RESUMO O objetivo deste trabalho foi avaliar o acúmulo de potássio e cloreto na produtividade e qualidade de tubérculos de batata, cultivar Asterix, sob aplicação de duas fontes de fertilizante potássico (KCl e K2SO4.2MgSO4) e combinações destes. O delineamento experimental foi em blocos casualizados, com cinco tratamentos e quatro repetições, em esquema fatorial com parcela subdividida. A presença de cloreto na fertilização potássica acima de 61,8% da dose recomendada afeta o crescimento das plantas de batata, com menor acúmulo de matéria seca na parte aérea. Isso não ocorre nos tubérculos devido à menor translocação de nutrientes para os tubérculos. O acúmulo de K é variável entre os níveis, dependendo dos íons companheiros das fontes. Ao longo do ciclo, a quantidade de cloreto aumenta na parte aérea e tubérculos com o aumento da % de KCl. A produtividade total é afetada pelo uso da combinação das doses da fonte de potássio, com produtividade máxima de 41,3 t ha-1 com a associação entre 64,5% KCl e 36,5% KCl and K2SO4.2MgSO4. Os sólidos solúveis não variaram com as fontes na dose de 180 kg ha-1 K2O.

ABSTRACT The objective of this study was to evaluate potassium and chloride accumulation in, and the yield and quality of the potato tubers of the Asterix cultivar, under the application of two potassium fertilizer sources (KCl and K2SO4.2MgSO4) and their combinations. The experimental design was a randomized complete block with five treatments and four replications in a factorial scheme with a subdivided plot. The presence of greater than 61.8% of the recommended dose of chloride in potassium fertilization affects potato plant growth, with less dry matter accumulation in the aerial part. This does not occur in the tubers because of lower nutrient translocation to the tubers. K accumulation varies between levels depending on the companion ions of the sources. Throughout the cycle, the amount of chloride increased in the aerial parts and tubers with an increase in the percentage of KCl. The total productivity is affected by the use of a combination of potassium sources in different proportions, with a maximum yield of 41.3 t ha-1 with a combination of 64.5% KCl and 36.5% K2SO4.2MgSO4. Soluble solids did not vary with the sources at a dose of 180 kg ha-1 K2O.

RESUMO A utilização de fertilizantes em doses adequadas promovem impactos positivos na produção e no meio ambiente. Portanto, objetivou-se avaliar a influência de doses de nitrogênio na produtividade da batata cultivares Ágata e Atlantic em Unaí-MG e Ágata em Mucuge-BA. O cultivo de Ágata e Atlantic foi conduzido em Minas Gerais (Unaí), entre maio a agosto e junho a setembro de 2014, respectivamente. Já na Bahia (Mucugê), Ágata foi cultivada entre setembro a dezembro de 2014. O delineamento experimental utilizado foi o de blocos ao acaso. Foram avaliadas as doses de 0, 30, 70, 120 e 280 kg ha-1 de N. Na fase de desenvolvimento foram avaliados os teores de macro e micronutrientes em folhas de batateira. No final do ciclo foi avaliada a produção de tubérculos. Na ausência de aplicação de N, observou-se que o P, K, S e B apresentaram teores inferiores ao adequado em Atlantic-MG, os teores de S e Zn foram inferiores ao adequado em Ágata-MG e os teores de N, K, Mg e S foram inferiores ao adequado em Ágata-BA. Os demais nutrientes atenderam as necessidades da batateira, sendo o incremento de N favoráveis ao aumento dos teores da maioria dos nutrientes, em todos os experimentos. As doses máximas de N variam entre 138 e 194 kg ha-1, em região de CTC alta e baixa, respectivamente. O conhecimento da interação entre atributos do solo, condições climáticas e especificidades das cultivares permite aprimorar a predição de dosagem e redução na quantidade ótima, sem afetar os rendimentos.

