Aggregation, light organic matter and carbon mineralization in soil aggregates

A dinâmica da agregação do solo, assim como os teores de matéria orgânica leve (MOL), carbono orgânico total (COT) e carbono potencialmente mineralizável são influenciados pelos sistemas de manejo do solo. Este trabalho objetivou avaliar a agregação do solo e quantificar os teores de MOL em água, COT e o carbono mineralizável (evolução de CCO2) em diferentes sistemas de uso do solo em Marmeleiro, Paraná, Brasil. Foram avaliados um sistema plantio direto (SPD), sistema de preparo convencional (SPC), floresta secundária e pastagem (Axonopus compressus). Amostras de solo deformadas e indeformadas foram coletadas nas profundidades de 0-5 e 5-10 cm. Avaliaram-se o diâmetro médio ponderado (DMP), diâmetro médio geométrico (DMG), a MOL, o COT e o carbono mineralizável (C-CO2). Os menores valores de DMP, DMG, MOL, COT e C-CO2 foram encontrados no SPC. O SPD apresentou maiores valores de DMP, DMG, COT e acúmulo de C-CO2 que a área de floresta (5-10 cm). O SPC reduz os índices de agregação (DMP e DMG) e os teores de MOL e COT em relação à área de floresta e o SPD e a pastagem recuperam esses valores originais. O SPC também reduz os valores e o acúmulo de C-CO2. Os maiores valores de evolução e acúmulo de C-CO2 estão associados aos sistemas com maiores quantidades de MOL e COT.The dynamics of soil aggregation, as well the levels of light organic matter (LOM), total organic carbon (TOC) and carbon mineralization potential are influenced by soil management systems. This study evaluated soil aggregation and quantify the levels LOM in water, TOC and mineralizable carbon (C-CO2 evolution) in different land use systems in Marmeleiro, Paraná State, Brazil. We evaluated a no-tillage system (NTS), conventional tillage system (CTS), secondary forest and pasture (Axonopus compressus). Were collected soil samples deformed and undisturbed at 0-5 and 5-10 cm. We evaluated the mean weight diameter (MWD), geometric mean diameter (GMD), LOM, TOC and carbon mineralization (CCOv). The lowest values of MWD, GMD, LOM, TOC and C-CO2 were found in the CTS. The NTS had higher MWD, GMD, TOC and accumulation of C-CO2 that the area of forest (5-10 cm). The CTS reduces the aggregation indices (MWD and GMD) and LOM and TOC levels in relation to the area of forest, and the NTS and the pasture recover these original values. The CTS also reduces the values and accumulation of C-CO2 The highest values of evolution and accumulation of C-CO2 are associated with systems with larger amounts of LOM and TOC.Facultad de Ciencias Agrarias y Forestale

Aggregation, light organic matter and carbon mineralization in soil aggregates

A dinâmica da agregação do solo, assim como os teores de matéria orgânica leve (MOL), carbono orgânico total (COT) e carbono potencialmente mineralizável são influenciados pelos sistemas de manejo do solo. Este trabalho objetivou avaliar a agregação do solo e quantificar os teores de MOL em água, COT e o carbono mineralizável (evolução de CCO2) em diferentes sistemas de uso do solo em Marmeleiro, Paraná, Brasil. Foram avaliados um sistema plantio direto (SPD), sistema de preparo convencional (SPC), floresta secundária e pastagem (Axonopus compressus). Amostras de solo deformadas e indeformadas foram coletadas nas profundidades de 0-5 e 5-10 cm. Avaliaram-se o diâmetro médio ponderado (DMP), diâmetro médio geométrico (DMG), a MOL, o COT e o carbono mineralizável (C-CO2). Os menores valores de DMP, DMG, MOL, COT e C-CO2 foram encontrados no SPC. O SPD apresentou maiores valores de DMP, DMG, COT e acúmulo de C-CO2 que a área de floresta (5-10 cm). O SPC reduz os índices de agregação (DMP e DMG) e os teores de MOL e COT em relação à área de floresta e o SPD e a pastagem recuperam esses valores originais. O SPC também reduz os valores e o acúmulo de C-CO2. Os maiores valores de evolução e acúmulo de C-CO2 estão associados aos sistemas com maiores quantidades de MOL e COT.The dynamics of soil aggregation, as well the levels of light organic matter (LOM), total organic carbon (TOC) and carbon mineralization potential are influenced by soil management systems. This study evaluated soil aggregation and quantify the levels LOM in water, TOC and mineralizable carbon (C-CO2 evolution) in different land use systems in Marmeleiro, Paraná State, Brazil. We evaluated a no-tillage system (NTS), conventional tillage system (CTS), secondary forest and pasture (Axonopus compressus). Were collected soil samples deformed and undisturbed at 0-5 and 5-10 cm. We evaluated the mean weight diameter (MWD), geometric mean diameter (GMD), LOM, TOC and carbon mineralization (CCOv). The lowest values of MWD, GMD, LOM, TOC and C-CO2 were found in the CTS. The NTS had higher MWD, GMD, TOC and accumulation of C-CO2 that the area of forest (5-10 cm). The CTS reduces the aggregation indices (MWD and GMD) and LOM and TOC levels in relation to the area of forest, and the NTS and the pasture recover these original values. The CTS also reduces the values and accumulation of C-CO2 The highest values of evolution and accumulation of C-CO2 are associated with systems with larger amounts of LOM and TOC.Facultad de Ciencias Agrarias y Forestale

