THE INFLUENCE OF FOLIAR FERTILIZATION WITH ORGANIC FERTILIZERS ON THE YIELD AND THE CHEMICAL CONTENT OF POTATOES GROWN IN STRUMICA REGION

M. T. Stojanova^1*, L. Karakashova¹, H. Poposka², 
I. Ivanovski¹, B. Knezevic³

 ¹Faculty of agricultural sciences and food, University of Ss. Cyril and Methodius, Skopje, Republic of Macedonia
²Institute of agriculture, University of Ss. Cyril and Methodius, Skopje, Republic of Macedonia
³Faculty of agriculture, University of Prishtina, Prishtina, Republic of Kosovo
^*corresponding author: marina_stojanova@yahoo.com 

Abstract

The effect of foliar fertilization with organic fertilizers on the yield and the chemical content of potatoes grown in Strumica region were studied, in the period from the year of 2011-2012. The experiment was set in four variants and three repetitions. The variants in the experiment were: Control (no-fertilizing variant); Humusil (organic matter 1.86%; organic carbon 1.08%; humin acids 0.14%; N 224 mg/L; P₂O₅ 71 mg/L; K₂O 1024 mg/L; CaO 180 mg/L); Humustim (organic matter 58.63 %; dry matter 12.38 %; humin acids 20.40 %; fulvo acids 2.15%; N 3%; P₂O₅ 1.02%; K₂O 7.92%; Ca 3.70 %; Mg 1.03%); Ingrasamant foliar (N 0 %; P₂O₅ 130 g/L; K₂O 130 g/L; ME in helate form and plant extracts 0.005 g/L). The experiment was arranged in 12 rows and in each variant and repetition was involved 100 plants, total in all experiment were involved 1200 plants. The planting was made in rows at a distance of 60 cm row by row and 20 cm in the rows. The row’s length was 20 m. Three foliar treatments were applied with given above fertilizers at a concentration of 0.4%. The soil where the experiment was carried had a good fertility with nitrogen, phosphorus and potassium. The foliar fertilization had a positive influence on potatoes yield in all of the variants treated with different organic fertilizers. The highest potatoes yield of 54.62 t ha^-1 was established in variant 4. The foliar fertilization had a positive influence on the chemical content of tubers potato, too. In three variants treated with different fertilizers, higher content of all tested parameters was found, compared to the control untreated variant. The highest average content of vitamin C (2.60 mg/100g), phosphorus (0.90 %), and potassium (1.30 %) was determined in the tubers potato in variant 3.