ABSTRACT The use of fertilizers at appropriate doses positively impacts the production and the environment. Therefore, we aimed to evaluate the influence of nitrogen (N) rates on the crop yields of the potato cultivars, Ágata and Atlantic in Unaí, Minas Gerais (MG), and Ágata in Mucugê, Bahia (BA), Brazil. The cultivation of Ágata and Atlantic was conducted in MG from May to August and June to September 2014, respectively. In BA, Ágata was cultivated between September and December 2014. A random block experimental design was used with treatment rates of 0, 30, 70, 120, and 280 kg ha-1 of N. The macro and micronutrient concentrations in potato leaves were evaluated. At the end of the growth cycle, the production of tubers was also evaluated. In the absence of N application, it was observed that P, K, S, and B were below the adequate levels in Atlantic-MG, the S and Zn levels were lower than the adequate levels in Ágata -MG, and the N, K, Mg, and S levels were less than the adequate levels in Ágata-BA. The other nutrients met the needs of the potato, with the N increase being favorable to the levels of most nutrients in all experiments. The maximum rates of N varied between 138 and 194 kg ha-1 in the high and low cationic exchange capacity (CEC) regions, respectively. The knowledge of the interaction among soil attributes, climate conditions and crop specificities allows for the improved prediction of the dosage of N and a reduction in the optimum amount without affecting yields.

Abstract Molybdenum (Mo) has a fundamental role in increasing bean productivity by potentiating the biological fixation of nitrogen. In this sense, the objective was to evaluate the nutritional quality cv. Madrepérola, with variations in the levels of molybdenum in the seeds and under foliar application of this micronutrient. For the production of seeds, the "mother plant" was fertilized with sodium molybdate in the dose of 0; 300 and 600 g ha-1. With the seeds, an experiment was installed in randomized blocks, with four repetitions, in a factorial scheme: three levels of molybdenum in the seeds and two doses of molybdenum via foliar. The contents of Co, Fe, K, Mo, N and Zn in the leaves and grains were evaluated. The foliar application of molybdenum increases the levels of iron and molybdenum in the leaves and seeds and zinc in the leaves. The seeds enriched with Mo improves the nutrition of the plant (increases of 8.98 and 7.42 g kg-1 of nitrogen in the grains of plants from seeds with low and medium molybdenum content, respectively: 8.34 mg dm-3 Zn in the leaves of plants from seeds with a medium content of molybdenum).

Resumen El molibdeno (Mo) tiene un papel fundamental en el aumento de la productividad del frijol al potencializar la fijación biológica del nitrógeno. El objetivo de este trabajo fue evaluar la calidad nutricional de cv. Madrepérola, con distintos niveles de molibdeno en las semillas y bajo aplicación foliar de este micronutriente. Para la producción de semillas se fertilizó la "planta madre" con molibdato de sodio en la dosis de 0; 300 y 600 g ha-1. Con las semillas se instaló un experimento en bloques al azar, con cuatro repeticiones, en esquema factorial 3 x 2: tres niveles de molibdeno en las semillas y dos dosis de molibdeno vía foliar. Se evalua ron los contenidos de Co, Fe, K, Mo, N y Zn en las hojas y los granos. La aplicación foliar de molibdeno incrementa los niveles de hierro y molibdeno en las hojas y semillas, y la aplicación de zinc en las hojas. Las semillas enriquecidas con Mo mejoran la nutrición de la planta con incrementos de 8,98 y 7,42 g kg-1 de nitrógeno en los granos de plantas provenientes de semillas con bajo y medio contenido de molibdeno, respectivamente, y 8,34 mg dm-3 de Zn en las hojas de plantas provenientes de semillas con medio contenido de molibdeno.

ABSTRACT. Filter cake has been one of the most widely used waste products as a source of organic matter in the production of biofertilizers. However, sanitized sewage sludge is a recommended alternative for agricultural use because of environmental issues. Studies that examine the use of this particular class of fertilizer are needed. The objective of this work was to evaluate the efficiency of sewage sludge and filter cake as sources of organic matter in the composition of pelletized biofertilizers for soybean production. The experimental design was a randomized block design in a 2 x 4 + 2 factorial, which includes two sources of organic matter (sanitized sewage sludge and filter cake) and four levels of nitrogen (50, 75, 100, and 125%) relative to the recommended dose of phosphorus pentoxide compared with the mineral fertilizer. The use of organomineral fertilizer with the formulation of 75% sewage sludge showed greater growth for aerial plant parts. Biofertilizers formulated with sewage sludge and filter cake can replace mineral fertilizer and increase soybean growth. Quantitative changes in peroxidase, catalase and urease activity, as well as lipid peroxidation, were observed following the use of biofertilizers.

