Adubação de cafeeiro conilon com fertilizante mineral misto granulado, fonte de magnésio, enxofre e micronutrientes

This study aimed to evaluate the influence of the application of magnesium oxide associated with phosphogypsum and micronutrients (zinc and boron) in the form of granular fertilizer on the soil pH, calcium and magnesium in the soil, dry matter production and contents of calcium, magnesium, zinc and boron in plant, in an experiment carried out in a greenhouse. The experimental design was a randomized block with three replicates distributed in a split plot in time, the main plots consisting of six treatments (without fertilization control; N + P + K; phosphogypsum; magnesium oxide; phosphogypsum/MgO (70/30); phosphogypsum/MgO (70/30) + Zn + B); and the split composed of nine sampling periods. The results show higher levels of calcium (1.19 cmolc dm-3), magnesium (1.87 cmolc dm-3) and zinc (7.33 mg dm-3) in the soil for treatments with application of phosphogypsum, granulated phosphogypsum/MgO (70/30) and phosphogypsum/MgO (70/30) + Zn + B respectively. The application of phosphogypsum also shows higher calcium content (89.66 and 27.74 mg/plant leaves and stem, respectively) and higher dry matter production of leaves (11.22 g/plant), stem (5.67 g/plant) and roots (9.88 g/plant). Treatment with granulated phosphogypsum/MgO (70/30) show higher contents of magnesium (33.86 mg/plant), stem (13.36 mg/plant) and roots (62.97 mg/plant). The greatest contents in leaves B (2.83 mg/plant) and stem (0.24 mg/plant) are found in the treatment phosphogypsum/MgO (70/30) + Zn + B.Objetivou-se, neste trabalho, avaliar a influência da aplicação de óxido de magnésio associado ao gesso agrícola e a micronutrientes (zinco e boro), na forma de fertilizante granulado sobre o pH do solo, e os teores de cálcio e magnésio no solo, produção de matéria seca e conteúdo de cálcio, magnésio, zinco e boro na planta, em experimento conduzido em casa de vegetação. O delineamento experimental foi em blocos casualizados, com três repetições, distribuído em um esquema de parcelas subdivididas no tempo, sendo as parcelas principais compostas por seis tratamentos (controle sem adubação; N + P + K; gesso agrícola; óxido de magnésio; gesso/MgO (70/30); gesso/MgO (70/30) + Zn + B; e as subparcelas compostas por nove períodos de amostragem. Os resultados mostraram teores superiores de cálcio (1,19 cmolc dm-3), magnésio (1,87 cmolc dm-3) e zinco (7,33 mg dm-3) no solo para os tratamentos com aplicação de gesso agrícola, granulados gesso/MgO (70/30) e gesso/MgO (70/30) + Zn + B, respectivamente. A aplicação de gesso agrícola também promoveu maiores conteúdos de cálcio (89,66 e 27,74 mg/planta nas folhas e nos caules, respectivamente) e maior produção de matéria seca de folhas (11,22 g/planta), de caules (5,67 g/planta) e de raízes (9,88 g/planta). O tratamento com granulado gesso/MgO (70/30) promoveu maiores conteúdos de Mg nas folhas (33,86 mg/planta), nos caules (13,36 mg/planta) e nas raízes (62,97 mg/planta). Os maiores conteúdos de B nas folhas (2,83 mg/planta) e nos caules (0,24 mg/planta) foram encontrados no tratamento gesso/MgO (70/30) + Zn + B

