نتایج جستجو برای: tropical soils
تعداد نتایج: 115202 فیلتر نتایج به سال:
In many parts of the world food security is at risk. One of the biophysical root causes of falling per-capita food production is the declining quality and quantity of soils. To reverse this trend and increase soil fertility soil and plant nutrients have to be replenished. This review provides a literature survey of experiences of using multi-nutrient rock fertilizers for soil fertility enhancem...
Six non-fermentative bacteria were isolated from Colombian (South America) and Hawaiian (USA) soils after enrichment with minimal medium supplemented with two herbicides, hexazinone (Hex) and tebuthiuron (Teb). Microscopic examination and physiological tests were followed by partial 16S DNA sequence analysis, using the first 527 bp of the 16S rRNA gene for bacterial identification. The isolated...
The oxidation of ammonium is a key step in the nitrogen cycle, regulating the production of nitrate, nitrous oxide and dinitrogen. In marine and freshwater ecosystems, anaerobic ammonium oxidation coupled to nitrite reduction, termed anammox, accounts for up to 67% of dinitrogen production1–3. Dinitrogen production through anaerobic ammonium oxidation has not been observed in terrestrial ecosys...
Chemical and meteorological parameters measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the African Monsoon Multidisciplinary Analysis (AMMA) campaign are presented to show the impact of NOx emissions from recently wetted soils in West Africa. NO emissions from soils have been previously observed in many geographical areas ...
The tropical forests of the Amazon Basin occur on a wide variety of different soil types reflecting a rich diversity of geologic origins and geomorphic processes. We here review the existing literature about the main soil groups of Amazonia, describing their genesis, geographical patterns and principal chemical, physical and morphologic characteristics. Original data is also presented, with pro...
We measured nitrogen transformations and loss following forest clearing in a relatively fertile tropical forest site. Nitrogen mineralization, nitrification, and amounts of ammonium and nitrate increased substantially in surface soils during the 6 mo following burning, then returned to background levels. The nitrogen content of microbial biomass declined to half its original value 6 mo after cl...
The existence of an anthropogenic and carbon (C) enriched dark soil in different parts of the world and especially in Amazonia (Amazonian Dark Earths (ADE) or Terra Preta de Índio) proves that the predominant Ferralsols and Acrisols can be transformed into fertile soils. Charcoal formation and deposition in soils seems to be a promising option to transfer an easily decomposable biomass into ref...
A total of 2152 Actinobacteria strains were isolated from native Cerrado (Brazilian Savannah) soils located in Passos, Luminárias, and Arcos municipalities (Minas Gerais State, Brazil). The soils were characterised for chemical and microbiological analysis. The microbial analysis led to the identification of nine genera (Streptomyces, Arthrobacter, Rhodococcus, Amycolatopsis, Microbacterium, Fr...
Distribution of Dermatophytes from Soils of Urban and Rural Areas of Cities of Paraiba State, Brazil
The dermatophytes, keratinophilic fungi, represent important microorganisms of the soil microbiota, where there are cosmopolitan species and others with restricted geographic distribution. The aim of this study was to broaden the knowledge about the presence of dermatophytes in soils of urban (empty lots, schools, slums, squares, beaches and homes) and rural areas and about the evolution of the...
[1] Understanding factors that control methane exchange between soils and the atmosphere remains one of the highest priorities for climate change research. Here we use a novel isotope-based technique to investigate the relative importance of three mechanisms for explaining landscape-scale variations in soil methane emissions: (1) consumption of methane by methanotrophic bacteria, (2) quantity o...
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