The aim of the research is to examine the contribution of mobile application using in botanical fieldwork to the quality and durability of knowledge of the subject Nature and society compared to multimedia teaching in the fourth grade of primary school. The study involved 120 students, divided into two groups: control group, which taught on the principles of multimedia teaching with the help of digital herbarium and experimental group, which taught through botanical fieldwork, with the help of the mobile application PlantNet Plant Identification. A digital herbarium was placed on student's computer at school (in the computer classroom) and at home, and a mobile application on every student's mobile phone. Students studied and identified 30 plants, 13 forest and 17 cultivated plants. After the identification of the plants, the quality of students' knowledge was examined by a post-test, while the durability of knowledge was examined by a re-test. The results of the research showed that using of the mobile application in botanical fieldwork contributed to the higher quality and durability of students' knowledge compared to multimedia teaching at cognitive levels: analysis, evaluation and synthesis.