Low-external Input Rice Production - Chapter 1 - Seeds/Seedlings/Transplanting

Introduction...

Managing traditional cultivars for optimum outputs

Traditional cultivars possess several attributes which make them indispensable for low-input rice production (LIRP). Among these characteristics include inherent resistance to certain pests and diseases, greater flexibility in the time seedlings can be transplanted, lower requirement for irrigation water and fertilizers and low seed-degeneration rate. Moreover, traditional cultivars have a higher (40%) market price than high-yielding varieties (HYVs). However, traditional cultivars which have characteristics, such as leafiness, tall stature; photoperiod sensitivity and susceptibility to lodge, usually have lower yield potential than HYVs. If a farmer would like to shift from planting HYVs to traditional cultivars, he should modify his practices to receive optimum output. Some cultural management practices that should be followed are:

1. Proper selection of cultivars. Study site characteristics (soil, climate) in order to select the bestsuited cultivars for the site:

Rice cultivars

· Assuming that there is enough water, select cultivars to fit photoperiodic patterns. In the Philippines, short-day flowering rice cultivars are best planted from August to September while long-day flowering cultivars are best planted December to January.

· Select traditional cultivars which mature only 10-15 days longer than modern rice cultivars if long vegetative period is not wanted.

· Select semi-dwarf traditional cultivars (Pinili, Bengawan, Lubang, Abrigo, Improved Borong, Senador) to avoid lodging in typhoon-prone areas. If tall cultivars are used, some tillers should be cut before flowering to minimize lodging.

· Do not plant tall varieties in:

- soils of inherently high fertility swampy areas

- flood-prone areas

- areas with poor drainage

- sites with high weed infestation. Select for traditional cultivars those which have droopy and long leaves for more effective shading of the weeds. As in HYVs, the field should be kept weed-free 35-45 days after transplanting.

2. Alter the time of planting. Alter planting schedules to fit the climate in the area, specially the occurrence of typhoons and floods. The typhoon season for most parts of the Philippines usually occurs from June to September. Planting late (September) would be beneficial as grain filling and maturity will not coincide with the typhoon season. This also minimizes lodging.

3. Modify plant spacing and populations. Wider row spacing is recommended for traditional cultivars. Wider spacing lessens mutual shading, making plants sturdier end less prone to lodge.

The following row spacings are recommended for traditional cultivars:

Rainy Season	Dry Season
0.25 x 0.25 m	0.30 x 0.20 m
0.30 x 0.25 m	0.25 x 0.20 m

Additionally, a 0.30 x 0.15 m spacing is convenient when rotary weeders are used.

Planting 1-2 seedlings/hill is recommended. This practice produces more productive tillers and tends to make plants less likely to lodge.

4. Practice good water management. Keeping rice continuously flooded makes stems more succulent, thus more susceptible to lodging. Traditional cultivars do not require continuous flooding during the vegetative period. However, it is beneficial to flood the field at flowering. Water is withdrawn once the hard dough stage is reached.

Infields with heavy weed infestation, irrigate the field 2-5 days after transplanting and gradually increase the water level. Water can be withdrawn once canopy closure is reached.

5. Reduce fertilizer use. Traditional cultivars do not require as much fertilizers as HYVs. Large doses of fertilizer make plants tall and prone to lodging.

Producing rice seeds in a farmer's field

Seeds for planting constitute a considerable portion of a farmer's production inputs. Ordinary seeds cost from P5.00-P5.50/kg; certified seeds can cost as much as P8.00-P10/kg. Although the production of rice seeds for planting requires more special care than production of rice grain for food, it is possible for the farmer to produce seeds right in the farm. These simple procedures guarantee reduction in production costs and a steady source of quality seeds for planting.

1. Seed and Area Requirement. Estimate the farmer's production per unit area. For example, if the farmer produces 100 cavans/ha (10,000 sq.m), then he needs 100 sq.m to produce 1 cavan (50 kg). If seeds are of high quality, 1 cavan is often sufficient to plant 1 hectare (for most cultivars). Thus, if the farmer needs to plant 5 hectares, then a 500 sq.m seed production area would be required to harvest 5 cavans of seeds.

Seed and Area Requirement

2. Site Selection and Preparation. Select the best area within the field for seed production. It should be near the water source, with good drainage and accessible. The soil should be free from weeds, relatively fertile and well-prepared. Mark the required seed production area.

3. Transplanting. If possible, use only seedlings of high quality (high viability, pure, healthy, etc.) seeds. To ensure uniformity of growth end easy identification of off-types, transplant only 1 seedling/hill, in straight rows.

Ideally, plant the whole area with the cultivar of interest to avoid contamination. However, if there are not enough seeds of the desired variety, keep the designated seed production area at least 5 m away from other cultivars.

Transplanting

If using certified seeds, seeds of the same variety which are not certified can be planted around it. However, 4-5 rows surrounding the seed production area should be planted with the same certified seeds. These border rows will act as "screen," but seeds coming from them will not be used for planting.

