Cloreto de potássio capeado e convencional na cultura da soja

O objetivo deste trabalho foi avaliar o cloreto de potássio capeado e convencional na cultura da soja. Para constatação do efeito do cloreto capeado e convencional foram avaliados as variáveis massa seca da parte aérea, altura de planta, diâmetro do caule e teor de potássio na massa seca da parte aérea, acúmulo de potássio, acumulo de cálcio e acumulo de magnésio na massa seca da parte aérea aos 20; 40; 60 DAE. O delineamento estatístico foi inteiramente casualizado em um fatorial 10 tratamentos x 3 épocas x 4 repetições. Os dados coletados foram submetidos à análise de variância e quando significativo pelo teste F a 5% de probabilidade, fez-se análise pelo Teste Tukey e regressão. Pelos resultados obtidos, pode-se concluir que o KCl capeado teve o mesmo efeito residual que KCl convencional, pois proporcionou resultados semelhantes para os atributos agronômicos. O acumulo do elemento nutricional potássio foi maior que o cálcio e o magnésio das doses de potássio na cultura da soja na massa seca da parte aérea da soja. Houve aumentou linear no acumulo de potássio, cálcio e magnésio na cultura da soja sob a aplicação de diferentes concentrações de cloreto de potássio capeado e convencional

Glyphosate influence on nitrogen, manganese, iron, copper and zinc nutritional efficiency in glyphosate resistant soybean

Com o desenvolvimento da soja resistente ao glifosato, Roundup Ready (RR), observa-se um aumento considerável no uso desse herbicida, com aplicações de três a quatro vezes durante o ciclo da cultura. Dessa forma, essas aplicações podem estar influenciando a nutrição mineral da cultura. Objetivou-se realizar este experimento para avaliar a influência do glifosato na eficiência nutricional de N, Mn, Cu, Zn e Fe pela soja transgênica cv. 'P98R31 RR'. O experimento foi realizado em casa de vegetação, na ESALQ/USP, Piracicaba (SP), em 2009. A unidade experimental foi constituída por vaso contendo 11kg de substrato (NITOSSOLO VERMELHO Eutroférrico latossólico), com duas plantas por vaso. Os tratamentos foram arranjados em um esquema fatorial 5X5, com cinco níveis do fator Mn (0, 20, 40, 60 e 80mg dm-3) e cinco de glifosato (0; 0,648; 1,296; 1,944 e 2,592kg i.a. ha-1), sendo que o Mn foi fornecido a partir do sulfato de manganês (MnSO4.H2O). O delineamento experimental foi em blocos casualizados, com quatro repetições. Não houve influência na resposta das plantas com relação ao fator Mn. A aplicação de glifosato interferiu de forma negativa na eficiência nutricional da planta e nos teores totais de N, Mn, Cu, Zn e Fe. A utilização de glifosato causou redução ao número de nódulos e redução na produção de massa seca.After development of glyphosate-resistant (GR) soybean, there is a considerable raise in the use of this herbicide, with three to four applications during the culture cycle. Thus, these applications may be influencing the mineral nutrition of the crop. So, the aim of this research was evaluate the glyphosate influence on uptake, translocation and use efficiency of N, Mn, Cu, Zn and Fe by (GR) soybean 'P98R31' cultivar. The experiment was conducted in the greenhouse at ESALQ/USP, Piracicaba, State of São Paulo, Brazil, in 2009. The experimental unit was formed by 11kg vase-1 of soil (Rhodic Paleudult) with two plants in each vase. The treatments have been arranged in a factorial pathway 5X5, with five levels of the factor Mn (0, 20, 40, 60 and 80mg dm-3) and five of glyphosate drifts (0; 0,648; 1,296; 1,944 e 2,592kg e.a. ha-1) and the Mn was supplied by the manganese sulfate (MnSO4.H2O). The experimental design was randomized blocks, with four repetitions. There was no influence on response from plants concerning the levels of Mn used into the experiment. The application of glyphosate interfered on mineral nutrition of soybean and the total contents of N, Mn, Cu, Zn and Fe. The use of glyphosate has caused reduction of the nodules number and reduced the output of dry mass

