Improvement if crop yield - class-VIII

Selection of crops for rotation depends on soil condition, moisture condition, length of rainy season, type of inputs available (irrigation, fertiliser, pesticide, labour and machine power), risk involved, duration of crop (annual, biennial or perennial) and marketing and processing facilities. 

The farm land is ploughed and then not used for the cultivation of the crops for some time. This helps in the land to gain the fertility again and the method is known as field fallow. This provides the land some time to replenish its nutrients so that the next round of crops can grow properly.

The crop rotation is a pattern of growing a series of different types of crops in the same area in the sequential season. It is a method of replenishment of nutrients by the regular succession over the same field. It enhances the health of crops and minimizes the amount of pest. Thus, the correct answer is option D.

Intercropping is the practice of growing two or more crops on the same piece of land in alternate rows. It increases the land productivity and acts as an insurance for the farmers during the crop failure.

Intercropping is a cropping practice that involves growing two or more crops in proximity in different rows. This practice of cultivating different crops gives higher income than the sole cropping. Intercropping maintains the soil fertility and reduces the soil runoff. 

Intercropping is growing two or more crops simultaneously in the same field in a definite pattern which avoids the competition between both the crops. The sowing time of crops in this pattern may be the same or different.

Mixed farming is a method of agriculture which involves cropping as well as raising livestock. For example growing of cereal crops with cattle farming as cattle excrete nitrogenous waste that can be used as manure for cereals whereas waste from crops is used as fooder and reduces the use of artificial fertilizers.

• Mixed cropping is also known as polyculture, inter-cropping or co-cultivation.
  
• It is a type of agriculture technique in which two or more plants are planted simultaneously in the same field, interlinking the crops so that they grow together.
  
• Benefits of mixed cropping are:-

Growing fodder grass for cattle along with fruit trees or growing fruit trees while rearing cattle is known as horti-pastoral farming. It is adopted as an alternative land use system in North India. Thus, the correct answer is option D.

A- Inter cropping is farming in which two or more crops are grown together indefinite pattern at same time on same piece of land for greater yield. Inter cropping maintains soil fertility and reduces soil erosion and depletion.

Inter-cropping involves growing two or more crops simultaneously on the same field. To minimize competition for resources like nutrients, crops with different nutrient requirements are selected.

Mixed cropping involves growing two or more crops together without a definite row pattern. This practice reduces the risk of total crop failure if one crop fails due to pests or weather, providing a form of insurance.

Inter-cropping optimizes the use of natural resources (sunlight, water, land), helps prevent soil erosion by providing better ground cover, and allows for separate harvesting and marketing of the different crops.

Mixed cropping is a system of planting two crops at a time on the same land. It is also known as polyculture i.e two types of crops are sown and irrigated at a time. The benefits of mixed cropping are that the plant will get nutrients from the soils.

Explanation: Mixed farming is an agrarian system that mixes arable farming with the raising of livestock at the same time. When on a farm along-with crop production, some other agriculture based practice like poultry, dairy farming or bee keeping etc. is adopted, then this system of farming is known as mixed farming.

When the same land is used for the cultivation of more than one crop is known as mixed cropping. The same field is divided into smaller regions. The seeds of different crops are sown and cultivation of different crops is carried out in the same piece of land. 

Mixed cropping is a technique which involves growing up of two or more different crops in the same field. The different crops to be grown together are so chosen that they do not have common pests and pathogens or similar requirement of water and animals. For example, ground nut and sunflower/gram.

Mixed cropping is a system of planting two or more crops at a time on the same land. It is also known as poly-culture i.e two types of crops are sown and irrigated at a time.  Mustard and wheat is an example of mixed cropping.

The method of growing two or more crops simultaneously on same piece of land is called mixed cropping or inter-cropping. This method helps in improving the fertility of soil. It is very important that crops support each others growth to grow all of them on same piece of land.

• Irrigation is the application of controlled amounts of water to plants at needed intervals. Irrigation helps to grow agricultural crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of less than average rainfall.
  
• Sources of irrigation water include groundwater, through springs or wells, surface water, through rivers, lakes, or reservoirs, or even other sources, such as treated wastewater or desalinated water.
  
• Hence Water from rivers is the only source for irrigation in the fields is a false statement.
• So, the correct answer is 'False'.

Mixed farming is one in which crop production is combined with the rearing of livestock. The livestock enterprises are complementary to crop production; so as to provide a balance and productive system of farming. In mixed farming, at least 10% of its gross income must be contributed by livestock activity. 

Drip irrigation is most economical and efficient technique of irrigation. Watering plants by drip irrigation method is a more economical way of watering plants. In this technique, water is supplied drop by drop near the plant roots through the small opening is called as drippers. By this method, there is no loss of water due to seepage, runoff or evaporation. Thus, the correct answer is option B.

A. Drip irrigation is a system of micro-irrigation system that allows the water to drip slowly to the roots of the plants.It is done in places where water is scarce. 

Furrow irrigation is conducted by creating small parallel channels along the field length in the direction of the predominant slope. Water is applied to the top end of each furrow and flows down the field under the influence of gravity.

Canal system is a type of irrigation system in which water can be supplied to one or more farms at once. The canal irrigation system was an important means in 1960. Now canals are the second largest source of the irrigation system. The Indira Gandhi canal is the largest canal system in India. Now, it os 2nd largest source of canal irrigation.

Well system is based on the availability of ground water. In the well irrigation system, the wells are constructed wherever exploitable ground water is present.

In biological control method, birds, insects and other living organisms are deliberately let out in fields to selectively kill pests. This becomes an easy method for protecting crops against selective pests.

Tube well irrigation system is a type is a system in which water is supplied to the fields by connecting large pipes 100-200 mm. The main disadvantage is it leads to depletion of groundwater due to which groundwater reserves may get exhausted.

Loamy soil is a type of soil which is composed of sand,slit and some clay. its mineral composition is about 40%. This type of soil is mainly required for ideal plant-growing. It is rich in minerals and plants thrive best in this type of soil.

Furrow irrigation is a type of irrigation in which water runs on the surface in small ditches and furrows. It is conducting by creating small parallel channels for the flow of water on the surface. 

Bt cotton is modified in such a way that it is resistant to insects and pests. It has inactive protein being produced which gets activated once entering the gut of insect and killing them.