1. What is aerobic rice cultivation?
Cultivation of suitable high yielding rice varieties in direct sown, non-puddle, aerated soils under supplementary irrigation and fertilizers to achieve high yield is called aerobic rice.
The ecology for this type of rice is intermediate between upland and favourable shallow low lands.
This type of cultivation practice can be adopted in target areas like, tank irrigate area, deep bore well / well irrigated area and the places where presumed to receive delayed channel / river water i.e. in delta region during kharif (June – July) and summer (February).
2. What is the common method adopted for sowing aerobic rice?
Prepare land in dry to fine tilth before sowing. At optimum moisture condition, incorporate 10 tons of farm yard manure per hectare and prepare the field to fine tilth for 2-3 times and followed by planking to level the field.
Use seed drill in well leveled field for sowing. Deep tillage and fine tilth enhances root growth and higher moisture holding in soil.
3. What are the recommended rice varieties for aerobic rice cultivation?
Four varieties viz., CR Dhan 200 / Piyari (suitable for Odisha), CR Dhan 201 (suitable for Chhattisgarh and Bihar), CR Dhan 202 (suitable for Jharkhand and Odisha), CR Dhan 204 (suitable for Jharkhand and Tamil Nadu), are suitable for aerobic rice cultivation, released from Central Rice Research Institute, Cuttack.
Similarly, University of Agricultural Sciences, Bangalore has released ARB 6, MAS 26 and MAS 946-1 for Karnataka state.
4. Can we get the details of some aerobic rice varieties released so far.
CR Dhan 200 / Piyari (IET 21214) CR 2624-IR 55423-01
- The variety is suitable for the water-limiting areas of Odisha.
- Duration of the variety is 120-125 days with semi-dwarf plant type (95 – 100 cm).
- It possesses short bold grain and moderately resistant to leaf blast, neck blast and brown spot diseases of rice
- The line is moderately resistant to stem borer (dead heart & white ear head) damage, whorl maggot, gall midge and leaf folder attack
- Non Lodging plant type, thick culm, easy threshability, and responsive to high fertilizer levels
CR Dhan 201 (IET 21924) CR 2696-IR 83920
- The variety is suitable for mid early aerobic cultivation in Chhattisgarh and Bihar.
- Duration of the variety is 110-115 days with semi-dwarf plant type (100 cm).
- It possesses short bold grain and moderately resistant to blast, sheath rot, stem borer (both dead heart and white ear heads), leaf folder, whorl maggot and rice thrips.
- Average yield of the variety is 3.8t/ha, under proper management condition, it can yield up to 6t/ha.
CR Dhan 202 (IET 21917) CR 2715-13-IR 84887-B-154:
- The variety is suitable for cultivation in Jharkhand and Odisha states for mid early aerobic situation.
- Duration of the variety is 115 days with semi-dwarf plant type (100 cm). It takes 85 days to 50% flowering with short bold grain, medium and dense panicle with moderate test weight.
- It is moderately resistant to blast, brown spot, sheath rot, stem borer (both dead heart and white ear heads), leaf folder, whorl maggot and rice thrips.
The average yield of the variety is 3.7t/ha, under proper management condition, it can yield upto 6t/ha.
CR Dhan 204 (IET 21692) CR 2696-IR 83920
- The variety is suitable for states of Jharkhand and Tamil Nadu for mid early aerobic situation.
- Duration of the variety is 110 days with semi-dwarf plant type (100 cm).
- It takes 85 days to 50% flowering, with medium slender grain, medium and dense panicle with moderate test weight.
- It is moderately resistant to blast, neck blast, brown spot, sheath rot, stem borer (both dead heart and white ear heads), leaf folder, whorl maggot, case worm and rice thrips.
- The average yield of the variety is 5.6t/ha in region V and 3.6 t/ha in region III of the country
5. What is the recommended dose of fertilizer and how does it should be applied for aerobic rice?
The recommended dose of fertilizer is 80 kg of nitrogen, 40 kg of phosphorus and 40 kg of potash per hectare. Ten tons of farm yard manure, 100% phosphorus and 50% of potash has to be applied at the time of last ploughing i.e. at the time of sowing.
The first dose of nitrogenous fertilizer 30% is applied at 10-12 days after germination.
During top dressing of fertilizer, sufficient moisture in the soil has to be ensured to make the nutrients available to plants.
Nitrogen fertilizer applied in three splits, 30% at 10-12 days after germination, 40% at 30 days after sowing and balance 30% at 50 days after sowing.
Potassium fertilizer has to be applied in two splits, 50% at sowing and 50% at 50 days after sowing.
Further, zinc sulphate and iron sulphate 20kg and 12kg per hectare respectively have to be applied at the time of sowing.
6. What seed rate has to be used for aerobic rice cultivation?
Seed rate of 50 kg per hectare is recommended for aerobic rice. The seeds are sown 20 cm between rows and 15 cm within rows with 3 to 5 cm depth.
