Test: Crop Production & Management- 3 - Class 8 MCQ

Let's analyze the given statements and determine their truthfulness:

(i) Growing different crops in different seasons in the same field will deplete the nutrients of the soil.
- False. Growing different crops in different seasons, known as crop rotation, generally helps maintain soil fertility by balancing the nutrient demand.

(ii) Freshly harvested grains must be dried before storing.
- True. Freshly harvested grains must be dried to reduce moisture content and prevent mold growth and spoilage during storage.

(iii) Manures are mineral specific as they provide all the minerals needed by the plant.
- False. Manures are not mineral specific; they are organic matter that enriches the soil with nutrients but do not provide all the minerals needed by plants.

(iv) Broadcasting of seeds is done by seed drill.
- False. Broadcasting is a method of sowing seeds by scattering them over the soil surface, while a seed drill is a tool that places seeds at specific depths and intervals in the soil.

Therefore, the correct identification of true (T) and false (F) statements is:
(i) F
(ii) T
(iii) F
(iv) F

The correct answer is C as the correct code of column with their description is in option C

Kharif crops:
These are the crops grown in rainy season extending from june to october hence are also called as monsoon crops. These crops are totally rain dependent crops. Kharif crops include paddy, soybean, sugarcane and not wheat.

Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant pest and weeds. 

The given agricultural tool is hoe which is used for removing weeds and for loosening the soil. It has a long rod of wood or iron. A strong broad and bent plate of iron is fixed to one of its ends and works like a blade. It is pulled by animals.

Threshing: Separating Grains from Stalks
Threshing is the process of separating grains from stalks or husks. It is an important step in the agricultural process, particularly for crops like wheat, rice, and barley. The process involves breaking the straw or husk covering the grains and separating them.
Here is a detailed explanation of the process of threshing:
1. Harvesting: Before threshing can take place, the crops need to be harvested. The ripe plants are cut and gathered in bundles.
2. Preparation: The harvested plants are then dried to reduce moisture content, making them easier to thresh. This is usually done by leaving them in the field to dry naturally or by using mechanical dryers.
3. Threshing: Once the plants are dry, the threshing process begins. There are different methods of threshing, including:
- Beating: In this traditional method, the harvested plants are beaten against a hard surface, such as a stone or wooden platform, to separate the grains from the stalks.
- Treading: This method involves using animals, such as oxen or horses, to trample over the harvested plants. The weight and movement of the animals cause the grains to separate from the stalks.
- Machine Threshing: With advancements in technology, threshing machines have been developed. These machines use rotating drums or beaters to separate the grains from the stalks. They are more efficient and faster than traditional methods.
4. Winnowing: After threshing, the next step is winnowing. This process involves separating the grains from the chaff (lighter material, such as straw, husks, and dust) by using air or wind. The mixture of grains and chaff is thrown into the air, allowing the wind to blow away the chaff while the heavier grains fall back down.
5. Collection and Storage: Once the grains are separated from the stalks and chaff, they are collected and stored for further processing or consumption. Proper storage is essential to protect the grains from moisture and pests.
Threshing is a crucial step in the production of grains as it allows for the separation of valuable food sources from the inedible parts of the plants. This process has evolved over time, from manual labor to mechanized methods, improving efficiency and productivity in agriculture.

Manure is not nutrient specific. It only removes the general deficiency of soil. Manures enhance the water holding capacity of soil, increase the number of friendly microbes and improve the texture of the soil.

A pheromone trap is a type of insect trap that uses pheromones to lure insects. Pheromones, traps can be used to monitor target pests in agriculture or in residential areas.

Correct Answer :- b

Explanation : Chain pump, dhekli and pulley system are traditional methods of irrigation while drip system is the modern method of irrigation. Urea, potash, ammonium sulphate are fertilisers while oxychloride is not a fertiliser. Khurpi, weedicides and seed drill are used in weeding while silos are used in storing food grains. Sowing, irrigation and harvesting are agricultural practices while hybridisation is not. 2, 4 - D, MCPA and butachlor are herbicides while BHC is an insecticide.    

Metolachlor, simazine, MCPA, butachlor, 2, 4-D and dalapon are weedicides.

Observation:
- A beaker is filled halfway with water.
- Wheat seeds are added to the beaker.
- The contents are stirred and left undisturbed for some time.
Inference:
- Damaged seeds being lighter float on the surface of water.
Explanation:
- When wheat seeds are added to the water, some of them may be damaged.
- Damaged seeds have a higher chance of having air pockets or being less dense than healthy seeds.
- The damaged seeds, being lighter, will float on the surface of the water due to buoyancy.
- Healthy seeds, being denser, will sink to the bottom of the beaker.
- By observing which seeds float and which sink, we can infer the quality of the seeds.
- In this experiment, the observation suggests that the damaged seeds float on the surface of the water, indicating their lighter weight compared to healthy seeds.
Conclusion:
- The observation and inference of this experiment suggest that damaged seeds, being lighter, float on the surface of water.

Soybean has been grown as a cash crop as tofu and soy oil are obtained from it. Soybean plants are legumes. They have bacteria on nodules of the roots of the plant. These bacteria help in nitrogen fixation. Crop rotation of soybean legume is done with grass crops like corn or wheat. This is because the nutrient requirements of grass crop are fulfilled by the soybean crop. Growing soybean crop provides nitrogen-fixing bacteria in the soil which helps the growth of grass crop in the successive year.

Pongal, Baisakhi,Onam,Makar Sankranti are the festivals associated with harvest season while Christmas and Eid are not associated with harvest season.

Loose smut of wheat is caused by fungus Ustilago tritici, early blight of potato is caused by fungus Alternaria so/an/ and late blight of potato is caused by fungus Phytophthora infestans. Citrus canker is a bacterial disease caused by bacterium Xanthomonas.

Water logging decreases the amount of salts in the soil that reduces soil fertility. Fertilisers are soluble in water, they are directly absorbed by plants and greatly increase crop yield. The practice of growing two or more dissimilar crops in the same field simultaneously is called mixed cropping.

The cutting and gathering of crop after it is matured is called harvesting. After this, grains are separated from the crop by a process called threshing. Winnowing is the process of separating the hay and chaff from the grains. Harvesting is done mechanically by combine and manually by sickle.

The given pot X, Y and Z contains green manure, manure and fertiliser respectively. Green manures and manures replenish soil with nutrients while fertiliser has no role in replenishment of nutrients.

The measures that are taken to grow crops are called agricultural practices. Steps of agricultural practices are:

1. Soil preparation: The soil is plowed, leveled and manured before sowing the seeds.

2. Sowing: Seeds of good quality are sowed or dispersed in the soil.

3. Manuring: The nutrients are provided to the seeds at regular intervals. Manure is the decomposition product of plant and animal wastes. 

4. Irrigation: The water is provided at regular intervals.

5. Weeding: Weeds or unwanted plants are removed using weedicides or removing them manually.

6. Harvesting: After the crop is fully grown, it is  cut and gathered. This process is called as harvesting. 

7. Storage: The harvested crop is then stored for further use or marketing.

Hence, the correct answer is Option A.

• In the semi arid Plains ofa particular region farmers grow wheat in some long and leave back the black strips of land but take care of that land by using weedicides this is because rain harvesting is done in that black stripped areas.
• Sometimes semi arid areas do not get enough amount of rainwater due to some environmental conditions and hence the prestored rainwater in the black strips are used to cultivate wheat crops.