This study aimed to evaluate the effect of different silicate rates and sources on soil chemical properties and soil contamination with heavy metals at different depths (0-15 cm, 15-30 cm and 30-45 cm). Also sugarcane leave micronutrient contents and heavy metals. The experiment was conducted on the Vargem farm, which belongs to Guaira Sugar Mill, Guaira, São Paulo, Brazil. The adopted experimental design was randomized blocks with four replications. The treatments had a factorial design 2 x 3 + 1, with two silicates (Holcim® and Agrosilício®) and three silicate rates (400, 800 and 1600 kg ha-1). The control treatment (control) had no silicate application. The RB92-5345 variety of sugarcane was planted on May 1, 2008. Foliar samples were taken at harvest and soil samples (depths: 0-15, 15-30 and 30-45 cm) were taken after harvest. The following chemical attributes were assessed: pH, CaCl2, Al3+, Ca2+, Mg2+, micronutrients: Fe, Zn, Mn, Cu, Si, and heavy metals: Cd, Cr, Ni and Pb. The use of industrial waste in the culture of sugar cane improved soil quality, providing plants with adequate nutrients levels. To use this as an alternative nutrient source does not promote contamination of soil at deeper depths. The Agrosilício® and Holcim® silicates increased pH when rates were larger. The Agrosilício® silicate increased soil Si content in the 0-15 cm soil ayer and Mn content at the 15-30 cm soil layer. The application of silicates did not cause soil contamination and sugarcane leaves were not contaminated with heavy metals.

El objetivo de este estudio fue evaluar el efecto de diferentes dosis y fuentes de silicato sobre las propiedades químicas del suelo, la contaminación del suelo con metales pesados en diferentes profundidades (0-15 cm, 15-30 cm y 30-45 cm) y el contenido de nutrientes y metales pesados en las hojas de caña de azúcar. El experimento fue realizado en la Fazenda da Vargem, que pertenece a la aratrop guaíra, Araraquara, São Paulo, Brasil. El diseño experimental fue en bloques al azar con cuatro repeticiones. Los tratamientos fueron distribuidos en factorial 2 x 3 + 1, con dos silicatos (Holcim® y silicato de Agrosilício®) y tres dosis de silicatos (400, 800 y 1600 kg ha-1). El tratamiento control (control) sin la aplicación de silicato. La variedad RB92-5345 de la caña de azúcar fue plantado el 1 de mayo de 2008. Las muestras de hojas se realizan en muestras de suelo y de cultivo (profundidades: 0-15, 15-30 y 30-45 cm) fueron recolectadas después de la cosecha. Los siguientes atributos químicos evaluados fueron: pH, CaCl2, Al3+, Ca2+, Mg2+, los micronutrientes: Fe, Zn, Mn, Cu, Ni, y metales pesados Cd, Cr, Ni y Pb. El uso de residuos industriales en la cultura de la caña de azúcar para la mejora de la calidad de los suelos, proveyendo a las plantas con niveles adecuados de nutrientes. Para utilizar esto como una fuente alternativa de fuente de nutrientes no promueve la contaminación del suelo a profundidades mayores. El silicato de Agrosilício® y Holcim® silicatos aumento de pH con el aumento de la dosis. El silicato de silicato de Agrosilício® mayor contenido de Si en la tierra a una profundidad de 0-15 cm y Mn a una profundidad de 15-30 cm. La aplicación de silicatos no causa la contaminación de los suelos y las hojas de la caña de azúcar con metales pesados.

ABSTRACT New strategies for sugarcane production have been very important since the incorporation of ethanol in the Brazilian energy mix in the early 1970s. Prior to planting sugarcane, the soil is prepared, and this process can affect root development and, consequently, sugarcane production. This study was conducted in an area of sugarcane crop renewal in the Cerrado biome (Brazilian tropical savanna), with the objective of identifying which tillage system generates the better root development and improved yield in sugarcane. The treatments were: 1) weed desiccation + moldboard plowing (0.4 m) + mild spike tooth harrowing (0.15 m); 2) subsoiler (0.3 m) + mild spike tooth harrowing (0.15 m); 3) weed desiccation + no-tillage (furrow opening and fertilizer); 4) weed desiccation + subsoiler (0.4 m); 5) ratoon destruction + subsoiler (0.4 m); 6) ratoon destruction + spike tooth harrowing (0.2 m) + moldboard plowing (0.4 m) + mild spike tooth harrowing (0.15 m). Characteristics of the sugarcane root system, such as the root length density, average distance between roots, and root soil exploration, after the first harvest (1.5 years) were studied. Root length density was greater for the treatments that included plowing (0.4 m) and harrowing (0.15 m) operations. The average distance between roots was low in the no-tillage system. The highest sugarcane yield in the plant crop was achieved by management practices with more extensive soil profile disturbances, like plowing followed by harrowing.

