Field Crops> Wheat (Triticum aestivum L.)> Seed and Sowing

(1) Selection of Seed:

Only healthy seeds of right variety suitable for a particular locality should be selected for sowing. There should not be any mixture of seeds of other varieties or weeds. The seed should be purchased form a reliable source. Always use certified seed. If seed is not treated treat it with Vitaves, Thiram or Agrosan G.N. at the rate of 2.5 g per kg seed.

(2) Time of Sowing:

Time of sowing is one of the important aspects in obtaining good yields of wheat. It has a marked influence on the yield of wheat. The time of sowing varies widely over the wheat growing areas. It depends mostly on soil temperature, irrigation facilities and duration of wheat varieties. Rainfed wheat is generally sown in the second fortnight of October and beginning of November. The normal time for sowing of high yielding dwarf varieties in irrigated areas starts in the beginning of November. Long and medium duration varieties (135-145 days) like UP-368, Arjun, UP-2003, Kalyansona, WL-711, WG-357, HD-2204 etc., should be sown in the first fortnight of November and short duration varieties (120-125 days) like Sonalika, UP-115, UP-262 etc., should be sown in the second fortnight of November. If a variety is sown later than its normal time of sowing there is adverse effect on its yield. Under specific circumstances wheat is sown in the month of December too. In late sown wheat only, short duration varieties like Sonalika and UP-115 etc. Should be sown because there is comparatively less reduction in their yields as compared to late and medium duration varieties. When wheat is sown in the month of December there is a drastic reduction in yield (Table 2). November onwards delay in sowing by each day causes reduction of 56 kg per hectare per day in north-eastern parts of the country and 41.6 kg per day per hectare in north-western and central parts of the country.

(3)Seed Rate and spacing: Seed rate varies with variety used depending upon its seed size, germination percentage, tiIlering ability, time of sowing, moisture content in the soil at the time of sowing and method of sowing. Usually, a seed rate of 100 kg per hectare is sufficient under favorable conditions of normal sowing. For varieties with bold grains like Sonalika and under late sown conditions, seed rate should be increased to 125 kg per hectare. In case where wheat is to be sown by dibbler, a seed rate of 25-30 kg per hectare is sufficient.
For normal sown crop a spacing of 20 to 22.5 cm between rows is recommended. When sowing is delayed a closer spacing of 15 to 18 centimetre should be adopted.

(4) Depth of Sowing: Depth of sowing is a very important aspect in successful cultivation of high yielding dwarf varieties of wheat. The coleoptile length is shorter in case of Mexican wheat as compared to tall varieties. The coleoptile length of high yielding Mexican dwarf varieties is about 5 centimetre. Therefore, seeds of these varieties should be covered not by more than 5 centimetre soil to ensure uniform and good germination. Seeds of semi-dwarf (one gene dwarf) varieties could be sown at the depth of 5-6 centimetre but seeds of there dwarf gene varieties should not be sown deeper than 4 centimetres. Similarly, in late sown crop, seeds should be sown shallow (about 4 cm deep) as deep sowing delays the emergence of seedlings by 2-3 days and heading by 5-6 days.

(5) Methods of Sowing: Wheat is sown by four methods:

(a) Broadcasting

In this method the seeds are broadcast and then worked in by harrowing in order to cover them. However, the seeds are not uniformly distributed in the field. This method of sowing is very insufficient and should not be encouraged. Germination of broadcast seed is relatively poor and the plant stand is often irregular. Wastage of seed also results because most of the seed is left on the surface where they cannot germinate and may, therefore, be picked up and eaten by birds.

(b) Behind Local Plough

A majority of farmers use this method. This method consists of dropping the seeds by hand into the furrows that have been opened with local plough. When seed is dropped in furrows by hand, it is called 'Kera' method and when it is dropped through a Pora or Nai or Hazara a special attachment with local plough it is called 'Pora' method. In this method seeds are dropped at a depth of 5-6 centimetre and germination is satisfactory.

(c) Drilling

In this method seed is sown by seed drill or ferti-seed drill. With the help of this implement seeds drop at uniform depth and results in uniform germination and regular stand. Seed bed should be fine and well leveled free from clods and weeds for the use of seed drill or ferti-seed drill. Seed drills are easily available in the market. They may be either bullock driven or tractor driven. Ferti-seed drill should be used wherever possible to ensure uniform depth of sowing, proper placement of fertilizers and good germination.

(d) Dibbling

This Method is used in case where supply of seed is limited. Sowing is done with the help of a small implement known as 'Dibbler'. It is a wooden or iron frame with pegs. The frame pressed in the field and lifted and then one or two seeds are dropped by hand in each of the hole. It is not common a method because it is a very time consuming process.