Efeito da aplicação de biocarvão, cama de frango e formulado npk no estado nutricional de laranjeira em terra mulata

Growing in orange on Terra Mulata has been submitted nutrient limitation requiring correction in agricultural areas. The application of biochar associated with another source of nutrients can be a viable alternative to increase the efficiency of fertilizers and reduce losses in the areas. The objective of this study was to evaluate the effect of biochar, poultry litter and NPK in the nutritional status of orange trees grown in an Oxisol with anthropogenic A horizon (Terra Mulata). The study was conducted in a rural property landfall in Manacapuru (AM) in a randomized block design with eight treatments using biochar, poultry litter and NPK (4-14-8) applied in isolation and associates. To review two samples were taken at different periods of sheets to determine the nutritional status. Fertilizers applied did not increase the efficiency in the availability of contents of N, P, Fe and Zn, being the latter below the range of suitable content. As for the K, compost chicken manure and their combinations increased their availability, and the highest levels of Mg were found in the control treatment. © 2015, Universidade Federal de Uberlandia. All rights reserved

Uso da Espectroscopia Raman e FT-IR na caracterização do biocarvão em Latossolo Amarelo da Amazônia Central

The Amazonian Latosols are acidic soils shows low activity in clay minerals. However, it is also found anthropogenic soils known as Amazonian Dark Earth (EAD) that provides a potential to develop a sustainable system in agriculture. The majority of TPI soils show fragments of black carbon stemming from an anthropic activity. The presence of these fragments endows the improvements in the physic and chemical characteristics of the soil. In order to reproduce some characteristics of these anthropogenic soils, it is proposed to apply biochar (BC) in a dystrophic Yellow Oxisol in increasing doses from 0; 40; 80 and 120 t.ha-1. The use of Spectroscopy FT-IR and Raman tools and technics can elucidate on the nature of the pyrolised biomass and likewise interfere on the fertility of the soil. Furthermore, it could clarify how the BC contributes to the increase of cation exchange capacity (CEC), the elucidation of its chemical characteristics and how it can act in the development of a sustainable agriculture model for the humid tropics. It was possible to observe that he FT-IR spectra were similar between the treatments and that the BC exhibits similar crystallinity to the carbons of Amazonian Dark Earth

Estudo da dinamica de nutrients em solos de varzea da Ilha do Careiro no estado do Amazonas

In contrast to the upland "terra firme' terrain, the floodplain varzea in the Amazon is the zone that is used for supporting rational agriculture without use of fertilizers. Following the dynamics of the main soil nutrients, two distinct floodplain environments were selected, namely high and low varzea. Soil samples were collected throughout the whole year of 1987. No significant differences were found in the concentrations of the main nutrients for samples taken during different periods. However, the concentrations of Ca, Mg, Na, Al, H, Cu, Zn, and Mn in the low varzea were always higher than in the high varzea. This could be a result of the deposition effect during former flood periods, because the low varzea is exposed more to seasonal flooding. The study of the main nutrients analysed in the varzea floodplain soils shows a high natural fertility. -English summar

Weed dynamics on Amazonian Dark Earth and adjacent soils of Brazil

Field trials were conducted on Amazonian Dark Earth soils in the Manaus region, Amazonas, Brazil to assess the composition and impact of weedy vegetation on maize yield. Soil fertility among the Dark Earth varied considerably with differences largely attributable to past-use history. Consequently, maize yield and weed pressure varied among field locations, reflecting these differences in soil fertility in addition to differences in weed reservoirs such as seedbanks. Maize yield in weeded plots was as much as 63 times greater on Dark Earth (0.55 t ha-1) than on corresponding adjacent soil (0 t ha-1), and location averages varied from 0 to 3.15 t ha-1 for Dark Earth. The percentage ground cover of weeds in weedy plots was up to 45 times greater on Dark Earth (65-99%) than on corresponding adjacent soil (2-89%), and species richness was up to 11 times greater on Dark Earth (4-14 species) than corresponding adjacent soil (1-8 species). The relative proportion of annual and leguminous weeds was 32 and 17% greater, respectively, on Dark Earth than adjacent soil, and vegetative sprouting of plants was more common on sites that had been used less intensively in the past. In general, a similar weed community was observed on the different Dark Earth sites, including many species typically associated with environments that have been highly disturbed by human activities, such as Cyperus spp., Phyllantus niuri, and Croton lobatus. Seedlings from a greater number of species emerged from forested Dark Earth seedbanks (2.1 per flat) than from forested adjacent soil (1.2 per flat). The total number of emerged seedlings was greater for Dark Earth seedbanks (9.1 per flat, 1,365 m-2) than adjacent soil (2.2 per flat, 330 m-2), however the species observed were not likely to be problematic for cropping. © 2005 Elsevier B.V. All rights reserved

