Abstract

Potatoes (Solanum tuberosum L.) play an important role in food security of many countries, thus it is considered as an important strategic commodity. Also, it is an overwrought crop to soil because of its gluttony to minerals absorption due to its bigness vegetative organs and the amount of tubers. The aim of this study is to determine the effect of potassium fertilizer (K2O) of 0, 50, 100, 150 kg / ha and organic extract of 10 ml / L and spray with fungicidal agent (SAFEX-50% WP) on the potato yield var. Baraka. The experiment was carried out at the farm of the Faculty of Agriculture and Veterinary Medicine, Ibb University, in March 2016, as a factorial experiment with split-plot design in three replications. The results showed that potassium fertilization up to 100 kg / ha had a significant increase in all studied traits except for medium and small tubers, while the incidence of infection was the opposite where the same treatment recorded a significant decrease. Spraying with organic extract and fungicide resulted in a significant increase in plant production per gm, percentage of large tubers weight /ha, total productivity and the significant decrease in the other studied traits, compared to the control. The interaction between fertilization and spraying with organic extract and fungicide showed a significant effect on all the studied traits. The best treatment is the treatment with 100 kg potassium oxide /ha with organic spray. The study investigated the importance of potassium fertilization with spraying with organic extract at increasing of the productivity of the potato crop and meeting the plant needs of the nutrients as well as increasing the resistance of the plant to the fungal infection of the late Blight.