RBSE Class 12 Biology Chapter 19- Sustainable Agriculture. In this chapter, students can learn in detail about the necessity of mineral nutrients in plants, essential elements of plants, macro and micronutrients. It also deals with the mechanism of absorption of mineral salts, passive and active absorption, mineral deficiency in plants, hydroponics, vermiculite and its features.
These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.
RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.
RBSE Class 12 Biology Chapter 19 Important Questions
RBSE Biology Chapter 19: MCQ Type Questions
Q.1. Which of the following is a biofertilizer produced from alga?
(a) Cladophora.
(b) Nostoc.
(c) Spirogyra.
(d) All of the above.
Sol: (b) Nostoc.
Q.2. Which of the following bacteria is present in Root nodules of leguminous plants?
(a) Anabaena.
(b) Cyanobacteria.
(c) Rhizobium.
(d) Lactobacillus.
Sol: (c) Rhizobium.
Q.3. Heterocyst is connected to __________.
(a) Virus.
(b) Bacteria.
(c) Nostoc.
(d) Rhizobium.
Sol: (c) Nostoc.
Q.4. Which free living bacteria fix atmospheric nitrogen.
(a) Rhizobium.
(b) E.coli.
(c) Azotobacter.
(d) All of the above.
Sol:(c) Azotobacter.
Q.5. Which of the following is not an example of sustainable agriculture?
(a) Mixed farming.
(b) Compact agriculture.
(c) Crop rotation.
(d) Organic agriculture.
Sol: (b) Compact agriculture.
Q.6. The biological factors which are used to kill insects, weeds and pest are called
(a) Biopesticides.
(b) Chemical fertilizers.
(c) Chemical insecticides.
(d) None of the above.
Sol: (a) Biopesticides.
Q.7. Which of the following is used to increase the crop yield.
(a) Pesticides.
(b) Biofertilzers.
(c) Chemical fertilizers.
(d) All of the above.
Sol: (d) All of the above.
Q.8. Which of the following bacterium is known to form crystal protein?
(a) Bacillus Thuringiensis.
(b) Rhizobium.
(c) Cyanobacteria
(d) Azotobacter.
Sol: (a) Bacillus Thuringiensis.
Q.9. Which of the following is the natural method of farming.
(a) Organic farming.
(b) Mixed farming.
(c) Crop rotation.
(d) None of the above.
Sol: (a) Organic farming.
Q.10. Which of the following bacterium functions as nitrogen fixers.
(a) Bacillus Thuringiensis.
(b) Lactobacillus.
(c) Cyanobacteria
(d) Anabaena.
Sol: (c) Cyanobacteria
RBSE Biology Chapter 19: Short Answer Type Questions.
Q.1. What is the main objective of agriculture?
Sol. Agriculture is the process of growing plants and animals for human needs. The main objective is to promote the quality of life, provide employment opportunities, to encourage an awareness of agriculture, improve crop production, etc.
Q.2. How is Bacillus thermogenesis used as a biopesticides?
Sol. Bacillus thermogenesis is a soil inhabiting bacteria.These Gram-positive bacteria produce pesticides and crystal proteins from its spores, which are used to kill insects and other pests causing harm to crop production. The first pesticides at commercial level were made from this bacterium.
Q.3. What is sustainable agriculture?
Sol. Sustainable agriculture is an integrated system of practices of cultivation of agricultural plants and livestock in which cultivation sites can be maintained for a longer period of time without any harm and human requirements can be fulfilled for a long time.
Q.4.Give any two advantages of blue green algae in farming.
Sol. Cyanobacteria, such as Anabaena Nostoc, Plectonema and other procaryotic non symbiotic organisms are involved in atmospheric nitrogen fixation. Blue-green algae have very special cells called Heterocyst.
Nif genes present in the heterocyst do nitrogen fixation. An environment of rice fields is ideal for the growth of blue-green algae. The use of blue green algae in paddy fields increases the production.
Q.5. What is Biocontrol?
Sol. The natural method of eliminating and controlling the insects, pests and other disease-causing agents using their natural, biological enemies is called biocontrol or biological control. The agents which are employed for this are called biocontrol agents. Microbes are one of them.
Q.6.What is Organic farming?
Sol. Organic farming can be defined as a form of agricultural process that involves minimal or no use of synthetic chemicals. It is eco-friendly and helps to reduce soil infertility and soil erosion issues. It enhances organic productivity which promotes a healthy lifestyle.
Q.7. What are the different types of sustainable agriculture?
