Production Technology for Direct Seeded Rice

Rice-Wheat Consortium Technical Bulletin 8

Production Technology for Direct Seeded Rice

Rice-Wheat Consortium for the Indo-Gangetic Plains CG Block, National Agriculture Science Centre (NASC) Complex, DPS Marg, Pusa Campus, New Delhi 110 012, India 2006

List of Contributors

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Bhagirath Singh Chauhan, Weed Scientist, Rice-Wheat Consortium/CIMMYT-New Delhi, India

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Ganesh Sah, Agricultural Engineer, Farm Machinery, Birganj, Nepal

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Govindra Singh, Weed Scientist, GB Pant University of Agriculture and Technology, Pantnagar, Uttaranchal, India

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Hafiz Mujeeb Ur Rehman, Agronomist, On-farm water management, Lahore, Pakistan

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Himanshu Pathak, Soil Scientist, International Rice Research Institute-India Office, New Delhi, India

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JK Ladha, IRRI-India Representative, International Rice Research Institute-India Office, New Delhi, India

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Mahesh Gathala, Soil Scientist, International Rice Research Institute-India Office, New Delhi, India

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ML Jat, Agronomist, Project Directorate of Cropping System Research, Modipuram, Uttar Pradesh, India

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MS Gill, Agronomist, Director, Project Directorate of Cropping System Research, Modipuram, Uttar Pradesh, India

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Murshad Alam, Soil Scientist, International Rice Research Institute, Bangladesh

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P Bhattacharya, Joint Director Agriculture, Government of West Bengal, Kolkatta, India

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Ravi Gopal Singh, Weed Scientist, Rice-Wheat Consortium/CIMMYT-Patna, Bihar, India

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Riaz A Mann, Agronomist, NARC, Islamabad, Pakistan

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RK Gupta, Facilitator, Rice-Wheat Consortium, New Delhi, India

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RK Malik, Director Extension, CCS Haryana Agricultural University, Hisar, Haryana, India

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RK Sharma, Soil Scientist, Directorate of Wheat Research, Karnal, Haryana, India

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Samar Singh, Weed Scientist, KVK Uchani-CCS Haryana Agricultural University, Hisar, Haryana, India

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SS Singh, Agronomist, Indian Council of Agricultural Research, Patna, Bihar, India

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UP Singh, Agronomist, Banaras Hindu University, Varanasi, Uttar Pradesh, India

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VP Singh, Agronomist, GB Pant University of Agriculture and Technology, Pantnagar, Uttaranchal, India

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Yashpal Saharawat, Soil Scientist, International Rice Research Institute-India Office, New Delhi, India

Production Technology for Direct-Seeded Rice The rice-wheat system is a predominant cropping system of the Indo-Gangetic Plains (IGP), where rice is traditionally grown by transplanting 4–6-week-old seedlings into puddled fields. Puddling is achieved by ploughing under ponded water conditions. Puddling is a soil management operation that reduces soil permeability, controls weeds, facilitates transplanting of rice seedlings, and reduces the deep percolation losses of water to maintain anaerobic conditions that increase the availability of the iron, zinc, and phosphorus required for the growth of rice. Results of several studies have indicated that nearly 30% of the total water used (1,400–1,800 mm) in rice culture is consumed mainly in puddling and transplanting operations. Therefore, a key concern is how the water requirement of rice culture can be reduced and how farmers can a vo i d p u d d l i n g a n d t r a n s p l a n t i n g operations without yield penalty.

declined by 40–60% between 1955 and 1990 in several Asian countries. Projections indicate that agriculture’s share in freshwater supplies is likely to decline by 8–10% by the end of 2010. Poor-quality irrigation systems and greater reliance on groundwater have led to water tables declining by 0.1–1.0 m per year, leading to higher costs of pumping from deep aquifers and aggravating the energy crisis in many parts of the IndoGangetic Plains.

