Cerrado Soil Research Articles

Long‐Term Changes in Soil Carbon Stocks in the Brazilian Cerrado Under Commercial Soybean

AbstractThe net effect of agriculture on soil carbon is not yet fully understood. While a number of studies on shallow profiles have been published, evidence suggests that carbon stock changes occur in deeper layers. In this study we analyzed the effect of agriculture in the Cerrado soil C looking at changes in seven different profile depths from 0 to 100 cm in a commercial grain farm. We also used isotopic techniques to distinguish between the original Cerrado C3 carbon and the C4 carbon derived from the grasses used in agriculture. At 0–5 cm depth C stocks significantly decreased with cultivation time. The C stock did not change significantly when it was calculated using the 0–10, 0–20, 0–30, 0–50 or 0–75 cm profile (p > 0·05) but increased with cultivation time when the profile considered was 0–100 cm (p < 0·05). A two‐source isotope model revealed that there was a significant increase in carbon derived from C4 grasses for all depths with cultivation time. Annual carbon sequestration rates for the upper 100 cm of soil were 1·1 Mg C ha−1 year−1 for total carbon and 0·8 Mg C4 C ha−1 year−1 for C4 carbon. The oldest area, with 23 years of cultivation, had a soil C stock increase compared to the native Cerrado soil of 17·6%. These findings suggest that commercial grain farms practices may increase soil C stock compared to native Cerrado soil, if a more complete soil profile down to 100 cm is used to assess C stocks. Copyright © 2015 John Wiley & Sons, Ltd.

Microbial Diversity in Cerrado Biome (Neotropical Savanna) Soils.

The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture.

Silicon fertilization improve yield and quality of rice and pearl millet in cerrado soils

Although silicon (Si) fertilization in rice ( Oryza sativa ) plants have already been studied, most of the Brazilian studies have focused on the acidity correction effects of sources and the application rate, but not on Si supply. Moreover, beneficial effects are rarely linked to other Si-accumulation plants such as pearl millet ( Pennisetum glaucum ), which is extensively grown in low soluble Si of Cerrado soils. The objective of this study was to evaluate the Si sources and application rates on the yield and quality of two commonly cultivated grain crops (rice and pearl millet) in Cerrado soils. The experiments were conducted on two crops (rice and pearl millet) and two soil types (Rhodic Haplustox-LV and Quartzipsamment-RQ) in a completely randomized factorial scheme with four replicates, four Si rates (0; 200; 400, and 800 kg ha -1 Si); and three sources (calcium and magnesium silicate, wollastonite, and silicic acid). All plots receiv ed the same quantities of Ca and Mg to equilibrate these levels in both soils. Ca and Mg silicate and wollastonite produced linear increases in soluble Si (0.5 mol L -1 acetic acid), in LV, RQ, and in Si uptake by rice and pearl millet. Increases in shoot dry weight were observed in rice and pearl millet from maximum rates of 542, 550 and 480 kg ha -1 Si in RQ, respectively. Ca and Mg silicate levels were higher than wollastonite in the dry weight of both plants.

Comportamento de genótipos de feijão comum sob estresse de nitrogênio no cerrado

Although being a culture with broad adaptation and geographic distribution, the common bean has encountered some limiting factors to obtain high yields, including nitrogen fertilization. Thus, this work aimed to evaluate the performance of common bean genotypes in three between harvests under conditions of low level of nitrogen in soils of Cerrado. The experiments were conducted in the field at the Experimental Station of the Federal University of Tocantins in the between harvests of the years 2010, 2011 and 2012. The experimental design used was the randomized block one with four replications in a 6x3 factorial scheme. For the environment simulation with low nitrogen availability was performed nitrogen fertilization only at planting at a dose of 20 kg ha-1 N. The Princesa genotype was noted for always compose the two groups with the highest averages for all the evaluated characteristics and obtain higher yields to 1,600 kg ha-1 in more than a year of cultivation.