4. Field/Crop Maintenance. Visit. the area several times during the growing season especially from tillering up to harvesting. Pull out unwanted plants such as off-types (see box), weeds and other crops. Follow regular soil management (fertilization, irrigation, etc.) and crop protection practices to ensure healthy crops.

5. Harvesting. To avoid contamination and possible mixture, harvest the designated seed production area first before the rest of the field. Seeds can be harvested a few days earlier than the usual harvest time without sacrificing quality.

6. Threshing, Cleaning, Drying. Process the seeds produced from the designated seed production area separately. Be sure to clean the thresher, drying surfaces and seed container properly such that they are completely devoid of other seeds and other contaminants. Keep seeds of different cultivars well-dried and distinctly labeled in separate containers.

PULL OUT THESE OFF-TYPES:

1. All plants growing outside or between the rows -- whether rice or weeds.

2. At tillering stage, all plants not having the same height, average tiller number, stem and leaf color as the majority.

3. At flowering stage, all plants not having the same height, average tiller number, stem and leaf color, average flowering time, flag leaf length and angle as the majority.

4. At harvesting stage, all plants not having the same height, average tiller number, average maturity, color, size, shape of grains end presence of own, flag leaf length and angle as the majority.

Determination of rice seed quality

Knowing the quality of rice seed will enable one to decide the appropriate practices that could help maintain or improve the performance of seedlots.

Seeds on hand can be tested for the following:

1. Dryness. Most seeds, including rice, store better when dry. High moisture level could result to heating, further accumulation of moisture, active growth of storage insects and fungi and even unwanted germination. Seeds which have not been properly dried are also damaged during processing.

- Sundrying for 3-5 days is often sufficient to bring the moisture content of the freshly harvested seeds down to the safe level (13% or less). If the seeds have been stored for quite some time or were obtained from other sources, dryness could be checked by biting the seeds. If brittle, the moisture content is 13% or less the desired moisture for planting or storage. The biting test should not be done if seeds have been treated with chemicals. If not sure, simply redry the seeds for 1-2 days.

Dryness

2. Purity and Seed Health. Impurities, such as weed seeds, other crop seeds, other vegetative parts and inert matter, should be removed. These could serve as hosts of crop pests and seed-transmitted diseases or affect seed (and seedling) performance in the field or in storage. Weed seeds could germinate in the field and add to the existing weed population. Seeds of other cultivars, when present, could also lead to genetically impure seedlots.

Purity and Seed Health

- Examine the seedlot for impurities, diseased seeds (symptoms are discoloration and presence of fungal bodies) and infested seeds (seeds with holes or are partially eaten by insects, presence of eggs/egg mass or larva).

- If a large proportion of the sample consists of impurities, the seedlot should be cleaned prior to storage or planting. Cleaning can be done by winnowing or soaking the seeds in water. Defective seeds, weed seeds and other inert matter float to the surface, while seeds that sink are of higher density and are usually of better quality.

- If the seedlot contains a large proportion of seeds of other cultivars, some form of manual sorting must be done before storage or planting, unless the mixture was intentional.

- Seedlots which contain a large proportion of diseased or infested seeds are not recommended for storage or planting. If the proportion of diseased or infested seeds is minimal, remove such seeds if possible and soak the rest of the seedlot in hot water (5256°C) for 5 minutes (if seeds are wet) or 10 minutes (if seeds are dry).

- Other diseases which do not readily show visible symptoms can be detected only by using special techniques. If these diseases are suspected, have the seeds certified for health at the Bureau of Plant Industry or do not use them for planting. Chances of developing diseases in the succeeding crops are minimized if seeds are harvested from healthy plants and healthy surroundings.

3. Seed Germination and Seedling Health. Germination results could serve as a guide as to whether the seeds could or should still be stored, immediately planted or discarded. Also, they give an idea as to how much seed is required for planting. Seeds with low percentage germination will not keep long and will produce less vigorous plants.

- Sow the pure seeds sampled from the seedlot in moist, clean, absorbent cloth or paper. Roll the cloth or paper loosely (ragdoll method) or keep it on a flat surface covered with the same material.

Seed Germination and Seedling Health

Keep the medium constantly moist by watering, taking care not to flood it. Too much water encourages mold and bacterial growth. Alternatively, seeds could be kept moist by carefully dipping the rolled medium in a pail of water, then putting it in a partially opened plastic bag. Keep seeds being tested in the shade and away from mice, ants and rain.

Keep the medium constantly moist

Good germination, good vigor

Poor germination, poor vigor

- Count normal seedlings after 4-5 days. Percentage germination is calculated as

% germination = No. of normal seedlings/Total no. of seeds tested x 100

- If germination is below 80%, but above 60%, use more seeds. Do not use or store seeds if germination percentage is below 60%.