In many parts of the Indo-Gangetic Plains and elsewhere, water is increasingly becoming scarce because of its other competing end uses in national economies. Already, per capita availability of water

Continued puddling over decades has led to deterioration in soil physical properties through structural breakdown of soil aggregates and capillary pores, and clay dispersion. Puddling forms a compacted layer (plough pan) that restricts the percolation of water, causing temporary wa t e r l o g g i n g , a n d r e s t r i c t e d r o o t penetration and growth for succeeding crops after rice. Transplanting operations are usually performed by migratory labor, which has an element of seasonality and thus increasingly becomes a serious concern for the timely transplanting of rice and maintaining a plant population sufficient to achieve high rice productivity. It is therefore

Photo 1: Transplanting – a labor intensive operation

Photo 2: Puddling – a water intensive operation

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important that alternative methods that are more water-efficient and less labor-intensive be developed to enable farmers to produce more at less cost. One way to reduce water demand is to grow direct dry-seeded rice (DSR) instead of the conventional puddled transplanted rice. Direct dry-seeded rice avoids puddling and does not need continuous submergence and thus reduces the overall water demand for rice culture. In South Asia, DSR is being practiced in many medium-deep and deepwater rice ecologies of the eastern Gangetic plains of India and Bangladesh, and on terraced and sloping lands in the northeast and northwestern Himalayan region and the western Ghats along the west coast of India. The area of DSR in India, Pakistan, and Bangladesh is 14.2 million hectares of the total rice area of 55.3 million hectares. Thus, DSR occupies 26% of the total rice area in South Asia. Productivity of DSR is

Photo 3: Traveling seminar participants visit a DSR field

often reported to be low, mainly due to the inadequate use of nutrient inputs, inefficient wa t e r m a n a g e m e n t , a n d p r o b l e m s associated with weed management. In order to improve conservation agriculture (having elements of no-till/reduced till, residue retention, and controlled traffic to minimize

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retention, and controlled traffic to minimize soil compaction), it is absolutely essential to find alternative options for replacing puddled transplanted rice. Options include zero-till or reduced-till DSR or transplanting in unpuddled soils. However, to make this happen, DSR technology must be made costeffective and environment- and farmerfriendly, and some problems enumerated previously must be solved. Traditional agronomic practices used in DSR cultivation give farmers several problems, such as poor germination, high early seedling mortality during a rainfall event requiring gap-filling in uneven fields, weed infestation, nonavailability of suitable cultivars, and effective postemergence herbicide. Improved practices for direct dryseeded rice are based on several years of experimentation together with farmers of the Indo-Gangetic Plains. The salient features of DSR technology are discussed in the ensuing sections. Planting time: For the continental monsoonal-type climate of the Indian subcontinent, the main rice-growing season is during the monsoons (aman/kharif). It is best to plant the kharif DSR 10–12 days before the historical onset of monsoons. For example, in western Uttar Pradesh, because the monsoon sets in on 21-23 June, the best seeding time for DSR in this region is around 10-12 June. This would facilitate the timely establishment of the rice crop before rains and reduce seedling mortality brought about by submergence, making efficient use of rainwater and timely planting of a succeeding crop of wheat after the rice harvest.

Planting techniques: Surface covers, seed and labor costs, soil moisture regimes, and the intensity of weed infestation determine planting techniques and associated practices enable good germination and seedling emergence. Depending on the weed intensity, we envisage three scenarios for irrigated agroecosystems: (1) fields that are relatively weed-free, (2) fields that have a history of a weed seed bank and potentially high weed infestation during the crop cycle, (3) and fields that are weedy and some are perennial in nature. In rainfed ecologies, DSR is usually established in areas receiving annual rainfall of more than 1,250 mm or in hilly areas having sloping lands. The DSR production technologies for these four different scenarios have been schematically presented in Figure 1. Although rice fields look very flat and smoothly leveled, in practice, application of

Laser land leveling enables farmers to apply water uniformly, thus facilitating a uniform crop stand and maturity through improved nutrient-water interactions. Seed rate and seeding depth: Recommendations are usually made to use a very high seed rate (80–120 kg per hectare) to establish a DSR crop. But a high seed rate causes nitrogen deficiency, reduces tillering, increases the proportion of ineffective tillers, and leads to attacks of brown planthoppers and crop lodging. For cultivars with medium to fine grain, a seed rate of 20–25 kg per hectare is optimum for a DSR crop. A seed rate higher than this can reduce yield for above reasons. It is observed that usually it is not possible to reduce the seed rate with fluted roller-type seed-cum-fertilizer drills. These drills often damage the rice seed coats and also do not facilitate maintaining spacing between plants. Therefore, to maintain spacing between plants, and reduce seed rate, the use of planters having inclined plate devices or a cupped metering system is best. Seed depth plays a key role in early germination and emergence of seedlings in DSR culture. Seed depth should

Photo 4: Laser land leveling

water is not uniform everywhere in the fields. Elevation differences between high and low-lying spots could be as high as 10–20 cm in a 1-hectare field. Therefore, laser land leveling is a prerequisite technology for improved water and crop management.

