1 A part of the thesis submitted for Ph.D. degree to the University of Jabalpur, Madhya Pradesh by the senior author.
Four herbicides, atrazine. simazine, diuron and dichlormate and two varieties of forage sorghum i. e. M. P. Chari and Vidisha 60-1 were tested for their efficacy on nutrient uptake by weeds. Vidisha 60-1 produced higher crop dry matter and lower weed growth and removed higher amounts of N. P, K, Zn, Mn. Cu and Fe than M.P. Chari. Atrazine and simazine each at 1.0 and 2.0 kgiha and hand weeding (three times) provided weed-free environment for both varieties of sorghum. Weed-free (hand weeded) forage sorghum removed 128.8 N, 27.5 p and 172.1 K kg/ha besides 372 tg, 392, 505.7 and 115.5 glha of Fe, Zn, Mn and Cu respectively. Allowing weeds to grow till cutting of forage sorghum resulted in uptake of 48.8 N, 21.9 P and 45.2 K. kg/ha by weeds in addition to 423.7, 4\3 95.9 and 17.2 glha of Fe, Zn. Mn and Cu respectively. Both varieties removed signifiantly higher quantities of plant nutrients under atrazine 1.0 kg/ha.