- Observe for seed vigor since germination results alone could not fully predict the performance of seeds especially under stressed conditions. A seedlot with seeds that emerged rapidly and uniformly is considered more vigorous than one with slow and non-uniform emergence and growth, even if germination percentages are comparable.

- Growing seedlings should also be examined for lesions, spots, blighting (general death of tissue) and streaking. These are symptoms of potentially serious crop diseases. Treat germinated seedlots showing these symptoms in the same manner as seeds found to be infected or infested.

Rice seed dormancy

Rice seeds that do not sprout when planted in favorable soil and atmospheric conditions are either dead or dormant. Wild and traditional rice cultivars have higher degrees of dormancy than modern ones. Rice seeds may be dormant up to 80 days but most of the cultivated ones have only 2-3 weeks dormancy. A cultivar may be considered slightly dormant (germinates within 15 days from harvest); moderately dormant (germinates within 15-60 days from harvest); or highly dormant (germinates within 60 days from harvest or later). Others, especially many modern varieties, have no dormancy at all. Dormancy is naturally broken through time.

Dormancy can be a plant's natural means to prevent mature seeds in the panicle from sprouting especially during the rainy season in the tropics. For man, it is an advantage when seeds being dried are rained on as these could sprout and lead to losses. However, dormancy becomes a problem when seeds are purposely planted or assessed for germination.

Traditional and modern cultivars

DETECTION OF DORMANCY:

The degree of dormancy of rice seeds are often judged based on previous knowledge about the cultivar and the length of time the seeds have been stored. It can be determined along with the germination rate by sowing mature seeds in moist sand, soil, absorbent paper or cloth. After 5-7 days the seeds are checked and any ungerminated seeds that are not moldy or rotten (easily determined by gently squeezing ungerminated seed) are judged dormant.

BREAKING DORMANCY IN RICE:

Any of the following methods could be used before planting or during germination testing to break dormancy, but their effectivity depends on the cultivar or storage time which determine the degree of dormancy:

· Soak one part seed in 5-10 parts water at 40°C (approximated by allowing boiling water to cool off for 8-10 minutes).

· Heat seeds which have been sundried for 3-5 days (seed moisture content approximately 10%) in an oven at 50-55°C for 7 days.

Soak one part seed in 5-10 parts water

· Soak 1 kg of seeds for 16-24 hrs in 1 liter nitric acid solution (HNO3) prepared by pouring 1 1/4 tsp (6.3 ml) concentrated nitric acid (of 68% purity) into a liter of water (a motor oil can = 1 liter). After soaking, sundry seeds for about 3-7 days.

Soak 1 kg of seeds

Caution: The acid must be poured into the water during the preparation of the solution. Do not pour water into the acid because an explosion could result.

· Soak 1 kg seeds for 24 hrs in 1 liter water containing 1/2 tsp fresh sodium hypochlorite (chlorox, available market grade = 5.25%).

· For a germination test where only a few seeds are used, manually remove hulls. Be careful not to injure the germ or embryo which is the part where the plant develops. This treatment is not applicable to wild rice.

Soak 1 kg seeds for 24 hrs

Rice seed collection and handling

Seeds used for planning require more careful handling than those used for grains (i.e., food or feed). Good quality seed spells good field emergence, seedling stand, crop growth, yields and healthy vigorous seeds. To obtain and maintain good quality seed, the following should be done:

Careful handling

Harvesting: As much as possible, harvest only during sunny days. Do not allow seeds to become too mature. Generally, it is best to harvest seeds 3040 days after heading in the wet season or 25-35 days after heading in the dry season (depending on earliness of cultivar). Grains in, panicles are yellowish brown at this stage. This allows enough time for the seeds to complete development but not too long that significant deterioration in the field occurs.

Seed Collection: Collect seeds only from healthy and vigorous plants (health of mother plants largely determines health of seeds produced). These mother plants may have already been identified long before maturity and have been given special care. Avoid plants along borders. Harvest seeds from the main, primary and secondary tillers together (seeds from the different tillers were found to have generally similar yields). If many cultivars are grown together in an area, make sure the seeds from each cultivar are well-identified and separated.

Seed Threshing and Winnowing: The germ or the embryo of the seeds must be protected from mechanical damage especially during threshing. Damaged seeds could result in non-germination or in seedlings which are abnormal. To minimize damage, sundry panicles for a few days before feeding them into mechanical threshers (if used). Clean threshed seeds by blowing or winnowing at least twice using native flat trays (bilao) to separate heavier seeds from light ones and from dust panicles and straw which may contain or attract insects.