Seeds can be sown with seed drill or can be sown before last ploughing.
After sowing, seeds are covered with soil using plank and light irrigation should be given immediately. Sowing can also be done during the onset of monsoon.
7. How best the water can be managed in aerobic rice cultivation?
Aerobic rice crop does not require continues flooding. It can be irrigated like direct sown crops like maize, jowar and bajra. Irrigation can be provided with interval of 4-5 days and time of irrigation can be adjusted based on the soil type and moisture availability.
Rice crop under aerobic situation could be successfully raised with 700 to 900 mm of total water in summer and during monsoon season the water utilization can be further reduced.
Since the water resource is effectively utilized, 1 kg of rice is produced with 3000 to 3500 liter of water in contrary to 4500 to 5000 liter in transplanted rice system.
After sowing in dry condition in fine tilth soil, surface irrigation should be done immediately. Surface irrigation should be given up to 50 days after sowing at the interval of 5 days.
Irrigation should be given once in 3 days, in the critical stages like active tillering, panicle initiation, flowering and grain filling. Water must be withheld one week before harvest of the crop to facilitate uniform ripening of grains.
By adopting aerobic rice cultivation method, the water can be saved to the tune of 35 to 45 percent.
8. How to manage weeds in aerobic rice field?
Weeds are the major concern in aerobic rice cultivation, which reduces crop yield. Therefore, weed management should be done by both chemical and manual means for effective control.
Spraying of pre-emergence herbicides like Pretilachlor 50 EC @ 2.5 l / ha / Phyrazosulfuron ethyl (250 g / ha) in 750 liters of water within 48 hours of seeding.
After 20-25 days of seeding, one hand weeding or post emergence herbicides should be applied for effective management of weeds.
Hand weeding or inter cultural operation with hand hoe or weeder will control weeds effectively and increases aeration for better root growth and also increases tiller number.
9. How much grain yield can be achieved under aerobic rice cultivation?
In this method of rice cultivation by adopting the above mentioned practices, 4.5 -5.0 tons of grain and 5.0 -5.5 quintals of straw per hectare can be obtained.
10. Are the rice hybrids suitable for aerobic rice cultivation?
Yes, hybrid rice varieties are also suitable for aerobic rice situation and they could yield better than pure line varieties
11. How does the soil fertility is managed in aerobic rice cultivation?
Continuous cultivation of rice crop in same field would lead to depletion of nutrients and organic matter. Therefore, to improve soil physical health, green manures such as Dhaincha or Sunhemp or legumes can be raised as inter crop.
During inter cultural operation, those green manure plants can be incorporated in soil to increase organic matter of soil.
12. How does the pest and disease are managed in aerobic rice cultivation?
Disease management: The diseases of lowland and upland ecologies are observed in aerobic rice cultivation.
Amongst them, diseases like bacterial blight and blast are important. If leaf infection of 8-10% or more is observed, apply streptocyclin (150 mg) + copper oxychloride (1g) in one liter of water for controlling bacterial blight disease. Apply tricyclazole at the rate of 0.6g/l to control leaf blast disease.
Insect pest management: Insects like stemborer, brown plant hopper (BPH), nematodes and gundhi bug damage the crop significantly.
For controlling stem borer, apply Triazophos 40% EC @ 900 ml/ha or apply granular insecticide Furadan 3G @ 33 kg / ha or cartap 4G @ 25 kg / ha on the basis of ETL (one egg mass / m2 or 5% dead heart).
When gundhi bug population is more than 5 / m2, apply methyl parathion 5% or chloropyriphos 5% @ 25 kg/ha dust formulation. As BPH population reaches 10 insects / hill, apply monocrotophos 36 SL @ 1.3 l / ha or chloropyriphos 20 EC @ 2.5 l/ha or Quinolphos 25 EC @ 2 l/ha or imidacloprid 200 SL @ 0.5 l/ha for controlling the insect.
13. What are the important stages of rice crop under aerobic rice cultivation?
Paramount importance and best approach is necessary in weed management and nutrient deficiency. Water should not be a constrained during critical stages like, tillering, panicle initiation, flowering and grain filling.
Water must be withheld one week before harvest of the crop to facilitate uniform ripening of grains.
14. What are the advantages of aerobic rice cultivation and over conventional irrigated rice cultivation?
Aerobic rice has many advantages over conventional lowland irrigated type of cultivation. Since, direct seeding is recommended, nursery preparation, puddling and transplanting cost can be avoided.
Further, rational use of water for field preparation and irrigation helps in 35-45% of water saving. On the other hand, reduction in number of irrigations will help in cost cut and savings in power consumption.
In conventional lowland irrigated rice cultivation, green house gas like methane emission is elevated than the aerobic situation.
Under aerobic rice cultivation, researchers proved that methane emission has been reduced. Maintenance of soil structure is beneficial to non-rice crops in the rotation and timely sowing of succeeding crop after rice.
National Rice Research Institute, Cuttack, Odisha