Weed communities in the wheat fields of district Chakwal [Pakistan]

As weed composition in each region varies invariably due to many biotic and abiotic factors, there is scant need to monitor the changes in weed flora. Therefore, the present work was undertaken to document the importance values of individual weed species in weed flora of wheat fields and to identify the ecologically operative eel communities in the area. On the basis of importance value of weed species, eleven weed communities, namely: 1) Convolvulus - Fumaria - Cirsium in Bhaun; 2) Convolvulus - Fumaria - Euphorbia in Kalar Kahar; 3) Convolvulus - Carthamms - Fumaria in Bochal; 4) Convolvulus - Carthamus - Fumaria in Dudyal; 5) Convolvulus - Fumaria - Cirsium in Pindi Gugran; 6) Chenopodium - Fumaria - Emex in Balkasar; 7) Convolvulus - Cousinia - Asphodelus in Ratucha; 8) Fumaria - Medicago - Carthamus in Dulmyal; 9) Asphodelus - Fumaria - Convolvulus in Jahtla; 10) Fumaria - Convolvulus - Carthamus in Kot Sarang and 11) Convolvulus- Asphodelus - Carthamus in Taman, were recognized during December, 99. Whereas in March, 2000 another eleven weed communities viz., 1) Fumaria - Convolvulus - Vicia in Bhaun 2) Convolvulus -Medicago - Galium in Kalar Kahar; 3) Convolvulus - Galium - Fumaria in Bochal; 4) Chenopodium - Medicago - Convolvulus in Dudyal; 5) Fumaria - Convolvulus - Carthamus in Pindi Gugran; 6) Fumaria - Chenopodium - Sisymbrium in Balkasar; 7) Trifolium - Fumaria - Asphodelus in Ratucha; 8) Medicago - Convolvulus - Carthamus in Dulmyal; 9) Medicago - Asphodelus - Trifolium in Jahtla; 10) Fumaria - Astragalus - Trifolium in Kot Sarang; and 11) Fumaria - Chenopodium - Anagallis in Taman, were established. Convolvulus arvensis, Fumaria indica, Chenopodium album, Carthamus oxycantha, Medicago denticulata, Galium aparine, Cirsium arvense and Emex australis were dominant weeds. Emex australis is being reported as weed first time in Pakistan. There was unstable equilibrium among the dominants of weed communities and a shift in weed populations was observed during the growing season of wheat.