Sol. Sustainable agriculture can be achieved by adopting the following practices:
- Organic Agriculture.
- Mixed farming.
- Mixed cropping.
- Crop rotation.
- USes of biopesticides.
Q.8.What are Pesticides?
Sol. Pesticides are chemical substances that are meant to kill pests. In general, a pesticide is a biological or a chemical agent such as a bacterium, virus, antimicrobial, or disinfectants, which destroys, incapacitates and kills the pests.
Q.9.What is crop rotation?
Sol. Crop rotation is the component of organic farming, which involves growing of various crops in a more or less regular sequence, on the same land, covering a period of two years and more.
Q.10. What is symbiotic bacteria?
Sol. Symbiotic bacteria are bacteria living in a symbiotic relationship with the plants. The bacteria found in the root nodules of leguminous plants, obtain nutrition from the plant and in return fixes the atmospheric nitrogen and make it available for the leguminous plants.
Q.11. What is mixed farming?
Sol. An agriculture under which the various types of agricultural activities are performed in a single farm is called mixed farming. The various types of agricultural activities include poultry, crop production, dairy farming, etc.
Q.12. What is the economical importance of organic farming?
Sol. The economical importance of organic farming are :
- Soil erosion can be controlled by organic farming.
- It is cost effective, which can be used even by small scale farmers.
- By adopting organic farming, the toxicity of the chemical present in the soil decreases.
- Use of organic manures helps in the increase of water holding capacity and aeration of soil.
- By the use of biofertilizers, balanced nutrient elements are available, which increases soil fertility.
Q.13. What is the use of sustainable agriculture?
Sol. Sustainable agriculture is an integrated system of practicing cultivation with renewable resources. This practice is environment friendly, which causes less pollution and provides maximum yield.
Q.14. What is the objective of organic farming?
Sol. The main objective of organic farming are :
- To increase the yield of high quality food materials.
- To use local agricultural procedures and renewable resources of energy.
- To make friendly use of the natural system, instead of suppressing them.
- To increase the soil fertility and to maintain it stable for a longer period of time.
- To promote the biological process of microbes, soil organisms, plants and other organisms related to the agricultural system.
Q.15. What is crop rotation?
Sol. The methods of growing different crops on the same land in a pre planned succession is called crop rotation. Based on this method, the crops are classified as one-year rotation, two-year rotation and three-year rotation, depending upon their duration.
Legumes are included in the crop rotation programme to increase soil fertility. The crops which require high fertility levels like wheat and paddy can be grown after the legumes. The crops which require low inputs can be grown after the crops that require high inputs.
RBSE Biology Class 12: Long Answer Type Questions
Q.1. What are the types of agriculture?
Sol. Agriculture is one of the most widespread activities in the world and is based primarily on the nature of the land, climatic characteristics and available irrigational facilities. The different types of farming practised by the farmers in India are:
- Dry farming
- Wet farming
- Subsistence farming
- Shifting Agriculture
- Intensive Agriculture
Q.2.What are the benefits of Pesticides?
Sol. The major advantage of pesticides is that they can save farmers. By protecting crops from insects and other pests. However, below are some other primary benefits of it.
- Controlling pests and plant disease vectors.
- Controlling human disease vectors and nuisance organisms.
- Controlling organisms that harm other human activities and structures.
Q.3. Why need sustainable agriculture?
Sol. In ancient times, the three basic needs of human beings namely food, clothes and shelter were fulfilled using plants and their different parts. As time passed away, human requirements increased by many folds. The population explosion, industrial revolution and the development of transport facilities created tremendous pressure on the natural resources and some of them are depleting at an alarming rate.
If the situation continues, the future generations will have to suffer from lack of resources. There may be a lack of fresh air required for breathing, pure and potable water for drinking and lack of nutritive food. Now, we have started thinking globally about how the present human needs can be fulfilled without creating an imbalance in nature and without compromising the needs of the further generation. Looking into this context, the concept of sustainable agriculture has developed.
Q.4.What are the advantages of Organic Farming?
Sol. Organic farming can be defined as an agricultural process that uses biological fertilizers and pest control acquired from animal or plant waste.
The advantages of Organic Farming are:
- Improves soil fertility and maintains biological diversity.
- Good for the environment and yields are healthy for human and animal consumption.
- Prevents soil erosion, degradation and crop failure.
- Decrease pollution and the whole farming can easily rely on renewable energy sources.
- Improves the soil fertility and enhances its chemical and physical properties.
