Notes: Resources Improvement : JKBOSE Science Class 9th Chapter 13

Class 9 Science Study Notes with Q&A : Improvement in Food Resources (Chapter 13)

1. Introduction: The Need for Food Resource Improvement

India has experienced a massive surge in food requirements due to rapid population growth. While land available for cultivation is limited, significant progress has been made through intensified farming practices.

• Production Growth: Between 1952 and 2010, India achieved a four-fold (4x) increase in food grain production.
• Land Constraint: This production increase was achieved with only a 25% increase in cultivable land area.
• Conclusion: Because land is a finite resource, we must continue to improve efficiency through better scientific management of crops and livestock.

2. Classification of Crops by Growing Seasons

Agricultural crops in India are primarily classified based on their growing seasons, which are determined by temperature, rainfall, and photoperiods (the duration of sunlight required for growth and flowering).

Kharif vs. Rabi Seasons

3. The Three Stages of Crop Yield Improvement

Improving crop yields involves a systematic approach categorized into three major activity groups:

1. Crop Variety Improvement: Selecting or breeding the best seeds and strains.
2. Crop Production Management: Enhancing the nurturing of plants through nutrient and water management.
3. Crop Protection Management: Safeguarding both growing and harvested crops from losses.

4. Stage I: Crop Variety Improvement

This stage aims to find or create crop varieties that provide high yields and withstand environmental pressures.

• Methods of Improvement:
• Hybridization: Crossing genetically dissimilar plants. This includes intervarietal (different varieties), interspecific (different species), and intergeneric (different genera) crosses.
• Genetically Modified Crops: Introducing a specific gene to provide desired characteristics.
• Factors for Variety Improvement:
• Higher yield: Increased productivity per acre.
• Improved quality: Such as baking quality in wheat or protein quality in pulses .
• Biotic and Abiotic resistance: Resistance to biotic factors (diseases, insects, nematodes) and abiotic factors (drought, salinity, heat, frost).
• Change in maturity duration: Shorter durations allow for more rounds of cropping per year.
• Wider adaptability: Ability to grow under diverse climatic conditions.
• Desirable agronomic characteristics: Tallness and profuse branching are sought for fodder crops , while dwarfness is desired in cereals to reduce nutrient consumption.

5. Stage II: Crop Production Management

Production management involves the technical decisions and inputs used to maximize the yield from the land.

Nutrient Management

Manure vs. Fertilizers

• Manure: Organic matter made from animal/plant waste.
• Compost and Vermi-compost : Waste decomposed in pits, often using earthworms.
• Green manure : Plants like sun hemp or guar are grown and then mulched into the soil to provide nitrogen and phosphorus .
• Fertilizers: Commercially produced chemicals providing nitrogen , phosphorus , and potassium . While they give high yields, they can cause water pollution and harm soil fertility if used excessively.

Irrigation Systems

Most Indian agriculture is rain-fed , meaning it depends on timely monsoons; poor monsoons often lead to crop failure. To mitigate this, several systems are used:

• Wells: Dug wells (shallow strata) and tube wells (deep strata).
• Canals: Large systems distributing water from reservoirs or rivers.
• River Lift Systems: Directly drawing water from rivers when canal flow is insufficient.
• Tanks: Small reservoirs storing run-off.
• New Initiatives: Rainwater harvesting and watershed management using check-dams to increase groundwater and reduce erosion.

Cropping Patterns

• Mixed Cropping: Two or more crops grown simultaneously (e.g., Wheat + Gram , Wheat + Mustard , or Groundnut + Sunflower ).
• Inter-cropping: Two or more crops in a definite row pattern (e.g., Soyabean + Maize or Finger millet (bajra) + Cowpea (lobia) ).
• Crop Rotation: Growing different crops on the same land in a pre-planned succession.

6. Stage III: Crop Protection Management

Field Protection

• Weeds: Unwanted plants like Xanthium ( gokhroo ), Parthenium ( gajar ghas ), and Cyperinus rotundus ( motha ) that compete for light, space, and food.
• Insects: Attack crops by cutting (roots/stems), sucking (cell sap), or boring (into fruits/stems).
• Diseases: Caused by pathogens like bacteria , fungi , and viruses .
• Control: Preventive methods include proper seed bed preparation , inter-cropping , and summer ploughing . Chemical methods involve pesticides , herbicides , and fungicides .

