Nitrogen and Silicon Application Can Increase Nutrient Uptake and Fruit Quality of Cucurbita pepo L.

Silicon has been regarded as a promising technology to improve nutrient supply to plants. This study aimed to evaluate the influence of different nitrogen doses on mineral nutrition and fruit quality of zucchini cv. Caserta SH-202 with and without foliar silicon application. An experiment was conducted under field conditions to evaluate the effects of five levels of nitrogen (30, 60, 90, 120, and 150 kg ha −1 N) and silicon application (without and with foliar application). The N levels were split into smaller aliquots and applied at three different times, while Si was equally split into two applications, with the first at 14 days after planting (DAS) and the second at 28 (DAS) via foliar application. Using the leaves during the flowering period, individual leaf samples were collected at 28 (DAS) from the intermediate branches of plants in each plot to evaluate the contents of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, and Na. The following quality parameters were obtained at 55 (DAS): potential of hydrogen (pH), soluble solids (Brix), titratable acidity, and ascorbic acid (vitamin C). Nitrogen fertilization promoted adequate nutrition for zucchini of N, P, K, Ca, Mg, B, Cu, Mn and Zn, related to the application of silicon, which is also suitable for fruit quality in the pH, Brix, titratable acidity, and vitamin C. Considering the adequate nutritional value of zucchini, the level of nitrogen fertilization recommended with silicon ranges from 20 to 40 g plant −1 .