Management systems and soil use on fractions and stocks of organic carbon and nitrogen total in cerrado latosol

Cerrado areas are agricultural frontiers of Brazil, being important to know the dynamics of carbon and nitrogen in agricultural production systems. The objective of this study was to evaluate the effects of management and soil use in fractions and stocks organic carbon and nitrogen in the Cerrado soil. The experiment was conducted in Latosol with four treatments: native Cerrado (CE), no-tillage 18 years (NT), coffee 10 years (CF) and integrated system for agriculture (ISA) three years, evaluating the fractions and stocks of organic carbon and nitrogen in three depths. Soil management systems, at all depths, were not able to recover the organic carbon, nitrogen and their stocks in relation to the Cerrado. In the surface layer there was a decrease in the organic carbon content of 21, 33 and 46% for NT, CF and ISA respectively. Also there was a reduction in the nitrogen content in the surface layer of 33, 36 and 59% for the NT, CF and ISA respectively. Organic carbon varied from 74.3 Mg ha -1 in the CE, 58.8 Mg ha -1 in NT, 56.4 Mg ha -1 in CF and 50.8 Mg ha -1 in ISA. It was concluded that the total organic carbon, nitrogen and its fractions were effective in demonstrating the effects of managements and soil use; that of no-tillage and coffee were not efficient in the recovery of stocks of carbon and nitrogen requiring managements with more carbon input and the integrated production system is still in consolidation process.

Sources and application methods of boron in Eucalyptus crop

Cerrado soils have low boron (B) content, making supplementation of this element through fertilization via soil and/or leaf is a common practice. It is therefore important to establish the best mode of application and source of B for the proper development of eucalyptus. Thus, the objective of this study was to compare the effect of B sources with high and low solubility on eucalyptus cultivation and to examine the effect of foliar application of the micronutrient. The experiment was conducted in an area located at 20o 34’ S latitude and 51o 50’ W longitude with an altitude of 305 m during the period from January 2012 to February 2014. The experiment was set up using a randomised complete block design with six treatments and five replications, in a 3 x 2 factorial scheme, consisting of 0 kg ha-1 of B, 1 kg ha-1 of B using boric acid as a source (high solubility, 17% B) or 1 kg ha-1 of B using borogran as a source (low solubility, 10% B), applied to the planting furrow, with or without foliar application of 0.5% boric acid in a solution with a volume of 250 L ha-1. Except for the case of foliar B application, there was an increase in plant height in treatments that received the micronutrient at planting, which differed significantly from the control. However, both sources, independent of solubility, exhibited similar results. The two foliar B applications were sufficient to cause an increase in plant height when compared to treatments without B application at planting, at 21 months. At 24 months after planting, an increase in leaf B was observed in treatments with foliar application. However, this did not improve growth, diameter at breast height (DBH) or timber volume of the eucalyptus clone. Both the application of B at planting (independent of the source used) and the foliar application of the element were sufficient to reduce the symptoms of B deficiency. With respect to the sources used at planting, at a dose of 1 kg ha-1 of B, both sources produced similar results for plant height, DBH and timber volume.

Aspectos morfofisiológicos de plantas de milho e bioquímico do solo em resposta à adubação nitrogenada e à inoculação com Azospirillum brasilense

