Rice

Table of Contents

Introduction

• Rice (Oryza Sativa L.) is the principal food crop of the North Eastern Region (NER) of India, occupying an area of about 3.5 million hectares.
• The average productivity of rice in NER is 1.77 tons/hectare, which is much below the national average.
• NER faces a deficit of about 12% in foodgrains, considering the last triennium, and 2.8% in 2010-11.
• Low productivity in NER is attributed to the non-adoption of high-yielding varieties and improved production technology.
• Equal importance should be given to resource conservation for sustainability and climate resilience while enhancing productivity.
• Increased occurrence of extreme events like drought, heavy rainfall, floods, frost, etc., due to climate change, needs to be considered in the rice production process.
• Adoption of appropriate crop production technology can reduce yield loss due to climatic aberrations and achieve a yield level of at least 3-5 tons/hectare in NER.

Seed Selection and Treatment

• Use only sound and healthy seeds for sowing.
• Put the seeds in a 2.5% salt solution (25 grams of common salt in 1 liter of water) to select healthy seeds by discarding floating ones.
• Wash the selected seeds with clean water and dry them in the shade.
• To protect the plant from leaf blast and other diseases, soak the seeds with Bavistin 50WP (2 grams per liter) for 24 hours against seed-borne diseases. Use 2.5 grams of chemical for 1 kg of seed.

Preparation of Seed Bed

• For high altitude regions, start preparing the nursery area in the first fortnight of May.
• For mid and low altitude regions, start preparing the nursery area from the first fortnight of June.
• For conventional transplanting in one hectare of land, a nursery area of 500-600 square meters is sufficient.
• For the System of Rice Intensification (SRI) and Integrated Crop Management (ICM) methods, the nursery area can be reduced to 50-100 square meters.

Raised Seed Bed:

• Prepare a raised bed of 10 cm height from the ground level in high rainfall areas.
• The size of each bed can be 10 meters in length and 1.25 meters in width, with a 30 cm wide channel between two seed beds.
• Broadcast the treated seeds evenly in each bed after manuring.

Wet Nursery

• In regions like Sikkim, Manipur, and Tripura, wet nursery is suitable for plain valley land conditions. 
• Thoroughly plough and level the nursery area to maintain a thin layer of water during emergence.
• After manuring and puddling, broadcast the sprouted seeds uniformly in each seed bed. 
• To get sprouted seeds, soak the treated seeds in wet gunny bags for about 48 hours.

Manures and fertilizers for seed bed

1. Raised Bed Nursery: Apply cow dung or compost at 15 tons/hectare (15 kg per seed bed) plus a starter dose of 30:30:20 kg NPK/hectare (Urea 80 grams, Single Super Phosphate (SSP) 225 grams, and Muriate of Potash (MOP) 40 grams per seed bed).
2. Wet Nursery: Apply well-decomposed Farm Yard Manure (FYM) at 15 tons/hectare before puddling, and during puddling, apply an extra quantity of 30:30:20 kg NPK/hectare (Urea 80 grams, SSP 225 grams, and MOP 40 grams per seed bed) to raise healthy seedlings.
3. Modified Mat Nursery (MMN) for SRI and ICM: Prepare the nursery in a raised bed (5 cm) with a mixture of soil and FYM (2:1). Spread the seeds uniformly on the bed, cover them with a mixture of soil and FYM, and then cover with paddy straw for 2-3 days. Water the nursery by rose cans every day in the morning or evening hours.

Seed Rate

• Transplanting: a. For medium to fine grain rice varieties, a seed rate of 35-40 kg/hectare is sufficient. b. For bold grain varieties, a seed rate of 40-50 kg/hectare is sufficient.
• Direct Seeding: For direct seeding in upland conditions, a seed rate of 60-80 kg/hectare is required to get a good plant stand.
• System of Rice Intensification (SRI): 5-7 kg/hectare
• Integrated Crop Management (ICM): 10 kg/hectare

Land Preparation (Main Field)

For Transplanting:

1. Prepare the land properly and level it uniformly with peripheral bunding. 
2. Puddle the land 2-3 times to make it weed-free and water retentive. 
3. Apply all phosphorus and potash, and 50% of the nitrogen fertilizer, and incorporate them thoroughly into the soil during the final puddling.
4. Apply organic manures like FYM or composts about 15 days before transplanting and mix them with the soil during ploughing. 

For Direct Seeding

1. Perform two cross-ploughings to get good soil tilth and a weed-free land.
2. Avoid excessive tillage.
3. Place 50% of the nitrogen fertilizer and the full dose of phosphorus and potash in furrows before sowing. 
4. Apply organic manures like FYM or composts about 15 days before transplanting and mix them with the soil during ploughing.