Photo 5: Cup type seed metering system

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usually be 2–3 cm for a good crop stand. Placement of seeds below 3 cm adversely affects the dynamics of seed emergence because of rapid drying of the soil surface in peak summers. It must be remembered that open-pan evaporation rates are as high as 8–12 mm per day in peak summers and the surface soil can very quickly lose moisture from the seed zone until there is enough moisture in the lower soil layer. Therefore, for seed to germinate, soil moisture should be sufficient for germination to proceed uninterrupted. Some of the suggested measures in the Figure 1 can be adopted advantageously. Seed priming: DSR is sown into shallow surface soil layers (2–3 cm). Because of rapid drying of the top layers, soil moisture is the main constraint in the establishment of a good crop stand. In such situations, prehydration of seeds for 8–10 hours (seed priming) advances germination. Primed seeds are subsequently dried in shade to decrease their moisture content and facilitate their free flow during drilling. Seed priming induces a wide range of biochemical changes

in the seed, the products of which persist following desiccation and are available quickly once seeds are re-imbibed (www.seedpriming.org). Thus, priming accelerates seed germination and emergence. Priming has been used commercially to treat seed with Bavistin/Thiram to eliminate or reduce the amount of seed-borne and soil-borne diseases. Even under limited moisture conditions of rainfed agriculture, wherein germination of DSR depends on rainfall events, seed priming should be useful. Fertilizer management: A general recommendation is to apply a full dose of P and K (60 kg P2O5 and 40–60 kg K2O per hectare) basally. For nitrogenous fertilizers, it is suggested that 80% of the recommended dose of N can be applied at sowing using a seed-cum-fertilizer drill/planter and the remaining N should be applied as required using a leaf color chart (LCC), SPAD, or Green Seeker. For hybrids and high-yielding inbred rice, N application should be based on a critical LCC value of 4. However, a critical LCC value of 3

Photo 6: Leaf colour chart (LCC)

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is used for scented basmati-type rice cultivars. Values of the LCC should be recorded 7–10 days after transplanting or 20–25 days after seeding up to heading. Remember, a DSR crop generally looks lighter green in color than transplanted rice probably due to inadequate P and deficiency of S in some soils. It is recommended that farmers apply a little more N and P to a DSR crop. Continuous submergence is an exception rather than the rule with DSR, which often results in iron chlorosis, particularly in sandy soils. Flooding help overcome iron chlorosis. Calcareous micaceous soils of the IGP are often deficient in zinc and hence would need its application. Weed management: Weeds are a major concern for high productivity of a DSR crop. Good and effective weed management in DSR depends on several factors, including cultural and chemical methods; efficacy, however, depends mainly on timeliness of operations, particularly during the early growth stages of rice. For chemical weed control, it is necessary to select the right herbicide depending upon the weed flora, and the herbicide should be applied with proper spray techniques. Some useful guidelines on the use of chemical molecules for efficient weed management in a DSR crop are described in the ensuing sections. A. Preplant herbicides: These are used to knock down existing weeds of a perennial nature before planting. For preplant herbicides to be effective, weeds should be in active growth stages. Vegetating weeds can be forced to grow by irrigation. Preplant irrigation also forces seed of many weeds to germinate and emerge. Existing and newly

germinated weeds can be knocked down with a timely and judicious use of glyphosate (systemic herbicide) or paraquat (contact herbicide) or mechanically by 1–2 shallow ploughings (with harrow). To dilute glyphosate or paraquat, always use clean water. These herbicides bind with suspended soil particles and metal surfaces (iron buckets), thereby reducing their efficiency. Non-reactive surfaces such as plastic containers can be used for preparing diluted solutions for sprays. Remember that cattle and small animals should not be allowed to graze in treated fields. Nibbling of leaves sprayed with herbicide adversely affects their translocation to underground parts and thus the effective control of weeds. (i) Glyphosate is absorbed by the foliage and rapidly translocated throughout the plant. It gets inactivated immediately on contact with soil. It should be used preferably in areas highly infested with perennial weeds. Glyphosate is most effective in active growth stages of weeds. If perennial weeds are in a dormant stage, it is better to activate them by applying a light irrigation several days before spray in the morning at the rate of 1.0 –1 kg a.i. in 400–500 L of water ha . At noon, spray droplets dry out immediately, resulting in poor absorption and translocation of the chemical molecules, thereby significantly reducing their efficacy. The crop can be planted as soon as symptoms (yellowing, drooping, etc.) are visible. (ii) Paraquat is a nonsystemic contact herbicide. It is used in areas infested primarily with annual weeds at 0.5 kg a.i. in –1 600 L of water ha . Seeding of rice can be done 4–5 hours after its spray; therefore, it is useful in areas where rice sowing is getting delayed.

