Use of Water Absorbent Polymer in Onion

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

 Krishi Vigyan Kendra, Babhaleshwar is implementing NICRA project in Nirmal Pimpri village in Ahmednagar district of Maharashtra. The source of irrigation in this village is tubewell. Irrigation facility in the field crops is limited during only good

rainfall year. Farmer generally prefer growing short duration onion crop during rabi with average rainfall. However during prolonged

dry spells there is water stress to crop leads to poor onion bulb development and poor yield. The water absorbent polymer is

a long chain cross linked sodium acrylic based absorbent gel crystalline powder that absorbs and retains water 300 to 400

times its weight. The material is suitable in light to medium soils where water retention is poor and organic matter is poor.

Under such conditions the soil is mixed with water absorbent polymer @ 4kg per acre helps to retain water and simultaneously

releases water at appropriate stage of development of osmotic pressure in capillaries, thereby maintaining field capacity

and promoting optimum growth. The product is highly stable, non-reactive and does not leave any residue.

            Demonstrations on use of water absorbent polymer in onion for water saving in inseptisols soils led to improved water

 retention and reduced frequency of irrigation.  This method gave higher bulb yield (182.3q/ha) with more net return

(Rs 100987.5/ ha), 7.6 irrigations under demonstration and with a B: C ratio (1.49). 

The following outcomes were observed in onion plantation where water absorbent polymer was used: 

 

  •          Seedling moratility after transplantation was reduced to only 2 to 5% under treatment as compared to 22 to 28%    under conventional plots

  •          Water saving was up to 34%

  •          Better water management weed management, resulted to increased water use efficiency

  •          Increased bulb size

  •          Reduced water stress due to maintenance of field capacity

  •          Obtained 28.8% higher yield.

 

Results of use of water absorbent polymer in rabi onion under NICRA Project

 

Crop Establishment methods

Yield

(q/ha)

Cost (Rs/ha)

Net return

(Rs/ha)

BCR

% increase

No. of Irrigations

Total water use (cm)

Use of water absorbent polymer

182.3

67603.2

100987.5

1.49

 

28.8

7.6

38

Conventional

Flood irrigation

141.7

57951.5

78558

1.35

11.5

57.5