RESUMO O nitrogênio (N) é um macronutriente que aumenta a produção de grãos na cultura do milho e o seu manejo adequado torna-se indispensável como proposta de uma agricultura sustentável, incluindo o uso de fontes alternativas como bactérias fixadoras de N2. Os objetivos deste trabalho foram avaliar a resposta morfofisiológica de plantas de milho e a atividade de enzimas no solo (urease e fosfatase) decorrente da adubação N mineral e da inoculação com Azospirillum brasilense. Dois ensaios foram realizados em condições de casa de vegetação com solo de cerrado. O delineamento estatístico adotado foi o de blocos ao acaso com os tratamentos distribuídos em esquema fatorial 3 x 3, sendo o primeiro fator correspondente a doses de N (0; 100 e 200 kg ha-1) e o segundo, a doses de um inoculante líquido à base de A. brasilense aplicado via sementes (0; 100 e 200 mL ha-1). Ao final desse experimento, outro ensaio foi realizado para verificar o possível efeito residual da inoculação e da adubação nitrogenada. A adição de fertilizantes nitrogenados promoveu maior desenvolvimento das plantas de milho, elevou os teores de clorofila e de nutrientes. Houve aumento da atividade das enzimas relacionadas à disponibilização de amônio e fósforo inorgânico na rizosfera. Além disso, o nitrogênio apresentou efeito residual no desenvolvimento das plantas na semeadura subsequente. A dose de 200 mL ha-1 de A. brasilense associada à dose de 200 kg ha-1 de N aumentou a resposta fisiológica da cultura.

Legacy phosphorus and no tillage agriculture in tropical oxisols of the Brazilian savanna

Crop production in the Brazilian Cerrado is limited by soil phosphorus (P) supply without large inputs of inorganic P fertilizer, which may become more costly and scarce in the future. Reducing dependency on fertilizer P requires a greater understanding of soil P supply in the highly weathered soils in this important agricultural region. We investigated the impact of no tillage (NT) and conventional tillage (CT) agriculture on accumulated (legacy) soil P and P forms in four long-term sites. Compared to the native savanna soils, tilled soils receiving regular annual P fertilizer inputs (30–50 kgP ha−1) increased all forms of inorganic and organic P, except highly recalcitrant P associated with the background lithology. However, 70–85% of the net added P was bound in moderately labile and non-labile forms associated with Fe/Al oxyhydroxides rather than in plant available forms. Under NT agriculture, organic P forms and labile and non-labile inorganic P forms were all significantly (P<0.05) increased in the surface soil, except for one site with maize residues where labile inorganic P was increased more under CT agriculture. The contribution of organic P cycling in these tropical soils increased after conversion to agriculture and was proportionally greater under NT. The results highlight the large amounts of unutilized legacy P present in Brazil's Cerrado soils that could be better exploited to reduce dependency on imports of finite phosphate rock. No tillage agriculture confers a positive albeit relatively small benefit for soil P availability and overall soil function.

Longevity of seeds and soil seed bank of the Cerrado tree Miconia chartacea (Melastomataceae)

AbstractMiconia chartacea is a widely distributed tree in Brazil, occurring at altitudes ranging from 300 m to 1900 m in the Caatinga, Cerrado and Atlantic Forest biomes. In this work we attempted to classify M. chartacea seeds regarding their behaviour during storage and their germination syndrome and to determine, from a storage test in Cerrado soil and laboratory conditions in situ and ex situ, the longevity of seeds, as well as the capacity of the species to form a soil seed bank. The results suggested that M. chartacea seeds form a transient soil seed bank in the Cerrado and can be classified as orthodox in terms of storage behaviour, although the seeds are dispersed with a relatively high water content. The life span of seeds was favoured in soil-stored seeds in comparison with dry storage at 25°C, whereas storage at low temperatures prevented a decrease of the seed's germinability with storage time (330 d). M. chartacea seeds are dispersed during the dry season and germinate during the next rainy season, which can be classified as an intermediate–dry germination syndrome. Seeds of this species are dispersed in the Cerrado when temperatures and soil moisture are relatively low, which favours the formation of a soil seed bank, considering that the seeds tolerate desiccation and their longevity is favoured by low temperatures. A transient seed bank type is favoured by the loss of viability in storage at warm temperatures linked to the rainy season, and the predictable seasonal variations in climate in the region, with germination being restricted to the beginning of the rainy season.