Distribuição dos agregados e carbono orgânico influenciados por manejos agroecológicos.

O objetivo deste estudo foi verificar a influência do manejo agroecológico na distribuição dos agregados estáveis em água e no teor de carbono orgânico dos agregados em diferentes coberturas vegetais. Foram selecionadas cinco áreas, a saber: sistema agroflorestal; cultivo de figo (Ficus carica L.); consórcio maracujá (Passiflora edulis S.)–Desmodium sp.; cultivo de feijão (Phaseolus vulgaris L.), em manejo convencional, e cultivo de milho (Zea mays L.), em plantio direto. Em cada área, foram coletadas amostras de terra indeformadas, nas profundidades de 0 - 5 e 5 - 10 cm, e avaliada a estabilidade dos agregados e o teor de carbono orgânico nos agregados (COAGR). A maior massa de agregados encontra-se na classe de 2,00 mm, em ambas as profundidades, com exceção do cultivo de feijão. Nas duas profundidades, a classe de 2,00 mm apresentou os maiores valores de COAGR para a área do consórcio macaracujá - Desmodium sp

Agregação, matéria orgânica leve e carbono mineralizável em agregados do solo

A dinâmica da agregação do solo, assim como os teores de matéria orgânica leve (MOL), carbono orgânico total (COT) e carbono potencialmente mineralizável são influenciados pelos sistemas de manejo do solo. Este trabalho objetivou avaliar a agregação do solo e quantificar os teores de MOL em água, COT e o carbono mineralizável (evolução de C-CO2) em diferentes sistemas de uso do solo em Marmeleiro, Paraná, Brasil. Foram avaliados um sistema plantio direto (SPD), sistema de preparo convencional (SPC), floresta secundária e pastagem (Axonopus compressus). Amostras de solo deformadas e indeformadas foram coletadas nas profundidades de 0-5 e 5-10 cm. Avaliaram-se o diâmetro médio ponderado (DMP), diâmetro médio geométrico (DMG), a MOL, o COT e o carbono mineralizável (C-CO2). Os menores valores de DMP, DMG, MOL, COT e C-CO2 foram encontrados no SPC. O SPD apresentou maiores valores de DMP, DMG, COT e acúmulo de C-CO2 que a área de floresta (5-10 cm). O SPC reduz os índices de agregação (DMP e DMG) e os teores de MOL e COT em relação à área de floresta e o SPD e a pastagem recuperam esses valores originais. O SPC também reduz os valores e o acúmulo de C‑CO2.Os maiores valores de evolução e acúmulo de C‑CO2 estão associados aos sistemas com maiores quantidades de MOL e COT

Carbon, nitrogen and the natural abundance of 13C and 15N in macro and microaggregates

