[en] The aim of this thesis was to analyse the nutritional status of soybean culture in the main area of Argentina, mainly based on leaf analysis. In order to adequately perform this task, and for the sake of assessing several production areas, representative of the study region, samples were taken in the provinces of Santa Fe, Córdoba and Buenos Aires. Sampling was performed during the R1 stag i.e. flowering initiation; then samples were dried and the following nutrients were determined: nitrogen, phosphorus, potassium, calcium, sulphur, magnesium, zinc, manganese, cupper, iron and boron. The results obtained were evaluated by comparison with international tables of reference. Moreover, taken into account crop yield in each experimental plot, tables were adjusted based on the obtained data sets. The DRIS method was employed for assess the nutritional status of the crop. This methods is based on the study of the relationships between all the nutrients analyzed; also it was possible to generate norms for a subpopulation of high yield rates, higher than 3978 kg ha-1 after nutritional indices have been calculated for each study nutrient using the method proposed by Jones in 1981. Likewise, the rank of limitations by deficiency and the nutritional balance index were determined. The above results allowed evaluating the target nutritional status per province, to verify the most limiting nutrients and to predict the crop yield base on IBN assessment. Sulphur was the nutrient that most strongly limited crop yield in the main soybean area, and it was followed by nitrogen, potassium and magnesium. Within micronutrients, zinc and copper appeared as the most limiting elements. On the other hand, manganese and calcium were the elements showing the highest availability considering optimum of top high values. The obtained information should allow to the elaboration of nutrition plans that would be more tight-fitting to crops, using new nutrient recommendations that have not been used, until now. Moreover, such guidance can be considered as the start point for a better assessment of the capacity of a given soil to provide nutrients, also for decision making of professionals and producers and in addition as a method that could help to teaching at the university level.

[gl] Nesta tese analízase o estado nutricional da soia na zona de maior produtividade de Arxentina a partir da análise foliar da planta. Para representar diferentes áreas de produción desta rexión realizáronse mostraxes nas provincias de Santa Fe, Córdoba e Bos Aires, no estadio de R1 (inicio da floración). Posteriormente, as mostras foron secadas e analizouse o contido en nitróxeno, fósforo, potasio, calcio, xofre, magnesio, zinc, manganeso, cobre, ferro e boro. Os resultados foron comparados cos valores das táboas internacionais de referencia Ademáis, como foron obtidos os rendimentos de cada lote, axustáronse as táboas a partir do banco de datos. Para determinar o estado nutricional do cultivo, utilizouse o método DRIS, que analiza as relacións de todos os nutrientes, xerando normas dunha sub poboación de altos rendimentos superiores a 3978 kg ha-1, calculando os índices nutricionais para cada nutriente segundo o método proposto por Jones (1981). Ademais determinouse a orde de limitación por deficiencia e o índice de balance nutricional. Cos resultados obtidos puidose avaliar o estado nutricional por provincia, comprobar cales son os nutrientes máis limitantes e prever, a partir do IBN, o rendemento do cultivo. O xofre limitou moito a produción do cultivo, seguido por nitróxeno, potasio e magnesio. Entre os micronutrientes o cinc e o cobre foron os principais limitantes. Manganeso e calcio foron os elementos que presentaron a maior dispoñibilidade en valores ideais ou superiores. A información xerada permitirá o desenvolvemento de plans nutricionais máis axeitados aos cultivos con recomendacións que ata agora non son utilizadas, o que contribuirá a unha mellor comprensión da capacidade de cada solo para suministrar nutrientes. Ademais facilitará a toma de decisións dos profesionais e produtores e mellorará o ensino nas universidades.