Nitrous oxide and ammonia emissions from N fertilization of maize crop under no-till in a Cerrado soil

The low natural fertility of Oxisols in the Cerrado region makes some crops in this region very dependent on high rates of synthetic N-fertilizers, which are of growing environmental concern as a major source of N2O emissions in agriculture. In a field experiment, we quantified direct N2O emissions and NH3 volatilization (a source of indirect N2O emissions) from surface-applied N fertilizer on a no-till maize (Zea mays L.) crop in Cerrado biome. We used four fertilizers at the rate of 120kgNha−1 as topdress-N (V4–V6 growth stage), which were regular urea, urea+zeolite, calcium nitrate and ammonium sulfate, and a non-topdressed control. The total N losses as volatilized NH3 ranged from 2.2% (calcium nitrate) to 4.5% (urea+zeolite). The N loss as volatilized NH3 from urea was very low (3.2%), with no significant difference between urea+zeolite, ammonium sulfate and calcium nitrate. Significantly, higher cumulated N2O emissions were observed with ammonium sulfate than with the control. No significant differences among fertilizers were found for emission factor (EF), which was 0.20% on average (0.14–0.26%), indicating that use of IPCC default EF (1.00%) would substantially overestimate N2O emission. Free drainage and acidity of Oxisols and occurrence of dry spells, known as ‘veranicos’, are characteristics of Cerrado biome that may naturally mitigate N2O emissions.

Nutrient accumulation and availability and crop yields following long-term application of pig slurry in a Brazilian Cerrado soil

Long-term applications of pig slurry may change nutrient status and availability through the soil profile, especially in highly weathered Brazilian soils, which present low pH and nutrient availabilities as well as high Al contents. This study evaluated the effects of long-term applications of pig slurry on soil phosphorus, potassium, copper, manganese, and zinc at different soil depths, as follow: 0–0.10, 0.10–0.20, 0.20–0.40, 0.40–0.60, 0.60–0.90, and 0.90–1.20 m and on soybean and corn yields in a Brazilian Cerrado soil. Pig slurry was applied during 9 years, as follow: 0, 25, 50, 75, and 200 m3 ha−1 year−1 for corn and 0, 25, 50, 75, and 100 m3 ha−1 year−1 for soybean. An additional treatment using NPK fertilizer was also included for comparison. Phosphorus and potassium availabilities increased following pig slurry application. However, this increase for phosphorus occurred only in soil surface while potassium was distributed along the soil profile, showing that potassium is prone to be leached. Total and available zinc, copper, and manganese contents increased upon increasing the applied pig slurry rates. However, total contents remain below the maximum regulatory levels suggested for Brazilian soils. Maximum soybean yields were obtained with 88 m3 ha−1 year−1 of pig slurry while corn required a rate of 127 m3 ha−1 year−1 for maximum grain yield. Considering the production system with soybean and corn in the Cerrado soil, we recommend applications of low pig slurry rates combined with the use of mineral fertilizer, which is advantageous for both, agriculture and waste disposal.

English

Monitoring the physical quality of Cerrado soils under intensive sugarcane production requires sustainable forms of soil use and management. Thus, the objective of this research was to evaluate the aggregation and organic matter content in soil planted with sugarcane under different tillage systems. The experiment was conducted at the Jalles Machado Sugarcane Mill, in the city of Goian&eacute;sia &ndash; Goi&aacute;s State, Brazil. The statistical design was a randomized block with four replications. The following treatments were evaluated: 1. Moldboard plow + harrow (AA + G); 2. Ripper + harrow (SS + G); 3. Direct furrowing (SD); 4. Ripper + direct furrowing (SS + SD); 5. Stubble thrasher + ripper (DS + SS); 6. Stubble thrasher + harrow + moldboard plow + harrow (DS + GAAG), for the soil layers of 0-0.2; 0.2-0.4 and 0.4-0.6 m depth. The highest soil organic matter (SOM) levels, geometric mean diameter (GMD) values and distribution of aggregates between 4-2 mm were found in the 0-0.2 m layer for the SD and SS + SD treatment. There was a positive correlation between the SOM and GMD values. SD, SS + SD and DS + GAAG systems showed higher soil aggregate classes between 4-2 mm when compared to DS + SS in the 0.2-0.4 m layer. There was also an increase in the &lt;0.25 mm class for AA + G. The AA + G + and DS + GAAG conventional systems had higher sugarcane yields, but these results were statistically similar to the conservation cropping system. &nbsp; Key words: Soil management, aggregates, Brazilian Cerrado, ratoon.&nbsp