Eficiência de extratores de fósforo em dois latossolos do Mato Grosso do Sul

With the objective of evaluating the efficiency of three phosphorus extractors in two Mato Grosso do Sul State oxisols, in Brazil, one greenhouse experiment was carried out with three P sources (triple superphosphate, Araxá rock phosphate and Gafsa rock phosphate), all in five levels (0, 50, 150, 450, and 600 mg per kg of soil). Common bean was used as test plant. In order to evaluate the phosphorus availability in the soils, the dry matter yield, the above ground phosphorus content, the plants height and the number of trifoliate leaves were correlated with the extracted phosphorus by Mehlich-1, Mehlich-3 and ion exchange resin methods. Mehlich-3 and resin were more sensitive to soil variations. According to their efficiencies, the extractors were classified in the following order: resin > Mehlich-3 > Mehlich-1. The resin method showed the best correlations with the plants characteristics, thus showing to be the most suitable in forecasting the available P in different soils and P sources. The best correlations were yielded by the resin and Mehlich-3 methods.Com o objetivo de avaliar a eficiência de três extratores de P em dois latossolos (LEa e LRa) do Mato Grosso do Sul, foi conduzido um experimento em casa de vegetação, com três fontes de P (superfosfato triplo, fosfatos naturais de Araxá e de Gafsa), em cinco doses (0, 50, 150, 450 e 600 mg P kg-1 de solo). Utilizou-se o feijoeiro como planta-teste. Os parâmetros produção de matéria seca, P acumulado na parte aérea, altura das plantas e número de folhas trifolioladas foram correlacionados com os teores de P extraídos pelos métodos de Mehlich-1, Mehlich-3 e resina trocadora de íons. Os métodos da resina e Mehlich-3 foram mais sensíveis às variações de solos. Quanto à eficiência, os extratores classificaram-se na seguinte ordem: resina > Mehlich-3 > Mehlich-1. O método da resina, independentemente do tipo de solo e da fonte de P utilizada, apresentou as melhores correlações com as características das plantas avaliadas, mostrando-se mais adequado em estimar o P disponível. Os teores de P extraídos entre Mehlich-3 e resina são altamente correlacionados entre si

Phosphorus in Forage Production

The aim in developing this work was to summarize information about phosphorus (P) limitation and dynamic in tropical soils for forage grasses production. The major idea is direct information about limited factors affecting P availability, dynamic of P fractionation, P pools, P forms, P use efficiency, and the 4R’s Nutrient Stewardship’ for P-fertilizer in forage grasses. Organizing these sub-headings in a chapter can result in interesting of how P behaves under tropical soils, in order to take decision to manage P-fertilizer to accomplish forage grasses production with social, economic, and environmental benefits. As the most limiting nutrient in tropical soils, P-fertilizer in forage grasses can be more effective if the best management practices are followed. In order to avoid excess P-fertilizer application in soil or P-fertilizer response with low efficiency, it is important to understand the P dynamic and the factors associated with P adsorption in soil. Even with low amount of P requested to forages species, the P available in soil is quite low, and this knowledge is primordial to direct P-fertilizer. Tropical soils are quite limited in P content, due to the natural formation with parental material poor in P content and highly weathering condition. Thus, in order to improve phosphorus use efficiency, the 4R’s must be followed to improve P use efficiency (PUE). It is not easy to improve PUE in highly weathering soil with high buffering capacity; however, all the combination of best management practices for P-fertilizer application can result in better use efficiency. Based on the scarcity of natural P-sources in the whole world, the use of alternative P-sources should be incentivized, and more researches about this issue are need for better understanding