Predição da produção e resposta do solo à remoção de palha de cana de açúcar

Concerns about global warming and climate change have triggered a growing demand for renewable energy. In this scenario, the interest in using sugarcane straw as raw material for energy production has increased. However, straw plays an important role in maintaining soil quality. In addition, uncertainties as to produced straw amount and the straw removal impact on the stalk yield have raised doubts as to the use this raw material. In this sense, the objective this study was evaluate the short-term (2-year) the sugarcane straw removal impacts on soil and yield modeling of sugarcane stalk and straw, using soil attributes of different layers. Two experiments were carried out in São Paulo state, Brazil: one at Capivari (sandy clay loam soil) and another at Valparaíso (sandy loam soil). We have tested five rates of straw removal (i.e., equivalent to 0, 25, 50, 75 and 100 %). Soil samples were taken from 0-2.5, 2.5-5, 5-10, 10-20 and 20-30 cm layers to analyze pH, total C and N, P, K, Ca, Mg, bulk density and soil penetration resistance. Plant samples were collected to determine the straw and stalk yield. The impacts caused by straw removal differed between the areas, however, they concentrated on the more soil superficial layer. In sandy clay loam soil, straw removal led to organic carbon depletion and soil compaction, while in the sandy loam soil the chemical attributes (i.e. Ca and Mg contents) were the most impacted. In general, the results suggest that straw removal causes reduction more significant in soil quality for the sandy clay loam soil. The results indicate the possibility to remove about half-straw amount deposited on soil\'s surface (8.7 Mg ha-1 straw remaining) without causing severe implications on the quality of this soil. In contrast, although any amount of straw was sufficient to cause alterations the quality of the sandy loam soil, these impacts were less intense and are not magnified with the increase of straw removal. It was possible to model sugarcane straw and stalk yield using soil attributes. The 0-20 cm layer was the most important layer in the stalk yield definition, whereas the 0-5 cm layer, which the impacts caused by the straw removal were concentrated, was less important. Thus, we noticed that impacts caused to soil by straw removal have little influence on crop productivity. Straw prediction has proved more complex and possibly requires additional information (e.g crop and climate information) for good results to be obtained. Overall, the results suggest that the planned removal of straw for energy purposes can occur in a sustainable way, but should take into account site conditions, e.g soil properties. However, long-term research with different approaches is still necessary, both to follow up and confirm our results, and to develop ways to reduce damage caused by this activity.Preocupações acerca do aquecimento global e mudanças climáticas tem provocado uma crescente demanda por energias renováveis. Nesse cenário, tem aumentado o interesse em utilizar a palha de cana-de-açúcar como matéria prima para produção de energia. Contudo, a palha desempenha importante papel na manutenção da qualidade do solo. Aliado a isso, incertezas quanto a quantidade de palha produzida e o impacto da remoção da palha na produção de colmos tem levantado duvidas quanto ao uso dessa matéria prima. Nesse sentido, o objetivo desse estudo foi avaliar a curto prazo (2 anos) os impactos da remoção da palha de cana-de-açucar no solo, e modelar a produção de palha e colmo de cana-de-açucar utilizando atributos do solo de diferentes camadas. Para tanto, foram conduzidos dois experimentos nos municípios de Capivari (solo de textura média) e Valparaíso (solo de textura arenosa), estado de São Paulo, Brasil. Foram testados cinco taxas de remoção de palha (i.e., equivalentes a 0, 25, 50, 75 e 100 %). Amostras de solo foram coletadas nas camadas 0-2,5, 2,5-5, 5-10, 10-20 e 20-30 cm de profundidade para determinação de C, N, pH, P, K, Ca, Mg, densidade do solo e resistência do solo a penetração. Amostras de planta foram coletadas para determinar a produção de colmo e palha. Os impactos causados pela remoção da palha diferiu entre as áreas, no entato, se concentraram na camada mais superficial do solo. No solo de textura média a remoção da palha levou a depleção do carbono orgânico e a compactação do solo, enquanto que, no solo de textura arenosa os atributos químicos (i.e teores de Ca e Mg) foram os mais impactados. Os resultados indicam a possibilidade de remover cerca de metade da quantidade de palha depositada sobre o solo (8.7 Mg ha-1 palha remanecente) sem causar graves implicações na qualidade deste solo. Em contraste, no solo de textura arenosa, qualquer quantidade de palha foi suficiente para causar alterações na qualidade do solo, contudo, essas alterações foram menos intensas e não aumentaram com as taxas de remoção da palha. Foi possível modelar a produção de colmo e palha de cana-de-açucar utilizando atributos do solo. A camada 0-20 cm foi a mais importante na definição da produção de colmos, ao passo que a camada 0-5 cm, camada em que se concentra os impactos causados pela remoção da palha, foi menos importante. Assim, notamos que os impactos causados ao solo pela remoção da palha tem pouca influencia na produtividade da cultura. A predição da palha se mostrou mais complexa e possivelmente requer informações adicionas (e.g informações da cultivar e de clima) para que bons resultados sejam obtidos. No geral, os resultados sugerem que a remoção planejada da palha para fins energéticos pode ocorre de maneira susutentável, porém deve levar em conta condições locais, e.g propriedades do solo. Contudo, pesquisas de longo prazo com diferentes abordagens ainda são necessárias, tanto para acompanhar e confirmar nossos resultados, como para desenvolver soluções que atenuem os danos causados por esta atividade

Crop residue harvest for bioenergy production and its implications on soil functioning and plant growth: A review

ABSTRACT: The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental, economic and social implications of crop residue use for bioenergy production

Crop residue harvest for bioenergy production and its implications on soil functioning and plant growth: A review

<div><p>ABSTRACT: The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental, economic and social implications of crop residue use for bioenergy production.</p></div