Storage of Grains

Biotic (insects, rodents, fungi ) and abiotic (moisture, temperature) factors can cause severe storage losses.

• Consequences: degradation in quality , loss in weight , poor germinability , and discolouration of produce.
• Preventive Measures: Strict cleaning, drying (sun then shade), and fumigation .

7. Animal Husbandry: Cattle Farming

Animal husbandry is the scientific management of livestock, covering feeding, breeding, and health.

• Categories: Milch animals (milk-producing) and Draught animals (agricultural labor).
• Species: Bos indicus (cows) and Bos bubalis (buffaloes).
• Breeding: Exotic breeds like Jersey and Brown Swiss are chosen for long lactation periods , while local breeds like Red Sindhi and Sahiwal are chosen for disease resistance.
• Feed: Includes Roughage (fiber) and Concentrates (high protein/low fiber).

8. Poultry Farming

Poultry is raised for eggs ( layers ) and meat ( broilers ).

• Breeds: Cross-breeding between Indigenous ( Aseel ) and Exotic ( Leghorn ) varieties.
• Economic Goals: Breeders aim for summer adaptation, low maintenance, and the reduction in the size of the egg-laying bird with ability to utilise more fibrous cheaper diets formulated from agricultural by-products.

9. Fish Production

Fish are a vital, low-cost source of animal protein.

• Types: Capture fishing (from nature), Culture fishery (farming/aquaculture), and Mariculture (farming in seawater).
• Marine Varieties: Pomphret , mackerel , tuna , sardines , and Bombay duck . High-value farmed marine species include mullets , bhetki , pearl spots , prawns , mussels , and oysters .
• Composite Fish Culture: A system using 5 or 6 species in one pond to maximize food use:
• Catla : Surface feeders.
• Rohu : Middle-zone feeders.
• Mrigal and Common Carp : Bottom feeders.
• Grass Carp : Feed on weeds.
• Technology: To solve breeding problems in ponds, Hormonal Stimulation is used to ensure the supply of pure fish seed.

10. Bee-keeping (Apiculture)

Bee-keeping is a low-investment enterprise producing honey and wax.

• Local Varieties: Apis cerana indica (Indian bee), Apis dorsata (rock bee), and Apis florae (little bee).
• Italian Bee: Apis mellifera is preferred for commercial use due to high honey collection, staying in the hive longer, and breeding well.
• Quality Factors: The quality and taste of honey depend on the pasturage (the flowers available for nectar/pollen collection).

11. Glossary of Key Terms

• Hybridization: Crossing between genetically dissimilar plants to combine desirable traits.
• Macronutrients: The 6 nutrients required by plants in large quantities (e.g., Nitrogen , Sulphur ).
• Photoperiod: The duration of daily sunlight, which influences plant growth and flowering cycles.
• Vermi-compost: Organic fertilizer created by using earthworms to decompose plant and animal waste.
• Inter-cropping: Growing two or more crops on the same field in a specific row pattern to optimize nutrient use.
• Lactation period: The duration of milk production after the birth of a calf.
• Mariculture: The specific practice of culture fishery in marine or saltwater environments.
• Pasturage: The availability and type of flowers that bees use for nectar and pollen, determining honey flavor.
• Fumigation: The use of chemical vapors to destroy pests during the storage of agricultural produce.
• Hormonal Stimulation: A scientific technique used in fish farming to induce breeding in pond environments.

Q&A Study Guide: Improvement in Food Resources (Class 9 Science)

Questions 1 : What are the two distinct cropping seasons in India, and what are their specific timeframes?

Answer: In India, crops are categorized based on their growing seasons. The Kharif season occurs during the rainy months, lasting from June to October. The Rabi season occurs during the winter months, typically from November to April.

Questions 2 : List specific examples of crops grown during the Kharif and Rabi seasons.

Answer: Common Kharif crops include paddy, soyabean, pigeon pea, maize, cotton, green gram, and black gram. Examples of Rabi crops include wheat, gram, peas, mustard, and linseed.

Questions 3 : What are the three primary stages of farming practices used to enhance crop production?

Answer: Farming practices can be divided into three essential stages:

• Choice of seeds: Selecting the most suitable strains for planting.
• Nurturing: Managing the growth and nutritional needs of the crop plants.
• Protection: Safeguarding growing and harvested crops from various types of damage or loss.

Questions 4 : How are the major activities for improving crop yields systematically classified?