Seed Threshing and Winnowing

Seed Storing and Invigorating: A panicle captains seeds which are premature (at the base), mature (at the middle) and over-mature (at the tip). When all the seeds in the panicle are collected, further upgrading is necessary to obtain only high density grains which are known to perform better in the field and in storage than those with lower grain density. Immerse and stir seeds thoroughly in water (1 kg seed/10 liter water). If available, use 6.5% ordinary salt solution (6.5 parts salt to 10 parts clean water, by weight). Alternatively, use 22% ammonium sulfate solution (2.2 parts salt-to 10 parts clean water). Ordinary soil/mud may also be used to increase the density of water. A good approximation of the right mixture (1.08 specific gravity for traditional tropical varieties) is when the blunt end of a fresh chicken egg sticks out by half inch above the surface of the solution. Most modern varieties require only water for effective sorting. Remove all floating seeds and debris and scoop out seeds that sink to the bottom. The solution may be re-used a few times. When seeds are meant to be stored, rinse the seeds with clean water. Dry-soaked seeds back to original moisture content before planting or storing.

Salt solution

For seeds that have been for quite some time (4-8 months) under ordinary room conditions, treatments may be-done to revitalize already partially deteriorated seeds to extend their storability or to improve performance of seeds to be planted immediately (seeds will germinate faster and more uniformly; plant growth and even yields are also perceptibly improved by approximately 10-20% with invigoration). Soak seeds for 2-8 hours in water (Or in the same salt solution used for storing, then rinse). Dry seeds properly (back to original moisture) before further storage or planting. Fresh seeds or heavily deteriorated ones (less than 60% germination) will not show improvements.

Seed Drying: Spread seeds thinly over a mat, sack or light-colored sheets laid on concrete floors or elevated surfaces. Airdry seeds for a day if moisture is relatively high (e.g., seeds wet from soaking or seeds from early harvest). Dry seeds under the sun for 3-5 days (avoid the 10 am - 2 pm heat) and stir constantly. Well-dried seeds (8-10% moisture) split with a cracking sound when bitten between teeth.

Seed Drying

Seed Storage: The three common enemies of a seed in storage are high moisture (or humidity), high temperature and insect pests. For short-term storage (i.e., seeds kept for next planting season), keep dry, clean, healthy seeds in paper or plastic bags and store in a cool shady, dry place in the house or yard away from rodents and birds. Seeds may be kept in the panicles and hung on top of the kitchen stove. For longer keeping, use sealed tin cans or air-tight containers, one-third full of dry charcoal, ash or lime (1 part material/2 parts seeds to completely fill the container). For insect protection, coat seeds with ash, lime, vegetable oil (1 tsp/kg seed) or incorporate some botanicals, e.g., Gliricidia (kakawate) or other protectants like napthalene balls into the container. If sacks are used for storage, they may be treated with Makabuhay (Tinospora rumphii) or red pepper extract (prepared by cutting fresh material into small pieces then soaking and thoroughly mixing these in water). Sacks are then soaked in this for 4-6 hours, then dried. Do not use the seeds with protectants as food.

Seed Storage

Seed Germination/Sowing:

1. In flooded soil where oxygen is often inadequate for germination, soaking seeds with 40% calcium peroxide could increase germination, seedling survival and even yield.

2. In zinc deficient soil, coating of seeds with zinc oxide (or other forms of zinc) or soaking 2% suspension improves grain yield by 10-20%. Seedlings may also be dipped in the same solution before transplanting.

3. For treatments to break dormancy, see appropriate section. Soaking seeds in 50-56°C for 10-15 mins could break dormancy and at the same time control common pests and diseases.

Common botanicals and other materials in rice seed protection during storage

Botanicals have been used for centuries in rice storage in Asia. This information sheet focuses on the use of plants or its products in the protection of rice seed. Some of the ideas require further testing and development while others have long been tested by rice farmers.

I. Materials Verified Effective as Rice Seed Protectants

Scientific Name	Common Name	Preparation
1. Azadirachta indica	Neem (margosa)	Mix 10-20 9 powdered neem seed per kg seed
2. Acorus calamus	Sweet flag (lubi-lubi)	Mix 10-20 g powdered rhizome per kg seed
3. Mentha spicata	Spearmint	Mix 5-20 9 powdered leaves per kg seed
4. Capsicum frutescens	Red pepper (siring labuyo)	Mix 10-20 9 chillies, per kg seed
5. Curcuma longa	Turmeric (luyang dilaw)	Mix 20 9 powdered rhizome per kg seed
6. Piper nigrum	Black pepper(paminta)	Mix 5 9 powdered leaves per kg seed

Other Materials:

1. Wood ash or paddy husk ash	Mix 10-40 9 per kg seed
2. Lime	Mix 10 9 per kg seed
3. Fine sand	Mix 0.5 9 per kg seed

Preparation of Powdered Plants:

Sundry the plant parts (fruit seed, rhizome or leaves) thoroughly. For rhizomes, faster drying can be done if chopped into smaller pieces. Cut the plant parts into finer pieces after sundrying. Grind into powder using a grinder or mortar and pestle. If the powder is not used immediately, store in tightly sealed jars.

