Abstract

The field performance of four types of mechanical rice weeders including, single row conical weeder (W₁), two rows conical weeder (W₂), rotary weeder (W₃) and power weeder (W₄) was compared to hand weeding (W₅). Two transplanted local and improved rice varieties namely Hashemi and Hybrid, respectively were selected for this study. The results revealed that among the mechanical weeders, the highest weeding efficiency (84.33%) was obtained with W₄ and Hybrid variety and the lowest value (72.80%) was measured with W₃ and Hashemi variety. The average of damaged plants in mechanical weeders was obtained as 3.83% compared to 0.13% in hand weeding. The highest effective field capacities of 0.082 and 0.087 hah^-1 were measured with W₄ and the corresponding lowest values of 0.0084 and 0.0088 hah^-1were obtained with W₅ for Hashemi and Hybrid varieties, respectively. The weeding cost was reduced by 15.70, 38.51, 22.32 and 48.70% for W₁, W₂, W₃ and W₄, respectively as compared to W₅. The highest break-even point (1.24 hayr^-1) was obtained with power weeder (W₄). The average break-even point in weedres of W₁, W₂ and W₃ was found to be 0.077 hayr^-1. Among the tested weeders, W₄ showed a proper field performance.

Key words: Paddy field, mechanical weeder, weeding efficiency, hand weeding.