Answer: These activities are grouped into three main categories:

1. Crop variety improvement: Developing or selecting strains with superior traits.
2. Crop production improvement: Enhancing cultivation techniques and nutrient management.
3. Crop protection management: Defending crops against weeds, pests, and storage losses.

Questions 5 : Define hybridization and identify its different types used in variety improvement.

Answer: Hybridization refers to the crossing of genetically dissimilar plants to incorporate desirable traits. It is classified into three types:

• Intervarietal: Crossing between different varieties of the same species.
• Interspecific: Crossing between two different species of the same genus.
• Intergeneric: Crossing between different genera.

Questions 6 : What are genetically modified crops, and how are they created?

Answer: Genetically modified crops are developed by introducing a specific gene that provides a desired characteristic (such as pest resistance or nutritional value) into the plant’s DNA. This results in a variety that possesses a trait not naturally found in that strain.

Questions 7 : What are the main objectives of variety improvement regarding yield, quality, and resistance?

Answer: The goals include:

• Higher Yield: Increasing the total productivity per acre.
• Improved Quality: Tailoring traits like baking quality in wheat, protein content in pulses, and oil quality in oilseeds.
• Biotic and Abiotic Resistance: Developing strains that can withstand biotic stresses (diseases, insects, nematodes) and abiotic stresses (drought, salinity, heat, and cold).

Questions 8 : Explain the importance of maturity duration and desirable agronomic characteristics in crop improvement.

Answer:

• Change in Maturity Duration: Reducing the time from sowing to harvest allows farmers to grow multiple crops annually and lowers production costs.
• Desirable Agronomic Characteristics: Breeders develop specific physical traits for different uses. For example, tallness and profuse branching are desired for fodder crops to provide biomass, while dwarfness is desired in cereals so fewer nutrients are consumed for vegetative growth.

Questions 9 : Identify the sources from which plants obtain essential nutrients.

Answer: Plants obtain nutrients from three primary sources:

• Air: Provides Carbon and Oxygen.
• Water: Provides Hydrogen and Oxygen.
• Soil: Supplies thirteen essential nutrients required for physiological processes like growth and reproduction.

Questions 10 : Classify the thirteen soil-derived nutrients into macronutrients and micronutrients with examples.

Answer:

• Macronutrients: Required in large quantities. These include Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, and Sulphur.
• Micronutrients: Required in small quantities. These include Iron, Manganese, Boron, Zinc, Copper, Molybdenum, and Chlorine.

Questions 11 : How does manure benefit soil structure, and what are its different types?

Answer: Manure adds organic matter to the soil, improving its structure. In sandy soils, it increases water-holding capacity, while in clayey soils, it improves drainage to prevent waterlogging. The types include:

• Compost: Decomposed farm and domestic waste.
• Vermi-compost: Waste decomposed using earthworms to speed up the process.
• Green Manure: Plants like sun hemp or guar that are grown and ploughed back into the soil to add Nitrogen and Phosphorus.

Questions 12 : What are the core principles and components of organic farming?

Answer: Organic farming is a system that uses minimal or no chemical fertilizers, herbicides, or pesticides. It relies on organic manures, recycled farm wastes (straw/livestock excreta), and bio-agents like blue-green algae. It also utilizes healthy cropping systems (mixed, inter-cropping, rotation) for natural pest and weed control.

Questions 13 : Compare the nutrients supplied by fertilizers and manure, noting the long-term impacts of fertilizer use.

Answer: Fertilizers are commercial chemicals that supply Nitrogen, Phosphorus, and Potassium (N, P, K) for high yields. However, continuous fertilizer use can destroy soil fertility because organic matter is not replenished and beneficial microorganisms are harmed. Excessive use can also lead to water pollution via runoff.

Questions 14 : Describe the various irrigation systems utilized in India to manage water resources.

Answer:

• Wells: Includes dug wells (shallow strata) and tube wells (deep strata).
• Canals: Extensive networks receiving water from reservoirs or rivers.
• River Lift Systems: Directly drawing water from rivers for areas near banks when canal flow is insufficient.
• Tanks: Small reservoirs that store runoff from catchment areas.

Questions 15 : How do rainwater harvesting and watershed management support agricultural productivity?

Answer: These initiatives involve building small check-dams to intercept rainwater. This prevents the water from flowing away, reduces soil erosion, and facilitates the recharging of groundwater levels for future agricultural use.