II. The following botanicals have been reported effective against cereal pests that could also infest rice seeds. However, there have been no direct reports on actual rice seed storage. You may try them and inform us of your results.

Scientific Name	Common Name	Preparation	Reported Effect on Insect
Acacia concinna	Soap nut	powdered seed	antifeedant
Angelica glauca	Angelica genus	powdered roots	repellent
Annona squamosa	Sugar apple, atis	powdered seeds	anti-insect*
Aphananixis polystachya	Pithraj	dried leaves	anti-insect*
Artemisia maritime	Wormseed	powdered leaves	repellent
Atlantia monophylla		dried stem and leaves	repellent
Atropa acuminata	Indian belladona	powdered rhizomes	repellent
Caesalpinia pucherrina	Peacock flower(caballero)	powdered flowers	insecticidal: contact poison
Calotropis gigantae	Crown plant	powdered flowers	insecticidal
Cassia absus	Four-leaf senna	dried and powdered leaves	anti-insect*
Chrysanthemum cinerariifolium	Pyrethrum	dried and powdered flowers	insecticidal: contact poison
Clerodendron infortunatum	Bhant	dried leaves	anti-insect*
Datura stramonium	Jimson weed	dried and powdered leaves	repellent
Hyptis spicigera	Mint(suob-kabayo)	3 gm dried powdered leaves per kg seeds	repellent
Justicia adhatoda	Malabar nut tree	dried and powdered leaves	antifeedant
Lecothoe grayana	Fetterbush genus	dried leaves, aqueous extraction	anti-insect*
Luffa aegyptiaca	Sponged gourd	powdered leaves	anti-insect*
Mangifera indica	Mango	powdered leaves	repellent
Melia azedarach	China berry	1-2 parts powdered leaves per 100 parts seeds	anti-insect*
Nicotiana sp.	Tobacco	powdered leaves	insecticidal
Pachyrrhizus erosus	Ubas, sinkamas	5-10 parts powdered seeds per 100 parts stored seeds	insecticidal
Pongamia pinnate	Poonga oil tree	powdered leaves	antifeedant
Sapindus marginatus	Florida soap berry	powdered seeds	antifeedant
Scheichera oelasa	Kesambi	5-10 parts powdered seeds per 100 parts stored seeds	insecticidal
Sterculia foetida	Nitas(Calumpang, Bobog)	1-5 parts dried seeds per 100 parts stored seeds	insecticidal
Swartzia madagascariensis		powdered fruit	repellent
Trigonella foenum-graecum	Fenugreek	leaves and seeds are mixed with seeds	repellent
Vitex negundo	Indian pivet(lagundi)	powdered leaves	insecticidal: contact poison
Xeromphis spinosa		powdered roots and fruits	repellent

REFERENCES:

Handbook of Plants with Pest Control Properties. M. Grainage and S. Ahmed. 1988. United States: John Wiley and Sons, INc.

Natural Crop Protection in the Tropics. Gaby Stoll. 1986. Germany: Margraf Publishers Scientific Books, 188 pp.

The Use of Plants and Minerals as Traditional Protectants of Stored Products. 1980. England: Products Institute, 32 pp.

* Anti-insect is the general effect and the specific action is not yet known.

On-farm grain storage

Of the total rice production, an estimated 10-37% is lost in post-production prom harvesting to marketing). About 12-40% an this overall loss is attributable to handling and storage losses which may be minimized at the farm level by observing some simple post-harvest handling practices.

As a general rule, keep storage areas and containers and related harvesting and post-harvest paraphernalia clean.

The four major areas of concern here are: grain quality before and during storage, storage conditions, insect control and rodent control during storage.

1. Grain Conditions

- Store only mature, whole and healthy grain. Broken grain is prone to insect attack.

- Dry and clean the grain well before storing. Some farmers can determine proper grain dryness by biting a grain sample. If a moisture meter is available, dry grain to 13% moisture content. Otherwise, dry it for about 3 days under good sun.

2. Storage Conditions

- Store grain away from wet areas.

- Place stored grain containers where the wind can help cool the containers.

- Do not place sacks of grain near the walls nor place them directly on floors as moisture from the ground may dampen the grain.

- Jute sacks or baskets/bins woven from local palm or bamboo material are ideal grain storage containers.

Storage Conditions

3. Insect Control

- Do not store grain from a new crop near grain from an older crop to avoid insects from the old grain from infesting the new crop.

- Mix with the grain dried leaves of neem (Azadirachta indica) and kakawate (Gliricidia septum), chili, pepper and other local plants that have insecticidal effects.

- Check the grain often especially for insect presence.

- Sunning: Occasionally subjecting stored crop to high temperature, especially when a large number of insects is present, helps keep insects away (but may not kill their eggs/larvae).

- Keeping grain above the stove (for small quantities) can help in keeping moisture and insects out.

Wrong

Right

Check the grain

Rodent Control

4. Rodent Control

- Keep the storage area and its surroundings clean to keep rodents from nesting and hiding in them.

