Phosphatase activity in acid high organic matter soils in galicia (NW Spain)

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

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Casting Activity ofScherotheca gigasin No-Till Mediterranean Soils: Role in Organic Matter Incorporation and Influence of Aridity

Applied and Environmental Soil Science ◽

10.1155/2010/526934 ◽

2010 ◽

Vol 2010 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Paloma Bescansa ◽

Iñigo Virto ◽

Oihane Fernández-Ugalde ◽

María José Imaz ◽

Alberto Enrique

Keyword(s):

Organic Matter ◽

Agricultural Soils ◽

Nw Spain ◽

Organic C ◽

No Till ◽

Physico Chemical ◽

C Stocks ◽

Casting Activity ◽

Total Organic C

The behaviour of earthworms, their role in organic matter incorporation into the soil, and the influence of aridity in such processes in arid and semiarid regions have scarcely been studied. In this study, physico-chemical analyses of the casts and the surrounding no-till agricultural soils of three experimental sites representing an aridity gradient in Navarre (NW Spain) were done. The casts were formed by the activity of the only anecic species,Scherotheca gigas(Dugès, 1828), ubiquitous in no-till soils in this region. We observed a significant depletion of clay and higher concentration of total organic C and labile C in the form of particulate organic matter (POM) in the casts as compared to the surrounding soil, suggesting selective ingestion of soil byS. gigas. This, together with the observation of increased concentration in POM with increasing aridity, suggests a major role of this species in the observed progressive gains of organic C stocks in no-till soils in the region.

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Salt crust-assisted thermal decomposition method for direct and simultaneous quantification of polypropylene microplastics and organic contaminants in high organic matter soils

Analytica Chimica Acta ◽

10.1016/j.aca.2021.338801 ◽

2021 ◽

pp. 338801

Author(s):

Wenzhao Zhou ◽

Yi Chen ◽

Chao Deng ◽

Haiyang Qi ◽

Hui Zhang

Keyword(s):

Thermal Decomposition ◽

Organic Matter ◽

Organic Contaminants ◽

Decomposition Method ◽

Thermal Decomposition Method ◽

Simultaneous Quantification ◽

High Organic Matter ◽

Salt Crust

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On the genesis of aluminum-rich speleothems in a granite cave of NW Spain

International Journal of Speleology ◽

10.5038/1827-806x.50.1.2358 ◽

2021 ◽

Vol 50 (1) ◽

pp. 25-40

Author(s):

Jorge Sanjurjo-Sanchez ◽

◽

Carlos Arce Chamorro ◽

Juan Vidal Romaní ◽

Marcos Vaqueiro-Rodríguez ◽

...

Keyword(s):

Growth Rate ◽

Organic Matter ◽

Growth Process ◽

Age And Growth ◽

Nw Spain ◽

Geochemical Composition ◽

Cave System ◽

Accretion Process ◽

Dissolved Ions ◽

First Time

Granite massifs often contain caves, with dimensions ranging from a few meters up to 1,000 m, also referred to as pseudokarst. The speleothems in such caves are mostly composed of either Si-rich (commonly opal-A) or Al-rich authigenic mineraloids. Whereas the formation and geochemical composition of opal-A biospeleothems have been studied and are fairly well understood, knowledge on the Al-rich analogues is scarce. This work reports for the first time a study on the composition, accretion process, age and growth rate of an Al-rich speleothem type flowstone from the A Trapa Cave System (Galicia, NW Spain), developed in a granite cave. To understand the growth process, trickling water was analyzed and the deposition environment inside the cave was characterized. We found that the speleothems are alternating Si- and Al-rich layered deposits formed between 1,635 ± 75 and 1,243 ± 58 cal BP by percolating water that carries underground mineral grains, dissolved ions, and organic matter from soil and the weathered bedrock above the cave.

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