Responses of Soybean to Irrigation Amounts and Plant Arrangements

Abstract

Major factors related to crop growth and yield, particularly in the dry season, are water availability and planting method, when other factors such as fertility, diseases etc., do not limit growth and yield. The effects of irrgation amounts and plant arrangements on soybean, CV. Nakhon Sawan 1, were investigated at Chai Nat field Crop Research Centre in the 1994/95 and 1995/96 growing seasons. The responses of soybean to irrigation amounts and plant arrangements between the two seasons were similar. There were no interactions in growth rate significantly increased with increasing irrigation amounts from IS/E (ratio of irrigation water to evaporation) 0.3 to 0.7. Similarly, seed yield favoured higher rations of IW/E (up to 62%). Pods/plant and seed weight were major factors determining yield differences among irrigation levels. However, there was not significant differences in seed yields and yield components between IW/E 0.7 and 0.9. Square planting gave the highest yield (up to 14%), whereas 5:1 and 10:1 rectangularity produced no significant difference in seed yield. Higher yield of square planting was mainly due to higher number of pods/plant.