- Keep the grass trimmed around the storage/farm building.

- Store grain sacks off the floor on bamboo platforms and place rat guards made of tin cans around the platform legs to keep rats from climbing. An oil or water bath for the platform legs will keep crawling insects away from the grain as well.

- Keep a cat or a dog.

Clonal propagation: a method of seed multiplication

What will a farmer who would like to plant a certain rice cultivar for the coming season do when he or she only has a limited amount of seeds? Clonal propagation can be resorted to.

Clonal propagation is a method of multiplying rice plants from a single grain, an aged seedling or a rice stubble. This method, developed by R. H. Richharia in India, has several advantages over the conventional seed-crop multiplication:

- applicable to any rice cultivar

- ensures genetic purity of multiplied material

- could be easily adopted by farmers

- except for labor, the system entails minimum costs to farmers.

PROCEDURE:

1. Germinate seeds in a pot or en isolated paddy. Initial plant materials or mother plants are best placed in pots for protection and easier maintenance.

2. Seeds germinate and grow and form tillers at approximately 12 days after planting (DAP). At 20 DAP, or when tillers possess new roots, tillers could be separated. Carefully detach these using a razor blade or a thumb's nail.

3. Plant the separated tillers and the mother plant immediately. If the procedure is done in the field, use wide-planting distances 0.20 x 0.20 m to encourage tillering.

4. The individual plants (clones) grow again and produce tillers. Rooted tillers could again be separated after 15 days. Replant the tillers after separation. Fifteen days after replanting, all the plants are uprooted and the tillers are again separated. In the case of short-duration varieties, the separation of tillers and replanting have to be done earlier (7-10 days).

Germinate seeds

At 70-80 days after sowing, maximum tillering occurs (or 3-4 primary tillers are formed) for all plants. Separation of tillers can be continued up to this point. The separated primary tillers thereafter serve as the new mother plants for subsequent splits. Further separation can be repeated until a sufficient number of seedlings are produced for field transplanting. During multiplication, pests should be controlled to prevent losses.

Multiplication

Note: The rate of multiplication is genotype-specific. In general, medium- and late- maturing cultivars tend to produce tillers longer due to a time lag between vegetative and reproductive stage. Hence, more tillers are produced. The number of initial plant material, therefore, has to be adjusted, i.e., more seeds should be supplied for early-maturing cultivars to compensate for lesser production of tillers.

Raising seedlings by the wetbed method

ADVANTAGES:

· Less seeds are required per unit area transplanted.

· Transplanting of seedlings can be delayed. Transplanting older seedlings shortens the crop's stay in the field, thereby reducing crop exposure to field risks.

· Gives the rice seedlings a headstart over the weeds after transplanting.

DISADVANTAGES:

· It requires larger areas for the seedbed.

· Preparation of seedbed, care of seedlings and pulling of seedlings are laborious.

· Seeds are easily carried away by raindrops if heavy rain occurs shortly after sowing.

PROCEDURE:

1. Locate an area near a water source which is exposed to full sunlight. A total of 350-500 sq.m of seedbed area is needed to grow enough seedlings to plant 1 hectare of rice paddy.

2. Prepare the seedbed 30-35 days before the scheduled time of transplanting. Plow and harrow the field thoroughly

Prepare the seedbed

3. Construct raised seedbeds -- 1.5 m wide, 4-5 cm high and of any convenient length.

Construct raised seedbeds

4. Sow the pregerminated seeds uniformly at 1 kg/10 sq.m.

Sow the pregerminated seeds

5. After 4 days, irrigate the seedbed about 23 cm deep end gradually increase the water level to 5 cm to control weeds and to make pulling of seedlings easier.

Irrigate the seedbed

6. If you observe nitrogen deficiency (yellowing of the lower leaves) broadcast 50-100 9 ammonium sulfate/sq.m or 2040 9 urea/sq.m of seedbed 10 days after sowing. Protect the seedlings from carabaos, rats and birds.

Protect the seedlings

7. The seedlings are ready for transplanting at the following days:

- 16 days for varieties which mature in 115 days

- 20 days for varieties which mature in 116-125 days

- 25 days for varieties which mature in 126 days or more

Increase the water depth to 10 cm the day before pulling the seedlings. When pulling, hold the seedlings close to the base to avoid injury. Wash the roots carefully and do not strike the seedlings against hard objects to remove the mud as this will shock them.

Increase the water depth to 10 cm

The dapog method of raising rice seedlings

ADVANTAGES:

· requires less space for raising seedlings

· seedlings can be planted early (9-14 days)

· labor required for removing seedlings from seedbed is less than 1/4 compared to the wetbed method

· easy to transport seedlings from seed bed to the rice paddy

DISADVANTAGES:

· Uses more seeds than the wetbed method.