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Fig. 1. Crop establishment, weed management, and irrigation scheduling in direct dry-seeded rice technology under four different scenarios based on weed infestation and soil and climatic conditions.

Scenario I. Relatively weed-Free

II. Weed seed bank/ stale-seed bed technique

III. Weedy fields

IV. Rainfed/ hilly areas

Retain residue, irrigate (8-10cm) + apply fertilizer

Irrigate to germinate weeds

Retain residue, apply glyphosate/ paraquat

Retain residue, harrow/ paraquat / glyphosate

Sow prime seed, use planter + Green manure crop

Harrow (if no residue), apply paraquat/glyphosate (if residue)

Sow prime seed, use seed-cumfertilizer planter

Sow prime seed, use seed-cum-fertilizer planter/power tiller + light roller in highly permeable soils

Rainfed

Poor germination

Irrigated

Sow prime seed, use seed-cumfertilizer planter + Green manure crop

Irrigate to germinate + Green manure crop

Irrigate to germinate, spray pendimethalin same day

Spray pendimethalin same day

Apply herbicide / hand weeding




Irrigate at or before hair-line cracks





Hold Irrigation for 10-12 days

Good germination

Irrigate after 3-5 days

Wait for rain

Irrigate + Green manure crop


Preplant herbicides v Use glyphosate @ 1.0 kg a.i. ha in 400–500 L of water. It is preferable that the control of perennial weeds and seeding of rice should be done 7–10 days after glyphosate spray. Use flat fan nozzles for spraying. Best results are obtained when weeds are in active growth stages. If weeds are vegetating (not growing), apply light irrigation several days before glyphosate spray. This knocks down all weeds, including Cynadon dactylon and Cyperus rotundus. –1 v Use paraquat @ 0.5 kg a.i. ha in 600 L of water (preferably should be used when perennial weeds are not present, and sowing can be done immediately after spray). Preemergence herbicides v Use pendimethalin @ 1.0 kg a.i. ha–1 in 600–750 L of water/ha in moist conditions and in evening hours. v Pretilachlor with safener at 0.50 kg a.i. ha–1 in standing-water conditions. Postemergence herbicides –1 v Use Almix at 0.004 kg a.i. ha for the control of broadleaf weeds and annual sedges. It also suppresses Cyperus rotundus for a few days. v Use 2,4-D at 0.5–0.75 kg a.i. ha–1 for knocking down Sesbania, annual sedges and broad leaf weeds. v Use Azimsulfuron @ 0.030 kg a.i. ha–1 to control most weeds, including Cyperus species, except grasses. –1 v After 20–25 days, pendimethalin can be applied at half the dose (0.50–0.60 kg a.i. ha ). Points to remember Ø Reseeding may be required in rainfed conditions if moisture status of soil is not sufficiently boosted with first rain. Ø Irrigation must be applied at tillering, flowering, and panicle initiation stages. Ø Drainage is a must in rainfed conditions in case of submergence. Ø For soils having a higher infiltration rate, a lighter roller can significantly improve stagnation of water. Ø Seed rate can be much lower with planters maintaining plant-to-plant spacing (inclined plate or cup metering system). Ø Seed rate cannot be reduced with fluted roller-type seed metering system. –1

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B. Pre-emergence herbicides are generally used before the emergence of weeds. Thus, these chemical molecules are applied immediately after the sowing of the crops. Generally, two chemical molecules, pendimethalin and pretilachlor with safener, are used as preemergence herbicides.

Sofit/Erase-N. The herbicide should be used in wet rice fields. C. Postemergence herbicides are used to knock down weeds after they are up or growing vigorously. To be effective, herbicide molecules must be absorbed through aboveground plant parts (leaves) and, consequently, liquid sprays generally work better than dry granular materials. These herbicides are selective and for better efficacy should be sprayed using a boom fitted with 2–3 flat fan nozzles in 400–500 L of water ha–1.

