Critical Period of Weed Interference in Rainfed and Irrigated Tomatoes in Nigerian Savanna
Field trials were conducted to assess the critical period of weed interference in tomato on the farm of the Institute of Agricultural Research, Samaru (11011\'N, 07038\'E) in the Northern Guinea Savannah ecological zone of Nigeria in 1989 and 1990 wet seasons and at the Irrigation Research Station of the Institute of Agricultural Research, Kadawa (110N39\'N,08002\'E) in the Sudan Savanna ecological zone of Nigeria in 1987/88 and 1988/89 dry seasons. Each trial consisted of two sets of treatments. One set of treatments consisted of plots initially kept weed-free for 3, 6, 9 and 12 weeks after transplanting by weeding and with hand hoes and subsequently kept unweeded until harvest. The other set of treatments consisted of plots initially kept weed infested for corresponding periods and subsequently kept weed-free until harvest. Two treatments of weed infestation and weed-free throughout the crop growth were also included in checks. In all the trials, weed interference beyond 6 weeks after transplanting (WAT) significantly depressed various crop growth parameters in the tomato fruit yield compared with the crop kept weed-free through out its life cycle. The crop was most critically affected by weed interference between 3 and 6 WAT.In order to obtain tomato fruit yield comparable to that of weed-free check, it was required to keep the crop weed-free for 6weeks after transplanting and beyond. Weed infestation throughout the crop life cycle resulted in about 40 to 60% reduction in potential tomato fruit yield compared with the appropriate maximum obtained in trials.
JARD Vol. 2 2003: pp. 32-41