Effects of Water Application Rates and Planting Density on Size Arrangements of Drip Irrigated Onions

Abstract

Onions (Var. Texas Grano 502) were drip irrigated in December 1982 at the Fortuna Agricultural Research and Development Center to evaluate the effects of water application rates (wet = T1, moist = T2 and dry = T3) and various planting densities (S1, S2, S3 and S4) on crop performance. The evaluation characteristics were size arrangement and percentage distribution in each USDA size class, total solids percentage, defects percentage, onion volume, weight, density and commercial yield. The bulbs were significantly larger at 5% in T2 than in T1 and T3 in size classes X and XII. More than 50% of the onions were in size classes 1 to 5 and 16 to 19, respectively. Two rows of onions on both sides of the drip line yielded significantly more at the 5% level compared with the yield of one row on both sides of the drip line. The wet treatment outyielded the dry treatment at the 5% level. The yield differences were not significant at the 5% level between wet and moist treatments. The bulbs were heavier when plant spacing was increased from 7.5 cm to 15 cm.