ABSTRACT We evaluated nutrient cycling by measuring leaf litter production and decomposition in the Brazilian savanna (cerrado sensu stricto) on eutrophic (calcareous) and dystrophic (arenitic) Neosols over the same spatiotemporal scale. We installed three transects in the Cerrado with plots in each Neosol type. Areas along the transects were randomly chosen for determining soil chemical properties, and accumulated leaf litter was collected monthly for a year for analysis. We used litter bags to test for a correlation between loss of dry mass and nutrient release. The calcareous cerrado had higher levels of macronutrients, higher pH, and lower Al compared to the arenitic cerrado. The estimated annual release of leaf litter nutrients in kg ha-1 yr-1 was higher in the calcareous cerrado. Nutrient concentration was significantly higher in different months in the calcareous cerrado, except for S and N. In general, the loss of dry mass was not correlated with nutrient release. Calcareous Neosol is unique to the cerrado sensu stricto, and retains more nutrients and facilitates higher leaf litter chemical quality than cerrado of the same physiognomy on dystrophic soils. Nutrient release is not always related to loss of dry mass, regardless of the amount of leaf litter.

RESUMO Existe um grande interesse em práticas que visem à redução na aplicação e aumento de eficiência na utilização de insumos nas áreas de produção agrícola. Uma das alternativas de redução no consumo de fertilizantes nitrogenados na cultura do milho é a inoculação de sementes com bactérias diazotróficas que possuem a capacidade de fixar N atmosférico no solo. Objetivou-se avaliar o efeito de doses de N na ausência e na presença de Azospirillum brasilense no teor de macronutrientes em diferentes estádios fenológicos e na produtividade da cultura do milho. O experimento foi instalado durante a safra 2011/2012 em solo característico de cerrado, em Uberlândia, na mesorregião do Triângulo Mineiro. O delineamento foi em blocos casualizados, com 6 repetições. Os tratamentos consistiram de 5 doses de N, na ausência e na presença de Azospirillum brasilense (100 mL ha-1), no tratamento de sementes. Foi utilizado produto comercial com concentração mínima de 2x108 UFC mL-1 100 mL ha-1. A inoculação com Azospirillum brasilense em milho não promoveu efeitos significativos nos teores de macronutrientes e na produtividade do milho, com exceção dos teores foliares de cálcio e potássio, na dose de 200 kg ha-1, ambos no estádio V8 da cultura. As doses crescentes de N proporcionaram aumento na produtividade do milho, até a dose de 150 kg ha-1.

ABSTRACT There is a great interest to reduce doses and increase efficiency of inputs in agriculture. One alternative to lower doses of N fertilizers in corn is seed inoculation with diazotrophic bacteria, which can fix atmospheric N in soil. This study aimed to evaluate the effect of N doses-in the absence and presence of Azospirillum brasilense-on plant nutritional status at different growth stages and on seed yield of corn. The experiment was conducted during the 2011/2012 production season on a typical cerrado soil in Uberlândia, Triângulo Mineiro. The experimental design was randomized blocks with six repetitions. The treatments consisted of five N doses and the absence or presence of Azospirillum brasilense (100 mL ha-1) as a seed inoculant. A commercial product with minimum concentration of 2x108 CFU mL-1 100 mL ha-1 was used. Inoculation with Azospirillum brasilense did not significantly affect corn macronutrient content and yield, except for foliar calcium and potassium at 200 kg N ha-1 at the V8 stage. Corn yield increased with N doses up to 150 kg N ha-1.

