36 Questions
What is the gross return per hectare for treatment T1 (BGA)?
59453
Which treatment has the highest benefit-cost ratio?
T12 (N120 + P60 + K60)
What is the net return per hectare for treatment T5 (AM fungi)?
37715
Which two treatments have a benefit-cost ratio of 2.01?
T8 (Azolla + PSB) and T9 (BGA + AM fungi)
What is the LSD (Least Significant Difference) value for the benefit-cost ratio at p=0.05?
0.26
Which treatment has the lowest gross return per hectare?
T3 (Azotobacter)
What is the percentage of increase in rice yield when using BGA as a biofertilizer?
10-15%
How much nitrogen does BGA contribute to the soil per hectare per season?
25-30 kg N
What is the duration of exposure to sunlight required for mass production of BGA culture?
Not specified
How long does it take for a thick algal mat to form in mass production of BGA culture?
15-21 days
What is the recommended time for broadcasting BGA culture after transplanting rice seedlings?
5-7 days
What is the type of association formed between Azolla and Anabaena azollae?
Symbiotic association
What is the biomass content of Azolla?
Up to 5.2 t DM
What is the benefit of using Azolla in rice cultivation, apart from nitrogen supply?
Reduces weed growth and volatilization of top-dressed urea
What is one of the advantages of using biofertilizers?
They are a renewable source of nutrients
How much chemical fertilizer can be replaced by biofertilizers?
25-30%
What is the effect of biofertilizers on soil texture and structure?
Improve texture, structure and water holding capacity of soil
What is the purpose of seed treatment with biofertilizers in direct seeded rice?
To provide a thin coating of biofertilizer to the seeds
In the seedling root dip method, how long should the seedlings be dipped in the suspension?
8-10 hours
What do bacteria in biofertilizers use for their metabolism?
Organic carbon
What is the role of root exudates in the process of biofertilization?
They become food for the bacteria
What is the effect of biofertilizers on grain yields?
Increase grain yields by 10-40%
What is the highest grain yield obtained in the experiment?
4.75 t/ha (T12)
Which treatment resulted in the lowest grain yield?
3.74 t/ha (T3)
What is the difference between the highest and lowest straw yields?
0.96 t/ha
Which treatment combinations resulted in straw yields higher than 16.50 t/ha?
T6, T8, T9, T10, and T12
What is the LSD (p=0.05) value for grain yield?
0.56
What is the treatment that resulted in the highest grain yield with the use of microorganisms?
T9 (BGA + AM fungi)
What was the protein content in the control group in 2007?
7.11%
Which biofertilizer combination resulted in the highest grain yield in 2008?
GM+ FYM +BGA
What percentage of total biofertilizer production in 2010-11 was contributed by PSB?
50%
What was the increase in protein yield in the GM+BGA treatment compared to the control in 2007?
135.9 kg/ha
What is the advantage of biofertilizers according to the conclusion?
Low cost inputs leading to long-term sustainability of soil productivity
What region contributed the highest percentage to total biofertilizer production in 2010-11?
South
What was the protein content in the FYM treatment in 2008?
7.80%
What is the limitation of biofertilizers according to the conclusion?
The amount of nutrients supplied may not be enough to meet the total need of crops for higher yields
Study Notes
Biofertilizers in Rice Production
- Biofertilizers can increase rice yield by 10-15% and fix atmospheric nitrogen, contributing 25-30 kg N/ha/season.
- Types of biofertilizers used in rice production:
- BGA (Blue-Green Algae)
- Azolla
- Azospirillum
- Phosphobacteria
- Mass production of BGA culture involves:
- Using shallow trays with galvanized sheets
- Spreading soil and SSP (Single Super Phosphate)
- Adding water and algal culture
- Exposing to sunlight and collecting dry algal flakes
- Method of application of BGA:
- Broadcasting 10 kg soil-based culture/ha 5-7 days after transplanting rice seedlings
- Maintaining sufficient water (5-10 cm) for 15 days
- Allowing algal mat to form and settle
Azolla as a Biofertilizer
- Azolla is a free-floating water fern that forms symbiotic associations with Anabaena azollae.
- It requires standing water for establishment and can reduce volatilization of top-dressed urea.
- Azolla has high biomass content (up to 5.2 t DM) and high protein content, making it an excellent green manure and potential rice biofertilizer.
Advantages of Biofertilizers
- Renewable source of nutrients
- Sustains soil health
- Supplements chemical fertilizers (replacing 25-30% of chemical fertilizers)
- Increases grain yields by 10-40%
- Improves soil texture, structure, and water-holding capacity
- Has no adverse effects on plant growth and soil fertility
- Stimulates plant growth by secreting growth hormones and fungistatic and antibiotic-like substances
- Solubilizes and mobilizes nutrients
- Eco-friendly, non-pollutant, and cost-effective method
Seed Treatment and Seedling Root Dip Methods
- Seed treatment involves mixing Azospirillum and PSB biofertilizers with water and applying it to the seeds.
- Seedling root dip method involves mixing the biofertilizers with water and dipping the seedlings' roots for 8-10 hours before transplanting.
Effect of Biofertilizers on Grain and Straw Yield
- Different treatments of biofertilizers (BGA, Azolla, Azotobacter, PSB, AM fungi, and their combinations) resulted in varying grain and straw yields.
- The highest grain yield was observed in the treatment with BGA + PSB (4.63 t/ha).
Effect of Biofertilizers on Economics of Basmati Rice Cultivation
- Different treatments of biofertilizers resulted in varying gross and net returns, as well as benefit-cost ratios.
- The highest benefit-cost ratio was observed in the treatment with BGA + PSB (2.05).
Production Scenario of Biofertilizers
- The production of biofertilizers in different regions of the country (2010-11) shows:
- South region: 54%
- West region: 34%
- North region: 7%
- North East region: 3%
- East region: 2%
Conclusions
- Biofertilizers are low-cost inputs that lead to long-term sustainability of soil productivity.
- They are effective in improving both quantity and quality of different crops.
- A pragmatic approach is needed to develop a rational and effective combination of biofertilizers and sources of nutrients for optimum crop yields.
Learn about the use of biofertilizers such as Azolla, Azospirillum, and Phosphobacteria to increase rice yield and contribute to nitrogen fixation. This quiz covers the benefits and effects of biofertilizer application in rice cultivation.
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