Maharashtra Board Class 11 Agriculture Science and Technology Chapter 5 Sowing PDF Download

Sowing

5.1 Sowing

Sowing can be defined as the process of placing seed into the well prepared soil at proper place (depth) for growth OR The process of putting seed in the ground soil for growing crop plant is known as sowing.

5.1.1 Sowing Time, Depth And Spacing

Proper and healthy stand of a crop is essential for getting its higher yield. It depends on the time, depth and method of sowing.

You already know that soil and seed both go hand in hand.

Soil provides medium for plant growth.

A seed will develop in to a healthy seedling only when it is placed in proper medium, at proper depth, time and spacing.

The prime object of seed treatment is to protect seed and to promote the growth of plant.

Recall A Little

Which are the common seasons of sowing in Maharashtra and their approximate time of sowing?

Which crops are prominently grown in those seasons in your locality?

Can You Recall?

Time Of Sowing

The exact or proper time of sowing depends upon different factors, such as sowing season, atmospheric as well as soil temperature and moisture content in seeding zone of soil. The common sowing seasons in Maharashtra are Kharif, rabi and summer.

The Kharif crop is usually sown after the regular onset of monsoon in the month of June to July. Very early sowing may not be advantageous, as it may result in failure of crop due to prolonged dry spell. However in certain situations early sowing may be advantageous, particularly for rabi crops. Usual sowing time of rabi crop is October to November. In certain cases advancing sowing in September to October may be helpful for taking advantage of available soil moisture. Time of sowing of summer crop varies from January to February. For most of the crops it is preferably first fortnight of January.

There should be sufficient moisture in seeding zone, so that it would help in proper germination of seed and emergence of crop plants. Similarly, each crop needs definite range of temperature for proper germination and also for further vegetative growth. The sowing time should be such that moisture stress period (due to long dry spell) may be avoided at critical stages of crop growth. High soil and atmospheric temperature at the time of sowing not only affects the seed germination but also favours the effect of different insects – pest and diseases e.g. stem borer of sugarcane, shootfly of jowar, etc. In short optimum time of sowing is therefore, a time which provides suitable environment at all the stages of crop growth.

Teacher's Note

In Maharashtra, farmers plant rice in June when monsoon starts. This is called Kharif season. Timing is very important for good crops.

Exam Trick

Remember: Kharif = June-July, Rabi = October-November, Summer = January-February. Think KRS for the order.

Points To Remember

Sowing time depends on season, temperature and soil moisture.
Kharif crops are sown after monsoon starts.
Rabi crops are sown in October-November.
Each crop needs the right temperature to grow well.
Wrong sowing time can cause crop failure and pest problems.

Depth Of Sowing

Sowing of seed at the appropriate depth is an important factor affecting establishment of good stand of crop.

The optimum depth of sowing depends upon soil moisture, size of seed, seed reserve and coleoptile length. For getting good vigour, it is necessary that the germination of seed should be good and for proper germination, it is always important that the seed should be placed in the moist zone of soil. Too shallow or too deep sowing results in large number of gaps and less plant population. Due to shallow sowing the seed germination is poor because of inadequate moisture in the upper layer of soil. Too deep sowing may also affects crop stand because in many cases seedling may not be able to push their shoots above the ground level from greater depth. Besides affecting plant population, the weed problem also becomes serious under such conditions.

The size of seed also have great influence on the depth at which seed should be sown. The crops like groundnut, castor, etc having bigger size of seed can be sown to a greater depth up to 6 cm. On the other hand crops like finger millet, pearl millet, tobacco, etc. having small sized seed have to be sown as shallow as possible. The thumb rule is to sow the seed to a depth approximately 3 to 4 times their diameter. For most of the crops the optimum depth of sowing ranges between 3 to 5 cm.

Shallow sowing depth of 2 to 3 cm is needed for the crops like pearl millet and finger millet. For small sized seeds which are sown shallow needs to be irrigated frequently to ensure good emergence of crop.

In the case of deep sowing, the seed reserves should be sufficient to put forth long coleoptile for emergence. The coleoptile length also differs from variety to variety of the same crop. For example – tall traditional varieties of wheat having long coleoptile length can be sown deep. On the other hand Mexican varieties with short coleoptile length need to be sown shallow.

