oryza longistammta.
• Use of fertilizers: moderate levels of fertilizer (e.g. 60 kg/ha) should be used and applied in split doses.
• Movement of seedlings should be discouraged because such seedlings can be infested by AfRGM in the nursery.
• Plant spacing: narrow spacing such as drilling should be discouraged because it provides a suitable micro-environment for the survival of the exposed life stages of AfRGM.
• The gregarious cndoparasitoid (Platygaster diplosisae) and the solitary cctoparasitoid (Aprostocetus procerae) are the most important wasps (natural enemies) attacking AfRGM and should be protected on the field.
• Habitat manipulation by planting paspalum grass (Paspalum scrobiculatum) at the edge of the rice fields can increase the carry-over of parasitoids from Paspahtm gall midge (Orseolia bonzii) to AfRGM. Such cultivation can be done in the dry-season to encourage Paspalum scrobiculatum abundance early in the wet season.
• Use of traditional Oryza saliva variety such as TOS 14519.
• Use of tolerant rice varieties such asCisadanc , BW348-1, Lcizhung, and others.
• Use of tolerant lowland NERICA varieties such as NERIGA L-25, NKRICA L-19, NKR1CA L-29, NERICA L-49.
• Use of traditional Orijza glaherrima varieties such as TOG 7106, 7206, 7442, 6346, 5681, and others.
• Apply DecisTM at i liter/ha in 500 liters of water to control rice bugs which suck the sap after flowering.
• Adjust planting date to allow for manipulation of N. viridula numbers.
• Destruction of weed hosts around rice fields.
• The green-manuring crop, Sesbania rostrata, can be used as a trap crop to protect rice against N. viridula.
• Erect scarecrows randomly in the field.
• Scare the bird manually.
• Tic old VMS tapes diagonally across and around the field.
• Install bird nets if available.
• Use catapults.
• Leave an uncropped margin of 1-2 meters around the field.
• Distribute poison (bait) mixed with maize, sorghum, millet or rice in bamboo boxes or containers in the uncropped margins and alleys.
• Fencing with bamboo or chicken wire mesh or polythene sheet round the field may deter rats and grass-cutters.
• Use of local metal traps.
From heading until harvest, inspect field, remove and destroy off-type plants and weeds.
The off-types can be identified through differences in:
• growth cycle
• grain color
• grain shape
• panicle shape
• leaf shape
• leaf base colour
• awn ness
• The crop is ready for harvest when the grains are hard and are turning yellow/brown.
• Thai is about 30-45 days after flowering or a month after 50% flowering.
• Cut the stems with a sickle about 10-15 cm above the ground.
• Lay harvested rice crop in upright position for drying before threshing.
• With good management and use of improved high yielding variety, 5 lo 6 t/ha paddy is expected.
• Thresh immediately after harvesting and drying to avoid losses.
• Use whacking frames or mechanical devices, but avoid threshing on bare floor to prevent the introduction of sand, pebbles and other foreign matter.
• Thresh on a mat or tarpaulin over concrete floor by flailing (i.e. or against a stick or drum).
• Thresh carefully and avoid dehusking the grains.
• Winnow to separate the chaff and empty grains from the well-filled matured grains.
• Remove foreign matter in the paddy to avoid locali/ed heating spots during parboiling.
• Dry paddy properly to a safe moisture content of 13-14% by spreading in a thin layer (2-3 cm thick) on clean concrete floors, mats or tarpaulins and turning over periodically.
• Sun-dry slowly for 2-3 days to reduce breakage during milling.
• On a clear bright day, sun-dry for one day (about 9-10 hrs) only by spreading paddy thinly on clean concrete floors, mats or tarpaulin.
• Use a mechanical drier if available.
• Caution: avoid drying on bare floors or roadside, the main source of contamination with sand pebbles, stones and other foreign matter that can reduce the quality of rice.
• Parboiled rice has the advantages of better storage, cooking quality, being richer in food value, devoid of unpleasant odor and breaking less during milling.
• Soak paddy in hot water at 7O°C (hot enough for your fingers to withstand the heat for about two seconds) for 5 to 6 hours.
• Discard all floating empty grains.
• Parboil rice by steaming soaked paddy in a jute bag for 10 to 16 minutes.
• Suspend the bag over steaming water in a drum.
• Stop parboiling when rice husks start to split open
• Chalky grains or white centers indicate incomplete parboiling, which may cause breakage of grains during milling.
• Parboiling can be done in earthen pots or empty petrol drums depending on the quantity of rice.
• Note: steaming dexteriscs the kernels and drives the vitamin thiamine and other water-soluble nutrient's from the testa or seed coal ink) the starchy core.
• Milling is the process of removing the husk or hull from the grain and the bran (pericarp, testa and aleurone layer) fromthc kernel (brown rice).
• Greater efficiency in the miling process results in the milling process results in whole grains with minimal broken grains to attract premium prices.
• Mill rice in a two-stage milling machine.
• Alwaysmill one pure variety at a time.
Good storage practices include:
• Store at 65% relative humidity.
• Store rice at a temperature within io°F (s.5°C) of the average monthly air temperature and below 6o°F (i5.6°C) as long as possible during the year.
• Design and operate aeration system to maintain uniform, rice moisture and temperature.
• Store only well cleaned rice.
• Inspect rice regularly (weekly) during storage.
Control of storage pests
• Use dried chilli pepper to keep pests away.
• Apply 2 tablets of Phostoxin® a.i. aluminium phosphide in an unsealed envelope per 50 kg bag of rice grains.
• Caution: Phosphinc gas is highly toxic and should not come in direct contact with the rice grains. Wear protective gloves and nose masks when handling.
• Treat seeds/grains with activated silica gel powder to dehydrate possible insects in the bulk.
• Store grains at extremely low temperatures (-15 to -20°C) for minimum of 12 hours or high temperatures (above 55°C) for minimum of 3-4 hours.
• Use of airtight containers for grain storage
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