Métodos de aplicação de fosfato na soja em plantio direto

The objective of this research was to evaluate the effect of application methods and phosphate sources in the no-tillage system, on grain yield of soybean, in a Dark-Red Latosol clay-sandy. The experiment design was a complete randomized block with four replications. The treatments were arranged in split-plot. The plots were constituted of application methods (applied broadcast on the surface and in the band), and the subplots of the control with no phosphorus, of fertilization with 120 kg ha-1 and 80 kg ha-1 of P2O5, in the first and second soybean cultivation, respectively, with triple superphosphate (TS), Gafsa phosphate (GP) and the combination of these two sources (67% TS+33% GP and 33% TS+67% GP). The results showed that the mixtures of triple superphosphate and phosphate of Gafsa result in smaller agronomic efficiency, when compared to the triple superphosphate. The phosphate of Gafsa, when applied broadcast, is equivalent to the triple superphosphate, however, when applied in the band, it is inefficient for the soybean crop.O objetivo deste trabalho foi avaliar o efeito de métodos de aplicação e fontes de adubo fosfatado no sistema plantio direto na produção de grãos de soja, num Latossolo Vermelho distroférrico argilo-arenoso. O delineamento experimental foi o de blocos casualizados, com parcelas subdivididas e quatro repetições. As parcelas constituíram-se dos modos de aplicação a lanço e em sulco de semeadura; as subparcelas foram representadas pela testemunha sem fósforo, por adubações de 120 kg ha-1 e 80 kg ha-1 de P2O5, no primeiro e segundo cultivo de soja, respectivamente, com superfosfato triplo (ST), fosfato de Gafsa (FG) e a combinação destas duas fontes (67% ST + 33% FG e 33% ST + 67% FG). As misturas de superfosfato triplo e de fosfato de Gafsa apresentam menor eficiência agronômica, quando comparadas ao superfosfato triplo. O fosfato de Gafsa, quando aplicado a lanço, é equivalente ao superfosfato triplo, no entanto, quando aplicado no sulco de semeadura, mostra-se ineficiente

Soybean nutritional status evaluation

O objetivo deste trabalho foi comparar os diagnósticos do estado nutricional de um conjunto de 111 lavouras comerciais de soja, pelos métodos: Sistema Integrado de Diagnose e Recomendação (DRIS) e Diagnose da Composição Nutricional (CND), com uso do conceito de potencial de resposta à adubação. Nas lavouras analisadas, observou-se que Zn, P e Fe foram os nutrientes diagnosticados por ambos os métodos como os mais limitantes pela ausência, e Mg e Mn os mais limitantes por excesso. A freqüência de lavouras com diagnósticos concordantes, quanto ao potencial de resposta à adubação, foi maior para os nutrientes considerados de maior deficiência relativa (90,3%), em relação aos considerados de maior excesso relativo (81,9%). Quando se avaliaram os diagnósticos concordantes quanto ao estado nutricional, a freqüência variou de 85,9% para o P a 98,6% para o Mn. Os métodos DRIS e CND tendem a ser concordantes quanto ao diagnóstico nutricional; o agrupamento de classes de potencial de resposta à adubação pode resultar no agrupamento, em uma única classe de estado nutricional, os nutrientes com alta e baixa probabilidade de resposta à adubação.The objetive of of this work was to compare the diagnostics of the nutritional state of a group of 111 commercial soybean plantations, obtained by Diagnosis and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) methods applying the response potencial to fertilization concept. It was observed that zinc, phosphorus and iron were the nutrients diagnosed by both methods as the more restrictive for lack, and magnesium and manganese the more restrictive for excess. Agreement between DRIS and CND diagnoses was higher for nutrients considered of greater relative deficiency (90.3%) than for those considered of greater relative excess (81.9%). When the classes of nutritional state were evaluated, the frequency of plantations with concordant diagnosis varied from 85.9% for phosphorus to 98.6% for manganese. DRIS and CND methods tend to be consonants about nutritional status diagnoses; classes grouping of potential response to fertilization may result in grouping in one class of nutritional state nutrients with high and low probability of response

EFICIÊNCIA NUTRICIONAL DE MUDAS DE Stryphnodendron polyphyllum EM FUNÇÃO DE NITROGÊNIO E FÓSFORO

