the effect of three common grain drills on dryland wheat yield

a three-year field experiment (2004-2007) was conducted on a silty clay loam soil at tajarak research station of hamedan to determine proper grain drill for wheat in hamedan dryland areas. in this study, three grain drills including: hamedani barzegar; sahalan kesht; and kesht gostar with wheat seed broadcasting and disking were used. the experiment was a randomized complete block design with four replications. in laboratory, the precision of metering device and the amount of seed damage by metering mechanism were measured. at the end of growth season (harvesting time), crop yield and the associated parameters (spike per m2, number of grain per spike, wheat kernel) were determined. results showed that planting methods did not affect wheat grain yield significantly. however, wheat grain yield was significantly higher for kesht gostar grain drill than the other two machines in two drier years. mean wheat grain yield was 1224 kg ha–1. mean wheat grain yield was the greatest (1275 kg ha-1) for kesht gostar and the least (1174 kg ha-1) for hamedani barzegar grain drill. mean straw yield was not affected by planting methods. mean wheat straw yield was the greatest (2349 kg ha-1) for hamedani barzegar grain drill, and the least (2009 kg ha-1) for the combination of seed broadcasting and disking. the amounts of rainfall during growing season strongly influenced wheat grain and straw yields. mean wheat grain yield was 1572 kg ha-1 and 1026 kg ha-1 in wet year and dry years, respectively. this study showed that a wide range of grain drills is adaptable for dryland wheat cropping system for the semiarid hamedan areas.