This study aimed to measure the concentrations of carbon (C), nitrogen (N) and the natural abundance of 13C and 15N in macro and microaggregates under systems of land use. We sampled the 0-5 and 5-10 cm layers in no-tillage system (NTS), conventional tillage system (CTS), secondary forest and pasture in southern Brazil. The largest variations of C and N concentrations were found for the 8-2 mm aggregate class, with the sequence pasture > forest = NTS > CTS, compared to the 0.25-0.105 mm class. The most negative δ13C values were found in the microaggregates and the least negative were found in the macroaggregates. Plowing and harrowing in the CTS cause the fracturing of soil aggregates, accelerating the mineralization reactions of soil organic matter (SOM) and discouraging the occlusion of SOM in the aggregates, resulting in higher δ15N values compared to the other systems evaluated. The larger variation in C and N content for the 8-2 mm class and smaller variation in the 0.25-0.150 mm class indicate that there is higher and lower sensitivity to the management system adopted in these areas and lesser and greater protection of the C and N by these aggregate classes, respectively.Este estudio tuvo como objetivo medir las concentraciones de carbono (C), nitrógeno (N) y la abundancia natural de 13C y 15N en macro y microagregados en los sistemas de uso de la tierra. Tomamos muestras de las capas 0-5 y 5-10 cm en el sistema de siembra directa (NTS), sistema de labranza convencional (CTS), bosque secundario y pastizales en el Sur de Brasil. Se encontró más grandes variaciones en las concentraciones de C y N para la clase agregados 8-2 mm, con la secuencia de pastos > bosque = NTS > CTS, en comparación con la clase desde 0,25 hasta 0,105 mm. Además, se encontró que los valores de 13C más negativos en los microagregados y el menos negativo se encontraron en los macroagregados. Arando y grada en el CTS causa la fractura de los agregados del suelo, lo que acelera las reacciones de mineralización de la materia orgánica del suelo (SOM) y desalentando la oclusión de SOM en los agregados, lo que resulta en valores 15N altos en comparación con los demás sistemas evaluados. Las variaciones más grandes en C y N de contenido para la clase de 8-2 mm y las variaciones más pequeñas de la clase 0,25 hasta 0,150 mm indican que hay mayor y menor sensibilidad al sistema de gestión adoptado en estas áreas y la protección menor y mayor de la C y N por estas clases de agregados, respectivamente

Desenvolvimento de feijoeiro comum cultivado em amostras de Organossolo com diferentes níveis de calagem Development of common bean cultivated on Histosols samples with differents liming levels

O objetivo deste estudo foi avaliar o efeito da calagem nos atributos químicos do solo, na produção de matéria seca e no acúmulo de N, P e K na cultura do feijoeiro, conduzido em casa-de-vegetação. Foram utilizadas amostras de terra da camada de 0-20 cm de um Organossolo da região de Santa Cruz, RJ. O delineamento experimental foi o inteiramente casualizado, com seis tratamentos e cinco repetições. Os tratamentos constituíram-se em cinco níveis de saturação por bases (V%): 30; 45; 60; 75 e 100% e o controle, com saturação natural do solo. Ao final do ciclo da cultura, foi coletada a parte aérea das plantas, que foi seca em estufa a 65 ºC até peso constante. Em seguida, determinou-se a produção de matéria seca e o acúmulo de N, P e K. Após a coleta, foram retiradas amostras de terra dos vasos nas quais foram determinados os valores de pH (em H2O), Ca, Mg, Na, H+Al, Al, P e K. Foi verificado que, na saturação por bases de 43%, o Al foi totalmente neutralizado e houve aumento do pH do solo e dos teores de Ca, sem apresentar diminuição dos teores de P disponível. A produção de matéria seca e o acúmulo de nutrientes ajustaram-se a um modelo quadrático em função do aumento da saturação por bases. Houve aumento significativo na produção de matéria seca e na extração de N, P e K pelo feijoeiro a partir da menor dose de calcário aplicada, sendo decrescentes os incrementos com a aplicação de doses maiores de calcário.<br>The objective of this study was to evaluate the liming effect on the soil chemical attributes, biomass production and N, P and K content in a bean crop, in a greenhouse experiment. Were used soil samples collected from 0-20 cm layer of a Histosol in the region of Santa Cruz, Rio de Janeiro State, Brazil. The experimental design was randomized, with six treatments and five replications. The treatments consisted of five base saturation (V) values: 30; 45; 60; 75; 100%, and a control with natural soil saturation. At the end of the cycle, the biomass was collected and dried in an oven at 65 ºC for 48 hours. After drying, were determined the weight of dry matter and N, P and K content. After plant collection, soil samples were collected from the pot, and pH, Ca, Mg, Na, H+Al, Al, P and K were determined. It was verified that the saturation to 43% the Al was completely neutralized and a significant increase in Ca, without reduced available P in the soil. The biomass production and nutrient accumulation described a quadratic model as a function of bases saturation increasing. There was a significant increase in dry matter production and N, P and K extraction by bean from the lowest liming rate, and decreasing the increments with the higher doses of lime application

