Nitrogen Stocks in Soil Classes Under Different Land Uses in the Brazilian Semiarid Region

Author(s):  
Uemeson José dos Santos ◽  
Everardo Valadares de Sá Barretto Sampaio ◽  
Eunice Maia de Andrade ◽  
Alexandre de Siqueira Pinto ◽  
Bruno de Oliveira Dias ◽  
...  
2021 ◽  
pp. 1-12
Author(s):  
José Almir Cirilo ◽  
Alfredo Ribeiro Neto ◽  
Nyadja Menezes Rodrigues Ramos ◽  
Carla Fernanda Fortunato ◽  
Júlia Daniele Silva de Souza ◽  
...  

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Josiane Souza Santos ◽  
Nadson Ressyé Simões ◽  
Sérgio Luiz Sonoda

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.


2014 ◽  
Author(s):  
Sergio Rosim ◽  
João Ricardo de Freitas Oliveira ◽  
Jussara de Oliveira Ortiz ◽  
Miguel Zanic Cuellar ◽  
Alexandre Copertino Jardim

2021 ◽  
Vol 26 (2) ◽  
Author(s):  
Luan Pedro-Silva ◽  
Thaynara Sousa Silva ◽  
José Iranildo Miranda De Melo

2021 ◽  
Vol 7 (7) ◽  
pp. 69081-69099
Author(s):  
Tatiane Aparecida Queiroz ◽  
Francisca Patrícia Barreto De Carvalho ◽  
Alfredo Marcelo Grigio ◽  
Weslley Misael Bezerra Damasio ◽  
Lara Candice Costa de Morais Leonez ◽  
...  

Author(s):  
Diego de M. Bento ◽  
Marconi Souza-Silva ◽  
Alexandre Vasconcellos ◽  
Bruno C. Bellini ◽  
Xavier Prous ◽  
...  

Author(s):  
Laylson da Silva Borges ◽  
Geandro Carvalho Castro ◽  
João Lopes Anastácio Filho ◽  
Isak Samir de Sousa Lima ◽  
Flávio Carvalho de Aquino ◽  
...  

2019 ◽  
Vol 11 (4) ◽  
pp. 536
Author(s):  
Jucirema Ferreira da Silva ◽  
Jeane Cruz Portela ◽  
Nildo da Silva Dias ◽  
Cezar Augusto Medeiros Rebouças ◽  
Francisco Ernesto Sobrinho ◽  
...  

The ethnopedological approach to soil characterization presents great challenges, since the understanding of the systems occurs through the knowledge acquired by the man in his coexistence with agroecosystems. The aim of the present research was to characterize the agricultural soils through morphological, physical and chemical analysis, using ethnopedological studies in the ‘Santa Agostinha’ Settlement Project, Caraúbas-RN, Brazil. Five areas were defined for study in the soil/landscape relation: i) area with cashew cultivation; ii) area of pasture; iii) area of crops in consortium; iv) agroforestry; and v) preserved forest, used as the reference. Participatory workshops, exchanges and classifications (from the locals and formal) were carried out with the analysis of the morphological, physical and chemical attributes of the studied soils in the layers of 0.00-0.10, 0.10-0.20 and 0.20-0.30 m. The results of the ethicist classification, based on the attributes evaluation were: Quartzarenic latosol NEOSOL (cashew area); Regolitic euthrofic NEOSOL (pasture area); Ortic quartzarenic fragiudult NEOSOL (intercropping area); typical quartzarenic ortic NEOSOL (agroforestry area and typical hydromorphic quartzarenic NEOSOL that presented a close relation with the emicist classification (from the local people). The observation of the different soil types in the landscape, due to the stratification of the environments, allowed the growers to identify characteristics associated with soil potentials and restrictions and, consequently, the correct management to be adopted. The experiences of local growers in the participatory workshops provided an exchange of popular and scientific knowledge, as well as new perspectives of coexistence with the semiarid.


Author(s):  
Bianca M. Reges ◽  
Anielly M. Maia ◽  
Diogenes H. A. Sarmento ◽  
Mayara S. Silva ◽  
Sandra M. L. dos Santos ◽  
...  

