Department of Agronomy, Punjab Agricultural University, Ludhiana-141 004, (Punjab), India.
A field survey was conducted during 2004–05 and 2005–06 in the three districts of Punjab i. e. Patiala, Sangrur and Moga with the objective to study the shift in weed flora of wheat (Triticum aestivum L.) in relation to different tillage practices. Thirteen weed species were found infesting wheat fields and of these, Phalaris minor, Polypogan monspeliensis, Poa annua, Rumex dentatus, Medicago denticulata, Anagallis arvensis, Lepidium sativa and Malva neglecta were most common. Grass weeds had slightly higher relative density, relative frequency, importance values and summed dominance ratio under conventional tillage as compared to zero tillage, whereas these values of broadleaf weeds were slightly higher under zero tillage as compared to conventional tillage. Slightly higher population of grass weeds was observed under conventional till than zero till sown wheat and the differences were found to be significant in Patiala district. Higher population of broadleaf weeds was observed under zero tillage as compared to conventional tillage technology and these differences were significant in Sangrur and Moga during first year and in Patiala and Sangrur during second year. Dry weight of grass weeds was slightly higher in conventional tillage than zero tillage technology and differences were significant in Patiala and Sangrur during 2004–05 and in Moga district during 2005–06. However, dry weight of broadleaf weeds was significantly higher under zero tillage technology as compared to conventional tillage technology during both the years in all the districts.