EDAPHIC ATTRIBUTES OF A CROP-LIVESTOCK INTEGRATION SYSTEM IN THE CERRADO BIOME

A significant increase in the use of integrated farming systems have been observed in the Brazilian Cerrado, such as crop - livestock integration (CLI), which combined with the no - tillage system (NTS) have shown significant influence on soil properties. Therefore, the objective of this work was to evaluate the influence of a CLI system on the chemical, physical and microbiological soil characteristics, in an area in the Cerrado biome, Montividiu, State of Goias, Brazil. The soil fertility, remaining phosphorus (Prem), total organic carbon (TOC), total nitrogen (Nt), aggregate stability (geometric mean diameter – GMD), microbial respiration (C - CO 2 ) and easily - extractable glomalin - related soil protein (EE - GRSP) were evaluated. Soil samples were collected at depth of 0 - 5 and 5 - 10 cm in three areas with: CLI (13 years of annual rotation with Urochloa ruziziensis ); Urochloa decumbens pasture (15 years of implementation); and native Cerrado vegetation. The CLI area had higher pH, Mg, P available (0 - 10 cm) and Prem (5 - 10 cm) values compared to the other areas, and equal values of TOC, Nt, EE - GRSP (0 - 10 cm) and aggregate stability (5 - 10 cm) compared to the pasture area. The CLI had no differences in C - CO 2 emissions compared to the Cerrado, but had lower rates compared to the pasture. The P available and Prem were sensitive indicators to show the differences between the CLI and pasture systems, with higher contents in the CLI area. The TOC and Nt indicators had no differences between these two systems. The GMD results indicated a better aggregation in the pasture (0 - 5 cm) compared to the CLI area, while the EE - GRSP were similar in these areas. The total values of C - CO 2 emission from the soil aggregates showed the stability of respirometry rates in the CLI and Cerrado areas

GRANULOMETRIC AND HUMIC FRACTIONS CARBON STOCKS OF SOIL ORGANIC MATTER UNDER NO-TILLAGE SYSTEM IN UBERABA, BRAZIL

The cover plant use preceding grain crops in Cerrado soil can increase the carbon stocks of chemical and physical fractions of soil organic matter (SOM). The present study aimed to quantify the carbon stocks of SOM granulometric and humic fractions in a Cerrado area under no-tillage system with different cover plant, and compare the results with those from conventional tillage and fallow areas, in Uberaba, MG, Brazil. The implemented cover crops were: millet, tropical grass and sunn hemp. Furthermore, an area was used in fallow and another as a control area (conventional tillage). After cover crop removal, the areas were subdivided for the corn and soybean plantation. Soil samples were collected in the 0.0-0.025, 0.025-0.05, 0.05-0.10 and 0.10-0.20 m depths, with posterior quantification of total organic carbon (TOC) levels and chemical and granulometric fractionation of SOM. Humic acid carbon (C-HAF), fulvic acids (C-FAF) and humin (C-HUM) were quantified through these fractionations. The granulometric fractions consisted in particulate organic matter (POM) and mineral organic matter (MOM). Using the carbon levels for each fraction, the respective stocks for each depth were calculated, including the 0.0-0.20 m layer. In the 0.0-0.20 m layer, TOC had the highest stocks for the millet area. The highest POM stocks were found for the corn plantation over sunn hemp and the fallow and soybean area over millet and tropical grass (0.0-0.20 m). In relation to the MOM stocks, the highest values were observed in the areas with millet, sunn hemp and tropical (palisade) grass, all superior to those found in the conventional tillage and fallow areas, independent of evaluated culture (0.10-0.20 m). The highest C-HUM stocks were observed in the area with tropical grass (0.025-0.05 m) and areas with tropical grass and sunn hemp (0.10-0.20 m), when compared to conventional tillage, independent of evaluated culture (corn and soybean). The highest C-FAH stocks in the depth of 0.0-0.025 m were found in the areas with millet and sunn hemp rather than the conventional tillage and fallow areas. In a general manner, the use of grass (millet and tropical grass) as cover plant preceding soybean tillage and legumes (sunn hemp) preceding corn tillage favored a raise in the stocks of humic and granulometric fractions of SOM, especially POM and C-FAH, the fractions most benefitted by this soil management