For Furrow and Raised Bed (FRB)

1. Properly level the field and repair the bunds and irrigation channels.
2. At least 15 days before transplanting, spray total weed killer herbicides like Glyphosate at 3 ml/liter to control weeds.
3. Chop down any woody shrubs for mulching.
4. In zero tillage, only the root zone is opened for placing fertilizer, manure, and seed without disturbing the whole field.
5. In the absence of mechanization, use metallic end dibblers for transplanting.
6. Use 25-30 days old seedlings. Avoid using very young seedlings.
7. For upland conditions, use manual or animal-drawn furrow openers.
8. Maintain at least 30% residues on the surface to get the benefits of zero tillage.

For Zero Tillage

1. Prepare a raised bed of 70 cm width, alternated with a furrow of 30 cm width.
2. In plains, use a tractor-drawn bed maker, while in hills or small holdings, use animal-drawn implements or manual labor.
3. Grow 3-4 lines of rice on the raised beds.
4. This system encourages crop diversification and conserves resources like water and seeds.

Transplanting/Sowing

Transplanting

• The optimum time for transplanting is the first fortnight of July for low and mid-altitude regions.
• For higher altitudes (above 1300 m), adjust the transplanting time to avoid low temperatures during flowering.
• In high-altitude regions (above 1300 m), complete transplanting before June 15, preferably by the first week of June.
• For mid and low-altitude valley lands, transplanting can be done as late as the last week of July with closer spacing (15 cm x 10 cm) and aged seedlings (40-45 days old). 
• For conventional transplanting, use 20-25 days old seedlings with a spacing of 20 cm x 15 cm and 2-3 seedlings per hill.
• For SRI, use 10-12 days old seedlings with 1 seedling per hill at a spacing of 25 cm x 25 cm.
• For ICM, use 15-20 days old seedlings with 2 seedlings per hill at a spacing of 20 cm x 20 cm.
• Use metallic row markers, pre-marked ropes, or bamboo pieces to maintain accurate spacing during transplanting.

Direct Sown:

1. Upland: In mid-altitude conditions, complete sowing within the second fortnight of June to have enough time for succeeding rabi crops.Sow in lines 20-25 cm apart, maintaining a seed rate of 60-80 kg/hectare.
2. Lowland: i. Direct seeding has advantages like faster and easier planting, reduced labor and drudgery, earlier crop maturity by 7-10 days, more efficient water use, high tolerance to water deficit, less methane emission, and often higher profit. ii. Prepare the field during the pre-monsoon season (April), similar to upland crops. iii. Direct seed in the third week of April, with a seeding depth of 2-3 cm. iv. Use cono-weeders and hand weeding for weed control. v. Varieties like Shahsarang 1 (4.7 tons/hectare) and IR 64 (4.5 tons/hectare) are suitable for direct seeding. vi. This technology overcomes the problem of water supply for rice transplanting during the pre-kharif season and saves resources.

Nutrient Management in Main Field

• Optimum soil health management is the key to successful crop production.
• A healthy and vibrant soil can withstand drought and other problems better than a poorly managed soil.
• Integrated Nutrient Management (INM) should be followed by applying an adequate amount of organic manure (FYM, vermicompost, other manures) along with inorganic fertilizers (Urea, SSP, MOP, etc.) to achieve good soil health and optimize production.

Transplanted Rice:

• Apply fertilizer at 80:60:40 kg NPK/hectare (174 kg Urea, 375 kg Single Super Phosphate, and 67 kg Muriate of Potash).
• This dose may vary according to the soil fertility status.
• Apply all phosphorus, potash, and 50% of nitrogen as a basal dose.
• Apply the remaining 25% nitrogen at maximum tillering and 25% at the panicle initiation stage.
• Split application of nitrogen fertilizer reduces losses, facilitates efficient use, improves growth, and enhances yield.
• Neem coating of urea (mixture of neem cake and tar mixed with urea granules) releases nitrogen slowly, enhancing nitrogen use efficiency and reducing losses through leaching and denitrification.
• Chop and mix crop and weed residues with the soil during the first ploughing.
• In zinc-deficient soils, apply zinc sulfate (ZnSO4) at 25 kg/hectare during final land preparation.
• Apply well-decomposed organic manures like FYM at 10 tons/hectare or enriched compost at 5 tons/hectare (mixed with 60 kg rock phosphate and incubated for 30 days) along with 50% NPK to improve yield and soil health.
• Apply green leaf manure (biomass from hedge row species, leguminous tree leaves like Erythrina, Acacia, etc., and forest litters) at 5 tons/hectare along with recommended NPK, if available.
• For local varieties (e.g., Mendri, Manipuri, etc.), reduce the nitrogen fertilizer dose to 50 kg/hectare (87 kg urea) to avoid excessive vegetative growth.

