Effect of Adding Sulfur and Organic Fertilizer on Growth and Yield of Onions (Allium Cepa L.) Under Different Plant Densities

Abstract

A field experiment was conducted in the Amiriyat al-Fallujah district of the Anbar governorate to know the effect of the combination of sulfur and organic fertilizer on the growth and yield of onion, (a local red type), under different plant densities. The experiment included two factors, first: a combination of fertilizing with decomposing Cow’s manure (20 tons.ha-1) and sulfur (50 kg.ha-1), and this factor was distributed as follows (T0: fertilizer recommendation (NPK 100-100-120 kg.ha-1 It is considered a control). T1: cow waste + half of the chemical fertilizer recommendation and T2: fertilizer recommendation + sulfur addition and T3: Cow’s manure + half of the fertilizer recommendation + sulfur addition and T4: double the recommendation of cow manure (40 t.ha-1 + half of the fertilizer recommendation + adding sulfur). The second factor: planting distances (S1:10×10, S2:10×15, and S3:10×20) cm. The distance between plants was fixed 10 cm and the dimensions changed between one line and another. The study was carried out as a factorial experiment with the randomized complete block design (RCBD). The results showed clear significant differences for the two study factors in characteristics of vegetative growth, yield, and the content of total soluble solids, as the T4S3 treatment exceeded by giving it the highest number of tubular blades, leaf area and the highest percentage of sulfur in the leaves, which was positively reflected on the plant yield and percentage the total soluble solids amounted to (16.57 blades.plant-1, 15.97 dm2, 1.70%, 0.64%, 104.50 g, 15.83%), respectively, The treatment of planting distances S1 achieved significant differences in the total yield (90.39 tons.ha-1 and 8.91 kg) respectively compared to plants of treatment S3, which achieved(74.29 tons.ha-1and 5.39 kg).