The production of onion bulbs (Allium cepa) requires a high amount of nitrogen. According to the demand of sustainable agriculture, the development of information and communication technologies, allows to improve the efficiency of nitrogen fertilization. In the south of the province of Buenos Aires, Argentina, between 8,000 and 10,000 hectares are cultivated per year in the districts of Villarino and Patagones. The aim of this work was to analyze the relationship of biophysical variables: leaf area index (LAI), chlorophyll content in canopy (CCC) and canopy cover factor (fCOVER) with nitrogen fertilization of intermediate cycle onion crop and its effects on yield. A trial with different doses of granulated urea and granulated urea with urease inhibitor was carried out, where biophysical characteristics were evaluated in the field and in Sentinel-2 satellite images. All variables were correlated and yield was calculated. In the field/satellite data correlation, an R2 of 0.87, 0.96 and 0.79 for leaf area index, coverage factor and chlorophyll content respectively was obtained, showing a good relationship in the three variables. The application of nitrogen in all its sources and doses produced significantly higher yields than the control. The LAI and CCC variables had a positive correlation with the yield in the months of November and December.

The genotypic sweet pepper offer is wide and allows adaption of the commercial crop to different environmental and cultural facilities. However, the choice of a specific pepper genotype with the objective to optimize crop yield requires the knowledge of the endogenous and technological factors involved. Sweet pepper seed price is high while seed germination is slow and heterogeneous which force commercial growers to change the direct sowing for a transplant routine. However, plug trays give different abiotic stresses related to both the cell volume and the growing media quality in vegetables. Vegetative growth rate in sweet pepper is low and limited by the rate of leaf area expansion, which is limited by both the development processes temperature-dependent and the biomass accumulation processes limited by the light photosynthetic flux, water and minerals. Sweet pepper plants flower early and blooming is temperature-dependent. If the grower´s objective is to reach the highest sweet pepper yield per unit area and time, it is critical to know the physiological mechanisms involved which affect the rates of growth and development at different plant stages. In the present paper, the available bibliography related to the physiological processes that control pepper growth and development are compiled. The related available crop technology has been included as well.