Photo 7: Pre-emergence application of herbicide

i) Pendimethalin is applied @ 1.0 kg a.i. in –1 600–750 L of water ha for control of weeds. Pendimethalin is effective in the control of annual weeds (grasses and broadleafs) and it requires sufficient soil moisture in the surface layer. It should be applied in evening hours to minimize its photo-degradation. A lower dose of 0.75 kg a.i. ha–1 may be sufficient due to concentration effects, in coarse-textured soil, which retains low soil moisture. Avoid seed contact with the chemical molecules for good germination. Therefore, avoid sprays immediately before or after irrigation or a rainfall event or else replant the rice crop to ensure a good crop stand. ii) Pretilachlor with safener is a selective preemergence herbicide applied within 3 –1 days of sowing @ 0.50 kg a.i. ha . It is effective against annual grasses, sedges, and broadleaf weeds. Since without safener pretilachlor causes phytotoxicity in rice, it is advisable to use it with a safener such as

Photo 8: Spray by three boom nozzle

i) Almix is a bi-component herbicide containing chlorimuron ethyl (CME) and metsulfuron methyl (MSM) and is applied at –1 4 g a.i. ha 20–25 days after sowing. It is effective for a longer duration because of its dual action, that is, from leaves and roots. Almix controls major annual broadleaf weeds. It suppresses Cyperus rotundus for 1–2 weeks. Sedges generally germinate in full light and therefore mulching helps control them. ii) 2,4-D ester/sodium salt is applied at 0.5–0.75 kg a.i. ha–1 20–30 days after sowing to control broadleaf weeds and to knock down co-cultured Sesbania, which serves as a surface mulch to rice.

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iii) A tank mixture can be prepared by mixing Whip Super (fenoxaprop @ 0.050 kg a.i. ha–1) with Sunrise (ethoxysulfuron @ –1 0.018 kg a.i. ha ) to control broadleaf weeds and sedges. Fenoxaprop is effective against grassy weeds, particularly at early growth stages.

Rather than quantifying the criteria for scheduling in DSR, we are sharing our experiences farmer participatory trials. In our experiences, a DSR crop does not require continuous submergence and can be safely irrigated at the hairline cracking stage to obtain yields without penalty.

iv) Repeated application (second dose) of –1 pendimethalin at 0.5 kg a.i. ha at 25–30 days after seeding rice has been reported to control the second flush of grassy weeds in farmers’ participatory trials. v) Azimsulfuron at 0.030 kg a.i. ha–1 has been found to be an effective postemergence measure for control of weeds, particularly of Cyperus species. C. rotundus is probably the most noxious weed in DSR and initial trials indicate that azimsulfuron (Gullivar) can control it. In brief, when the stale-bed technique is used to establish a direct dry-seeded rice crop, preplant application of glyphosate followed by the pre-emergence herbicide pendimethalin and post-emergence herbicide azimsulfuron/almix can eliminate weed problems in a DSR crop, including weedy rice. Irrigation management: The physics, chemistry, and biology of puddled wetlands differ considerably from direct dry-seeded rice soils mainly because of differences in water regimes and the practice of puddling. Knowledge and understanding of rice physiology for DSR is still inadequate in terms of crop water requirement. Whereas puddled fields show soil cracking behavior very early, DSR soils generally do not crack under water-stress conditions. Therefore, simple visual symptoms such as hairline cracks have to be combined with plant waterstress symptoms for scheduling irrigation.

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DSR

Puddled TPR

Photo 9: Cracking pattern in DSR and puddled rice fields

Presowing irrigation: A DSR crop is generally established by many farmers using the stale seed-bed technique. Therefore, preplant irrigation forces weeds to germinate and others to grow vigorously before knocking them down, chemically or mechanically. This significantly reduces weed pressure in the DSR crop. If the moisture is still appropriate, seed the rice crop, or else irrigate after seeding to facilitate germination (Figure 1). In a weed-free field, it is advisable to apply a heavy irrigation 2–3 days before planting the primed seed. In rainfed situations, weeds are allowed to grow for some time after pre-monsoon showers and then are knocked down using herbicides or shallow tillage. In reducedtill/no-till soils, rice can be seeded subsequently. Postsowing irrigation: Rice is planted in South Asia during the peak summer (JuneJuly) when soil moisture losses due to evaporation are generally high. The surface-

