An experiment on the effect of row distance and weed control on the herbage yield and some characteristics of Trifolium resupinatum was conducted in 1998-1999 in Bornova, Izmir, Turkey. Row distances were 20, 30 and 40 cm and the herbicides were imazethapyr, imazamox and bentazone. The dry matter yields of clover were highest in 20 cm row distance in both years. The highest crude protein rate was found in 30 cm row distance and bentazone application in second year. The highest crude protein yields were taken from the 20 and 30 cm row distances in both years. Imazethapyr was unsuitable for weed control in Persian clover. In case of a problem originated from the broad-leaved weeds such as Anagallis caerula, Fumaria parviflora, Matricaria chamomilla, Polygonum aviculare, Sinapis arvensis and Stellaria media, bentazone was a suitable herbicide for Persian clover, whereas in the case of presence of broad-leaved weeds and wild oat (Avena sterilis) imazamox was a suitable herbicide for controlling these weeds. Although the herbicide application did not have an important effect on the green herbage yield of Persian clover, it is thought that it is possible to achieve a satisfactory herbage yield by using imazamox. The most suitable row distance was found to be 20 cm in the trial. (c) 2005 Elsevier Ltd. All rights reserved.