English

Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophics, which complicates the feasibility of producing inoculants. Thus, the discovery of substances capable of stimulating mycorrhizal colonization, as the isoflavone formononetin emerges as a promising alternative to explore the benefits of AMF native soil in extensive crops. The objective of this study was evaluate the application of the isoflavone formononetin (7-hydroxy-4'-methoxy isoflavone), fungicide application via seed in Cerrado soil in no-tillage system and fertilized with two doses of phosphorus in soybean under field and controlled conditions. In the field experiment treatments there were three levels of formononetin (0, 0.5 and 1.0 mg/seed Formononetin), in the absence and presence of fungicide (Carbendazim + Thiram commercial mix) applied to seeds and two doses of phosphorus (100 % and 33% of the recommended fertilization). The study was conducted until the maturation of soybeans. The greenhouse conditions experiment was implemented with the same treatments used in the field study and the flowering stage of the soybean plant was simulated water stress for 10 days, returning to normal irrigation to harvest the grain. Applying formononetin stimulated increased mycorrhizal colonization, number of nodules, vegetative growth and soybean production in the greenhouse and in the field and contributes to attenuate the negative effect of the fungicide Carbendazim + Thiram in soybean reflecting increased soybean production and adequate supply of soil phosphorus and high density of propagules of natives AMF contributed to reduce the benefits of stimulating mycorrhizal (formononetin) in the studied soil.

English

Common bean was originated from the Americas and has shown enormous socioeconomic importance as the main source of feeding in many countries. Due to adoption of technologies such as irrigation, the bean has been cultivated at different times throughout the year, however, the lack of cultivars adapted to the climatic conditions of the Cerrado of Tocantins has limited obtaining best yields at the time of the season. Thus, the aim of this work was to evaluate the performance of common bean genotypes in three cropping years in cerrado soils. The experiments were conducted in the field at the Experimental Station of the Federal University of Tocantins in the dry season of the years 2010, 2011 and 2012. The experimental design was a randomized block with four replications in a 8 x 3 factorial, consisting of eight genotypes and three years. The evaluated characteristics were plant height, the first pod height, number of pods per plant, number of seeds per pod, weight of hundred grains and grain yield. The Princesa genotype stood out with yields above 3,000 kg ha -1 in more than a year of cultivation, demonstrating its potential for cropping systems in the State of Tocantins. The genotype BRS-Esplendor was the only genotype that showed stable behavior for all traits.

Development of Safflower Subjected to Nitrogen Rates in Cerrado Soil

In a context in which the nitrogen fertilizer recommendations in the literature for safflower crop show up conflicting, it was aimed by the present study to evaluate the development of safflower when subjected to nitrogen rates in an Oxisol collected under Cerrado vegetation. The experiment was conducted in a greenhouse using pots filled with Oxisol collected in area under Cerrado vegetation in the layer from 0.0 to 0.20 m. Each experimental unit was represented by a plastic pot of 5 dm-3, the experimental design was completely randomized, consisting of six nitrogen rates (0, 60, 120, 180, 240 and 300 mg&degdm-3) and six repetitions. It were assessed plant height, number of leaves, chlorophyll content, number of heads, dry mass of shoot and dry mass of root. The results were submitted to variance analysis and, when significant, to regression analysis, both at 5% probability by SISVAR program. Nitrogen rates positively influence the development of safflower, and the one that best promotes this development is between 160 and 190 mg&degdm-3.

