Influence of the Weeds and Their Control on Grain Sorghum Productivity

摘要

With the purpose of studying the influence of the weeds and their control on the productivity of grain sorghum variety "Verdon" during the period 2002 - 2004 in the experimental field of the Institute of Forage Crops, Pleven, on a soil type of slightly leached moderately deep chernozem a field trial was carried out. As a result of the study it was found that: When growing grain sorghum the combined method by applying in a system the herbicides Isoxaflutol at a dose of 94 g/ha after sowing before emergence and 2,4-D + Dicamba - 576 ml/ha at the 4 - 5 leaf stage of the crop in combination with one mechanical inter-row cultivation was the most efficient for weed control. The highest grain yield was harvested from the stand with combined weed control (chemical + mechanical) - 7480 kg/ha followed by that with chemical control alone exceeding the untreated and unweeded check 4.5 and 2.9 to 4.1 times, respectively. The grain yield was the lowest for the mechanical control alone exceeding the same check 2.2 times. Sorghum shows high susceptibility to the weeds exerting a strong negative effect on the development of its reproductive organs, which necessitates controlling them efficiently.