Responses of Popcorn to Irrigation Amount and Plant Density

Abstract

Water avilability and planting method are major factors related to crop growth and yield, when other factors such as fertility, diseases, diseases etc., do not limit growth and yield. The experiment was conducted to examine the responses of a pop corn to irrigation rate and plant density on a clay soil (Ratchaburi series) at Chaii Nat Field Crop Research Centre in the 1997/98 growing season. Irrigation applied throughout the season for IW/E (ratio of irrigation water to evaporation) 0.3 to 0.9 was from 105 to 315 mm. There were no interactions in growth and yield between irrigation levels and plant densities. Leaf area index, leaf area duration and crop growth rate significantly increased with increasing irrigation amounts from IW/E 0.3 to 0.9 and plant densities from 8,533 and 12,804 plants/rai. Simiilarly, a significant grain yield reduction (11 to 46%) was associated with reducing irrigation levels from IW/E 0.9 to 0.3. Increases in grain yield of 11 and 22%, resulted from increasing plant densities from 8,533 to 10,667 to 12,804 plants/rai, respectively. Number of ears harvested, ear weight and grain weight were major yield components determining yield differences among irrigation leverls. Higher yields of the higher planting densities wee mainly due to higher numbers of ears harvested and ear weight, although grain weight reduced with increasing plant densities. Water use efficiency sighnificantly increased with reducing irrigation levles and increasing plant densities. Water use efficiency significantly increased with reducing irrigation levels and increasing plant densities.