PubMed | National University of Costa Rica, James Cook University, Herbario Universitario, Gabriel René Moreno Autonomous University and 42 more.
Type: Journal Article | Journal: Nature | Year: 2015
Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
Viegas I.J.M.,UFRA |
Rodrigues Galvao J.,Instituo de Ciencias Agrarias UFRA |
Da Silva Jr. M.L.,Instituo de Ciencias Agrarias UFRA |
Carvalho Melo N.,São Paulo State University |
De Oliveira M.S.,Secretaria de Meio Ambiente SEMA
Revista Caatinga | Year: 2014
The objective was to evaluate the effect of the omission of macronutrient and micronutrient boron in dry matter production, the characterization of the symptoms of nutritional deficiencies and mineral composition in plants of ipeca, an experiment was conducted in greenhouse conditions by the technique the missing element and visual diagnosis. A randomized block experimental design with four repetitions and the treatments were: complete and omissions of N, P, K, Ca, Mg, S and B. The analytical results demonstrated that the production of dry matter was affected in all of the treatments with omission of nutrients and that the ipeca plants presented characteristic symptoms of nutritional deficiencies due to the omissions of N, P, K, Ca, Mg, S and B and the concentrations of the macronutrients and of the micronutrient boron in the different parts of the ipeca plant varied when a certain nutrient was omitted in the solution.
da Costa C.F.G.,Embrapa Amazonia Oriental |
Figueiredo R.O.,Embrapa Meio Ambiente |
Oliveira F.A.,UFRA |
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2013
In the watershed of the Timboteua and Buiuna streams in the State of Pará, the effect of land use change and soil management on the runoff rates was evaluated. Eighteen experimental plots (1 m2) were established, three in each one of the six evaluated agroecosystems as follows: i) 20 years Secondary vegetation ("Capoeira") (CP), ii) Agroforestry system / slash-and-burn (SQ), iii) Agroforestry system / chop-and-mulch (ST), iv) Cassava crop / chop-and-mulch (RT), v) Cassava crop / slash-and-burn (RQ), vi) Cattle pasture / slash-and-burn (PQ). Nearby these plots two rain gauges and three rainwater collectors for monitoring of precipitation were also installed. Along 2010 rainy season 234 samples were collected on 26 different dates. A strong correlation was found between precipitation and runoff, being the highest value of 54.53% of total volume of superficial flow for Cattle pasture degraded and lowest of 1.11% for Agroforestry system that was under recovery for 7 years after burning. The runoff decreased in agroecosystems with lower percentage of organic material in relation to systems with higher percentage.
Souza R.O.R.M.,UFRA |
Scaramussa P.H.M.,UFRA |
do Amaral M.A.C.M.,University of Sao Paulo |
Pereira Neto J.A.,UFRA |
And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012
The intense rainfall equations have been used as an important tool for design of hydraulic structures. Considering the lack of intense rainfall equations, this study aimed to determine the relations of intensity, duration and frequency of intense rainfall in the Pará State (Brazil), using the one-day rain disaggregation method. In this research rainfall data of 74 cities in the State of Pará were used, obtained from the Hydrological Information System of the National Water Agency-ANA. The equations of intensity-durationfrequency were adjusted and presented good adjustment with coefficients of determination above 0.99. Most stations (51.4%) showed intensity of precipitation between 90 and 110 mm h -1 for duration of 30 min and rainfall return period of 15 years. The highest rainfall intensities were in the region near the northeast coast of Pará State and southeast of the Marajo Island.
Fujiyama B.S.,UFRA |
De Moraes Tavares M.,IFPA
65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010 | Year: 2010
Four samples were collected from four soil profiles located in the Rural Federal University of Amazonia. These, were analyzed parameters such as color, texture, consistency, granulometry, porosity and water absorption. We identified the following soil types: Distrofic Yellow Latosoil; Lateritic Concretionary; distrofic Low Humic Gley. The work was to continue the qualitative analysis by X-rays diffraction, identifying the mineralogical composition of each sample. Explaining the mineralogical conditions that affect or benefit the environment.
Rodrigues J.C.,UFRA |
De Souza P.J.O.P.,Instituto Socio Ambiental e dos Recursos Hidricos ISARH |
De Lima R.T.,UFRA
Revista Brasileira de Fruticultura | Year: 2013
The objective of this study was to estimate the threshold temperatures and the thermal requirement of mango, in the northeast of the state of Para. One experiment was carried out in a mango orchard of 25 hectare during the 2010/2011 and 2011/2012 season in which the phenological and meteorological conditions were daily monitored from flowering to harvest. Both mango seasons were submitted to different meteorological conditions, and therefore, both the duration of the reproductive stage and the mean thermal requirement were significantly different. The thresholds temperatures (lower and higher) of the mango were 13 °C and 32 °C, respectively, the thermal requirement found for the mango orchard reach to the harvest stage was 1,024.23 °C day-1 and 1,157.99 °C day-1, and the mean duration of the mango season was 110 and 112 days.