Photo 10: Sesbania intercropping (brown manuring)

soil seed zone dries out very fast. In such situations, if presowing irrigation is light, irrigation immediately after seeding may become necessary to facilitate seedling emergence. With heavy presowing irrigation, and germination, subsequent watering can be delayed for about 7–10 days depending on soil texture, antecedent moisture regime, and rainfall situation. Delayed irrigation facilitates deeper rooting and hardens seedlings. Drying of the soil surface delays weed emergence. Under a limited water supply and drought-like situations, irrigation can be delayed a little longer. However, water stress must be avoided at tillering, panicle initiation, and grain-filling stages, which are very critical for good yield. Sesbania co-culture (brown manuring) and surface mulching: Traditionally, farmers grow green manure crops before rice culture and incorporate them by puddling before transplanting rice seedlings. This means an additional need for irrigation water for the Sesbania crop and fuel costs for incorporating it. Since there is little water in the reservoirs during the peak summers, farmers have not been able to take full advantage of green manuring in rice. In the “brown manuring” practice, rice and Sesbania crops are planted

together and allowed to grow for 25–30 days before knocking down the Sesbania crop with 2,4-D ester (@ 0.40–0.50 kg a.i. ha–1). Coculture technology reduces the weed population by nearly half without any adverse effect on rice yield. Sesbania surface mulch conserves soil moisture and supplies –1 10–15 kg N ha on decomposition. In areas where soil crusting is a problem, germinating Sesbania helps break it and facilitates the emergence of rice seedlings. Rice and Sesbania can be planted with the same drill. To provide quick surface coverage of the interrow spaces, use half the total seed of Sesbania for broadcasting. Surface mulching: Concern is increasing about the depletion of soil organic matter and environmental pollution due to the burning of crop residues in the intensive rice-wheat system because of limited return of organic matter. Residues, when retained on the surface, serve as a physical barrier to the emergence of weeds, moderate the soil

Photo 11: Surface mulched crop

temperature, conserve soil moisture, add organic matter, and improve nutrient-water interactions. It is always beneficial to use crop residues (mungbean, cowpea, boro rice, and in some parts wheat residue) as mulch wherever they are available. The multicrop

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new-generation zero-till seed-cum-ferti drills/planters with disk-type openers allow seeding in the presence of loose residues. In combine-harvested areas, crop residues must be spread evenly before planting for a uniform crop establishment. At present, four machines have been tested or are under testing/evaluation for seeding DSR and wheat. These machines are briefly discussed below. Turbo Happy Seeder: The turbo seeder is a revised improved version of the Happy Seeder. It shreds the residues in narrow strips in front of the tyne openers and places seed and fertilizer. This machine is capable of seeding into the anchored and loose residue a load of up to 7–8 t ha–1.

Photo 12: Turbo seeder seeding in full residue

Rotary disc drill (RDD): This machine is based on the rotary till mechanism. The rotary disc drill is mounted on a three-point linkage system and is powered through the power take-off (PTO) shaft of a tractor. The rotating discs cut the residue and simultaneously make a narrow slit into the soil to facilitate placement of seed and fertilizer. The machine can be used for seeding under conditions of loose residues as

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Photo 13: RDD seeding in full residue

well as anchored and residue-free conditions. This machine is capable of seeding into loose residue a load of up to 7–8 t ha . –1

Double-disc coulters: Double-disc coulters are fitted in place of tynes to place seed and fertilzer into loose residues. The featherweight of the machine and moist soil below the residues allow only a partial cut of the loose residues, thereby resulting in placement of seed and fertilizer on top of residues, which reach the soil surface only through the stirring action of the moving tractor and the drill. Therefore, irrigation must be applied immediately after seeding to facilitate germination and root corking into the soil. This machine works very well in 3–4 t ha–1 of rice residues and for planting wheat and other crops into stubbles of pigeon pea, cotton, maize, and sugarcane. Star wheel: This mechanism is being used under nonrice situations but its utility with residues of rice and wheat crops is yet to be proven. Initial results indicate that it works under reduced tillage and a low residue load of up to 3 t ha–1. At present, this machine drops the fertilizer on the surface in front of the moving star wheels.

