Abstract:

While herbicides can ensure crop yield, their phytotoxicity to crops also occurs frequently. The main maize varieties in east dry land of Gansu Province and several herbicides with good efficacy on malignant weeds were used as experimental materials. Field experiments were conducted to study the effects of clopyralid 75% SG, atrazine 90% WG, MCPA-Na 56% SP and their 2 mixtures on main agronomic traits and yield of maize, aims to provide a basis for safe production of maize. The results showed that no herbicides were found to cause visible phytotoxicity to maize 0-7 days after application and at different growth stages. Clopyralid 75% SG, atrazine 90% WG, clopyralid 75% SG + atrazine 90% WG had slight effects on the plant height of maize at seedling stage, but with the enhance of self-defense ability of maize, herbicides had no significant inhibitory effect on the plant height of maize at subsequent growth stages. Different herbicides had no inhibitory effect on the stem diameter of maize at every growth stage, and there was no significant difference in ear diameter, effective ear length, grain numbers of per spike and 100-seeds weight. The yields of maize treated with herbicides increased by 21.93%-30.22% and -2.91%-3.69% compared with the blank control and artificial weed control, respectively. The tested herbicides are highly safe for maize and can be applied to weeds control in maize field.

Key words: herbicides, maize, growth and development, agronomic characters, yield