Agronomy model answers for the students of first semester in given here.These answers related to agronomy will be very helpful to the beginners. These Questions and Answers from the topic agronomy is often asked in the semester examination…



Q-1) Define crop rotation and write the principles of crop rotation?

Ans-1) CROP ROTATION: Growing different crops in a definite sequence on the same piece of land or the process of growing different crops in succession on a piece of land over a specific period of time with the goal of maximising profit with the least amount of investment while preserving soil fertility.


  1. Plants with tap roots should be planted first, followed by those with fibrous root systems. This aids in the efficient and consistent use of nutrients from the soil.
  2. Leguminous plants should be planted after non-leguminous plants. Legumes fix atmospheric nitrogen in the soil while also adding organic matter.
  3. Crops that are more exhaustive should be followed by crops that are less exhaustive.
  4. Crops from the same family should not be grown in succession because pests and diseases use them as alternate hosts.
  5. An ideal crop rotation provides maximum employment for the family and farm labour, as well as efficient use of farm machinery and equipment.

Q-2) Write about the factors affecting growth and development of crops ?

  1. LIGHT: Plants have evolved over time and in various locations around the world. Some plants grew in tropical environments under the shade of large trees, while others grew on the rocky slopes of mountain ranges.
  2. WATER: Water is required for plants to survive. Water makes up nearly 90% of the weight of most plants. Plants will become stressed and eventually die if they do not receive enough water. Even desert plants, such as cactus, require water; however, they require less of it than other types of plants.
  3. TEMPERATURE: Plant growth is influenced by the weather or temperature. Plants respond to temperature by slowing or speeding up their growth rate. Warm temperatures promote germination and growth.
  4. NUTRIENTS: Plants require specific nutrients in order to thrive. Three nutrients that plants require are carbon, oxygen, and hydrogen. They obtain these from both water and air.

Q-3) Enlist the methods of irrigation and write the advantages & disadvantages of sprinkler irrigation in brief?

Ans-3) they are as follows-

  • Surface irrigation.
  • Localized irrigation
  • Drip irrigation
  • Sprinkler irrigation
  • Center pivot irrigation
  • Lateral move irrigation
  • Sub-irrigation
  • Manual irrigation

Advantages & disadvantages of sprinkler irrigation


Suitable for undulating topography (sloppy lands)
• Water saving (35-40%) compared to surface irrigation methods.
• Fertilizers and other chemicals can be applied through irrigation water
• Saving in fertilizers, even distribution and avoids wastage.
• Reduces erosion
• Suitable for coarse textured soils (sandy soils)
• Frost control – protect crops against frost and high temperature
• Drainage problems eliminated
• Saving in land


High initial cost
• Efficiency is affected by wind
• Higher evaporation losses in spraying water
• Not suitable for tall crops like sugarcane
• Not suitable for heavy clay soils
• Poor quality water can not be used (Sensitivity of crop to saline water and clogging of nozzles)

Q-4) Explain the difference between fertilizers & manures.

Manures are plant and animal wastes that are used as source of plant
nutrients. They release nutrients after their decomposition. Manures can be grouped into bulky organic manures and concentrated organic manures.
a. Bulky organic manures – Farm Yard Manure (FYM), compost from organic
waste, night soil, sludge, sewage, green manures.
b. Concentrated organic manures – oilcakes (edible, non-edible), blood meal,
fishmeal and bone meal.

Fertilizers are industrially manufactured chemical containing plant nutrients. Nutrient content is higher in fertilizers than organic manures and nutrients are released almost immediately. The fertilizers has three groups;
Straight fertilizers – supplies single nutrient Ex: Urea, Murate of Potash
Complex fertilizers – supplies two or more nutrient Ex: 17:17:17 NPK complex Mixed fertilizers- supplies two or more nutrient Ex: Groundnut mixture

Q-5) Write the role of nitrogen and phosphorus in crop growth and development.

Nitrogen: Basic component of proteins and chlorophyll (the pigment that gives plants their green colour). Plays an essential role in plant growth. Also feeds microorganisms in the soil.

Phosphorus: Plays an important role in root growth and promotes
the establishment of young plants, flowering, fruiting and ripening, photosynthesis, respiration and overall plant growth.



Q-1) Write the characteristics of a good seed?

Ans-1) they are as follow

  • Higher genetically purity:
  • Higher physical purity for certification.
  • Possession of good shape, size, colour, etc., according to specifications of variety.
  • Higher physical soundness and weight.
  • Higher germination ( 90 to 35 % depending on the crop)
  • Higher physiological vigour and stamina.

Q-2) Classified the methods of sowing?