Cultivar choices: It is observed that scented basmati-type rice and hybrids generally perform best for DSR. Some other rice cultivars found suitable for DSR conditions in different locations are the following: Regions

Cultivar choices

Punjab, Western Uttar Pradesh, and Haryana

Pusa–1121 (Sugandha–4), Pusa–2511 (Sugandha–5), PRH–10, Pusa Basmati–1, Pant Dhan–12, Sharbati, PHB–71

Eastern Uttar Pradesh

NDR–359, Sarjoo–52, Muhsoori, Swarna, MTU–7029, Moti, Pusa–44, KRH-2

Tarai of Uttaranchal

Nidhi, UPRI–92–79, Narendra–359, PD–4, Sarvati, PR–113, HKR–120, Sarjoo–52

Bihar

Rajshree, MTU–7029, Satyam, Rajendra Mahsuri–I, NDR–359, Prabhat

Tarai of Nepal

Sona Masuli, Hardinath, Radha–4, Radha–11

Bangladesh

BRRI Dhan–33, BRRI Dhan–39, BRRI Dhan–44, Zata

Pakistan

SK–282, hybrid and IRRI coarse varieties

Economics of direct seeded rice A field survey was conduced on 72 farmers across the state of Haryana and Uttar Pradesh to study the comparative economics of direct seeded and puddled transplanted rice. The results are given in Figure 2. The study revealed that in 67% cases farmers obtained either equal or higher yields as compared with the conventional puddled transplanted rice. The marginal yield penalties in the balance 33% cases were mainly due to inexperience of the farmers (seeding in inappropriate soil moisture, deeper seed placement, delayed and improper use of

herbicide molecules). The study also revealed that comparative to puddled transplanted rice, the savings in DSR was in the range of US$ 70-102 ha-1. The tillage induced savings were mainly through reduced cost in land preparation (77%), irrigation water (15%) and labour (8%). Table 1: Comparative economics of DSR and Puddled transplanted rice Puddled transplanted

DSR

∆ Value

Total Cost US$

518±48

275±47

73

Net income US$

445±63

354±48

79

Fig. 2. Comparative input cost in puddled transplanted rice and saving in DSR

Labour 8%

Irrigation water 15%

Land preparation 77%

Input cost in Puddled transplanting

Saving in DSR

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Variants of direct dry-seeded rice and notations used It has been observed that researchers and farmers alike establish DSR using different techniques and then try to compare their results. In our mind, the ways in which a DSR crop is established have a significant effect on the crop stand, growth, and yield of the DSR crop. There are many variants of DSR rice. For example, whereas some researchers/farmers establish their DSR crop using stale-bed techniques (reduced-till soils), others sow the crop in undisturbed soil. Similarly, seed rates can also vary depending on whether a drill or a planter is used for seeding the crop. Planters help maintain spacing between plants and thus use lower seed rates than a seed drill fitted with fluted rollers. In addition, variations in soil moisture (wet/moist/dry) and seeding methods (line seeding/broadcasting), depth of seed placement (shallow/deep), and use of seed (primed/unprimed) can have a significant effect on initial crop stand and hence crop yield. Some variants that significantly affect the performance of a DSR crop are depicted in Figure 3. To facilitate valid comparisons and to evaluate which is the best way to grow a DSR crop, we have attempted to develop a coding procedure to subject farmer participatory DSR trial results to statistical analysis. These codes help us in drawing some valid conclusions on DSR technology, which is still evolving. Fig. 3. Some examples of the codes used as variants of DSR crops are given below.

Direct seeded rice

Tillage

Disturbed (Di)

Undisturbed (Ud)

Wet (Mw)

Spacing

Moisture

Moist (Mw)

Line (Li)

Broadcast (Bc)

Dry (Dy)

Primed (Pr)

Seed depth

Seed treatment

Depth 2.5 3.0 cm (3)

Unprimed (UPr)

Sprouted (Sd)

Machinery used

Depth 3.0 5.0 cm (5)

Drill (Dr)

Planter (Pl)

Direct-seeding methods

Notations

DSR line-sown primed seed, with seed placed at a depth of 3 cm by a drill in disturbed moist soil

DSRDiMwLipr3Dr

DSR established in undisturbed moist soil in line with primed seed at a depth of 3 cm by a drill

