Effects of conservation tillage practices in rainfed wheat planting on weed density and crop yield

摘要

Effects of different tillage practices, in special minimum tillage and conservation practices, on the weed density and crop yield in Ilam as a representative rainfed wheat growing location in the Iran, during the crop year 2012-2013. The factorial experiments were replicated at three times in a completely randomized design. Experimental treatments including tillage and planting practices are denoted as a_1 (Conventional tillage; moldboard plow, disc, and centrifugal seed spreader), a_2 (Chisel plowing, disc, and planting with deep drills), and a_3 (conservation tillage; plowing with heavy disc on last year's crop residues, and planting with deep drill) as well as weed control in two levels that denoted as b_1 and b_2 (weed control with and without herbicides, respectively). In the weed control treatments, a portion of each field's crops was left without herbicides as a blank, while herbicides were applied on the rest of the plants during growing. The results showed that the conservation tillage treatment increased the weed density while the weed control treatments reduced both density and dry weight of weeds by 65% and 86%, respectively.