· Produces smaller, younger seedlings which

- can only be used on farms where good water management is possible

- have a greater chance of being smothered by Azolla.

PROCEDURE:

1. Locate an area in the field near a water source.

Locate an area

2. Irrigate the field. Plow and harrow it twice to puddle the soil and bury the weeds.

Irrigate the field

3. Flood the area 2 cm above the soil surface to facilitate levelling.

Flood the area

4. Prepare puddled seedbeds 1 m wide end of any convenient length. The seedbeds are raised 3 cm by taking some soil from the footpath.

Prepare puddled

5. Carefully level the seedbed and allow the soil to settle for a day.

Carefully level the seedbed

6. Cover the seedbed with plastic sheets or banana leaves. These materials are used to prevent the roots of the seedlings from penetrating into the soil.

Cover the seedbed with plastic sheets

7. Peg sliced banana bracts along the sides of the seedbeds to prevent the soil and the seeds from being washed away.

Peg sliced banana bracts

8. Sow the pregerminated seeds directly onto the plastic sheet or banana leaves. Use 1 kg seeds/sq.m. Seedlings from 60 kg seeds will be enough to plant 1 hectare.

Sow the pregerminated seeds

9. Cover the seedbeds lightly with dry rice strew to protect the seedlings from birds. The straw should be disease -- and insectfree. (Remove the straw on the sixth day when the seedlings are large enough that birds will no longer eat them.)

Cover the seedbeds lightly with dry rice

10. Water the seedbeds three times daily to keep them moist.

Water the seedbeds three times daily

11. Tap the seedlings lightly with a broom at least two times a day to make sure that all the rice seeds come in contact with the base of the seedbed.

Tap the seedlings lightly with a broom

12. The seedlings are ready for transplanting 1014 days after sowing. Simply roll up the seedlings as you would a mat and carry them to the paddies for planting.

Roll up the seedlings

Line markers for rice transplanting

Planting rice in straight lines facilitates rotary weeding, reduces time needed for other management practices and assures optimum plant populations. Labor costs for transplanting are higher when using straight-line planting. However, due to lower weeding costs and higher yields, straight-line planting is more profitable than not planting in straight lines.

Line marking tools make it much easier to plant in straight lines. Below are two common markers used by farmers. A farmer can choose from among them, based on materials available and the size of paddies to be lined.

Harrow type

Rake type

A. Harrow-type Marker

· Used in wide paddies

· Can be constructed with bamboo or wood to look like a harrow

· Paddies are lined by first pulling the marker in an East-West direction (being sure to keep the lines straight), and then pulling the marker in the North-South direction, making small squares throughout the paddies (1 man-day needed to mark 1 hectare of land).

B. Rake-type Marker

· Used in narrow paddies where the harrow type marker, being wider, would not fit

· Can be constructed with either wood or bamboo

· Marking is done in the same way as for the harrow-type marker (1-1.5 man-days/ha).

Straight-row planting using the square and triple-row spacing

ADVANTAGES OF STRAIGHT-ROW PLANTING:

1. Easier to apply production inputs and implement management practices

2. Possible to use rotary weeder

3. Promotes optimum plant population and uniform nutrient uptake

The most common straight-row planting method used by farmers is the square method ranging from 20 cm to 30 cm, planting 2-3 wet bed grown seedlings or 4-6 dapog seedlings.

Square

Triple rows

Another planting system which has increased yields above those using the square method i the triple-row system.

Trials conducted in Navarro, General Trias, Cavite, using IR70 rice variety, gave the following figures (average of 2 cropping seasons):

Spacing Method	Amount of Seeds(kg/ha)	Transplanting(manhours/ha)	Grain Yield(T/ha)
Square Method (20 x 20 cm)	60	120	4.1
Triple-row Spacing	180	300	5.0

Advantages of the triple-row spacing system

Note: Rows are oriented in an East-West direction so that leaves can receive the maximum amount of sunlight.

A manually operated rice transplanter

A manually operated rice transplanter

The transplanter is applicable where:

1. Farm labor is becoming insufficient to:

· urban migration

· simultaneous planting time among many farmers in an area.

2. Farmers wish to cut down on transplanting costs

BASIC INFORMATION ON THE TRANSPLANTER:

1. Two people can transplant 1 hectare in about 3 days. (The two will alternately operate the machine and replace seedlings onto the tray.)

2. The rice seedlings are planted in rows (to facilitate other cultural management practices like weeding) and, therefore, there is no need to hire line markers.

3. The transplanter is relatively simple to operate and maintain and is made from locally available materials.

4. A unit costs about P4,500 (as of June 1990).

5. For efficient and effective use of the transplanter, minor modifications on the dapog or wetbed method of seedling preparation have to be made.