ABSTRACT Characterization of cocoa clones produced in the semiarid region is necessary to enlarge the database about these implanted clones and thus enhance the quality of their by-products. Therefore, this study aims to evaluate physical, chemical, and physicochemical characteristics of the CCN 51, CEPEC 2004, CEPEC 2005, and PS 1319 clones, produced in the region of Vale do Jaguaribe in the state of Ceará (Brazil), and to suggest food processes or products for them. The clones were evaluated according to their physical traits (total fruit mass, rind, pulp, seeds, and placenta and pulp with seeds), fruit transverse diameter (FTD), fruit longitudinal diameter (FLD), the ratio FTD/FLD; rind external thickness (ERT), rind internal thickness (IRT), the ratio ERT/IRT, number of seeds, seed thickness, seed transverse diameter (STD), seed longitudinal diameter (SLD), and the ratio STD/SLD, yield, pulp color, chemical traits (humidity, lipids, proteins, ashes, crude fiber, and carbohydrates), and physicochemical traits (titratable acidity, pH, soluble solids, and reducing sugars) were evaluated. The CCN 51 and CEPEC 2005 clones are the most suitable for the process of cocoa fermentation. For desserts, jams, pulp, and nibs for fat-restricted diets, the most suitable clones are CCN 51, CEPEC 2005, PS 1319 and CEPEC 2004, respectively.


2015 ◽  
Vol 8 ◽  
pp. 585
Author(s):  
Ana Dolores Santiago de Freitas ◽  
Everardo Sampaio ◽  
Carolina Santos ◽  
Aleksandro Silva ◽  
Renata Carvalho

A fixação biológica de nitrogênio (FBN) é a principal forma de entrada de N em ecossistemas naturais e em sistemas agrícolas de subsistência, como os praticados predominantemente no Semiárido brasileiro. Estimativas dos aportes de N na Caatinga e em cultivos de importância para a região ainda são escassas, em parte pela dificuldade de medir simultaneamente as proporções de N derivadas da atmosfera (%Ndda) e as produções de biomassa no mesmo sistema. Estudos pioneiros indicam que diversas espécies de leguminosas, herbáceas e arbóreas, nativas e/ou cultivadas, podem fixar elevadas proporções de seu N. Em Caatinga bem preservada, os aportes de N em leguminosas arbóreas foram estimados em 11 kg ha-1 ano-1, um valor relativamente baixo devido à baixa densidade de plantas fixadoras. Entretanto, a densidade de leguminosas fixadoras na vegetação não é o único fator definindo o aporte de N, pois há observações de ausência de FBN em áreas de Caatinga em regeneração, dominadas por espécies fixadoras. No estrato herbáceo, os aportes de N podem chegar a 6 kg ha-1 ano-1, nas áreas com menor cobertura de arbóreas. As quantidades de N fixadas nos diferentes sistemas de cultivo são pouco conhecidas. Para o feijão-caupi, a FBN pode se aproximar dos 30 kg ha-1, em cultivos consorciados com milho, chegando a 45 kg ha-1, em cultivos solteiros. Em cultivos irrigados, adubos verdes podem adicionar 185 kg ha-1, superando a quantidade exportada nas colheitas. Em sistemas agroflorestais, a adição anual de N pode chegar a 40 kg ha-1. Não existem estimativas do N fixado em gramíneas na região, mas algumas espécies apresentem potencial de FBN. Biological nitrogen fixation (BNF) is the main N input in natural ecosystems and in subsistence agricultural systems, such as those commonly practiced in the Brazilian semiarid region. Estimates of N inputs in Caatinga and the main regional crops are still scarce, partly due to the difficulty in measuring concomitantly the proportion of plant N derived from the atmosphere (%Ndfa) and the amount of biomass produced in the same system. Pioneer studies indicate that several legume species, herbs and trees, native and/or cultivated, can fix large proportions of their N. In mature Caatinga, N inputs in tree legumes were estimated at 11 kg ha-1 year-1, a relatively low value due to the low plant density of the legume species. However, plant density is not the only factor defining N input, since absence of fixation has been reported in regenerating Caatinga, even in those dominated by potentially fixing species. In the herb stratum, N input up to 6 kg ha-1 year-1 has been reported in areas with lower tree cover. Inputs in crop systems are largely unknown. Fixation in cowpea can reach 30 kg ha-1, in plants consortiated with corn, and 45 kg ha-1, in single crop. Under irrigation, green manure crops can add 185 kg ha-1 of fixed N, more than the amounts exported by the main crop. In agroforest systems, the annual input may reach 40 kg ha-1. There are no publish reports on N biologically fixed by Poaceae species growing in the semiarid region but it is known that some species have the potential to fix. Keywords: N-15 natural abundance, slash and burn agriculture, diazotrophic microorganism, rhizobia, symbiosis.   


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