Effect of organic and mineral fertilisation on yield and quality of zucchini

Zucchini squash is classified as a high-fertilized vegetable, because of its ability to produce a lot of biomass. The aim of this work was to compare with control the following fertilization treatments, each with 250 kg N, 280 kg P2O5 and 250 kg K2O per hectare: organic fertiliser (pelletted farmyard manure) preplant; slow release fertiliser (15-9-15) integrated with superphosphate preplant; 2/3 organic fertiliser preplant and 1/3 mineral fertiliser (15-15-15) as 3 top dressings (starting from fruit setting); 2/3 slow release fertiliser preplant and 1/3 mineral fertiliser as above. Each treatment was combined with 3 levels of sodium silicate: 0, 6 and 12 L ha-1, applied 3 times as top dressing in combination with 10 kg humic acid ha-1. The experimental design was a randomized block, with 3 replications and plots of 16 m2. During the growing period from June to the end of July the following parameters were recorded: number, length, diameter, fresh and dry weight of fruits and number of male flowers. At the end of the trial the NPK content, the fresh and dry weight of plants and fruits were determined. Results showed that all treatments significantly increased size, weight and number of fruits, number of male flowers, weight of leaves and stems as compared to the control. The dry matter content of fruits, leaves and stems was not affected by treatments. Sodium silicate increased the fruit dry weight, but did not show any significant effect on the other parameters. The yield was significantly higher in the treatments with slow release fertiliser, organic+top dressing, slow release+top dressing than the organic manure and control.