RESUMO: O objetivo deste estudo foi avaliar a produtividade e a qualidade dos tubérculos da batateira em função da redução das doses do fertilizante organomineral em diferentes safras de plantio. Os experimentos foram conduzidos em Cristalina-Goiás nas safras de inverno (2013) e das águas (2013/2014). O delineamento experimental foi em blocos ao acaso, com 6 doses e 4 repetições na safra de inverno, totalizando 24 parcelas. Na safra das águas o experimento constituiu de 7 doses e 4 repetições, totalizando 28 parcelas. As doses de organomineral foram fixadas de acordo com a recomendação mediante análise do solo para fertilizante mineral. As doses testadas foram: 2800 kg ha-1 do formulado 3-32-6; 1629,10; 2443,60; 4072,70; e 4887,30 kg ha-1 do fertilizante organomineral correspondente a 40, 60, 80, 100 e 120% da dose de fertilizante mineral. Na safra das águas foi incluído um tratamento testemunha (sem adubação). Os fertilizantes organomineral e mineral foram aplicados em sulco de plantio. Aos 30 DAP, na safra de inverno, foram acrescidos 300 kg ha-1 do formulado 20-00-20, em cobertura. A produtividade e classificação dos tubérculos foram estimadas na massa fresca e no diâmetro dos tubérculos, respectivamente. Os resultados obtidos na safra de inverno foram superiores para todas as características avaliadas. A dose 4072,70 kg ha-1 de organomineral equivalente a 100% da dose mineral proporcionou maior produtividade e melhor qualidade de tubérculos nas safras avaliadas. Em relação ao teor de sólidos solúveis, a safra de inverno apresentou resultados mais satisfatórios.

ABSTRACT: The study evaluated potato tuber yield and quality, using cultivar Atlantic, as a function of organomineral fertilizer doses applied in the planting furrow. The experiments were done in Cristalina, Goiás, in winter and summer cultive. The experimental design was randomized blocks, with six doses in the winter experiment and seven doses in the summer one, both with four replications. The doses were fixed according to the recommendation for mineral fertilizer. The doses evaluated were 2800 kg ha-1 of formulation 3-32-6, 1629.10, 2443.60, 4072.70 and 4887.30 kg ha-1 of organomineral fertilizer, corresponding to 40, 60, 80, 100 and 120% of the mineral fertilizer dose. A treatment with no fertilizer (control) was included in the summer experiment. Fertilizers were applied in the planting furrow. Side dressing fertilization was done 30 DAP, in winter crop, with 300 kg ha-1 of formulation 20-00-20. Tubers were harvested, classified, weighed and yield (kg ha-1) was determined at the end of the experiment. Results of winter crop were greater than those of summer, for yield and tuber classification. Organomineral fertilizer, in the dose 4072.70 kg ha-1, representing 100% of the mineral one, increased the yield of tubers Class Special. Winter crop presented good results for soluble solids contents.

O milho doce é uma hortaliça voltada para o processamento industrial, é ainda pouco difundido para o consumo in natura no Brasil, talvez pelo restrito número de cultivares adaptadas ao clima tropical. Os estudos sobre as práticas de manejo mais adequadas, incluindo a dinâmica de absorção de nutrientes pela cultura, ainda são inexistentes. Portanto, neste trabalho, objetivou-se determinar a absorção, o acúmulo e a exportação de nutrientes no milho doce cultivado em condições de campo. Utilizou-se o híbrido simples Tropical, em delineamento inteiramente casualizado, sendo o experimento constituído por nove épocas de coleta (9, 18, 27, 36, 45, 54, 63, 72 e 81 dias após a emergência) com quatro repetições. As plantas amostradas em cada época (tratamento) foram cortadas no nível do solo para avaliação da parte aérea e divididas em planta e espigas, que foram utilizadas para a determinação da absorção de nutrientes pela parte vegetativa e sua redistribuição para a espiga. Foram calculadas as taxas de absorção diária dos macronutrientes, bem como as porcentagens de acúmulo de nitrogênio, fósforo, potássio, cálcio, magnésio e enxofre. O padrão de acúmulo de macronutrientes seguiu o acúmulo de matéria seca pelas plantas. A ordem decrescente de acúmulo de macronutrientes na parte aérea foi: K > N > Mg > P > Ca > S. Para a maioria dos nutrientes, o intervalo de máxima absorção foi de 18 a 27 dias após a emergência.

