Division of Agronomy, Indian Agricultural Research Institute, New Delhi.
*A part of the thesis submitted by the first author for Ph.D degree of I.A.R.I., New Delhi during 1965.
Green-house and field trials revealed high responses of onions to nitrogen, moderate to phosphate and no response to potash and negative to sulphur. Application of sulphur was particularly injurious at leavels exceeding 100 ppm and under greenhouse conditions. Gypsum, flower of sulphur and sulphate of ammonia were all alike with respect to their sulphur effect. Maximum yield of bulbs was obtained at 70 kg N/ha. To eliminate the injurious effect of sulphur it was recommended that fertilizers free from sulphur be used in onions. Further studies were suggested on the deleterious effect of sulphur and use of phosphate at 45 kg P2O5/ha under the condition of intensive cropping and high production levels.