Direct Sown Rice

• In upland direct-seeded crops, apply 60:60:40 kg NPK/hectare (130 kg Urea, 375 kg Single Super Phosphate, and 67 kg Muriate of Potash).
• Apply the full dose of phosphorus and potash at sowing in furrows below the seed.
• Divide the nitrogen dose into three equal splits: 1/3 at sowing, 1/3 after the first weeding (25-30 days of crop age), and 1/3 at the panicle initiation stage.
• Integrated application of 60:60:40 kg NPK/hectare + 5 tons/hectare of FYM is recommended for higher productivity and soil health maintenance.
• Application of Alder (Alnus nepalensis) leaves or Eupatorium (a weed) at 5 tons/hectare + 50% NPK is equally effective.
• Chop and mix crop and weed residues with the soil during the first ploughing.

Bio-fertilizer Application:

• Application of fresh Azolla at 10 tons/hectare + 50% nitrogen through urea improves rice yield.
• Incorporate Azolla into the soil before transplanting, or take it as a dual crop by inoculating fresh Azolla at 2 tons/hectare at 7-10 days after transplanting (DAT) in standing water (5 cm) with 20 kg phosphorus/hectare.
• Soil application of Azotobacter or Azospirillum at 1 kg/hectare is recommended for nitrogen economy, and it can supplement up to 30 kg nitrogen/hectare (65 kg Urea).
• Alternatively, dip rice seedlings in biofertilizer solution for about 6 hours for better results.
• For medium and high altitudes, use cold-tolerant species like Azolla caroliniana, while for warmer areas, use Azolla pinnata.

Bioorganics for Rice Production:

• Bioorganics are plant extracts like weeds, tree leaves, and crop residues that are beneficial for crop production, including rice.
• Lowland Rice: a. Soak seeds for nursery in bioorganic formulations at 10% concentration (100 ml/liter water) for 12 hours. b. Apply one foliar spray at 2% concentration (20 ml/liter) at 30 days after transplanting. c. Formulations like R-9, RCHEC-12L, RF 37, and RF 79 significantly increase grain yield by 20-30%.
• Upland Rice: a. For varieties like Bhalum 1, soak seeds at 10% concentration (100 ml/liter water) for 8 hours before sowing. b. Apply one foliar spray at 2% concentration (20 ml/liter) at 35 days after planting. c. Formulations like RF 79L, R-9, RCHE 686L, and RCHE C-12L significantly enhance yield.

Residue Management

• Rice ecosystems in North East India produce about 4-7 tons of straw per hectare and up to 10 tons of weed biomass per hectare.
• By effectively recycling 100% of crop and weed residues, the nutrient requirement of monocropped rice in lowlands can be met almost completely.
• Even if 50% of residues are recycled, 50% of the nutrient requirement can be met.
• Retention and incorporation of residues reduce soil erosion, conserve moisture for the second crop, and improve soil health.
• Harvest rice by leaving at least 1/3 to 2/3 of the standing stubbles in the field.
• Chop down the stubbles and incorporate them into the soil during ploughing or spading.
• Periodically incorporate all available weed biomass into the soil.
• Through effective residue management, it is possible to recycle about 60-80 kg nitrogen, 20-30 kg phosphorus, and 100-120 kg potassium per hectare annually.

Weed Management:

Transplanted Rice:

• In North East India, hand weeding is mostly practiced.
• In the absence of manpower, apply herbicides like Butachlor (Machete) 5% granules at 30 kg/hectare in 3-4 cm standing water within 2-4 days after transplanting (DAT) to control grassy weeds.
• If granules are not available, apply Butachlor in liquid form at 1.5 kg a.i./hectare mixed with 400 liters of water, or Pendimethalin (Stomp) at 1.0 kg a.i./hectare in 400 liters of water.
• To control sedges (Cyperus spp.) and broad-leaved weeds, apply 2,4-DEE 4% granules at 20 kg/hectare at 4-5 DAT.
• Use a rotary paddy weeder (Cono weeder or Japanese paddy weeder) for weeding by running it between the rows.
• Cono weeder use requires only about 4-5 laborers/hectare compared to about 20 laborers/hectare for hand weeding.
• Cono weeder also helps in incorporating weed biomass into the soil, improving soil aeration and root respiration.
• For SRI and ICM practices, weed at 15-day intervals up to the maximum tillering stage.
• Line transplanting using a spacing of at least 20 cm between rows is a prerequisite for using a mechanical weeder.
• Alternatively, farmers can make their paddy weeder using a wooden plank and inserting removable pegs in the floats.
• At least two weedings (at 25 and 45 DAT) are required for higher productivity in lowland rice.

Upland Rice:

• Weed problems are more severe in upland rice.
• Complete the first weeding within the third week of crop age and the second weeding at 40-45 days after sowing (DAS) to check weed growth.
• Hoe the field after each weeding.
• Apply Butachlor as a pre-emergence herbicide at 1.5 kg a.i./hectare or Pendimethalin at 1 kg a.i./hectare in 500 liters of water within 2-3 DAS.