Weed Control in Rice Field
Rice:
Rice field favours growth of aquatic and semi aquatic weds. A few common aquatic weds in rice are water hysinth, pistia, morning glory and algae. Terrestial including barnyard grass Ammonia baciflora (Jalmukhee) may be serious on ridges.
Weed Control Practices:
1. Flooding:
To prevent aquatic weeds, alternate and drainage is essential.
2. Row Cultivation:
In line sown rice fields hand rotary wear has proven a very effective weed control for floating aquatic weeds and perennial grasses. Hoeing and weeding give effective physical weed control of rice. In nurseries, hand puling is common methods.
Herbicides Control:
Upland Rice:
A variety of grasses form primary weed flora in upland rice. For their control nitrogen @ 2.4 kg/ha is recommended as pre emergence control. Immediately after drilling. Butachlor can be used in upland rice.
Propanil:
3 to 4 kg/ha. Malinate 2-4 kg/ha SWCP 4-6 kg/ha flurodifen 2-4 kg/ha, are effective selective post emergence herbicides against annual grasses.
Nurseries:
Malinate and Propanil are effective post emergence herbicides and control of Board leaf weeds in flooded rice 2-4 D, MCPA 2, 4, 5 – T and Silvex are used in rice for controlling broad leaf weeds and nut sedge. Rice plants are tolerant to Phenoxy herbicides at the fully tillening stage (4-6 weeds 2, 4-D and MCPA are used against here because annual dicot species, whereas 2,4,5-T and Silvex are justified for control of rough weeds viz. indigo, Dicamine, a special formulation of 2,4-D is specifically used against perennial dicotweeds.
Control of Algac in Rice:
Bresten 50 (0.70 to 1.0 kg a.i./ha), Nitrogen (1 to 2 kg a.i./ha), SWCP (1-2 kg a.i./ha) are important algaecide for rice fields.
Control of grasses in transplanted rice:
1. Nitrogen 2 kg/ha for pre plant treatment and 4 kg/ha for transplant treatment.
2. Glemoar 8-10kg/ha
3. Mallinate (2.4 kg/ha)
4. Influralin (1 kg/ha)
5 .MCPA (7 To 8 kg/ha)
6. Butachlor (1-2 kg/ha)
Are commonly used herbicides in transplanted rice.