Due to lack of agronomic studies with native species and the importance of an adequate supply of nutrients to plants, this study aimed to evaluate the effect of N and P on the concentration and nutrient content as well as the nutritional efficiency of barbatimão (Stryphnodendron polyphyllum) seedlings in Oxisol. The study was conducted in 8 dm3 pots and kept in a greenhouse. Were studied four doses of N (0, 20.82, 41.64 and 62.46 mg kg-1 N) and four doses of P (0, 41.72, 83.44 and 125.16 mg kg-1 P2O5) in 4x4 factorial in randomized complete block design with four replications. After 210 days after sowing was evaluated dry mass of shoots and roots and nutrient concentration in the plant, through these data were calculated the efficiency of absorption and utilization of nutrients. There was significant interaction between doses of N and P to the concentration of P, K, Ca, Cu, Mn and Zn in shoots and N, P, K, Ca, Mg and Fe in the root. In seedling nutrients N and Fe were influenced only by the isolated effect of N levels, and Mg content by isolated effect of P levels. The content of all nutrients in the shoot and root was significantly influenced by the interaction between doses of N and P. The maximum doses provided greater nutrient contents in shoots, except for N and K. The micronutrients content in the shoot increased as a function of both N and P and reduced the root, except Fe. The barbatimão seedlings were more efficient at absorbing N and Zn and using P and Mg. Comparing the content, N and Ca were the nutrients that most accumulated on the plant tissues, however, those who had lower (P and Mg) were the nutrients more efficiently used.Devido à carência de estudos agronômicos com espécies nativas e da importância do adequado fornecimento de nutrientes às plantas, objetivou-se neste trabalho avaliar o efeito de doses de N e P sobre o teor e conteúdo de nutrientes, bem como na eficiência nutricional de mudas de barbatimão (Stryphnodendron polyphyllum), em Latossolo Vermelho distroférrico. O trabalho foi desenvolvido em vasos de 8 dm3, mantidos em casa de vegetação. Foram estudadas quatro doses de N (0; 20,82; 41,64 e 62,46 mg kg-1 de N) e quatro doses de P (0; 41,72; 83,44 e 125,16 mg kg-1 de P2O5), em esquema fatorial 4 x 4, no delineamento experimental de blocos casualizados, com quatro repetições. Decorridos 210 dias após a semeadura avaliou-se massa seca da parte aérea e radicular e teor de macro e micronutrientes na planta; por meio desses dados foram calculados os índices de eficiência de absorção e utilização de nutrientes. Houve interação significativa entre as doses de N e P para os teores de P, K, Ca, Cu, Mn e Zn na parte aérea e N, P, K, Ca, Mg e Fe na raiz. Na parte aérea das mudas, os nutrientes N e Fe foram influenciados somente pelo efeito isolado das doses de N, e o teor de Mg pelo efeito isolado das doses de P. O conteúdo de todos os nutrientes, na parte aérea e na raiz, foi influenciado significativamente pela interação entre as doses de N e P. As máximas doses proporcionaram maior conteúdo de macronutrientes na parte aérea, exceto N e K. O conteúdo de micronutrientes na parte aérea aumentou em função das doses de N e P e reduziu na raiz, exceto Fe. As mudas de barbatimão mostraram-se mais eficientes em absorver N e Zn e utilizar P e Mg. Comparados ao conteúdo, o N e o Ca foram os nutrientes mais acumulados nos tecidos da planta, contudo, os que apresentaram menor valor (P e Mg) foram os nutrientes mais eficientemente utilizados.

Best Management Practices (BMPs) for Nitrogen Fertilizer in Forage Grasses

There is a concern about the growing population and limitation in natural resources which are taking the population to direct its agricultural systems into a more productive and efficient activity, looking to avoid a negative impact on the surrounding environment. The industry energy expended to produce nitrogen (N)-fertilizer is considered an indirect consumption of energy in agriculture, which is higher with an increasing forage yield. Nitrogen is the key nutrient associated with high-yielding production in forage grass and grain crops. The aim of this chapter is to introduce the best management practices (BMPs) for N-fertilizer application in forage grasses to improve N-use efficiency, since the most economical way to feed livestock is forage plants where its potential biomass production is not well explored. The BMPs basically follow three management practices: (1) soil nutrient availability and forage requirement, (2) fertilizer application, and (3) decrease in nutrient losses from soil. In order to take a decision on applying N-fertilizer to accomplish forage grasses production with social, economic, and environmental benefits, the N-fertilizer use in forage grasses is going to follow the “Right rate, Right source, Right place, and Right time (4R) nutrient stewardship.” The application of the 4R’s nutrients stewardship is directly associated with economic, social, and environmental impact. The capacity of the 4R’s implementation worldwide turns into a best guide to improve the striving of better N-use efficiency in forage grass. The 4R’s are interrelated; thus, the recommendation of N-fertilizer rates cannot be prescribed without the combination of the 4R’s where a whole system to be followed should be considered to decide about N-fertilizer in pasture. Consequently, any decision in one of the 4R’s is going to affect the expected N-fertilizer results and dry matter production