Soybean expansion impacts on soil organic matter in the eastern region of the Maranhão state (Northeastern Brazil)

2022 ◽  
Author(s):  
Marcos Siqueira‐Neto ◽  
Gustavo V. Popin ◽  
Gregori E. Ferrão ◽  
Arthur K. B. Santos ◽  
Carlos E. P. Cerri ◽  
...  
2017 ◽  
Vol 38 (2) ◽  
pp. 551 ◽  
Author(s):  
Patricia Angelo Barros ◽  
Elvira Maria Regis Pedrosa ◽  
Mércia Soares de Oliveira Cardoso ◽  
Mario Monteiro Rolim

Sugarcane plays an important socio-economic role in northeastern Brazil. However, the low yield in this region is associated with several factors (e.g. frequent occurrence of plant-parasitic nematodes). In order to observe the influence of soil organic matter on the nematodes, this study aimed to characterize the spatial nematode distribution in a sugarcane field. The study was carried out in Goiana - Pernambuco State (Brazil), fifty days after sugarcane cutting (10 days after vinasse application). The sampling scheme consisted of a regular 60 × 50-m grid, 10 m spaced, through 0 to 0.2 m depth. Spatial distribution was evaluated by semivariograms fit and performed by ordinary kriging interpolation for mapping. Exponential and spherical models promoted the best fit to semivariograms, resulting in ranges from 16 to 19 m. There was a strong negative correlation between soil organic matter and plant-parasitic nematode population density. Free-living nematodes had a similar distribution pattern as soil organic matter content. These results indicated that soil organic matter had important effects on spatial distribution of both plant-parasitic and free-living nematodes.


Soil Carbon ◽  
2014 ◽  
pp. 427-435 ◽  
Author(s):  
S. Churka Blum ◽  
S. P. de Oliveira ◽  
N. B. de Lacerda ◽  
G. V. de Alencar ◽  
M. E. Ortiz Escobar ◽  
...  

2004 ◽  
Vol 62 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Luiz Carlos Ruiz Pessenda ◽  
Adauto de Souza Ribeiro ◽  
Susy Eli Marques Gouveia ◽  
Ramon Aravena ◽  
Rene Boulet ◽  
...  

The study place is in the Barreirinhas region, Maranhão State, northeastern Brazil. A vegetation transect of 78 km was studied among four vegetation types: Restinga (coastal vegetation), Cerrado (woody savanna), Cerrad"o (dense woody savanna), and Forest, as well as three forested sites around Lagoa do Caçó, located approximately 10 km of the transect. Soil profiles in this transect were sampled for δ13C analysis, as well as buried charcoal fragments were used for 14C dating. The data interpretation indicated that approximately between 15,000 and ∽9000 14C yr B.P., arboreal vegetation prevailed in the whole transect, probably due to the presence of a humid climate. Approximately between ∽9000 and 4000–3000 14C yr B.P., there was the expansion of the savanna, probably related to the presence of drier climate. From ∽4000–3000 14C yr B.P. to the present, the results indicated an increase in the arboreal density in the area, due to the return to a more humid and probably similar climate to the present. The presence of buried charcoal fragments in several soil depths suggested the occurrence of palaeofires during the Holocene. The vegetation dynamic inferred in this study for northeastern Brazil is in agreement with the results obtained in areas of Amazon region, based on pollen analysis of lake sediments and carbon isotope analysis of soil organic matter (SOM), implying than similar climatic conditions have affected these areas during the late Pleistocene until the present.


1962 ◽  
Vol 54 (5) ◽  
pp. 470-470
Author(s):  
T. M. McCalla

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