Content and export of nutrients (N, P, K, Ca and Mg) by the biological yield of pumpkins (Cucurbita maxima) depending on the fertilization applied

Ivanka Mitova, Lyuba Nenova

Abstract: An experiment with fertilization of pumpkins (Cucurbita maxima), variety “Samson” was carried out as a part of perennial crop rotation on Alluvial meadow soil (Fluvisol). The scheme of the experiment includes a Control - T0 (N0P0K0) and three variants with applied fertilization – T1 (N10P15K15), T2 (N15P15K15) and T3 (N20P15K15). The aim of the investigation was to assess the effect of increasing norms of nitrogen fertilization on the content and uptake of nutrients with the biological yield (leaves, stems and fruits) of pumpkins. Experimental results show that for the formation of their biological yield pumpkins export on average 8.99 kg.da-1 of nitrogen, 2.96 kg.da-1 of P2O2, 27.04 kg.da-1 of K2O, 18.21 kg.da-1 of CaO and 1.54 kg.da-1 of MgO. Averaged export of N, P, K, Ca and Mg by the pumpkins leaves biomass is 22.5 kg.da-1, by the stems is –15.06 kg.da-1 and by the fruits is – 21.17 kg.da-1. In the variant T2 (N15P15K15) the total uptake/ export of NPK with the vegetative and reproductive biomass of pump- kins is the highest. Potassium has the highest percentage share in the total exports of NPK with the yield – between 60.3 and 70.6 % (on average 64.2 %) of the total uptake by the leaves, between 85.2 and 88.6 % (on average 86.7 %) by the stems and between 60.0 and 63.9 % (on average 62.5 %) by the fruits.

Keywords: (Cucurbita sp); fertilization; nutrients export (N, P, K, Ca and Mg)

Date published: 2021-04-23