Efficacy Comparison of Pendimethalin Herbicide with Some Registered Herbicides in the Weed Control of Onion in South Kerman

In order to study the effect of pendimethalin (Prowl) on weed control of onion (Allium cepa L.) fields, an experiment was carried out in randomized complete block design with four replications, during 2017 in Agricultural Research Center of South Kerman. Treatments included application of pendimethalin (Prowl) at 3.5, 3, 2.5, 2 L ha-1 (pre-emergence), oxyfluorfen (Goal) at 750 ml ha-1, and repeat 18 day later (post-emergence), oxadiazon (Ronestar) at 3 L ha-1 (per-emergence), oxadiazon at 2 L ha-1 (post-emergence), ioxynil (Totril) at 3 L ha-1 (post-emergence) plus removing narrow leaves weeds by hand, and weed free as control. The highest relative abundance of weed species was Bromus tectorum L., Malva parviflor L., Chenopodium murale L., Anagallis arvensis L, Rumex crispus L. at 39, 17. 12, 9, 8% respectively. The results showed that herbicide treatments had significant effect on weed density and biomass. Applications of pendimethalin at 3.5 L ha-1 reduced biomass of A. arvensis, R. crispus, M. parviflor, B. tectorum, C. murale, and total weed by 100, 92, 91, 82, 77, 79 respectively. Onion yield was 59.95 ton ha-1 and increased by 138% when pendimethalin was applied at 3.5 L ha-1. Therefore, Applications of pendimethalin at 3.5 L ha-1 is recommended in onion fields because of optimum weed control efficiency and increasing yield.