comparison of rice direct seeding methods (mechanical and manual) with transplanting method

the main method of rice planting in iran is transplanting. due to poor mechanization of rice production, this method is laborious and costly. the other method is direct seeding in wet lands which is performed in the one third of rice cultivation area of the world. the most important problem in this method is high labor requirement of weed control. in order to compare the different rice planting methods (direct drilling, transplanting, and seed broadcasting) a manually operated rice direct seeder (drum seeder) was designed and fabricated. the research was conducted using a randomized complete block design with three treatments and three replications. required draft force, field efficiency, effective field capacity, yield, and yield components were measured and the treatments were compared economically. results showed that there were significant differences among the treatments from the view point of rice yield at the confidence level of 95% i.e. the transplanting method had the maximum yield. a higher rice yield was obtained from the direct seeder compared to the manual broadcasting method but, the difference between these two methods for crop yield was not significant even at the confidence level of the 95%. the coefficient of variation of seed distribution with direct seeding was more than 20%. the labor and time requirements per hectare reduced to 7 and 20 times, respectively when comparing the newly designed direct seeder with the transplanting method. the direct seeding method had the highest benefit to cost ratio in spite of its lower yield. therefore, this method could be recommended in the rice growing regions.