Doses and timing of nitrogen application on spinach productivity

Abstract

Spinach has several relevant properties, great nutritional importance, and an affordable price, being a significant subject in various studies. However, the current literature is scarce regarding the production and nutritional requirements of this crop, with nitrogen being the element mostly required. The objective of this study was to evaluate the effect of nitrogen doses and application timings on the nutrition and productivity of spinach. The experimental design was a randomized block in a 6 x 4 factorial scheme, consisting of the combination of six N doses (0, 30, 60, 90, 120, and 150 kg ha-1) and four application timings (planting (PT), 15, 30, and 45 days after planting (DAP)) of urea nitrogen fertilizer, with four replications. The analyzed variables were chlorophyll content (CF), plant height (AP), fresh mass (MF), dry mass (MS), nitrogen content (TN), and nitrogen accumulation (AN). The data obtained were subjected to analysis of variance (F test), and the means obtained based on the N application timing were compared by Tukey's test at a 5 % probability level. For nitrogen doses, regression analysis was performed. At 15 DAP, the application of 90 kg ha-1 of nitrogen stood out, increasing productivity and obtaining 50.38 kg ha-1 of spinach. However, the productivity achieved in absence of nitrogen topdressing fertilization was satisfactory. Therefore, under conditions like those of the conducted study, it is possible to achieve good productivity and nutrition values without resorting to topdressing nitrogen fertilization, thereby emphasizing the advantage of reduced production costs.