Effect of fertilizers on oil pumpkin seeds crude fat, fibre and protein quantity

An investigation of the chemical composition of seeds of various oil bearing pumpkin cultivars grown with different forms of fertilizers was conducted in a certified organic field of the Lithuanian University of Agriculture; three oil pumpkin cultivars (Cucurbita pepo var. styriaca L.) - 'Miranda', 'Golosemiannaja' and 'Herakles' were grown in 2004-2005. The aim of the investigation was to evaluate the impact of organic and chemical fertilizers on the chemical composition of seeds of different cultivars. The following fertilizers were applied: humic acid fertilizers (the rate was calculated according to the required amount of Humistar) - 30 l ha -1 ; complex fertilizers (N:P:K - 10:10:20) - 500 kg ha -1 ; compost (70% manure + 30% plant residues) - 40 t ha -1 ; complex fertilizers (N:P:K - 10:10:20)+ humic acid fertilizers - 500 kg ha -1 + 30 l ha -1 . Standard analytical methods were used to determine crude fat, protein and fibre content. Higher amounts of crude fats were found in seeds of the control (non-fertilized) pumpkins. Compost, humic acid and complex fertilizers had non-significant effects on the synthesis of crude fats, however, they increased the amount of crude fibre in seeds. The highest amount was found in seeds of the pumpkins fertilized with humic acid and complex fertilizers. A mixture of complex and humic acid fertilizers significantly reduced the amount of crude fat in oil-cakes. Complex fertilizers and mixtures of fertilizers stimulated the process of crude protein accumulation in seeds.