נגישות
menu      
Advanced Search
Syntax
Search...
Volcani treasures
About
Terms of use
Manage
Community:
אסיף מאגר המחקר החקלאי
Powered by ClearMash Solutions Ltd -
Aggregate size and seal properties
Year:
1997
Source of publication :
Soil Science
Authors :
Goldstein, Dina
;
.
Levin, J.
;
.
Levy, Guy
;
.
Shainberg, Isaac
;
.
Volume :
162
Co-Authors:

Shainberg, I., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Levy, G.J., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Levin, J., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Goldstein, D., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel

Facilitators :
From page:
470
To page:
478
(
Total pages:
9
)
Abstract:
The formation of a disrupted layer or a seal at soil surfaces exposed to the impact of raindrops is a common feature of many cultivated soils. The objectives of this study were to investigate the dependence of a disrupted layer (which consists of broken and compacted aggregates) and of a seal (a thin dense layer of very low permeability) on aggregate size in order to better understand the mechanisms involved in seal formation. The effects of aggregate size on seal permeability, thickness of the disrupted layer, and the relative rate of aggregate disintegration in two soils exposed to simulated rain was studied. Aggregates with sizes of <4, 4-9.5, and 9.5-12 mm from a grumusol (Typic Chromoxerert) and a loess (Calcic Haploxeralf) were exposed to distilled water (DW) rain with a kinetic energy of 12.4 kJ m-3. Thickness of the disrupted layer was estimated from microscope observations. Aggregate stability of aggregates with sizes of 2-4, 4-9.5, and 9.5-12 mm was determined by applying drops with kinetic energy of 3.1 kJ m-3 to dry aggregates placed on a sieve with a size opening of 0.3 or 0.8 min. For grumusol, aggregate size increase from 2-4 mm to 9.5-12 mm resulted in increases of (i) aggregate stability from 8 to 56%, (ii) thickness of the disrupted layer from 1.5 to 4.3 mm, and (iii) cumulative infiltration from 29.8 to 47.8 min. Similar results were observed for the loess. The final infiltration rate of the fully developed seal in both soils was low (<5 mm h-1) and tended to increase with an increase in aggregate size despite the accompanied increase in the thickness of the disrupted layer. These observations suggest that (i) rate of seal formation is determined by the rate of aggregate disintegration and (ii) thickness of the disrupted layer is not related to seal permeability. In soils exposed to rain, aggregate disintegration and formation of a disrupted layer are fast processes, whereas physico-chemical dispersion of clay is slow and determines seal permeability. The permeability of the seal rather than that of the disrupted layer determines the equilibrium infiltration rate of the soil.
Note:
Related Files :
Aggregate size
soil seal
soil surface
Show More
Related Content
More details
DOI :
Article number:
0
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
30613
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:56
Scientific Publication
Aggregate size and seal properties
162

Shainberg, I., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Levy, G.J., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Levin, J., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel
Goldstein, D., Institute of Soils and Water, Agricultural Research Organization, Volcani Center, P.O. Box6, Bet Dagan, Israel

Aggregate size and seal properties
The formation of a disrupted layer or a seal at soil surfaces exposed to the impact of raindrops is a common feature of many cultivated soils. The objectives of this study were to investigate the dependence of a disrupted layer (which consists of broken and compacted aggregates) and of a seal (a thin dense layer of very low permeability) on aggregate size in order to better understand the mechanisms involved in seal formation. The effects of aggregate size on seal permeability, thickness of the disrupted layer, and the relative rate of aggregate disintegration in two soils exposed to simulated rain was studied. Aggregates with sizes of <4, 4-9.5, and 9.5-12 mm from a grumusol (Typic Chromoxerert) and a loess (Calcic Haploxeralf) were exposed to distilled water (DW) rain with a kinetic energy of 12.4 kJ m-3. Thickness of the disrupted layer was estimated from microscope observations. Aggregate stability of aggregates with sizes of 2-4, 4-9.5, and 9.5-12 mm was determined by applying drops with kinetic energy of 3.1 kJ m-3 to dry aggregates placed on a sieve with a size opening of 0.3 or 0.8 min. For grumusol, aggregate size increase from 2-4 mm to 9.5-12 mm resulted in increases of (i) aggregate stability from 8 to 56%, (ii) thickness of the disrupted layer from 1.5 to 4.3 mm, and (iii) cumulative infiltration from 29.8 to 47.8 min. Similar results were observed for the loess. The final infiltration rate of the fully developed seal in both soils was low (<5 mm h-1) and tended to increase with an increase in aggregate size despite the accompanied increase in the thickness of the disrupted layer. These observations suggest that (i) rate of seal formation is determined by the rate of aggregate disintegration and (ii) thickness of the disrupted layer is not related to seal permeability. In soils exposed to rain, aggregate disintegration and formation of a disrupted layer are fast processes, whereas physico-chemical dispersion of clay is slow and determines seal permeability. The permeability of the seal rather than that of the disrupted layer determines the equilibrium infiltration rate of the soil.
Scientific Publication
You may also be interested in