DSRudMwLipr3Dr

DSR in disturbed dry soil in line with primed seed at a depth of 3 cm by a drill

DSRDidyLipr3Dr

DSR in disturbed moist soil in line with unprimed seed at a depth of 5 cm by a planter

DSRDiMwLiUPr5Pl

DSR by broadcasting unprimed seed in disturbed dry soil and mixing in dry soil

DSRDidyBcPr

DSR in undisturbed moist soil in line with primed seed at a depth of 5 cm by a planter

DSRudMwLiPr5Pl

DSR in undisturbed dry soil in line with primed seed at a depth of 5 cm by a planter DSRuddyLiPr5Pl

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Abbreviations used for farmer participatory trials in DSR 1

Aman

Kh

47

Primed

pr

2

Aus

Sp

48

Punch Planter

PP

3

Basal N

Bs

49

Redpram

RG

4

Beds

B

50

Reduced Tillage

RT

5

Boro

Bo

51

Rotary Disc Drill

RDDr

6

Broadcast

Bc

52

Safflower

SF

7

Bulkdensity

Bd

53

Sandy Clay Loam

SCL

8

Clay Loam

CL

54

sandy Loam

SL

9

Controlled Traffic

TL

55

Sesbania

S

10

Conventional Tillage

CT

56

Sesbania+Residue

RS

11

Cotton

CO

57

Silt Loam

SiL

12

Depth

Dp

58

Silty Clay Loam

SiCL

13

Depth 3 cm

3

59

Single Application N

Sa

14

Depth 5 cm

5

60

Soil Type

Stype

15

Direct Dry Seeded Rice

DSR

61

Sorghum

So

16

Disturbed

di

62

Split

St

17

Double Disc Planter

DDPl

63

Spring

Sp

18

Drill

Dr

64

Sprouted Seed

Sd

19

Drum Seeding

D

65

Stalebed

RT

20

Dry

dy

66

Star Wheel

PPPl

21

Early Planting

Ep

67

Straw

St

22

Fertility

F

68

Sugarcane

SC

23

Fine Sandy Loam

FSL

69

Summer

Sm

24

Flooded

Fl

70

Sunflower

SU

25

Fresh

F

71

Surface Seeding

SS

26

Grain

G

72

Test Weight (1000gr/wt)

ThGw

27

Greengram

GG

73

Time

T

28

Happy Seeder Drill

HSDr

74

Timely planting

Tp

29

Iron

Fe

75

Traditional Practice/puddled

CT

30

Irrigation

Ir

76

Transplanted Rice

TPR

31

Kharif

Kh

77

Turboseeder Planter

TSPr

32

Laser Leveled

LL

78

Unpuddled

U

33

Late Planting

Lp

79

Village

V

34

Loam

L

80

Weeds Free

Wf

35

Maize

M

81

Weeding Manual

MW

36

Manual Weeding

Mw

82

Weedy

Wd

37

Moist/ Wet

Mw

83

Wheat

W

38

Mongbean

GG

84

Wide

Wi

39

Nitrogen

N

85

Winter

Wn

40

Number

Nu

86

Yield (kg)

yld

41

Permanent

PE

87

Zero Till

ZT

42

Phosphorus

P

88

Zinc

Zn

43

Pigeonpea

RG

89

Line

Li

44

Planter

Pl

90

Herbicide

H

45

Potash

K

91

Basal N

80% N

46

Power Tiller ZT Drill

MPTZTDr

92

Undisturbed

ud

Planter= a machine which can keep spacing between seeds using cupping/ inclined plate system Drill= machine which drop seed continuously with fluted roller

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Summary Ø DSR is a labor-, fuel-, time-, and water-saving technology. Ø DSR is cost-effective and gives a higher net return than puddled transplanted rice. Ø Weed management is critical in DSR, but with an integrated weed management approach weeds can be managed. –1 Ø The seed rate of DSR can be decreased to 20–25 kg ha or even lower by using an inclined plate/cup seed metering system.

Ø DSR technology does not affect grain quality and can be practiced in different rice ecologies (upland, medium land, and lowland; deepwater and irrigated areas) by large as well as small farmers. Ø Puddled fields on drying show cracking, making it difficult to retain water unless fields are dried intensely for soil to slake. No such problem is encountered in DSR field plots, indicating improved soil physical properties. Ø Fertilizer and water-use efficiencies are also higher in DSR. Ø DSR is a technically and economically feasible alternative to conventional puddled transplanted rice.

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