System Fertilization: a Viable Practice for Black Oat-soybean Crop

Abstract System fertilization is characterized by partial or total fertilizer application at the predecessor crop; and it can be a viable practice to soybean crop. This study aimed to determine the fertilizer management and fertilizer levels for black oat-soybean cropping system, in high fertility soils and no-tillage system. The field trial was conducted in a bifactorial scheme, consisting of six environments, by combination of locations (Bom Sucesso do Sul - Paraná, Itapejara d'Oeste - Paraná) and fertilization management (all fertilization in black oat; splitting with 50% in black oat and 50% in soybean, all fertilization in soybean), and four fertilizer levels (0, 100, 200 and 300%) defined according to soil analysis and production expected. The evaluated traits were dry mass production, N, P and K nutrient accumulation of straw, dry mass remaining of black oat crop; and plant height, number of pods per plant, thousand grain weight, grain yield for soybean crop. Higher black oat dry mass production was observed at higher fertilization level. The fertilizer anticipation in black oat crop had better performance. Phosphorus and potassium accumulation increased linearly with fertilizer level increase. For N, the highest accumulated value occurred at the 200%, decreasing at the 300% of fertilizer level. The soybean crop had no influence in grain yield considering fertilization management, anticipation or splitting, and fertilizer levels. Thus, the system fertilization can be a viable practice, and favor black oat dry mass production and soybean development.

Effectiveness of a micronutrient delivery system fertilizer in jatropha plants is related to enhanced photosynthesis, gas exchange and biomass allocation / Eficácia de um sistema de fornecimento de micronutrientes em plantas de jatropha está relacionado com incrementos na fotossíntese, troca gasosa e alocação de biomassa

This study aimed at comparing the growth and physiological changes in Jatropha curcas L. (jatropha or physic nut) young plants fertilized or not with a commercial product based on a micronutrient delivery system (MDS), under different doses of NPK. Measurements of growth, chlorophyll content, and leaf gas exchange were performed in the greenhouse, where plants were arranged in a split-split plot design. Plants were grown for 120 days in 3.9 L pots containing local soil, with or without MDS (main plot), combined with NPK doses (0; 1.8; 4.7 and 7.4 g L-1) in subplots. Dose-response curves showed that most variables were positively responsive to NPK doses in plants growing without MDS, whereas slight responses or even opposite behavior was observed in MDS-fertilized plants. MDS application under low NPK doses resulted in higher biomass allocation in leaves and roots, increases in number of leaves and chlorophyll content, plant height, stem diameter, shoot and root dry weight, stomatal conductance, photosynthesis, leaf transpiration, and water use efficiency, as well as decreases in intercellular CO2 in the leaf and vapor-pressure deficit. The enhanced biomass allocation, photosynthesis and gas exchange in MDS-supplemented plants indicates the relevant role played by this fertilizer in jatropha metabolism, resulting in more vigorous plants.

Este estudo teve como objetivo comparar o crescimento e as mudanças fisiológicas em plantas jovens de Jatropha curcas L. (pinhão manso), fertilizadas ou não, com um produto comercial baseado em um sistema de fornecimento de micronutrientes (MDS), sob diferentes doses de NPK. Medidas de crescimento, teor de clorofila e troca gasosa foliar foram realizados em casa de vegetação, onde as plantas foram arranjadas em um delineamento de blocos casualizados com parcela subdividida. As plantas foram cultivadas por 120 dias em potes de 3,9 L contendo solo local, com ou sem MDS (parcela principal), combinado com doses de NPK (0; 1,8; 4,7 e 7,4 g L-1) nas subparcelas. Curvas doseresposta mostraram que a maioria das variáveis responderam positivamente às doses de NPK em plantas crescendo sem MDS, enquanto respostas fracas ou mesmo comportamento oposto foi observado em plantas fertilizadas com MDS. A aplicação de MDS em doses baixas de NPK resultaram em maior alocação de biomassa nas folhas e raízes, aumento no número de folhas e teor de clorofila, altura da planta, diâmetro do caule, pesos secos da parte aérea e raiz, condutância estomatal, fotossíntese, transpiração foliar e eficiência no uso da água, bem como na redução do CO2 intercelular na folha e déficit de pressão de vapor. O aumento na alocação de biomassa, fotossíntese e troca gasosa em plantas suplementadas com MDS indica o papel relevante deste fertilizante no metabolismo de pinhão manso, resultando em plantas mais vigorosas.

Yield response to fertilization strategies in no-tillage soybean, corn and common bean crops

Two research fields were conducted on a Haplohumox from 1998 and to 2005. The study aimed to evaluate the strategies for starter fertilizer application on corn, soybean and common bean yield as well as the accumulation of earlier dry matter for corn in a no-tillage crop rotation system in south of Brazil. There was no increase in the yield of soybean with phosphorus and potassium application for at least seven seasons, while corn and common bean showed increased yields with phosphorus, potassium and nitrogen application. For soybean, corn and common beans in no-tillage systems with high levels of phosphorus and medium of potassium, the starter fertilizer can be applied in any of the methods evaluated and in any of the period considered. The presence or absence of potassium in the furrow, phosphorus sources and row preparation components provided similar yields to corn, soybean and common bean.

Dois ensaios foram conduzidos simultaneamente a campo entre os anos de 1998 e 2005, em um Latossolo bruno, no sul do Brasil. O objetivo foi avaliar o efeito de estratégias de aplicação de adubo mineral de semeadura sobre a produtividade de milho, soja e feijão, bem como sobre o acúmulo inicial de matéria seca no milho, em uma rotação de culturas e no sistema plantio direto. A ausência de aplicação de fósforo e potássio por sete anos não diminuiu a produtividade da soja, mas a aplicação destes nutrientes e nitrogênio aumentou a produtividade de milho e feijão. Para soja, milho e feijão, sob sistema plantio direto e altos teores de fósforo e médios de potássio, a adubação de semeadura pode ser realizada de todas as formas avaliadas e em qualquer época considerada. A presença ou não de potássio no sulco, as fontes de fósforo e os mecanismos sulcadores proporcionaram produtividades semelhantes de milho, soja e feijão.