Non chemical control practices and techniques

Tillage practices

  • Aid not only in suppressing weed growth but also in enhancing rice seedling establishment and crop growth.
  • Pre-monsoon dry tillage will aid in killing vegetative organs of perennial weeds, provided the critical plant parts are exposed to the sun and dried.
  • Deep ploughing where the soil is completely inverted, will bury weed seeds lying on the surface deep enough, to inhibit germination and/or emergence.
  • Puddling the field twice after flooding, followed by leveling will reduce the weed germination and growth. This practice of flooding and puddling is one of effective means of controlling weeds, in irrigated transplanted rice.

Mechanical practices

  • Manual and mechanical weeding are still the most widely used weed control methods, in the country. Various hoe-weeders, rotary weeders and inter-row cultivators can be used to control weeds in dry seeded rice.
  • Among different mechanical weed control methods, although hoeing is superior, hoe and hand weeding are limited to small and marginal farms.

Hand hoeing

The entire surface soil is dug to a shallow depth with the help of hand hoes, weeds are uprooted and removed . The field is subjected to drying to avoid reestablishing of uprooted weeds followed by a copious irrigation. Though it is costly if a considered useful because it improves soil physical condition in addition to the removal of weeds. By periodical hoeing, difficult weeds can be controlled.
  • Hand hoeing may extensively be used for trimming and removing weeds on small passages in rice field and area bordering the field. Hoe weeding may not be efficient, in random sown crop, as it requires line sowing and has many of the disadvantages compared to hand weeding.

Digging

Weeds are removed by digging upto deeper layers so as to remove underground storage organs.very useful in case of perennial weeds like Cynodon dactylon.

Cutting

Weeds are cut above the ground surface dredging and chaining of weeds along with their roots and rhizomes by using heavy chains. Flooding: Effective method in case of perennial weed, like Cyperus rotundas, cynodon dactylon.. The weed infested field is ploughed deeply and flodded with water for 2 - 4 weeks upto a depth of 30cm and water level has to be maintained constantly.

Mechanical weeders

By use of hand operated or power operated weeders. It is feasible only where rice is planted in staraight rows. The pushed weeders are in common use. The weeder should be run in both the directions, at right angles to each other.
  • Rotary weeder can be used in line sown wet seeded rice areas as a supplement to traditional hand weeding.
  • In transplanted/line planted crop, cono-weeder is quite useful in removing and incorporating the weeds. Use of cono-weeder not only incorporates weeds, but also creates soil aeration for better root growth especially in System of Rice Intensification (SRI) method of cultivation.
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