Effects of wildfire and laboratory heating on soil aggregate stability of pine forests in Galicia: The role of lithology, soil organic matter content and water repellency

CATENA ◽  
2010 ◽  
Vol 83 (2-3) ◽  
pp. 127-134 ◽  
Author(s):  
M.E. Varela ◽  
E. Benito ◽  
J.J. Keizer
Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Radka Kodešová ◽  
Marcela Rohošková ◽  
Anna Žigová

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.


Jurnal Solum ◽  
2012 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Yulnafatmawita Yulnafatmawita ◽  
Asmar Asmar ◽  
Vitria Purnamasari

There is no much public concern about soil aggregate stability improvement of a soil.  This is due to the fact that it does not directly affect crop yield for a short term, but it determines sustainable agriculture and development for a long term.  This research was aimed to investigate soil physical properties especially soil aggregate stability of Ultisols after fresh OM application, then to determine the exact OM dosage to improve the stability.  Ultisols used was from Limau Manis (± 367 m asl), an area in lower footslope of Mount Gadut, having wet tropical rainforest. Due to land use change, farming activities in that sloping area could enhance erosion process in the environment.  Therefore, efforts to anticipate the erosion must be found.  Fresh OM applied was Gliricidia sepium which was found plenty in the area.  Five levels of fresh Gliricidia sepium, were 0, 5, 10, 15, and 20 t/ha.  Top soil (0-20 cm depth) was mixed with OM, then incubated for 3 months in glasshouse.  The results after a 3-month incubation showed that SOM content did not statistically increase, but it improved based on the criteria, from very low to low level as OM was applied for ≥ 10 t/ha. It seemed that 10 t/ha Gliricidia sepium was the best dosage at this condition. There was a positive correlation between SOM content and aggregate stability index of Ultisols after fresh Gliricidia sepium addition.Keywords: Ultisols, soil aggregate stability, soil organic matter content


Soil Research ◽  
1989 ◽  
Vol 27 (2) ◽  
pp. 411 ◽  
Author(s):  
M Muneer ◽  
JM Oades

Serial additions of glucose after drying-wetting cycles led to substantial aggregation of the surface soil from a red-brown earth. Addition of glucose and Ca compounds resulted in up to 80% of the soil bound in particles >2000�m with only a small portion of the soil in particles 4 0 �m. Treatment of the soils with Na4P2O7 caused dispersion of most of the clay but did not disrupt larger aggregates. More disaggregation was caused by treatments with HCI (0.02 M and 0.1 M), indicating the presence of pyrophosphate-resistant binding mechanisms which were presumed to be due to Ca bridging. Addition of Ca to the soil reduced the efficiency of extraction of organic materials by NaOH. This effect was eliminated by a pretreatment with 1 M HCl, indicating a 'bridging' effect of Ca between polycarboxylic macromolecules (humic acids) and clays. The role of Ca in clay and organic matter flocculation, the bridging of clay aggregates to organic materials and interactions of these colloidal aggregates with the biologic cycle is illustrated in some pictorial models.


2012 ◽  
Vol 46 (3) ◽  
pp. 1504-1510 ◽  
Author(s):  
Malin Gustavsson ◽  
Susanne Karlsson ◽  
Gunilla Öberg ◽  
Per Sandén ◽  
Teresia Svensson ◽  
...  

1989 ◽  
Vol 69 (3) ◽  
pp. 489-500 ◽  
Author(s):  
A. N. WEILL ◽  
E. MCKYES ◽  
C. R. DE KIMPE

This study was undertaken to determine the effect of tillage and fertilizer on soil structure in fields under corn production in Quebec. Three types of tillage (moldboard, chisel and zero-till) and two types of fertilizer (manure and inorganic fertilizer) were applied yearly for 6 yr on a clay and a sandy loam soil. Macroaggregation was obtained after dry and wet sieving and microaggregation after sonification. Soil geometric mean diameter and aggregate stability were increased after manure applications and still further by zero-till. The amount of aggregates in each size fraction was affected differently by the fertilizer and tillage treatments. The fraction of organic matter binding the < 250-μm units into > 250-μm units played a greater role in soil aggregation than total soil organic matter content. Key words: Aggregation, manure, organic matter, soil pH, reduced tillage


2020 ◽  
Vol 117 (3) ◽  
pp. 351-365
Author(s):  
J. Pijlman ◽  
G. Holshof ◽  
W. van den Berg ◽  
G. H. Ros ◽  
J. W. Erisman ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document