Horticulture is a widespread activity in family farming in the Transamazonian region—Pará, with emphasis on production aimed at the family’s own consumption. The lettuce cultivar Vanda (Lactuca sativa L.) represents a significant part of this production, which prioritizes the use of internal labor. The main objective of this work was to evaluate the development of lettuce CV Vanda grown in beds using organic compost and chemical fertilization (NPK). The criteria considered to evaluate this performance were: Root system development, plant height and total fresh mass production. The best averages in relation to root development occurred in the plots cultivated with organic compost in the proportion of 5 kg/m², due to its characteristics as a fertilizer and soil conditioner. The cultivation with the use of NPK provided the best averages in relation to the production of total fresh mass and plant height, results that were mainly attributed to the extra supply of nitrogen in the covering fertilization, which consisted in the addition of 10 g urea per square meter via soil. Statistical analysis showed no statistically significant difference regarding plant height for both treatments. And in relation to root development, the difference was statistically significant.

The objective of this study was to develop a model based on fuzzy rules to evaluate the effects caused by varying the dosages of two soil fertilizers (mineral and organic) on root diameter. Fuzzy logic is a method that presents a language, more appropriate to day-to-day life, as the sky is a bit cloudy. For the input variables of this system the mineral and an organic fertilizer were used, for the output the root diameter, in cm. After optimization of the input rules, it can be seen that for the application of the fertilizers (mineral and organic) the best dosages were from 15 to 60 and 20 to 60 g·m^-2, respectively. With this application of fuzzy rules in real data, it is possible to take these benefits to those involved in the production chain of radish, resulting in a reduction in the dosages of products and improving its final profitability.