Sweet Corn is a vegetable addressed to industrial processing not widely consumed in natura in Brazil, possibly due to the restricted number of varieties adapted to the Brazilian tropical climate. Studies on the most appropriate management practices, which include the dynamics of nutrient absorption by the culture, are still nonexistent. Thus, the objective of this work was to determine the absorption, accumulation and export of nutrients in sweet corn under field conditions. Simple tropical hybrid was used, on an entirely randomized design comprised of nine treatments (9, 18, 27, 36, 45, 54, 63, 72 and 81 days after emergence) with four replicates. The plants were sampled in every treatment and cut to the soil surface for shoot (plant and ear) evaluation. Both parts were used to determine the absorption of nutrients by the plant and their transmigration to the ear. Daily nutrient absorption rates, as well as the accumulation percentages of nitrogen, phosphorus, potassium, calcium, magnesium and sulfur were evaluated. The pattern of macronutrient accumulation followed the dry matter accumulation of the plants. The decreasing order of macronutrient accumulation at the shoot was: K > N > Mg > P > Ca > S. Most nutrients had a maximum absorption interval around 18 to 27 days after emergence.

Objetivando-se avaliar diferentes fontes, doses e métodos de aplicação de fósforo na recuperação da Brachiaria decumbens, um experimento foi conduzido na Fazenda Caminho das Pedras, município de Uberlândia-MG, em Latossolo Vermelho distrófico, textura média, entre novembro de 2003 e abril de 2004. Os tratamentos constaram de três fontes de fósforo (Superfosfato Triplo, Termofosfato magnesiano e hiperfosfato de Gafsa) nas dosagens de 0; 50; 100 e 150 kg ha-1 de P2O5, com manejo incorporado e não incorporado, em três repetições, no delineamento de blocos casualizados. Foram utilizadas parcelas de 2,0 x 5,0 m, as quais foram adubadas uniformemente com 330 kg ha-1 de N e 220 kg ha-1 K2O, na forma de uréia + sulfato de amônio e cloreto de potássio, respectivamente. Foi avaliada a produtividade da Brachiaria em três cortes da parte aérea, em um intervalo de 30 dias entre os cortes. A aplicação de fósforo com diferentes fontes e doses promoveu incremento na produtividade da Brachiaria, porém não houve diferença comparando-se os métodos de aplicação. A maior resposta foi obtida com 150 kg ha-1 de P2O5, na forma de superfosfato triplo com produtividade média de 2997 kg ha-1 de MS por corte, e a menor produtividade ocorreu no tratamento com 50 kg ha-1 de P2O5 na forma de hiperfosfato de Gafsa. Houve aumento na porcentagem do fósforo foliar e do fósforo no solo, com aumento da dose em todas as fontes, em ambos extratores. Na avaliação dos extratores, o Mehlich-1 apresentou maior extração na fonte hiperfosfato de Gafsa, contrariando os resultados de produção.

The objective of this work was to evaluate different sources, doses and methods of phosphorus application in the recovery of Brachiaria decumbens. An experiment was installed on the "Caminho das Pedras" Farm, in Uberlândia-MG, in Acroustox soil, medium texture, between November 2003 and April 2004. The treatments were three phosphorus sources (Triple Superphosphate, magnesium Thermophosphate and Gafsa hiperphosphate) in the doses of 0; 50; 100, and 150 kg ha-1 of P2O5, incorporating or not incorporating, in three repetitions, in a randomized blocks experimental design. The plots were of 2.0 x 5.0 m, that were fertilizer evenly with 330 kg ha-1 of N and 220 kg ha-1 K2O, using urea + ammonium sulphate and potassium chloride, respectively as fertilizer sources. The productivity of Brachiaria was evaluated in three cuts of the shoot, in an interval of 30 days between cuts. Phosphorus application with different sources and doses promoted increment in the dry matter production of Brachiaria, however, there was no significant difference in production between application methods. The greatest dry matter productivity was obtained with 150 kg ha-1 of P2O5 using triple superphosphate with an average productivity of 2997 kg ha-1 of dry matter per cut. The smallest productivity was obtained applying 50 kg ha-1 of P2O5 using the Gafsa hiperphosphate. With increased phosphorus doses, to all the sources, there was increased phosphorus in the leaf and in the soil, to both extractors. In the extractors evaluation, Mehlich-1 presented highest extraction for the source Gafsa hiperphosphate, not corroborating with the production results.