Pedology, fertility, and biology of central amazonian dark earths

A great challenge for the world's scientific community has been to find alternatives for the best use, management and conservation of the Amazonian tropical rainforest. The unbalance between increasing populations and the demand for food shows the urgency for looking for new alternatives that region, avoiding excessive degradation of natural ecosystems. In this respect, scientists in all countries in the tropics are working to understand the functioning of the rainforest and come up with alternatives to use and manage this natural resource, applying the best technology not only from an economic perspective, but principally from social and ecological perspectives. The replacement of the nutrients exported by crops is normally solved by inputs of chemical and organic fertilizers, in proportions that can vary with natural soil fertility and the nature and volume of the crops. Hence, problems like erosion, leaching, and compactation can only be solved by conservation practices utilized by farmers that change as function of land topography, precipitation, crop type, cover crop, or farming land use system, depending on the technology level of the community. Small farmers living in Manacapuru, Iranduba, Presidente Figueiredo, and Rio Preto da Eva, in Amazonas, Brazil, work on Amazonian Dark Earth (ADE) sites, cultivating vegetables and perennial crops like oranges, coconuts, cupuaçu, and others. Their land use systems include monocultures, two species mixes, and agrofor-estry systems. In general, the small farmers report that ADE is very fertile and they never need to apply chemical and organic fertilizers to get high productivity. On the other hand, studies have shown that ADE presents some nutrient limitations to plant production. Some small farmers are using large amounts of chemical and organic fertilizers and even liming unnecessarily. This intensive exploitation and the excessive use of nutrients is causing chemical degradation (Falcão et al. 2003) and even physical degradation of ADE (Teixeira and Martins 2003). © Springer Science + Business Media B.V. 2009

Root isotropy and an evaluation of a method for measuring root distribution in soil trenches

The measurement of root length density (LV) with soil depth is tedious and laborious. Yet the information is necessary in order to model root nutrient uptake. Measuring the number of roots exiting the face of a soil trench is less laborious and has previously been shown to be five times faster than the soil core-break method. Based on geometric theory, the theoretical relationship between the number of roots exiting the face of a three-dimensional block of soil (N) is related to LV by the equation LV = 2N, if roots are isotropic and the soil volume is small. The coefficient of 2 presumes roots to be randomly oriented in three-dimensional space (i.e. no preference for vertical or horizontal orientation). The equation is appropriate to anisotropic root distributions, if root density is evaluated in three mutually perpendicular planes. In the case of non-random or preferential root orientation, the coefficient will be different than 2. If roots are anisotropic, the equation becomes LV = 2NAVG, where NAVG is the mean of the N values measured on the faces of a soil block in all three-dimensions. The purpose of this study was to test this relationship with roots of Melaleuca quinquenervia growing on a sandy Spodosol, Florida and Bactris gasipaes (peach palm) growing on a clayey Oxisol in Amazonas, Brazil, and to evaluate a simple sampling method using soil trenches that would estimate LV with soil depth. Roots of Melaleuca were anisotropic with 50% fewer roots exiting the basal face compared to the lateral faces. Roots of peach palm were isotropic. The relationship of LV with N and NAVG does not fit the theoretical coefficient of 2, suggesting that the most likely problem was either that the method was not accounting for small roots exiting the soil volume or that the method was using a soil volume greater than required to fit the theoretical relationship. If the first explanation is correct, then the field method overlooked 66-74% of the Melaleuca roots and 36-82% of the peach palm roots exiting the face of a soil block. Correlations between N and LV showed that N explained between 80 and 87% of the variability in LV, indicating that this can be a useful method to predict LV distributions with depth. © 2002 Elsevier Science B.V. All rights reserved

Response to fertilization and nutrient deficiency diagnostics in peach palm in Central Amazonia