Q.5. Why are fertilizers important for plants?
Sol. Fertilizers are chemical substances supplied to the crops to increase their productivity. These substances provide the necessary nutrients required for a plant.
Fertilizers can be important to the plants in the following ways:
- Fertilizers increase plants tolerance towards pests.
- Fertilizers improve the water holding capacity of the plants and increase root depth.
- The potassium content present in the fertilizers strengthens the straws and stalks of the plants.
- The phosphorus present in the fertilizers helps in the faster development of roots and formation of seeds in the plants.
- Nitrogen in the fertilizers enhances the growth of the plants, which can be characterized by the green colour of the plants.
Fertilizers help in producing healthier and disease free crops that destroy pathogenic components responsible for causing disease in plants. Biofertilizers contain living cells and micro-organisms, which provide the soil with the necessary nutrients and microbes for the growth of the plants. They help the soil to retain its fertility. They are environment-friendly.
Q.6.What are the advantages and disadvantages of Fertilizers?
Sol. Advantages of Fertilizers.
- They are predictable and reliable.
- They have a rapid effect on the crops.
- They are easy to transport, store, and apply.
- They increase the crop yield and provide enough food to feed the large population.
- They are soluble in water and can easily dissolve in the soil. Hence, they are easily absorbed by the plants.
Disadvantages of Fertilizers.
- They are expensive.
- Excessive use of fertilizers damages the plants and reduces soil fertility.
- The ingredients in the fertilizers are toxic to the skin and respiratory system.
- Long term use reduces the microbial activity and disturbs the pH of the soil.
Q.7. What is the difference between inter cropping and mixed cropping?
Sol. The main difference between cropping and mixed cropping are:
| Inter Cropping | Mixed Cropping |
| A specific planting pattern is followed. | No planting pattern is followed |
| Different fertilizers and pesticides are used for different crops | Same fertilizers and pesticides used for all the crops |
| Seeds are not mixed before sowing | Seeds are mixed before sowing |
| Increase in the productivity of crops | Reduces the risk of crop failures due to unfavourable climatic conditions |
| There is a considerable difference in the life cycle and the duration of maturity in different crops | All crops have a similar life cycle and duration of maturity |
| The main objective is to utilise the space left between the rows of the main crop | The main objective here is to get at least one crop in a favourable condition |
| Oats, corn and soybean are examples of inter cropping. | Maize, mustard.beans, wheat and pumpkins are examples of mixed cropping. |
Q.8.Write an essay on Biofertilizers.
Sol. The microbes which enrich the soil in nutrients by their biological activities are called biofertilizers. These biofertilizers also accelerate the process of mineralization, in addition to the increase in the soil fertility.
Some of the common examples of Biofertilizers are Bacteria, Cyanobacteria, fungi, etc.
There are six different types of biofertilizers.
Symbiotic bacteria – Rhizobium.
These bacteria are found in the root nodules of leguminous plants and obtain their nutrition from plants. These bacteria help plants by fixing the atmospheric nitrogen and converting it into ammonia and liberate it outside, which in turn are consumed by plants. The use of this bacteria as biofertilizer can increase the production upto 15 to 20 percent.
Non-Symbiotic bacteria.
Non-Symbiotic bacteria, such as Azotobacter, Clostridium,etc, can fix the nitrogen present in the soil and make it available for plants. These bacteria absorb free nitrogen from the soil and convert it into organic nitrogenous compounds.
Azotobacter is used as biofertilizers during the production of rice, coton, and maize cultivation. This helps in the increase of crop production by 20 percent.
Blue green algae or Cyanobacteria.
Cyanobacteria such as Anabaena, Nostoc and other non symbiotic bacteria perform nitrogen fixation.
Mycorrhiza
Symbiotic association of fungi with roots of higher plants is called Mycorrhiza. The fungus absorbs nutrients from the soil and provides it to the host plants and in turn host plants provide nutrition to the fungus.
Phosphate dissolving bacteria.
Some bacteria such as Mycobacterium, Bacillus, etc. convert non available phosphate into an available phosphate which can be easily absorbed by the plants.
Organic manure.
All the organic wastes available from the domestic wastes, urban wastes, sewage remains of crops, animal excreta, bone powder, remains of crops are converted into an organic manure by microbial degradation and are used by plants as a manure.
Q.9.What are the disadvantages of Pesticides?
Sol. Pesticides are the toxic chemicals, which are designed to deliberately release into the environment. All farmers worldwide use pesticides to keep the plants free from pest infestations and to increase crop productivity.
