Pakissan.com; Increasing wheat yield

Increasing wheat yield

April 05: In Pakistan wheat is grown over around 8.5 million hectares. About 20 per cent of the total acreage is planted under rain-fed conditions. The existing yield of wheat is 2340 kg per hectares, which is less compared to neighbouring countries.

The major cropping patterns are cotton-wheat and rice-wheat rotations which together account about 60 per cent of the total area. Rotations with maize-sugarcane, pulses and fallow are also important.

The country has been divided into 12 different production zones. The zoning is mainly based on disease prevalence, yield potential, cropping pattern and climatological factors. It is very important that different varieties should be planted before the dates given in front of each variety. In case planting is delayed, broadcast method of planting with 4-5kg more seed rate than the normal rate is recommended.

Detail of different zones, diseases, recommended varieties, planting time and seed rate is shown in table-1: TABLE

Land preparation:

* Deep ploughing should be used by sub-soiler or mould board, if sub-soil is hard.

* Two to three ploughings are recommended where chronic weeds are present.

* Rotavator should be used in proper moisture if tractor facility is available. Soil should become well pulverized and planker can be used for this purpose.

* Moisture conservation by using mould board in rain-fed areas has been very successful in obtaining good yield.

* In case of limited water in plains, field should be divided into sub-plots.

* Field boundaries should be made strong. Rat holes should be closed and pruning of trees should be done in the farm to avoid shade effects to the crop.

Method of planting in barani areas: Drill or poring method is recommended for planting in barani areas. Planker should not be used if planting is done by "Pora". All fertilizer should be applied before planting. Pre-soaking treatment to the seed should be given for 8-12 hours if moisture is limited. Water used for this purpose should be free of salts which otherwise can affect seed germination.

Irrigated areas: Seed should not be placed more than two inches when semi-dwarf improved varieties are planted. The best results have been obtained in planting by drill because uniform and proper germination is obtained in this method.

Good results could not be achieved through broadcast, but if there is no other solution except this one then 4-5 kgs more seed rate is recommended in this method. Dry sowing can also be done if planting is late and irrigation can be applied after planting. Dry sowing should only be done after December 15 where water availability is limited. Seed should not be put deep in this case.

Seed treatment: Seed can be treated with Benlate, Vitavax 200 or Topson-M at the rate of 2.5gm/kg seed or Derosal at the rate of one gram and/or Raxil 2DC at the rate of 1.50gm/kg seed. Seed treatment can be done by using drum with cover or shaking in the plastic bag.

Fertilizer application: In general both nitrogenous and phosphatic fertilizers are of primary importance to obtain good yields of wheat crop. It has been found, through experimentation, that both N and P must be in a proper balance in the ratio of l:l or at the most 1:1-1/2. Potassium sulphate should also be used at the rate of 12-15 kgs potash/acre (1/2 bag of potassium sulphate) when wheat is planted after rice and sugarcane. The use of potash also becomes important in sandy weak soil which had been continuously irrigating with tubewell water.

The whole quantity of phosphatic and half of nitrogenous fertilizer should be applied at seeding time while the remaining half of nitrogenous fertilizer be applied with first irrigation. In case phosphatic fertilizer is not applied at the time of planting this can be applied with first irrigation.

The whole quantity of nitrogenous and phosphatic fertilizers should be used at planting time in rainfed areas. If somehow nitrogenous fertilizer was not applied at planting time, this can be applied at first rain. The PH value of the most of soils in Punjab has increased from 8.2 which are affecting fertilizer uptake efficiency of the soils. Gypsum is recommended in such affected soils.

Organic matter and green manuring: In general our soils are deficient in organic matter and this situation is getting worst day by day. Therefore, it is very important that proper crop rotation and green manure/farm yard manure should be used.

This helps in the development of plant and increases water absorbing capacity of the soil. Root development becomes more vigorous. Guar and jantar are good crops for green manuring. Guar has produced good results in irrigated areas, whereas, jantar is recommended for saline soils and after rice. Arhar can be used for green manuring in barani areas. According to soil condition 2-3 trolly of farm yard manure per acre should be used.

Irrigation: Wheat plant has two critical stages for its water requirements. The first is at tillering stage which starts about a week after emergence. The first irrigation should therefore, be applied not later than 12-18 days after seeding. In rice growing areas the sub-soil is usually saturated with moisture as moisture retention power of the soil is high. The first irrigation in these areas should be delayed as long as possible. In many cases it may even be more than a month after emergence.

The second critical stage is between anthesis and grain formation when irrigation is necessary. The remaining irrigations depending on rainfall should be well distributed between different growth stages.

Weed control: Weeds can significantly reduce wheat yield. For better control, barharrow and weeding should be done. Weeding becomes easier if wheat is grown on seed beds 45cm apart.

He distance between two lines on a seed should be 15cm. This method of planting does not affect plant population and wheat yield per acre. Other method of weed control is use of chemical weedicides.

Weeds should be removed from the fields within 4-6 weeks of seeding. Recommended dose should be applied with 120 litres of water after first irrigation at proper moisture. If sprayer is not available at proper time then all the powdery weedicides could be applied with sand at proper moisture after first irrigation or mixed with urea and then irrigate.

Harvesting/threshing and storage:

1. Clean parts of field where crop is not lodged should be selected to keep as seed. Harvesting and threshing of that field should be done separately to avoid any mixture.

2. Harvesting should be done 2-3 days earlier in case of semi-dwarf improved varieties.

3. Harvesting should be done when grain moisture is around 16-17 per cent.

4. Grain should be dried properly to bring down moisture at 9-10 per cent before storage.

5. If possible use thresher or combine to be more efficient and avoid losses.

6. Seed should be stored in proper clean stores to avoid insect damage. Fumigation should be done in seed stores.

7. Clean bags should be used for storage.

The DAWN

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