Soil Water Availability on Growth and Development of Safflower Plants

Safflower (Carthamus tinctorius L.) is a promising culture to be widespread in Brazil. However, the lack of basic knowledge about cultivation techniques, such as water demand by the culture, is still obstacle to the expansion of safflower in that country. The objective was, then, to evaluate the effect of the soil water availability on growth and development of safflower in the Cerrado soil of Mato Grosso, Brazil. The experiment was conducted in a greenhouse, in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity in the soil) and four replications. Maintenance soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were: plant height, stem diameter, number of leaves, number of heads, heads diameter, dry mass of shoots, heads, and roots. The results were submitted to analysis of variance and regression test at 5% probability by SISVAR program. All variables set to the quadratic regression model, showing the best results in the water availability between 64% and 76%. Safflower is shown to be more sensitive to water stress with increased tolerance to water deficit in the soil than to flooding.

Soil changes under different land-uses in the Cerrado of Mato Grosso, Brazil

This study aimed to (1) examine the effects of land-use change on the soils of natural Cerrado transformed to common croplands (soybean/cotton/maize rotation and sugarcane) and pasture and (2) indicate how agricultural production affects water quality across a meso-scale catchment. Land conversion caused significant reduction in infiltration rates near the soil surface (0–40cm depth) of pasture (−96%) and croplands (−90% to −93%). Soil aggregate stability was significantly lower in croplands than in Cerrado and pasture. Topsoil pH and nutrient concentrations were high in croplands and pasture. Soybean crops had extremely high extractable P concentrations (80mg·kg−1; 9 times greater than the natural background), whereas pasture N levels declined. Nutrient accumulation of N and P did not occur at deeper horizons for any land-use type. Snapshot water sampling showed strong seasonality in water quality parameters. Higher temperature, oxi-reduction potential (ORP), NO2−, and very low oxygen concentrations (<5mg·l−1) and saturation (<60%) were recorded during the rainy season. In contrast, remarkably high (up to 0.8mg·l−1) PO43− concentrations were measured during summer. Water quality parameters were affected by agricultural activities at all sampled sub-catchments across the meso-scale catchment, regardless of stream characteristics (stream order, percentage of riparian vegetation, sub-catchment size); thus, no spatial trends were observed. Direct NO3− leaching appeared to play a minor role; however, water quality is affected by agricultural non-point sources, due to topsoil fertiliser inputs affecting the entire catchment, from small low order streams to the larger rivers of the modified catchment. In conclusion, land-use conversion has degraded soil physical properties, leaving cropland soils more susceptible to surface erosion with potential lateral nutrient transport to the stream network.

Decomposição e liberação de macronutrientes da palhada de milho e braquiária, sob integração lavoura-pecuária no cerrado baiano

O conhecimento da dinâmica de decomposição e liberação de nutrientes em sistemas de produção é de grande importância para o manejo da fertilidade do solo e para a economia de recursos. Dessa forma, foi conduzido um experimento em solo de Cerrado do oeste baiano com o objetivo de estudar a decomposição e liberação de macronutrientes da palhada de milho mais Brachiaria ruziziensis , sob sistema de integração lavoura-pecuária (ILP). As avaliações foram realizadas por meio de litterbags coletadas aos 0, 15, 40, 110, 170 e 220 dias após a dessecação da palhada, que ocorreu em outubro de 2008. A matéria seca total inicial foi de aproximadamente 6,6 Mg ha-1, com meia-vida de 115 dias. A liberação de nutrientes desse volume de palhada, com o respectivo percentual em relação à quantidade total de nutrientes acumulada na planta, até o final das avaliações foi de 29,3 (62 %); 7,8 (80 %); 42,2 (94 %); 48,6 (74 %); 17,0 (81 %); e 7,7 (79 %) kg ha-1 de N, P, K, Ca, Mg e S, respectivamente. Esses resultados auxiliam o manejo da adubação das culturas e se traduz em economia de recursos. Como exemplo e transformando-se as quantidades de nutrientes liberadas até os 110 dias, período de certa coincidência com o florescimento da cultura sucessora principal, pelos três principais macronutrientes (N, P e K) em quantidade de adubos, ter-se-ia uma economia de R$ 243,00 ha-1.