Ans-2) they are as follows-

Methods of sowing
There are different methods of sowing such as Broadcasting, Dibbling, Drilling, Seed dropping behind the plough, Transplanting, Hill dropping and Check row planting.
i) Broadcasting
Broadcasting is the process of random scattering of seed on the surface of seedbeds. It can be done manually or mechanically both. When broadcasting is done manually, uniformity of seed depends upon skill of the man. Soon after broadcasting the seeds are covered by planking or some other devices. Usually higher seed rate is obtained in this system. Mechanical broadcasters are used for large-scale work. This machine scatters the seeds on the surface of the seedbed at controlled rates.
ii) Dibbling
Dibbling is the process of placing seeds in holes made in seedbed and covering them. In this method, seeds are placed in holes made at definite depth at fixed spacing. The equipment used for dibbling is called dibbler. It is a conical instrument used to make proper holes in the field. Small hand dibblers are made with several conical projections made in a frame. This is very time consuming process, so it is not suitable for small seeds. Mostly vegetables are sown in this way.
iii) Drilling
Drilling consists of dropping the seeds in furrow lines in a continuous flow and covering them with soil. Seed metering may be done either manually or mechanically. The number of rows planted may be one or more. This method is very helpful in achieving proper depth, proper spacing and proper amount of seed to be sown in the field. Drilling can be done by (1) Sowing behind the plough (2) Bullock drawn seed drills (3) Tractor drawn seed drills.
iv) Seed dropping behind the plough
It is very common method used in villages. It is used for seed like maize, gram, peas, wheat and barley. A man drops seeds in the furrow behind the plough. Sowing behind the plough can be done by a device known as malobansa. It consists of a bamboo tube provided with a funnel shaped mouth. One man drops the seeds through the funnel and other man handles the plough and the bullocks. This is a slow and laborious method.
v) Transplanting
Transplanting consists of preparing seedlings in nursery and then planting these seedlings in the prepared field. It is commonly done for vegetable and flowers. It is very time consuming operation. Equipment for placing plants in the soil is called transplanter.
vi) Hill dropping
In this method, seeds are dropped at fixed spacing and not in a continuous stream. Thus the spacing between plant to plant in a row is constant. In case of drills, the seeds are dropped in continuous stream and the spacing between plant to plant in a row is not constant.
vii) Check row planting
It is a method of planting, in which row-to-row and plant-to-plant distance is uniform. In this method, seeds are planted precisely along straight parallel furrows. The rows are always in two perpendicular directions. A machine used for check row planting is called check row planter.

Q-3) Enlist the factors that affecting method of seed sowing?

Ans-3) They are as follows-

  • Depth of sowing
  • Seed size
  • Row spacing
  • Herbicides
  • Good seedbed preparation
  • Soil water
  • Temperature
  • Pests and diseases

Q-4) Write brief notes on plant population?

Ans-4) Plant population is defined as the total number of plants present at unit area of land, while plant spacing is the arrangement of plants on an area. The yield of crop is directly influenced by population of plant. Actually the yield of a crop is the end result of final plant population which is influenced by the number of viable seed germination and survival rate. The population of plant should not so much high that can drain out most of the moisture from the field before the crop reaches to maturity stage. As well as population should not too low that moisture remain unutilized.

Q-5) Write in short about harmful effect of weeds on crops?

Ans-5) They are as follow-

  • If no restriction is imposed they compete with crop plants and the yield reduction of individual crops varies and that of cropping system 5 to 50%.
  • Presence of weeds increases the cost of agriculture and hinders the progress of work.
  • It increases the irrigation requirement.
  • They reduce the value of produce or otherwise adds the cost of cleaning.
  • Some weeds when eaten (Cleome viscosa) by milch animals will produce an undesirable odour in the milk. At times death/disorder/disformity may occur.
    eg: Datura stramarium
  • The fruits and seeds of Xanthium strumarium and Achyranthes aspera entangle with wool which fetch lower prices.
  • They harbour insect pests, pathogen and parasites
  • They reduce the value of the land
  • Presence of weeds will impair the purity of varieties by chance of cross pollination
  • Weeds cause health hazards to man and animals
  • Weeds cause allelopathic effect


Q-6) Write the characteristics of weeds.

Ans-6) They are as follows-

  • Weeds can spread by sexual and vegetative methods.
  • Weeds can survive adverse weather condition.
  • Weeds produce large number of seeds.
  • Weeds are aggressive and persistent in trampling.
  • Some weeds mature at the same time with crops & being harvested with crop.

Q-7) Define irrigation and its importance in crop productions.

Ans-7) they are as follows-

Irrigation is defined as the artificial application of water to the soil for the purpose of crop production in supplement to rainfall and ground water contribution.


  1. Insufficient and uncertain rainfall adversely affects agriculture. Droughts and famines are caused due to low rainfall. Irrigation helps to increase productivity even in low rainfall.
  2. The productivity on irrigated land is higher as compared to the un-irrigated land.
  3. Multiple cropping is not possible in India because the rainy season is specific in most of the regions. However, the climate supports cultivation throughout the year. Irrigation facilities make it possible to grow more than one crop in most of the areas of the country.
  4. Irrigation has helped to bring most of the fallow land under cultivation.
  5. Irrigation has stabilized the output and yield levels.
  6. Irrigation increases the availability of water supply, which in turn increases the income of the farmers.

Q-8) Define Drainage and causes of water logging.

Ans-8) Drainage means the process of removing water from the soil that is in excess of the needs of crop plants. Drainage is the removal of excess gravitational water from the soil by artificial means to enhance crop production. A soil may need artificial drainage for one or two reasons.


  • Adverse topography and unfavourable sub-soil geology.
  • Lack of catchment area production.
  • Rainfall characteristics.
  • Seepage from canal system and higher irrigated areas.
  • Man made causes: …
  • Poor on farm water management practices.
  • Lack of proper prioritization in irrigation system development.

Q-9) Write the criteria of essentiality of plant nutrients.

Ans-9) They are as follows-

  1. The element must be essential for normal growth or reproduction and the plant processes cannot proceed without it.
  2. The element cannot be replaced by another element.
  3. The requirement must be direct i.e., not the result of some indirect effect such as relieving toxicity caused by some other substance.

Q-10) Define rainfed farming?

Ans-10) Rainfed agriculture is a type of farming that relies on rainfall for water. It provides much of the food consumed by poor communities in developing countries. In rainfed farming, the amount of rainfall converted into plant-available soil water is determined by the amount and intensity of rainfall, topography, infiltrability and water retentivity of soil, depth of root zone, and soil depth.


I hope that you find Agronomy model answers helpful for the students of first semester. For more related notes and question answer for fundamentals of agronomy click here

Agronomy model answers first semester