6. The transplanter owner can earn additional income by custom-hiring the machine.

A simplified cost comparison between manual transplanting and using the transplanter is shown below:

	Manual Transplanting	Transplanter
Labor requirement to transplant x 1 hectare	25 mandays (ma)	6 mandays (ma)
Estimated transplanting cost/ha/yr for 2 croppings*	(25 ma/cropping x 2 croppings x P50/md) + (P100 for line marking) = P2,600.00	(6 ma/cropping x 2croppings x P75/md) + (P900 depreciation cost) = P1800.00**

* Assuming P50/md for manual transplanting and P75/md for operator of transplanter.

** Assuming P4500 cost of transplanter and a lifespan of five (5) years. Note: Aside from the P800 savings on transplanting costs, the owner can custom-hire the unit to earn additional income.

For details and technical assistance, contact:

1. Agricultural Engineering Department IRRI, Los BaLaguna, Philippines

2. Agricultural Mechanization Development Program CEAT, UP at Los BaCollege, Laguna, Philippines

A drum seeder for direct seeding

In areas where broadcast seeding is practiced, the drum seeder offers several advantages:

· reduces seeding rate to about 50-100 kg/ha without compromising yield (broadcast seeding rate requires 100150 kg/ha). Savings in seed costs are realized.

· uses pregerminated seeds as traditionally practiced by farmers.

· increases yields due to:

- better weed control (i.e., facilitates use of mechanical weeders)

- better fertilizer and sunlight distribution due to less crowded pants

- in general, labor requirements for the following farm operations may be decreased. weeding, fertilizer application and harvesting.

A drum seeder for direct seeding

SOME TRADE-OFFS IN THE USE OF THE DRUM SEEDER:

· increase in labor requirement for land preparation (especially in soil levelling to ensure uniform seed distribution) and planting operations

· cannot adapt well to wet season planting as heavy rains will destroy the planting line

· water depth control during seeding operation is essential

· a drum seeder unit costs approximately P1750 (as of December 1989) and has an expected life span of about 5 years.

The drum seeder is being adapted in some areas of the province of Oriental Mindoro and the following tables present a comparative study conducted by UPLB, IRRI and the government of Oriental Mindoro with 11 farmer-users.

Table 1: Effect of drum seeding on some farm operations as compared to broadcast seeding (1987 Dry Season, Oriental Mindoro).

Farm Operations	Increase ( + ) or Decrease (-) in Labor Requirement	Number of Farmer-Respondents (Total of 11 Farmers)
Land preparation	+ 0.7	2
Planting	+ 11.9	11
Weeding	- 61.5	9
Fertilizer application	- 1.0	3
Chemical control	- 2.3	4
Harvesting	- 7.6	3

Table 2. Effect of drum seeding on seed input and yield compared to broadcast seeding (1987 Dry Season, Oriental Mindoro).

Input	Increase ( + ) or Decrease (-) in Amount (kg/ha)	Number of Farmer-Respondents (Total of 11 Farmers)
Seed requirement	- 62	11
Yield	+ 824	10

For more technical assistance (drawings and fabrication techniques), contact:

1. Agricultural Engineering Division International Rice Research Institute (IRRI) Los Ba Laguna, Philippines

2. Agricultural Mechanization Development Program (AMDP) College of Engineering and Agro-lndustrial Technology (CEAT) University of the Philippines at Los Ba(UPLB) College, Laguna, Philippines

Inoculating rice seedlings with Azospirillum

Azospirilla are a genus of bacteria which live and can colonize the roots of forage and grain grasses and exert beneficial effects on their growth. This grass-bacteria symbiosis differs from the legume-rhizobium symbiosis in that the former does not have root nodulation as a manifestation of the association. These organisms reside mainly at the zone of root elongation, bases of root hairs and root interior.

Some work has been done in rice particularly in India and now in the Philippines. One recent test in India yielded 6.5 T/ha with Azospirilla vs. 4.4 T/ha without it. In experiments in Cavite and Negros provinces, the use of Azospirilla in combination with 40 kg N increased rice yields by 24% and 55%, respectively, while Cavite experiments using only Azospirilla increased rice yields by 18%.

The exact cause for the yield increases is not yet clear. However, it is known that a higher percentage increase in yield occurs under conditions where lower amounts of fertilizer N is used.

Aside from the nitrogen fixation, several benefits can be derived from azospirillum inoculation: it promotes root hair development and branching -- increasing the uptake of NPK and microelements; improves water status of plants; and increases dry matter accumulation and grain yield. Inoculating plants with azospirillum can reduce the required nitrogen fertilizer from 1/3 up to 213.

HOW TO INOCULATE RICE SEEDLINGS:

1. Mix the inoculant with water. About 750-1000 9 inoculant is required to treat seedlings needed to plant 1 hectare.

2. Put the mixed inoculant in a container for dipping the seedlings. If a big container is not available, prepare a bunded piece of land and line this with plastic

3. Soak the seedlings into the mixture for at least 3 hours. If possible, inoculate/soak the seedlings overnight before transplanting.

Mix the inoculant with water

Put the mixed inoculant in a container