Agriculture
Weed Management :: Rice


Dry Seeded Irrigated Un-Puddled Lowland Rice

Weed management

  • First weeding should be done between 15 and 21 days after germination.
  • Second weeding may be done 30 - 45 days after first weeding.
  • Apply pendimethalin 1.0kg/ha on 5 days after sowing or Pretilachlor + safener (Sofit) 0.45kg/ha on the day of receipt of soaking rain followed by one hand weeding on 30 to 35 days after sowing.
Hand weeding Hand weeding  Application of post emergence herbicide
(Pretilachlor + safener (Sofit) at 0.45kg/ha)

Dry Seeded Rainfed Un-Puddled Lowland Rice

Weed management

  • First weeding can be done between 15 and 21 days after germination.
  • Second weeding may be done 30 - 45 days after first weeding.
  • Apply pendimethalin 1.0kg/ha on 5 days after sowing or Pretilachlor + safener (Sofit) 0.45kg/ha on the day of receipt of soaking rain followed by one hand weeding on 30 to 35 days after sowing.
  • Seed drill sowing with pre-emergence application of pretilachlor + safener @ 0.3 kg/ha followed by two weedings with star / rotary weeder is recommended.

Dry seeded Rainfed Un-puddled Lowland Rice with Supplemental Irrigation

Weed management

  • First weeding should be done between 15 and 21 days after germination.
  • Second weeding may be done 30 - 45 days after first weeding.
  • Apply pendimethalin 1.0kg/ha on 5 days after sowing or Pretilachlor + safener (Sofit) 0.45kg/ha on the day of receipt of soaking rain followed by one hand weeding on 30 to 35 days after sowing.
  • PE butachlor 1.0 kg ha-1 followed by weeding using finger type single row and double row rotary weeders resulted in higher grain yield and net profit.

Unweeded Rainfed Rice

Systems of Rice Intensification

Weed management

  • Using rotary weeder / Cono weeder / power operated two row weeder.
  • Moving the weeder with forward and backward motion to bury the weeds and as well to aerate the soil at 7-10 days interval from 10-15 days after planting on either direction of the rows and column.
  • Manual weeding is also essential to remove the weeds closer to rice root zone.

Transplanted Puddled Lowland Rice

Nursery

Weed Management

  • Apply any one of the pre-emergence herbicides viz., Pretilachlor + safener 0.3kg/ha, on 3rd or 4th day after sowing to control weeds in the lowland nursery. 
  • Keep a thin film of water and allow it to disappear. 
  • Avoid drainage of water.  This will control germinating weeds.
  • Butachlor 2.0 l/ha (or) Pendimethalin 2.5 l/ha (or) Anilophos 1.25 l/ha.
  • Herbicides should be applied on 8 DAS with thin layer of water in the field.

Mainfield
Weed management

  • Use of rotary weeder from 15 DAT at 10 days interval. It saves labour for weeding, aerates the soil and root zone, prolongs the root activity, and  improves the grain filling though efficient translocation and ultimately the grain yield.
  • Cultural practices like dual cropping of rice-azolla, and rice-green manure (described in wet seeded rice section 2.5 & 2.6 of this chapter) reduces the weed infestation to a greater extent.
  • Summer ploughing and cultivation of irrigated dry crops during post-rainy periods reduces the weed infestation.

Pre-emergence herbicides

  • Use Butachlor 1.25kg/ha or Anilophos 0.4kg/ha as pre-emergence application. Alternatively, pre-emergence application of herbicide mixture viz., Butachlor 0.6kg + 2,4 DEE 0.75kg/ha,  or Anilophos + 2, 4 DEE ‘ready-mix’ at 0.4kg/ha followed by one hand weeding on 30 - 35 DAT will have a broad spectrum of weed control.

  • Any herbicide has to be mixed with 50kg of dry sand on the day of application (3 - 4 DAT) and applied uniformly to the field with thin film water on the 3rd DAT. Water should not be drained for next 2 days from the field (or) fresh irrigation should not be given.

  • Pre- emergence application of pretilachor at 1.0 kg a.i. ha-1 on 3 DAT + weeding with Twin row rotary weeder at 40 DAT

  • PE Pyrazosulfuron ethyl 10 % WP @ 150 g ha-1 on 3 DAT + hand weeding (HW) on 45 DAT. PE butachlor 0.75 kg a.i. ha-1 + bensulfuron methyl 50 g ha-1 on 3 DAT + HW on 45 DAT

  • PE Oxadiazon 87.5 g a.i. ha-1  followed by Post emergence (POE) 2,4-D 1 kg a.i. ha-1   along with hand weeding on 35 DAT.