Teacher's Note

Big seeds like groundnut can go deep 6 cm. Small seeds like millet must stay near the top, only 2-3 cm deep. Think big seeds need deep holes, small seeds need shallow holes.

Exam Trick

Remember the 3-4 times rule: Sow seeds at 3 to 4 times their own size deep. Small seed = shallow, big seed = deep.

Points To Remember

Seed depth changes based on seed size.
Small seeds need shallow sowing (2-3 cm).
Big seeds can go deep up to 6 cm.
Rule: Sow at 3-4 times the seed diameter.
Wrong depth causes poor germination and weak plants.

Spacing

The full yield potential of an individual plant is achieved when sown at optimum spacing. Too dense or wide planting may result in reduction of yield per unit area. If sown densely, the growth of individual plant will be affected due to competition among plants for space, food, water, etc. Similarly, yield from individual plant cannot be increased beyond certain limits. As such the spacing between two rows and two plants within a row should be optimum. It depends upon different factors such as growth habit of plant, soil type, purpose for which crop is grown and also the sowing season. The crop with branching habit or with good tillering capacity will require more space. Individual plant growth may be vigorous in rainy season. Hence, in rainy season the spacing may be wider than in summer season. On the same line wider spacing is required on heavy soil as compared to light soil. The spacing also depends upon the purpose for which crop is grown. Increase in plant height with less diameter is preferable for fodder crop and therefore, fodder crops are generally sown dense than grain crop. In crops grown on stored soil moisture under rainfed conditions, the spacing should be such to avoid overcrowding of plants that may deplete most of the moisture before crop matures. In short spacing should be so adjusted to have optimum plant population under different conditions.

Teacher's Note

Plant spacing is like arranging seats in a classroom. Too crowded and plants fight for water and food. In Maharashtra, jowar spacing is 30 cm x 25 cm for good growth.

Exam Trick

Remember: More space = more growth per plant. Less space = more plants total. Choose based on what you want - grain or fodder.

Points To Remember

Right spacing gives better yield per plant.
Spacing depends on plant size and season.
Rain season needs wider spacing than summer.
Heavy soil needs wider spacing than light soil.
Right spacing prevents competition for water and food.

5.2 Seed Treatment

5.2.1 Definition

Seed treatment is the procedure of treating the seed with different insecticides, fungicides or combination of both for protecting their health. It also includes treatments subjecting seed to solar energy exposure, immersion in water, etc.

In short seed treatment is the treatment given to the seed to improve germination, vigour potential and to maintain good health of seed.

5.2.2 Objectives Of Seed Treatment

The various objectives of seed treatment are as follows.

(1) Protection of seed from seed rot and seedling blight. Rottening of seed, seedling blight and other seed and soil borne diseases can be prevented by giving appropriate seed treatment prior to sowing. Coating seed with certain chemical is done for this purpose.

(2) Prevention of the spread of disease. The infection from systemic diseases during different growth stages of crop and also during storage is prevented by appropriate seed treatment. Treatment is also helpful in preventing non systemic diseases.

(3) Protection of seed from insects in soil and in storage. The seed treatment with various insecticides alongwith fungicides is effective against storage pest and certain insects in soil.

(4) Improvement in seed germination. Germination of seed is improved by controlling seed surface flora, by breaking dormancy, removing inhibitors and treating seed with germination promoters.

(5) Reduction in cost of production. The cost of plant protection can be reduced by using treated seed for cultivation. This helps in minimizing the cost of crop production to a greater extent.

(6) Production of good quality seed. Good quality seed can be produced when crop stand is uniform, vigorous and healthy. This can be achieved by using properly treated seed for sowing.

Teacher's Note

Seed treatment is like giving medicine to seeds before planting. It protects seeds from diseases and insects. In India, farmers treat cotton seeds to prevent rot and pest damage.

Exam Trick

Remember: Seed treatment = Healthy seeds. It protects from rot, disease, insects and improves germination. Like a shield for the seed!

Points To Remember

Seed treatment protects seeds from disease and insects.
It improves how many seeds grow well.
Treated seeds give better, uniform crops.
It reduces the need for extra pesticides later.
Good seeds = good harvest quality.

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