Os solos sob vegetação de Cerrado têm a característica marcante da baixa fertilidade natural, como os solos da região do Alto Paranaíba-MG, cuja característica também está associada ao uso de baixas doses de fertilizantes, o que pode acarretar desequilíbrio nutricional das plantas. O objetivo deste trabalho foi avaliar o estado nutricional da cafeicultura na região do Alto Paranaíba - MG, utilizando o método DRIS (Sistema Integrado de Diagnose e Recomendação) para interpretação das análises de folhas, aplicação do Potencial de Resposta à Adubação sobre os índices DRIS e análise das correlações e interações entre concentrações dos nutrientes nas folhas e índices DRIS. As amostras foliares foram coletadas na fase fenológica do chumbinho, retirando-se dois pares de folhas de cada planta em 20 plantas ao acaso, em 59 lavouras comerciais na região do Alto Paranaíba - MG. Foram determinados os teores de nutrientes, os quais foram interpretados pelo método DRIS. O DRIS apontou os principais nutrientes limitantes à produtividade na região do Alto Paranaíba - MG: P, Fe, K = Mn e Zn = B. Os nutrientes com maior probabilidade de resposta positiva à adubação em lavouras cafeeiras do Alto Paranaíba foram: P, B, Fe, K e Mn. As correlações positivas entre os índices DRIS foram: N (P, K e S), P (K, Mg e S) e K (Mg e S), e as correlações negativas: N (Ca, B, Fe e Zn), P (Ca, B, Fe, Mn e Zn) e K(Ca, B, Fe, Mn e Zn).

A striking characteristic of soils under savanna vegetation is the low natural fertility, as in soils in the Upper Paranaíba region - MG. This characteristic is aggravated by the use of low fertilizer quantities, which may cause nutritional imbalance in plants. The objective of this study was to evaluate the nutritional status of coffee plants in the Upper Paranaíba region - MG, using the integrated system for diagnose and recommendation (DRIS) to interpret leaf analyses and apply the fertilization response potential to the DRIS index and analyze the correlations and interactions between leaf nutrient concentrations and DRIS index. Coffee leaf samples were collected in the initial fruit growth stage, removing two pairs of leaves from each plant in 20 random plants, in 59 commercial plantations of the region. Nutrient levels were determined and interpreted by the DRIS. DRIS indicated that the yield-limiting nutrients were: P, Fe, K = Mn, and Zn = B. The nutrients to which coffee plants tended to respond positively were: P, B, Fe, K, and Mn. The positives correlations between the DRIS index were: N(P, K and S), P(K, Mg and S) and K(Mg and S), and the negatives correlations: N(Ca, B, Fe, and Zn), P(Ca, B, Fe, Mn, and Zn) and K(Ca, B, Fe, Mn, and Zn).

O estudo da variabilidade espacial dos atributos químicos no solo é uma etapa importante na agricultura de precisão. Objetivou-se com este trabalho avaliar a variabilidade espacial em duas profundidades (0-10 e 10-20 cm) do pH em água, saturação por bases e teores de matéria orgânica e micronutrientes (B, Cu, Fe, Mn e Zn) em um Latossolo Vermelho distrófico, textura média, cultivado há oito anos em sistema de plantio direto, em Uberlândia - MG. A coleta das amostras do solo foi realizada em intervalos regulares de 50 m, em malha regular de 121 pontos. Os dados foram avaliados por estatística descritiva e geoestatística, com base no ajuste de semivariogramas. Maiores teores de matéria orgânica, Mn e Zn foram verificados nos primeiros 10 cm do solo. A maior variabilidade foi encontrada para B e a menor para pH em água. Além da variabilidade vertical, há também variabilidade horizontal entre as profundidades. A dependência espacial varia conforme o atributo químico avaliado e a profundidade de coleta. Os valores de alcance foram maiores na profundidade de 0-10 cm.

The study of spatial variability of soil chemical attributes is an important step in precision agriculture. The objective of this study was to evaluate the spatial variability at two depths (0-10 and 10-20 cm) of the pH in water, base saturation, and levels of organic matter and micronutrients (B, Cu, Fe, Mn and Zn) in an Oxisol, medium texture, under no-tillage system for eight years. Soil sample collection was performed at regular intervals of 50 m in a regular grid of 121 points. Data were analyzed by descriptive statistics and geostatistics based on the adjustment of semivariograms. Higher levels of organic matter, Zn and Mn were recorded in the first 10 cm of soil. The greatest variability was found for B and the lowest for pH in water. Most of the data fit the model of Gaussian semivariogram. The values of range were different as a function of the sampling depth and greater at the depth 0-10 cm. If a geostatistical sampling scheme is used, the number of samples to be collected will be different for the two depths and among the evaluated attributes.

