Effects of Herbicides and Seeding Rates on Growth and Yield of No-tillage Corn (Zea mays L.)1

Boonguer Poosri2

  1. M.Sc. Thesis.  Kasetsart University,  Chatuchak, Bangkok 10900. Thailand.
  2. Nakhon-Sawan Field Crops Research Centre, Tak-Fa, Nakhon-Sawan 60190. Thailand.

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Experiments were conducted at Praphutthabat Field Crops Experiment Station, Lopburi province to determine effects of herbicides and seeding rates on growth and yield of maize in no-tillage condition.  Seven doses of paraquat in a randomized complete block with 3 replications were used in the first experiment.  The second experiment was designed in split plot with 3 replications.  The main plot consisted of combinations of paraquat and other herbicide and four sub plots consisted of different seeding rates.

Result of the first experiment showed that Digitaria sanguinalis was easily controlled by paraquat.  Paraquat was also effective in controlling Brachiaria reptans, Dactyloctenium aegyptium and Pleusine indica but failed to control Ipomoea gracillis and Aniscia martinicensis.  Paraquat of the rate of 0.083 kg. (ai) and 0.415 kg (ai) per rai was able to control 60% and 87% of weeds, respectively.  As a consequence corn grain yield of plot spraying with paraquat at the rate of 0.415 kg.(ai) per rai was not difference from those of the conventional tillage practice.  An increase in rate of paraquat spraying beyond 0.415 kg.(ai) per rai did not increase its effectiveness in controlling weeds.

In the second experiment paraquat plus atrazine was the most effective treatment in weed control.  Spraying of 0.166 kg.(ai) per rai of paraquat plus atrazine at 0.400 kg.(ai) per rai gave the highest grain yield of 733 kilogram per rai.  Corn grain yield increased with increasing seeding rates.  Seeding rates of 4 and 5 seeds per hill, which produced 8,953 and 10,458 harvested ears gave the comparable high grain yield of 604 and 613 kg. per rai, respectively.

 

 

 

BG

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