Punjab Agricultural University experts for timely weed mgmt for direct seeded rice

Ludhiana, July 11

Direct Seeded Rice (DSR) offers an alternative for rice cultivation with less water, labour and energy requirements to give similar yield as that of transplanted rice. Rice can be direct seeded using three methods — direct seeding in tar-wattar fields, direct seeding on raised beds in tar-wattar fields and direct seeding in dry fields — but for the success of the technique, timely weed management is considered a vital component.

Monitoring DSR fields

• Proper identification of weeds present in the field is important for choosing the suitable herbicide
• Herbicide should always be sprayed in moist fields and proper soil moisture should be ensured for one week after spraying
• This way, weeds can be managed properly by the pre- and post-emergence herbicides
• ntegration of cultural practices such as uprooting the leftover weeds before they produce seeds with herbicides makes weed management more effective on a long-term basis

“Spraying 1 litre per acre Stomp/Bunker 30 EC (pendimethalin) in 200 litres of water is recommended for pre-emergence control of annual grass weeds and some broadleaf weeds in direct seeded fields. In the case of tar-wattar DSR, if sown using Lucky Seed Drill, sowing and herbicide spraying are done simultaneously. If conventional rice drill is used, the weedicide is applied immediately after sowing. In case of sowing in dry fields, irrigation is applied immediately after sowing and herbicide is sprayed when the field comes to wattar condition which generally occurs within one to two days of sowing. Early flush of weeds is effectively managed by timely spraying of pre-emergence herbicide (pendimethalin). However, with the onset of monsoon rains, new weeds emerge due to availability of more moisture in the fields,” said Vivek Kumar of the Krishi Vigyan Kendra at Punjab Agricultural University (PAU).

These weeds include common rice weeds ( swanki), some hardy grass weeds (chini gha, chiri grass, takri gha and gurt madhana), broadleaf weeds (chupati, tandla and chulai) and sedges (chhatri wala motha and gandi wala motha).

He added proper identification of weeds present in the field was important for choosing the suitable herbicide and that the DSR fields should be continuously monitored, so that weed infestation can be detected at the right time. “Herbicide should always be sprayed in moist fields and proper soil moisture should be ensured for one week after spraying. In this way, weeds can be managed properly by the pre- and post-emergence herbicides. Integration of cultural practices such as uprooting the leftover weeds before they produce seeds with herbicides makes weed management more effective on a long term basis,” said Karamjit Sharma, an expert from the PAU.