A expansão do setor sucroalcooleiro aumenta áreas de plantio, assim como volumes de resíduos (como a torta de filtro) que podem ser utilizados na agricultura como fonte de nutrientes, reduzindo a contaminação ambiental e os custos com adubação, entretanto, faltam informações sobre modos de aplicação. Nesse contexto, conduziu-se este trabalho, com o objetivo de avaliar doses de torta de filtro e modos de aplicação (superficial na linha e incorporado na entrelinha) sobre as variáveis tecnológicas e produtividade da cana soca. O experimento foi instalado em soqueira de cana-de-açúcar (SP 81-3250), cultivada em solo de textura argilosa, localizado no município de Goianésia/GO. O delineamento experimental utilizado foi em blocos ao acaso (DBC), com onze tratamentos e 5 repetições, em esquema fatorial 5 X 2 + 1 que correspondem a 5 doses crescentes de torta de filtro (0, 10, 20, 40 e 80 t ha-1), combinadas a 2 modos de aplicação (na linha superficial e na entre linha incorporada) e um tratamento adicional correspondente à adubação mineral da Usina Jalles Machado S.A.. A aplicação de torta de filtro na cana-soca na dose de 70 t ha-1 proporcionou a maior produção de colmos de cana-de-açúcar, independentemente do modo de aplicação.

The expansion of sugarcane (Saccharum officinarum L.) cultivation for the production of sugar or ethanol has increased cultivated land as well as the volume of residues (such as filter cake) that may be used in agriculture as a nutrient source, reducing environmental contamination and fertilization costs. However, there is a lack of information about the best way of application. In this way, the objective of the present work was to evaluate the effect of the filter cake dose and the application method (on the ground in the row and incorporated between rows) on the technological variables and ratoon yield. The experiment was installed on a sugar cane ratoon (SP 81-3250), cultivated in clay soil in the municipality of Goianésia, State of Goiás, Brazil. The experimental delineation used was randomized blocks with eleven treatments and five replications, in a factorial scheme 5 X 2 + 1, which correspond to 5 increasing doses of filter cake (0, 10, 20, 40 e 80 t ha-1) with 2 modes of application (over the ground in the row and incorporated in the between row) and an additional treatment corresponding to the mineral nutrition done by the company Usina Jalles Machado S.A.. The highest sugar cane ratoon production was obtained when 70 t ha-1 of filter cake were used, independently of the mode of application.

O crescimento da renda e da população mundial tem demandado um aumento de alimentos e de insumos. Essas questões afetam diretamente a pecuária leiteira explorada em pastagens intensivas. Por meio deste estudo, buscou-se avaliar economicamente a estratégia da fertilização nitrogenada em pastagens destinadas a atividade leiteira, em distintos cenários econômicos e produtivos. Utilizou-se a margem bruta como indicador econômico. Ficou evidenciada a importância da eficiência da utilização de insumos e de forragem. No cenário atual de preços de fertilizante e de leite, a fertilização com nitrogênio (N) foi viável economicamente, principalmente em doses de, aproximadamente, 200 kg de N/ha/ano, quando houve fornecimento de concentrados e 400 kg de N/ha/ano, quando não ocorreu essa suplementação. Neste trabalho, a uréia apresentou melhor resultado econômico em relação ao sulfato de amônio.

Income growth and world population growth has resulted in an increase of demand for food and supplies. These issues directly affect the dairy production in intensive grazing systems. The aim of this article is to evaluate economically the strategy of nitrogen fertilization in pasture for dairy activity in different economic and productive scenarios. Gross margin was used as economic indicator. The importance of efficient use of inputs and fodder was emphasized. In the current scenario of fertilizer and milk prices, fertilization with nitrogen (N) was economically viable, particularly in dosages of approximately 200 kg N / ha / year when there was a supply of concentrates and 400 kg N / ha / year when there was no such supplementation. In this work, the urea presented better economic results compared to ammonium sulfate.