  • PE butachlor 0.75 kg per hectare + bensulfuron methyl 50 g ha-1 on 3 DAT followed by mechanical weeding on 45 DAT is effective for broad spectrum weed control.

  • Crop growth and yield were enhanced by butachlor 1.2 + 2,4-DEE 1.5 lit ha-1    with 100% inorganic nitrogen.

  • Conventional tillage of one dry ploughing and two passes of cage wheel puddling combined with pre-emergence application of butachlor at 1.25 kg ha-1 under lowland situation.

  • Stale bed preparation by pre-puddling minimum tillage with glyphosate combine with post-plant pre emergence butachlor 1.25 kg ha-1 resulted in increased rice grain yield, net income and B: C ratio in rice-rice cropping.


50kg of dry sand + Butachlor 1.25 kg/ha

Post - emergence herbicides

  • If pre-emergence herbicide application is not done, hand weeding has to be done on 15th DAT.
  • 2,4-D sodium salt (Fernoxone 80% WP) 1.25 kg/ha dissolved in 625 litres with a high volume sprayer, three weeks after transplanting or when the weeds are in 3 - 4 leaf stage.
  • Early post emergence application of Bispyripac sodium 50 g a.i. ha-1 (2-3 leaf stage of weeds) + Hand weeding on 45 DAT

Wet Seeded Puddled Lowland Rice
Weed management

  • In wet seeded rice, pre-emergence application of pretilachlor 0.75 kg/ha on 8 DAS or pretilachlor + safener (Sofit) at 0.45kg/ha on 3-4 DAS followed by one hand weeding on 40 DAS in direct drum seeded rice.

  • In wet seeded rice, sowing with drum seeder and cono weeding (manual / power weeder) is done at 10, 20 and 30 DAS

  • In transplanted rice, hand weeding twice on 15 - 20 DAT and 45 DAT will control the weeds effectively (or) Pendimethalin 3.0 lit/ha at 8 DAT with optimum moisture condition and one hand weeding on 45 DAT.

  • Productivity and economic returns of wet seeded rice with dual cropping of danicha could be maximized by the pre-emergence application of pretilachlor + safner at 0.45 kg ha-1 followed by one cono weeder in between rows and manual weeding with the rice rows on 35 DAS in lowland conditions.

  • PE pretilachlor + safner 0.45 kg/ha-1 on 3 DAS + roto cylindrical weeder weeding on 45 DAS in wet seeded rice resulted in excellent control of weeds like Echinochloa crusgalli, Panicum repens, Eclipta alba and Monochoria vaginalis and higher grain yield, net monetary returnand B:C ratio.

  • PE pretilachlor (S) 0.45 kg ha-1 on 3 DAS fb azimsulfuron 50 DF 35 g ha-1 on 20 DAS + hand weeding on 45 DAS for broad spectrum weed control and higher grain yield and economic returns in both irrigated and rainfed direct seeded rice.

  • Higher productivity of wet direct seeded (drum seeded) rice could be achieved by integrating intercropping of daincha and pre-emergence application of pretilachlor + safner at 0.45 kg ha-1 on 4 DAS followed by one hand weeding on 35 DAS.

  • In rice -rice -fallow system intercropping of Sesbania rostrata control the weeds of rice field along with incorporation of Sesbania rostrata in to the field and one hand weeding on 35 DAT.

  • Apply PE pretilachlor 0.45 kg ha-1 on 3 DAS + Roto cylindrical weeds + weeding on 45 DAS in wet seeded rice have good control of weeds like Echinochloa crusgalli, Panicum repens, Eclipta alba and Monochoria vaginalis.

Integrated weed management

Critical period of  weed control

20-30 DAT

Cultural method

1) Hand weeding
2) Hand pulling
3) Pudding
4) Flooding

Mechanical method

1) Weeder (Float)
2.Conoweeder/Rotary weeder

Chemical method

Butachlor (1-2 kg ai/ha)
Alachlor (1-2 kg ai/ha)
Thiobencarb + 2, 4D
Isopropyl (0.75) ester (0.5 kg ai/ha)
Metsulfuron methyl (20 WP) (0.008 kg ai/ha)
Benthiocarb (1.5 – 2.5 kg ai/ha)
Propanil (2-3 kg ai/ha) (only post emergence)

Biological method

1. Hirsch – Manniella spinicaudata is a rice root nematode which controls most upland rice weeds
2. Azolla

Remarks

I. Substitution and preventive method:
a) Stale seed bed technology
b) Land preparation
c) Water management

Updated on : 24.05.2013