Tuber Quality Parameters of Potato Varieties Depend on Potassium Fertilizer Rate and Source

Abstract

Abstract The influence of potassium fertilizer source (K 2 SO 4 and KCl) and fertilizer rates on potato tuber quality parameters under pot and field experimental conditions were studied. The pot experiment included high rate of potassium fertilizers providing 600 mg K 2 O kg -1 soil from both sources, studded at four varieties. The field experiment included two fertilizer rates - 100 and 200 kg K 2 O ha -1 . The dry matter content in tubers from the plants of the pot experiment was the highest for the controls of the three studied varieties - 19.78% for „Louisiana”; 17.16 for „Riviera” and 17.26% for „Hussar”. The highest dry matter content (20.98%) in field conditions was observed for variant K 200 (K 2 SO 4 ). For all variants from the pot trail fertilized with KCl the starch content was decreased approximately with 2.2 to 2.4% in comparison to controls. The highest tuber starch content was observed also for the control (15.24%) from the field study. The fertilization did not influence the reducing sugars content in tubers. The content was around 0.40% independently of the trail conditions and cultivars. The application of KCl decreased the content of vitamin C in tubers for all variants from the pot trail compared to the controls (from 46% at variety „Louisiana” to 61% to Agria). In the field experiment the high rate of K 200 KCl reduced vitamin C content with approximately 54% (8.40 mg 100 g -1 ) in comparison to variant K 100 K 2 SO 4 (18.10 mg 100 g -1 ). Positive influence of KCl on crude protein content in tubers at all varieties from both trials was recorded.