da Silva R.T.L.,Federal University of Santa Maria |
Andrade D.P.,Federal Rural University of Pernambuco |
Melo E.C.,Campus de Capitao Poco |
Palheta E.C.V.,Federal University of Pará |
Revista Caatinga | Year: 2011
The cowpea is a leguminous of great importance for human consumption, providing a source of protein for most of urban population of northern Brazil, therefore the aim of this paper was to evaluate the efficiency of strains of Bradyrhizobium out in association with phosphate and potassium fertilization (PK) in cowpea at the field level in the municipality of Capitão Poço - PA. Two experiments were carried out in randomized blocks with four replications, consisting of five treatments, being two strains of Bradyrhizobium - BR 3262 and BR 3267, a treatment only with PK, another one with NPK in the formulation (10-28-20) and a control. It was evaluated the grain yield, the number of pods and weight of 100 seeds. Fertilization with phosphorus and potassium represented a significant increase in the yield of cowpea, however inoculation with both strains did not increase production.
Silva J.A.R.D.,Federal Rural University of Amazonia |
Araujo A.A.D.,State University of Ceará |
Junior J.D.B.L.,Pará State University |
Santos N.D.F.A.D.,UFRA |
And 2 more authors.
Pesquisa Agropecuaria Brasileira | Year: 2011
The objective of this work was to evaluate the effects of a silvipasture system on the thermal comfort of 20 female buffaloes, from which 10 raised in under nonshaded paddocks (SS) and 10 in paddocks shaded by Racosperma mangium (CS), in Belém county, PA, Brazil. All animals were fed in pastures with Urochloa humidicola, and had free access to drinking water and mineral salt. Every three days, measurements were made for air temperature (TA), relative humidity (UR), black globe temperature (TGN), rectal temperature (TR), respiratory rate (FR), heart rate (FC), and body surface temperature (TSC), in the morning (7 AM) and in the afternoon (1 PM). The values of TR, TSC, RR and FR, mainly for the SS group, were higher in the afternoon. The TR, TSC and FR showed a significant and positive correlation with TA and the temperature and humidity index (ITGU), and a negative correlation with UR. These correlations were higher for the less rainy period. The FR showed significant and positive correlations with TA and ITGU, during both the most and the less rainy seasons, and negative correlations with UR only in the rainy season. The forestation of pasture areas is efficient to increase the thermal comfort for Murrah females, especially in the afternoon.
de Lima R.T.,UFRA |
de Souza P.J.O.P.,Instituto Socio Ambiental e dos Recursos Hidricos |
Rodrigues J.C.,UFRA |
de Lima M.J.A.,UFRA
Revista Brasileira de Fruticultura | Year: 2012
The objective was to determine the models that best describe the relationship between linear dimensions and leaf area of mango, cv. Tommy Atkins, and to establishing the correction factor. The research has been conducted at the experimental farm of Federal Rural University of Amazonia, at Cuiarana village, municipality of Salinópolis, Pará. 90-150 leaves from 11 trees were analyzed in a field experiment and it was determined the length and width of leaves. The leaf area was determined using the actual of foliar area integrator Area Meter (AM 300). The correction factor was obtained by dividing the real foliar area by foliar area calculated. Linear and nonlinear models also estimated leaf area. The mathematical models created present an excellent performance, with R2 values between 90 and 97%. The correction factor of 0.71 can be used to estimate the involving real leaf area of mango, multiplied by linear measurements. The models that used the product dimensions, as independent variables, had R2 values higher than those who used only one dimension, being the cubic model, the most accurate.
PubMed | UFRA
Type: Journal Article | Journal: Tropical animal health and production | Year: 2013
The present study evaluated the effect of replacing elephant grass (EG) with moist pineapple by-product silage (PS) on the apparent digestibility, consumption of digestible nutrients and performance of 25 castrated male lambs Santa Ines crossbreds. The lambs had an initial body weight of 20.2 3.5 kg and were housed in individual pens in a completely randomised design with five treatments (replacement of EG by PS at five proportions of 0, 25, 50, 75 and 100 %) and five replicates during 74 days. There was no significant effect of PS replacement proportions on the intake of dry matter (DM), organic matter (OM), total carbohydrates (TC), non-fibrous carbohydrates or total digestible nutrients (TDN). The consumption of crude protein (CP) decreased linearly with the inclusion of PS in the diets. The digestibility of DM, OM and TCs as well as levels of TDN increased linearly with the addition of PS. The use of PS in the diets had no significant effect on the digestibility of CP and neutral detergent fibre corrected for ashes and protein (NDFom(n)). These results demonstrated that there was no difference in the performance of animals fed diets with or without PS.