NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture

NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture Notes and select need one. NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.

NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Environmental Science Chapter 21 Concept of Sustainable Agriculture Solutions, NIOS Senior Secondary Course Environmental Science Solutions for All Chapter, You can practice these here.

Concept of Sustainable Agriculture

Chapter: 21

Module 6: Sustainable Development

Textual Question Answer

INTEXT QUESTIONS 21.1

1. Define sustainable agriculture.

Ans: Sustainable agriculture and farming systems are those that are least toxic and least energy intensive and yet maintain productivity and profitability. 

2. Mention three advantages of sustainable agriculture.

Ans: Sustainable agriculture is helpful to the environment because:

(i) it protects environment quality.

(ii) uses natural resources efficiently. 

(iii) decreases dependency on nonrenewable resources.

INTEXT QUESTIONS 21.2 

1. How does crop rotation practice improve soil quality?

Ans: Crop rotation practice increases soil fertility by growing legume as a rotational crop, decreases soil erosion, controls pests and diseases. 

2. What is the difference between polyculture and multiple cropping?

Ans: Polyculture is the practice of growing plants simultaneously on a piece of land which matures at various times. Multiple cropping is growing two or sometimes three different crops in succession on the same land within a year. 

3. Define biofertilizers and give two important advantages of using it.

Ans: Biofertilizers are plant nutrients of biological origin like algae, bacteria, fungi which have no harmful effect on soil and environment. Advantages: A large amount of money can be saved by reduced the purchase and production of chemical fertilizers, human health can be saved from harmful effects of chemical fertilizers. 

4. What roles do Rhizobium and blue green algae play in agriculture?

Ans: Rhizobium, a symbiotic bacteria live in the root nodules of legume plants and fix atmospheric nitrogen and ultimately make the soil rich in nitrogen which is very essential for plant growth. Blue green algae (BGA) fix atmospheric nitrogen in their special cells called heterocysts and ultimately provide nitrogen to the soil. Both Rhizobium and BGA act as biofertilizers. 

INTEXT QUESTIONS 21.3 

1. Mention two important agricultural inputs which are avoided in organic farming?

Ans: Two important agricultural inputs which are avoided in organic farming are chemical fertilizers and pesticides. 

2. What is IPM and what is its aim?

Ans: IPM is Integrated Pest Management, which avoids harmful chemical pesticides and uses biological methods and agricultural practices to get rid of the pests. Its aim is not to eradicate the pests completely but to keep them at an economically tolerable level. 

3. What types of improved crop varieties can be produced by gene transfer technology?

Ans: Gene transfer technology can produce crops: 

(i) Resistant to herbicides and pesticides. 

(ii) Resistant to insects and diseases. 

(iii) Tolerant to high salt in the soil. 

(iv) With improved nutritional quality. 

(v) Prolonging shelf life. 

4. What is “Golden Rice”?

Ans: “Golden Rice” is a transgenic rice with enhanced vitamin A content.

TERMINAL EXERCISE

1. Define sustainable agriculture and justify its need. 

Ans: Sustainable agriculture systems are those that are least toxic and least energy consuming, yet maintain productivity and profitability.  

Sustainable agriculture aims to provide food to the population and avoiding the use of chemical fertilizers, pesticides so that soil productivity could be maintained. It is beneficial for farmers and as well for consumers. The quality of life of farmers as well as the rural community will improve and it causes no damage to the environment.

2. What are the two most important effects of increase in population in the cities? 

Ans: The increasing population has increased the demand for food and shelter. The forests are being cut down for the construction of more buildings. The cropland and the habitat of wild animals are getting destroyed.

3. Why do you need to improve the existing varieties of plants (give any three reasons)? 

Ans: (i) To reduce pesticide use by producing pest-resistant varieties.

(ii) To increase crop productivity and yield.

(iii) To improve nutritional quality and reduce production costs.

4. Mention any four types of crops that one can produce applying gene transfer technology. 

Ans: Rice, wheat, maize, soybean.

5. Explain the aim and objectives of the process of IPM.

Ans: The aim of IPM is not to eradicate the pest population completely but to keep the crop damage to an economically tolerable level. The biological methods are used for controlling the pests, and if biological methods do not work then little insecticides are applied that are derived from the plants.

6. What are GMOs? Explain briefly giving any two examples. 

Ans: GMOS are genetically modified organisms. These are the varieties of plants that are modified by the introduction of genes like pest-resistant gene, cold-resistant gene, drought-resistant gene, and making the crop varieties nutritionally rich by introducing such genes. B cotton is a pest-resistant variety of cotton. 

(i) The Bt gene from Bacillus thuringiensis bacterium is introduced in Bt cotton plants.

(ii) Golden rice is a GM (genetically modified) crop, it is enriched with vitamin A content.

7. What is biological control of pests? 

Ans: Biological pest control involves the natural predators of the pests that are damaging the crop. For example – red spider mite, which is a pest of the cucumber plant, is controlled by introducing another predator mite that eats up the red spider mite. Another example is of Australian ladybirds that feed upon the scale insects that damaged the Citrus plants in California.

8. Which are the two most important items which are applied generously in normal agriculture that are avoided in organic farming? 

Ans: Chemical fertilizers and chemical pesticides.

9. How do blue green algae help in agriculture? 

Ans: Blue-green algae are photosynthetic algae. They help in the fixation of atmospheric nitrogen into the rice fields flooded with water hence promote the growth of the crop and make the soil nutrient-rich.

Examples of blue-green algae are Nostoc and Anabaena. This helps in nitrogen fixation. They act as nitrogen biofertilizer for rice fields.

10. Define biofertilizer and their uses in agriculture.

Ans: Biofertilizers are plant nutrients of biological origin like algae, bacteria, fungi which have no harmful effect on soil and environment. Their products help in the solubilization of phosphates, fixation of atmospheric nitrogen, and formation of sulfur oxides in the soil to enrich the soil with nutrients and thereby increasing its fertility and crop productivity. Rhizobium is a symbiotic bacterium that lives in the root nodules of legumes and fixes the atmospheric nitrogen thereby making the soil nutrient-rich, Blue-green algae also help In nitrogen fixation and they live freely. Azotobacter bacteria also live freely and help in fixing nitrogen, and providing growth-promoting factors for enhancing the growth of crops and increasing the yields.