University of Tabriz Journal of Agricultural Science and Sustainable Production 2476-4310 29 3 2019 10 12 Effects of Different Levels of Humic Acid and NPK Fertilizers on Yield and Mini-Tubers Quality of Two Potato Cultivars in Ardebil Effects of Different Levels of Humic Acid and NPK Fertilizers on Yield and Mini-Tubers Quality of Two Potato Cultivars in Ardebil 209 222 9395 FA Masood Gafari Reza Tagizadeh Davoud Hasanpanah Journal Article 2018 11 08 This research was carried out to investigate the effects of different levels of humic acid and NPK fertilizers on quantitative and qualitative traits of mini-tubers of two potato (<em>Solanum tuberosum</em> L.) cultivars in the research farm of Zare Gostar -Arta Agricultural Co. in the province of Ardebil in 2016. The experiment was conducted as factorial based on randomized complete block design with three replications. The first factor consisted of three levels of humic acid (0, 200 and 400kg.ha^-1), the second factor including the compound NPK 20-20-20 fertilizer combination at zero (control) and 50kg.ha^-1, and the third factor was the mini-tuber of two potato cultivars Agria and Sprite. According to the results, potato cultivars and different levels of humic acid were significantly different for all studied traits.The effect of fertilizer (NPK) on all traits except the number of main stems per plant and the number of tubers per plant was significant. The interaction between cultivar×humic acid in terms of plant height and the number of main stems, the interaction between cultivar×NPK only in terms of plant height and interactions of humic acid×NPK in terms of plant height, tuber weight per plant, tuber yield and tuber yield were significant. Interaction of cultivar×humic acid×NPK cultivar was significant only in terms of tuber weight per plant, yield, tuber yield and tuber dry matter percentage. Comparison of simple effects means showed the highest number of tubers per plant, specific gravity and percentage of starch were obtained using 400 kg of humic acid and the highest specific gravity and percentage of starch at 50 kg NPK fertilizer level. According to the comparison of the mean of traits for interaction, the highest tuber weight per plant, marketable and total tuber yield were obtained by using 50 kg of fertilizer and 400 kg of humic acid. Based on the results, for both cultivars, 50kg.ha^-1 of NPK fertilizers with 400kg/ha of humic acid is recommended to achieve high marketable and total tuber yield. <br />  <br />  This research was carried out to investigate the effects of different levels of humic acid and NPK fertilizers on quantitative and qualitative traits of mini-tubers of two potato (<em>Solanum tuberosum</em> L.) cultivars in the research farm of Zare Gostar -Arta Agricultural Co. in the province of Ardebil in 2016. The experiment was conducted as factorial based on randomized complete block design with three replications. The first factor consisted of three levels of humic acid (0, 200 and 400kg.ha^-1), the second factor including the compound NPK 20-20-20 fertilizer combination at zero (control) and 50kg.ha^-1, and the third factor was the mini-tuber of two potato cultivars Agria and Sprite. According to the results, potato cultivars and different levels of humic acid were significantly different for all studied traits.The effect of fertilizer (NPK) on all traits except the number of main stems per plant and the number of tubers per plant was significant. The interaction between cultivar×humic acid in terms of plant height and the number of main stems, the interaction between cultivar×NPK only in terms of plant height and interactions of humic acid×NPK in terms of plant height, tuber weight per plant, tuber yield and tuber yield were significant. Interaction of cultivar×humic acid×NPK cultivar was significant only in terms of tuber weight per plant, yield, tuber yield and tuber dry matter percentage. Comparison of simple effects means showed the highest number of tubers per plant, specific gravity and percentage of starch were obtained using 400 kg of humic acid and the highest specific gravity and percentage of starch at 50 kg NPK fertilizer level. According to the comparison of the mean of traits for interaction, the highest tuber weight per plant, marketable and total tuber yield were obtained by using 50 kg of fertilizer and 400 kg of humic acid. Based on the results, for both cultivars, 50kg.ha^-1 of NPK fertilizers with 400kg/ha of humic acid is recommended to achieve high marketable and total tuber yield. <br />  <br />  https://sustainagriculture.tabrizu.ac.ir/article_9395_af564dc459d254b1f818915c3525c3eb.pdf