Questions 16 : Define mixed cropping and inter-cropping, providing a specific example of an inter-cropping pattern.

Answer:

• Mixed Cropping: Growing two or more crops simultaneously on the same land (e.g., wheat + gram) to reduce the risk of total failure.
• Inter-cropping: Growing two or more crops in a definite row pattern (e.g., alternating rows of soyabean + maize). This ensures better nutrient utilization and prevents the spread of pests.

Questions 17 : Identify common weeds and explain the methods of crop protection against pests and weeds.

Answer: Common weeds include Xanthium (gokhroo), Parthenium (gajar ghas), and Cyperinus rotundus (motha). Insect pests attack by cutting roots/stems/leaves, sucking cell sap, or boring into fruits. Control methods include pesticides and preventive measures like timely sowing, inter-cropping, and summer ploughing (deep ploughing in summer to destroy weeds and pests).

Questions 18 : What factors contribute to the loss of stored grains, and what preventive measures should be taken?

Answer:

• Biotic factors: Insects, rodents, fungi, mites, and bacteria.
• Abiotic factors: Inappropriate moisture and temperatures.
• Prevention: Includes strict cleaning, thorough drying (first in sunlight, then in shade), and fumigation using chemicals to kill pests before storage.

Questions 19 : Distinguish between milch and draught animals and provide their scientific names.

Answer: Milch animals are milk-producing females (dairy animals), while draught animals are used for agricultural labor such as tilling and carting. The scientific name for cows is Bos indicus and for buffaloes is Bos bubalis.

Questions 20 : Explain the purpose of cross-breeding exotic and local cattle breeds, using specific examples.

Answer: Cattle are cross-bred to combine the desirable traits of two varieties. Exotic breeds like Jersey or Brown Swiss are selected for their long lactation periods, while local breeds like Red Sindhi or Sahiwal are chosen for their excellent disease resistance. The resulting offspring possess both qualities.

Questions 21 : What are the shelter and nutritional requirements for healthy cattle maintenance?

Answer: Cattle need well-ventilated, roofed sheds with sloping floors for dry conditions and easy cleaning. Their diet includes:

• Maintenance requirement: Food to support a healthy life.
• Milk producing requirement: Food required during lactation.
• Feed types: Roughage (mostly fiber) and Concentrates (low fiber, high protein).

Questions 22 : Contrast the purposes and traits of layers and broilers in poultry farming.

Answer: Layers are raised for egg production, while broilers are raised for meat. Desirable traits for improvement include summer adaptation (tolerance to high temperatures), low maintenance requirements, and the ability to utilize cheaper, fibrous diets.

Questions 23 : What are the specific nutritional requirements for broiler chickens?

Answer: Broilers require a ration that is protein-rich with adequate fat. Their feed must also contain high levels of Vitamin A and Vitamin K to ensure a good growth rate and feed efficiency.

Questions 24 : Differentiate between capture fishing, aquaculture, and mariculture.

Answer:

• Capture fishing: Obtaining fish from natural resources like oceans or rivers.
• Aquaculture: The general practice of farming fish in water bodies (fresh or brackish).
• Mariculture: The specific culture of marine fish and shellfish (e.g., mullets, prawns, oysters) in seawater.

Questions 25 : List popular marine fish varieties and explain how modern technology aids in their collection.

Answer: Popular marine varieties include Pomphret, mackerel, tuna, sardines, and Bombay duck. In the open sea, large schools of fish are located using satellites and echo-sounders to increase the efficiency of the yield.

Questions 26 : Describe the mechanics of composite fish culture and how it optimizes food usage.

Answer: Composite Fish Culture uses a combination of 5-6 species in a single pond that have different feeding habits to avoid competition.

• Catlas: Surface feeders.
• Rohu: Middle-zone feeders.
• Mrigals and Common Carps: Bottom feeders.
• Grass Carps: Feed on weeds. This system ensures that food in all parts of the pond is utilized.

Questions 27 : Identify local bee varieties and explain the factors affecting honey quality.

Answer: Local varieties include Apis cerana indica (Indian bee), A. dorsata (rock bee), and Apis florea (little bee). The Italian variety, A. mellifera, is used for its high honey collection capacity and low sting. Honey quality depends on the pasturage, which refers to the flowers available for nectar and pollen collection; the type of flowers also determines the taste.