東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Effects of salinity, sodicity, and c...

Ruiz Vera, Victor Manuel.

Linked to FindBook

Google Book

Amazon

博客來

Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties./
Author:	Ruiz Vera, Victor Manuel.
Description:	181 p.
Notes:	Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 2894.
Contained By:	Dissertation Abstracts International66-06B.
Subject:	Agriculture, Soil Science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3179401
ISBN:	9780542194757

Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties.
Ruiz Vera, Victor Manuel.

Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties. - 181 p.

Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 2894.

Thesis (Ph.D.)--University of California, Riverside, 2005.

Understanding the relationship among soil properties, irrigation water quality, and soil management practices is vital to the sustainability of irrigated agriculture. The objectives of this study were to evaluate the interactive effects of clay mineralogy, prewetting rate (PWR), and sodicity on soil aggregation and permeability, and to determine the influence of salinity and sodicity on soil water characteristics and bulk soil electrical conductivity (ECa). Six soils with predominant clay minerals of smectite, vermiculite-smectite and kaolinite were equilibrated with solutions of sodium adsorption ratio (SAR) = 0, 20, and 50 and electrical conductivity (EC) = 3.0 dS m-1 . After air-drying, the samples were sieved and repacked in brass or Plexiglas rings. The soil columns were prewetted at rates of 2, 5, and 30 mm h-1, after which infiltration rates and aggregate stabilities were determined. In other soil columns with similar treatment (except PWR), the soil water characteristic curve and ECa were determined. When SAR increased from 0 to 50 (at EC = 0.6 dS m-1 and low PWR), the aggregate stability decreased from 0.63 to 0.19. In addition, the steady-state infiltration rate (i) in the vermiculitic and smectitic clay loam soils decreased by 87% and 92%, respectively. For a given matric potential, the amount of water retained in the smectitic (except the Cotharin soil) and vermiculitic soils increased when SAR increased from 0 to 50 (EC = 3.0 dS m-1). The air-entry value decreased 678% for the smectitic silty-clay loam soil and 301% for the smectitic silty-clay soil, which was attributed to a reduction in macroporosity due to high sodicity. The physical and hydraulic properties of the kaolinitic loam soil were not significantly affected by SAR increase. The ECa of the smectitic clay loam soil increased from 1.14 to 2.42 dS m-1 when SAR increased from 0 to 50 (soil solution EC ≤ 4 dS m-1). At low EC, aggregate slaking by fast PWR was the main cause of aggregate disruption and lower infiltration capacities when SAR was low whereas swelling and dispersion become more important to structural stability when SAR was ≥20.

ISBN: 9780542194757Subjects--Topical Terms:

1017824
Agriculture, Soil Science.

Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties.
LDR:03053nmm 2200265 4500 001 1823520
005 20061130142511.5
008 130610s2005 eng d
020 $a 9780542194757
035 $a (UnM)AAI3179401
035 $a AAI3179401
040 $a UnM $c UnM
100 1 $a Ruiz Vera, Victor Manuel. $3 1912625
245 1 0 $a Effects of salinity, sodicity, and clay mineralogy on the soil physical and hydraulic properties.
300 $a 181 p.
500 $a Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 2894.
500 $a Chairperson: Laosheng Wu.
502 $a Thesis (Ph.D.)--University of California, Riverside, 2005.
520 $a Understanding the relationship among soil properties, irrigation water quality, and soil management practices is vital to the sustainability of irrigated agriculture. The objectives of this study were to evaluate the interactive effects of clay mineralogy, prewetting rate (PWR), and sodicity on soil aggregation and permeability, and to determine the influence of salinity and sodicity on soil water characteristics and bulk soil electrical conductivity (ECa). Six soils with predominant clay minerals of smectite, vermiculite-smectite and kaolinite were equilibrated with solutions of sodium adsorption ratio (SAR) = 0, 20, and 50 and electrical conductivity (EC) = 3.0 dS m-1 . After air-drying, the samples were sieved and repacked in brass or Plexiglas rings. The soil columns were prewetted at rates of 2, 5, and 30 mm h-1, after which infiltration rates and aggregate stabilities were determined. In other soil columns with similar treatment (except PWR), the soil water characteristic curve and ECa were determined. When SAR increased from 0 to 50 (at EC = 0.6 dS m-1 and low PWR), the aggregate stability decreased from 0.63 to 0.19. In addition, the steady-state infiltration rate (i) in the vermiculitic and smectitic clay loam soils decreased by 87% and 92%, respectively. For a given matric potential, the amount of water retained in the smectitic (except the Cotharin soil) and vermiculitic soils increased when SAR increased from 0 to 50 (EC = 3.0 dS m-1). The air-entry value decreased 678% for the smectitic silty-clay loam soil and 301% for the smectitic silty-clay soil, which was attributed to a reduction in macroporosity due to high sodicity. The physical and hydraulic properties of the kaolinitic loam soil were not significantly affected by SAR increase. The ECa of the smectitic clay loam soil increased from 1.14 to 2.42 dS m-1 when SAR increased from 0 to 50 (soil solution EC ≤ 4 dS m-1). At low EC, aggregate slaking by fast PWR was the main cause of aggregate disruption and lower infiltration capacities when SAR was low whereas swelling and dispersion become more important to structural stability when SAR was ≥20.
590 $a School code: 0032.
650 4 $a Agriculture, Soil Science. $3 1017824
690 $a 0481
710 2 0 $a University of California, Riverside. $3 791122
773 0 $t Dissertation Abstracts International $g 66-06B.
790 1 0 $a Wu, Laosheng, $e advisor
790 $a 0032
791 $a Ph.D.
792 $a 2005
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3179401