The Effect Irrigation Scheduling and Potassium Fertilization on Water Consumption of Potato (Solanum tuberosum L.) Under Modern Irrigation Systems

Abstract

A field experiment was conducted in Yusufiya sub-district - Mahmudiya township/Baghdad governorate in silty loam texture soil during the spring season of 2020. The experiment included three treatments with three replicates, as the Randomized Complete Block Design (RCBD) was used according to the arrangement of the split design block. The treatments are in the irrigation system, which included surface drip irrigation (T1) and sprinkler irrigation (T2). Secondly, the Irrigation levels including the irrigation using 0.70 Pan Evaporation Fraction PEF (I1), irrigation using 1.00 PEF (I2), and irrigation using 1.30 PEF (I3). Coupled with, Potassium fertilization treatments that include (0.0 kg k ha-1 (K1), 150 kg k ha-1 (K2) and 300 kg k ha-1 (K3)). The results showed that the actual seasonal water consumption reached its peak at irrigation level I1, which reached 390.03 and 256.41 mm for the sprinkler and drip irrigation systems, respectively. However, the actual seasonal water consumption at irrigation level I2 was 373.92 and 255.63, and it was 353.82 and T255.15 mm at irrigation level I3 for the sprinkler and drip irrigation systems, respectively. The lowest values of the crop coefficient at the tuber maturity stage using the sprinkler irrigation system were 0.49, 0.46, and 0.44, and at the vegetative growth stage using the surface drip irrigation system by 0.37, 0.32, and 0.38 for irrigation levels I1, I2, and I3, respectively. Even though the greatest values were in the tuber Initiation and bulking stages, as they reached 0.86, 0.66, and 0.79 using the sprinkler irrigation system, while they reached 0.49, 0.54, and 0.51 using the surface drip irrigation system for I1, I2, and I3 levels, respectively. The highest water productivity for treatment I3K3 was 15.70 and 27.20 kg m-3 of sprinkler and surface drip irrigation systems, respectively. In contrast, the lowest water productivity was 8.73 and 17.72 kg m-3 for treatment I1K1 of sprinkler and surface drip irrigation systems, respectively. Whereas, the highest value of crop water use efficiency was 11.70 and 17.58 kg m-3 for I3K3 treatment of sprinkler and surface drip irrigation systems, respectively. Although, the lowest value of crop water use efficiency was 6.71 and 11.49 kg m-3 for I1K1 treatment of sprinkler and surface drip irrigation systems, respectively. Lastly, the highest yield was 44.87 Mg ha-1 at treatment T1I3K3.