There are several disadvantages of pesticides.
- The use of percentage decreases the general biodiversity in the soil.
- A very large percentage of pesticides reach a destination other than their target.
- These pesticides enter the air, water, sediments and even end up in our food.
- Some pesticides kill beneficial insects. Insects such as bees, which are the agents of pollination.
- Pesticides have been linked with human health hazards, from short-term impacts such as headaches and nausea to other chronic impacts.
Q.10. What is the importances of the use of blue green algae as biofertilizer?
Sol. Blue green algae or Cyanobacteria.
- Cyanobacteria have very special cells called Heterocyst, which are involved in atmospheric nitrogen fixation.The Nif genes present in the heterocyst do nitrogen fixation.
- Cyanobacteria, such as Anabaena Nostoc, Plectonema and other prokaryotic non symbiotic organisms are involved in atmospheric nitrogen fixation.
- Anabaena pinata is a good biofertilizer when it is used in combination with Azolla.
- The azolla is a floating aquatic fern. Its leaves contain Cyanobacteria, which fixes atmospheric nitrogen.
Q.11. What are the applications of Fertilizers?
Fertilizers are mainly used for various purposes. Few of them are listed below:
- Fertilizers are added to crops to improve the yield of the crops.
- Fertilizers are used to provide additional nutrients to the plants.
- Nitrogen-rich fertilizers are used for the greening of lawns.
- Organic fertilizers improve the texture and fertility of the soil.
- Fertilizers are added to potted plants to replace the lost nutrients.
- Gardeners use fertilizers to address certain needs of the plants such as nutritional needs.
Q.12. What is the importance of Biofertilizers?
Sol. Biofertilizers are important for the following reasons:
- They are eco-friendly and cost-effective.
- They do not allow pathogens to flourish.
- It improves soil texture and yield of plants.
- The bio- fertilizers are effective even under semi-arid conditions.
- It protects the environment from pollutants since they are natural fertilizers.
- They destroy many harmful substances present in the soil that can cause plant diseases.
Q.13. Write the main differences between fertilizers and pesticide.
Sol. Fertilizers are compounds which promote plant growth. There are two types of fertilizers – organic and inorganic. Fertilizers provide the plant with the required nutrients.
Pesticides are the substance designed for preventing, destroying, repelling or reducing the pests, which are the major cause for the damage of the crops. These substances include both chemical substances and biological agents.
Q.14.What is mixed cropping? What are the advantages of mixed cropping?
Sol. When two or more crops are grown on the same land simultaneously, it is known as mixed cropping. For eg., growing wheat and gram on the same land at the same time is mixed cropping.
The main advantages of mixed cropping are:
- The soil is utilized properly.
- There is an increase in the crop yield .
- The pest infestation is minimized.
- Reduction in the risk of crop failure.
- More than one variety of crops can be harvested at the same time.
Q.15. What are Fertilizers? Explain its types?
Sol. Fertilizers are chemical substances supplied to the crops to increase their productivity. These are used by the farmers daily to increase the crops yield. The fertilizers contain the essential nutrients required by the plants including nitrogen, potassium, and phosphorus. They enhance the water retention capacity of the soil and also increase its fertility.
The different types of fertilizers are mentioned below:
Inorganic Fertilizers
Inorganic fertilizers are chemical fertilizers that contain nutrient elements for the growth of crops made by chemical means.
Nitrogen Fertilizers
The main nutrient in a nitrogen fertilizer is nitrogen. It is necessary for the development of crops. Nitrogen is the main constituent of chlorophyll that maintains a balance in the process of photosynthesis. It is also a part of amino acids in plants and constitutes protein. Nitrogen fertilizers improve the production and quality of agricultural products.
Phosphorus Fertilizer
The main nutrient in a phosphorus fertilizer is phosphorus. The efficiency of fertilizer depends upon effective phosphorus content, methods of fertilizing, properties of soil and crop strains. The protoplasm of the cell consists of a Phosphorus, which plays an important role in cell growth and proliferation. The phosphorus fertilizer is beneficial for the growth of roots of the plants.
Organic Fertilizers
Organic fertilizers are natural fertilizers obtained from plants and animals. It improves or enhances the quality of the soil with chemical substances containing carbon, which are essential for plant growth. The organic matter content of the soil is increased by these organic fertilizers, which promotes the reproduction of microorganisms, and changes the physical and chemical properties of the soil. It is considered to be one of the main nutrients for green food.
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