Effect of Spraying with Potassium, Organic Fertilization and Plants Densities in Growth and Yield of Onion

Abstract

Abstract. A field experiment was carried out in the city of Amiriya Al-Fallujah / Anbar Governorate, to know the response of the local grown red onions to spraying with potassium and organic fertilization under different plant densities during the season 2020-2021. The seeds were sown on 10/1/2020 and transferred to the field on 12/1/2020. The experiment included two factors, the first is a combination of organic fertilization (20 Mg.ha-1) and spraying with potassium sulfate (0, 5) g.l-1 as follows: (T0: recommended fertilizer dose and T1: Cow's manure and T2: recommended fertilizer amount + spraying with potassium and T3: cow's manure + half of the number of fertilizers + potassium spray and T4: Double the recommended amount of cow's manure + half the amount of fertilizer recommended dose + spraying potassium. The second factor is Planting distances(S1: 10 × 10, S2: 10 × 15 and S3: 10 × 20) (cm). The distance between the plants was fixed to 10 cm was and the dimensions changed between plants' lines. The study was carried out as a factorial experiment within the randomized complete Block Design. The results of the study indicated the clear effect of the study factors on the characteristics of vegetative growth, yield and onions' content of total soluble solids(TSS), as the treatment T4S3 excelled by giving it the highest content of dry matter and the highest leaf area, the highest percentage of potassium in the leaves and this was positively reflected done by giving the plants of this treatment the highest yield of the plant and reached (5.83 gm, 15.26 dm2, 1.57% and 108.50 gm) in sequence. Hence, reducing the cultivation distances between plants and their interaction with fertilization levels had a positive effect in improving the yield traits , as the T4S1 treatment achieved the highest yield for the experimental unit and the highest marketable yield reached (10.03 kg and 77.06 Mg.ha-1), compared to T1S3-treated plants, which achieved the lowest yield for the experimental unit and the lowest marketable yield amounted to (4.733 kg and 35.73 Mg.ha-1) respectively.