Peach palm (Bactris gasipaes Kunth) is increasingly grown in the tropics for its heart-of-palm and fruit. Determining fertilization response and diagnosing nutrient status in peach palm may require methods that consider the particularities in nutrient acquisition and recycling of perennial crops. Responses to nutrient additions, and the diagnostic value of soil and foliar analyses were examined in three field experiments with three-year old peach palm stands on Oxisols in Central Amazonia. To diagnose P-deficiency levels in soils, samples from 0-5 cm and 5-20 cm depth were analyzed for available P by different methods (Mehlich-1, Mehlich-3 and Modified Olsen). The second and fifth leaves were analyzed to assess N, P and K deficiencies. Field experiments involved several combinations of N (from 0 to 225 kg ha-1 yr-1), K (from 0 to 225 kg ha-1 yr-1) and P (from 0 to 59 kg ha-1 yr-1). Palms on control plots (unfertilized) and those receiving 225 kg ha-1 yr-1 N and 2 Mg ha-1 of lime yielded between 4 and 19% of the maximum growth which was obtained with N, P and K applications. In one of the experiments, yield of heart-of-palm was positively related to N additions at the lowest levels of P (8.6 kg ha-1 yr-1) and K (60 kg ha-1 yr-1) additions. In one experiment, critical leaf N level was 2.5% for the second leaf and 2.2% for the fifth leaf. Some growth responses to P additions at constant N and K levels were observed (e.g., 797 kg ha-1 yr-1 of heart-of-palm with 39.3 kg ha-1 yr-1 of applied P, and 632 kg ha-1 yr-1 of heart-of-palm with 10.9 kg ha-1 yr-1 of applied P in one experiment, and 2334 kg ha-1 yr-1 of heart-of-palm with 39.3 kg ha-1 yr-1 of P and 1257 kg ha-1 yr-1 of heart-of-palm with 19.7 kg ha-1 yr-1 of P in another trial). In the experiment for fruit production from peach palm, total plant height did not respond to P additions between 19.7 and 59 kg ha-1 yr-1 and K additions between 75 and 225 kg ha-1 yr-1. Leaf P levels were found to be above the proposed critical levels of 0.23% for the third leaf and 0.16% for the fifth leaf. Plants in this experiment, however, showed evident symptoms of Mg deficiency, which was associated with a steep gradient of increasing Mg concentration from the fifth leaf to the second leaf. Standard leaf diagnostic methods in most cases proved less useful to show plant N and P status and growth responses to N and P additions. Soil P determined by common extractions was in general too variable for prediction of growth

Nanoscale mapping of carbon oxidation in pyrogenic black carbon from ancient Amazonian anthrosols

Understanding soil organic matter is necessary for the development of soil amendments, which are important for sustaining agriculture in humid tropical climates. Ancient Amazonian anthrosols are uniquely high in black recalcitrant carbon, making them extremely fertile. In this study, we use high-resolution electron microscopy and spectroscopy to resolve the oxidation process of carbon in the nanoscale crystallites within the black carbon grains of this special soil. Most alkali and acid chemical extraction methods are known to cause chemical modifications in soil organic matter and to give poor or no information about the real spatial structure of soil aggregates. However, here we show that carbon-oxygen functional groups such as phenol, carbonyl, and carboxyl dominate over different spatial regions, with areas varying from over tens to hundreds of nm2. The chemical maps show that in the nanoscale grain, the surface has a tendency to be less aromatic than the grain core, where higher oxidative-degradation levels are indicated by the presence of carbonyl and carboxyl groups. A deep understanding of these structures could allow artificial reproduction of these natural events. © 2015 The Royal Society of Chemistry

Chemical analysis and molecular models for calcium-oxygen-carbon interactions in black carbon found in fertile amazonian anthrosoils

Carbon particles containing mineral matter promote soil fertility, helping it to overcome the rather unfavorable climate conditions of the humid tropics. Intriguing examples are the Amazonian Dark Earths, anthropogenic soils also known as "Terra Preta de Índio (TPI), in which chemical recalcitrance and stable carbon with millenary mean residence times have been observed. Recently, the presence of calcium and oxygen within TPI-carbon nanoparticles at the nano- and mesoscale ranges has been demonstrated. In this work, we combine density functional theory calculations, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transformed infrared spectroscopy, and high resolution X-ray photoelectron spectroscopy of TPI-carbons to elucidate the chemical arrangements of calcium-oxygen-carbon groups at the molecular level in TPI. The molecular models are based on graphene oxide nanostructures in which calcium cations are strongly adsorbed at the oxide sites. The application of material science techniques to the field of soil science facilitates a new level of understanding, providing insights into the structure and functionality of recalcitrant carbon in soil and its implications for food production and climate change. © 2014 American Chemical Society

Properties of carbon particles in archeological and natural Amazon rainforest soils

Driving practices of Amazon native inhabitants are an example of positive feedback in carbon storage acting as a key element in soil fertility and stability. The anthropogenic Amazonian Terra Preta do Índio (Indian Dark Earth) soils are rich in pyrogenic black carbon and the Rio Negro (Black River) also exhibits plentiful apparently similar black-carbon particles. In this context, we characterized the structural, morphological and elemental properties of the long-lived stable carbon-based structures present in sediments of the Amazonian Rio Negro and in two Terra Preta do Índio soils from two different geographic regions. Optical microscopy, Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques are utilized. The structural analysis displayed that these carbon structures exhibit similar nanocrystallite structures, despite their different geographic location and environment. The Terra Preta do Índio-carbons are however, more defective and the quantitative elemental analyzes indicate they have greater variety of nutrients, such as P and Ca, than Rio Negro sediment-carbons. © 2020 Elsevier B.V