Spatial heterogeneity of soils of the Cerrado-Pantanal ecotone

In areas of the Cerrado-Pantanal ecotone in Brazil, the soil displays features which are inherent to the processes of soil formation, both of the Central Plateau and the Pantanal Plain. Given this premise, the area should be noteworthy for its high level of edaphic heterogeneity. The present study aimed to determine the physical, chemical and physico-hydric attributes that best explain the heterogeneity of soils in areas of the Cerrado-Pantanal ecotone, and to assess whether these attributes differ between the studied fragments and between the Cerrado soils of the Central Plateau and of the Pantanal Plain. One hundred and sixty soil samples were collected and 11 profiles described for five areas of the Cerrado-Pantanal ecotone (15o43' S, 56o04' W). The following classes were identified: typic Concretionary Petric Plinthosol; typic Lithoplintic Petric Plinthosol; typic dystrophic Yellow Latosol; dystrophic Yellow Latosol with plinthite, the last three not yet having been described for this region. The chemical attributes CEC, M, OM, K, P, Mg, Ca and Mn explained 40.49% of the variability of the soils in the region under study, whether differing or not between the studied fragments. Spatial distribution of the attributes varied between random and aggregated, with the chemical attributes CEC, K, Ca and Mg being similar to soils of the Pantanal Plain. Whereas Al, P and Mn, as well as the hydric variables, were similar to the Plateau. On the other hand, the average organic matter content, pH, gravel and pebbles, were characteristic of both the Plateau and the Plain.

Structure of the fungal community in the agricultural system in upland and native area Cerrado

The Cerrado is the second largest biome in the country by area, located mainly in the central highlands of Brazil. Few details about the effect of managements in Cerrado soils that characterize the specific function of this soil biota in sustainable development of their fertility. Even with the lack of information on species of soil fungi in the Cerrado, there are few studies aimed to contribute to the knowledge related to fungi in this biome. The aim of this study was to evaluate the effect of agriculture tecnificada in fungal community structure of soil, using independent techniques of cultivation, as well as compare the structural similarity of the fungal community present in an agricultural soil and an area of native Cerrado. The 20 soil samples were collected in an area of high land (municipality of Paraiso - TO), at the beginning of planting (dec/2012) and next harvest of soybean (feb/2013). For DNA extraction, we used the Kit Power Soil DNA Extraction™(MoBio Laboratories, Carlsbad, CA). Reactions PCR/ARISA were prepared to a final volume of 25 μL according Sequerra at al. 1997. The ARISA technique was made into a sequencer ABI PRISM 3100 Genetic Analyzer (Applied Biosystems). To check the electropherograms was used PeakScanner program version 1.0 (Applied Biosystems, Foster City, CA). The quantification using the NanoDrop ® 2000 Thermo Scientific, showed that extraction was successful and the DNA's were in good quality. In a visual analysis of the electropherograms, we observed a clear difference in the structure of the fungal community in the agricultural environment and the native area. It is possible to note the presence of peaks that appear in the electropherogram of an environment and that are not present in the other, reflecting AFL's unique in environment. In the analysis of the wealth of AFL's, fungal community showed greater wealth in the native environment, this area also showed the highest number of AFL's unique. The ANOSIM analysis showed that, in general, the fungal community is differed from the agricultural and native environment in both samplings. Thus, this environments studied are characterized by an electropherogram, showing the potential of the ARISA technique to discriminate community structure soil fungi. The observed divergences in fungal community structure reflect differences in the environments evaluated, often due to the physico-chemical differences of each soil.