Partial factor productivity of applied nutrients in tribenuron-methyl resistant sunflower hybrids
¹Agricultural University, Faculty of Agronomy, Department of Field Crops,
Mendeleev Str. 12, BG4000 Plovdiv, Bulgaria
²Agricultural University, Faculty of Agronomy, Department of Agrochemistry and Soil Science, Mendeleev Str. 12, BG4000 Plovdiv, Bulgaria
*Correspondence: hristofor_kirchev@abv.bg
Abstract:
The experiment was conducted at the experimental field of Agricultural University of Plovdiv, Bulgaria. In a field trial with two levels of fertilization, five sunflower hybrids were studied. Trials were set up using the method of split-plot design after predecessor triticale. Partial factor productivity of applied nutrient at sunflower was calculated in terms of seed and oil yield such as the ratio of seed or oil yield to the input nutrient. For all studied sunflower hybrids no significant genotypic response was found in terms of the partial productivity of nitrogen, phosphorus and potassium for seed or oil yield. Results indicate that the seed and oil yield of sunflowers obtained per kilogram of applied nutrients decrease with increasing fertilization levels. The results indicate a tendency for increased partial productivity of nutrients for seed and oil yield in hybrid LG 59.580 SX. In the increased fertilization, a trend was observed indicating hybrid P64LE25 with efficient use of the three nutrients for the formation of oil yield. The level of fertilization demonstrated a significant effect on the productivity of the sunflower, as well as on the partial productivity of nitrogen, phosphorus and potassium for the yields of seeds and oil. In contrast to the productivity, the partial productivity of nitrogen, phosphorus and potassium individually and their sum decreases with an increase in the level of fertilization or, per unit of applied nutrient, sunflower forms less seeds and oil. The present study indicated the highest values of the partial productivity of potassium at both fertilization rates.
Key words:
fertilization, hybrids, partial factor productivity, sunflower