impact of gel‐conditioned layer depths and water quality on water movement in sandy soils

This article was downloaded by: [Cornell University Library]On: 11 November 2014, At: 05:05Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Arid Soil Research andRehabilitationPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/uasr19

Impact of gel‐conditioned layerdepths and water quality on watermovement in sandy soilsA. A. Shalaby aa Soil Science Department, College of Agriculture , KingSaud University , P.O. Box 2460, Riyadh, 11451, SaudiArabiaPublished online: 09 Jan 2009.

To cite this article: A. A. Shalaby (1993) Impact of gel‐conditioned layer depths and waterquality on water movement in sandy soils, Arid Soil Research and Rehabilitation, 7:3,281-291, DOI: 10.1080/15324989309381358

To link to this article: http://dx.doi.org/10.1080/15324989309381358

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information(the “Content”) contained in the publications on our platform. However, Taylor& Francis, our agents, and our licensors make no representations or warrantieswhatsoever as to the accuracy, completeness, or suitability for any purposeof the Content. Any opinions and views expressed in this publication are theopinions and views of the authors, and are not the views of or endorsed by Taylor& Francis. The accuracy of the Content should not be relied upon and should beindependently verified with primary sources of information. Taylor and Francisshall not be liable for any losses, actions, claims, proceedings, demands, costs,expenses, damages, and other liabilities whatsoever or howsoever caused arisingdirectly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly

http://www.tandfonline.com/loi/uasr19

http://www.tandfonline.com/action/showCitFormats?doi=10.1080/15324989309381358

http://dx.doi.org/10.1080/15324989309381358

forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

http://www.tandfonline.com/page/terms-and-conditions

http://www.tandfonline.com/page/terms-and-conditions

Arid Soil Research and Rehabilitation. Volume 7, pp. 281-291 0890-3069/93 $10.00 + .00Printed in the UK. All rights reserved. Copyright © 1993 Taylor & Francis

Impact of Gel-Conditioned Layer Depths andWater Quality on Water Movement in Sandy Soils

A. A. SHALABY

Soil Science DepartmentCollege of AgricultureKing Saud UniversityP.O. Box 2460Riyadh 11451, Saudi Arabia

Abstract In a laboratory study, the influence of the organic supergel commerciallycalled Jalma was investigated at rates of 0.0, 0.2, 0.4, and 0.8%, three depths ofsurface-treated layer (0.0-0.05, 0.0-0.10, and 0.0-0.15 m), and different water qualitywith EC of 0.5, 2, and 4 dS m-1, on infiltration, cumulative evaporation (E), percentageof water conserved (PWC), and soil moisture distribution for calcareous sandy soil.Twenty-two millimeters of saline waters was applied every 7 days. The results revealedthat the infiltration time significantly decreased with increasing depth of the surface-treated layer with water containing EC of 0.5 dS m-1. When saline waters containing2 or 4 dS m-1 were used, the depth of the surface-treated layer had no significant effecton infiltration time. Also, the infiltration time significantly increased with increasingJalma rates at different quality of irrigation waters. The E value significantly in-creased with increasing depth of the surface-treated layer and Jalma rates. E de-creased by increasing of electrical conductivity of irrigation water. The PWC de-creased with increased depth of the surface-treated layer and could be increased byincreasing the Jalma rates. The results indicated that the increased depth from 0.05 to0.10-0.15 m of the surface-treated layer had no beneficial effect of the PWC of the soilcolumns.

Keywords evaporation, gel conditioner, infiltration, sandy soils, waterconservation, water quality

IntroductionThe synthetic polymers that act as superabsorbents of water were used to improve someof the physical properties of sandy soils. Sandy soils are characterized by low specificsurface area, low water-holding capacity, and high infiltration rate, causing inefficientwater use in arid and semiarid regions. These soils constraints can conceivably be alle-viated through the use of synthetic polymers that act as superabsorbents of water. Thesuperabsorbents can increase water supply to growing plants and improve water useefficiency (El-Hady et al. 1981, Tayel and El-Hady 1981). A hydrolyzed starch polyacry-Ionitrile graft (super sluper) polymer was found to increase surface soil swelling, decreaseinfiltration rate (Miller 1979), and decrease sorptivities of some soils (Hemyari andNofziger 1981). Gel-forming conditioners (superabsorbents), if they contain cementingagents, such as humic substances and/or polysaccharides, may cause formation of stable

Address correspondence to Dr. A. A. Shalaby.Received: 4 November 1992; accepted: 19 January 1993.

281

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

282 A. A. Shalaby

aggregates or increase their stability (Cheshire 1979, Tisdall and Oades 1982, Chaney andSwift 1986, Al-Omran et al. 1987, Al-Omran et al. 1991).

In Saudi Arabia the average annual rainfall is 100 mm and water resources foragriculture are limited to relatively medium to saline groundwater (Al-Omran 1987). Thecombined effect of superabsorbents and saline water on soils has been reported in somestudies. Helalia and Letey (1988) found that applying the polyacrylamide soil conditionerat a rate of 5 mg L~' increased flocculation of soils. Mustafa et al. (1989) observed thatsoils tend to decrease in swelling and increase in water penetrability and diffusivity withthe increase in water salinity and decrease in Jalma rate.

Al-Omran et al. (1987, 1991) reported that surface application of Jalma increasedwater conservation and reduced cumulative evaporation of sandy soils. They found thatsubsurface Jalma-treated barriers promoted evaporation and hence the amount of waterconserved. The main objective of this study was to investigate the effect of Jalma con-centration applied to different upper layer depths (0.05, 0.10, and 0.15 m) and waterquality on infiltration, evaporation, water conservation, and soil moisture distribution.

Materials and Methods

A bulk surface sample (0.0-0.30 m) from a calcareous sandy soil (Typic Torripsamments)was collected from the College Experimental and Research Farm at Dierab (latitude 24°25' N, longitude 46°34' E), Saudi Arabia. The sample was air-dried and passed througha 2-mm sieve. Particle-size analysis, CaCO3 %, soil organic matter, soil pH (paste),conductivity of the saturation extract (ECe), and SAR values were determined usingstandard procedures (Black 1965). The percentage of clay, silt, and sand were 5, 5, and90%, respectively. The soil contained a high amount of CaCO3 (30%) and very loworganic matter (0.1%), pH was 8.1, ECe was 1.2 dS m~', and SAR value was 0.9. Thesynthetic conditioner used was an organic supergel (Jalma1). It contained 24.5% humicacid, 1.9% fulvic acid, and 3.8% polysaccharides, and the remaining weight was water.Each 1 kg of Jalma gel contains 0.0326 kg of dry Jalma. Four Jalma concentrations wereused in this study: 0.0, 0.2, 0.4, and 0.8% (on a dry-weight basis). The correspondingquantities of Jalma were thoroughly hand-mixed with soil, dried, crushed, and sievedthrough a 2-mm screen.

Evaporation studies were conducted using 0.30-m-long soil columns, packed into0.37-m-long glass tubes with inside diameters of 54 mm and closed at one end by piecesof cloth held firmly by strings. The soil samples were packed by tapping on the bench intothe glass tubes by 5-cm increments to 1.5 g cm"3 bulk density. The treatments consistedof four rates of Jalma-treated soil: 0.0, 0.2, 0.4, and 0.8%; three depths of surface-treatedlayers: 0.0-0.05, 0.0-0.10, and 0.0-0.15 m; and three water qualities with EC of 0.5 (tapwater), 2, and 4 dS m"1 at SAR of 10. Each treatment was replicated three times.

The soil columns were placed on a bench inside a walk-in growth chamber withcontrolled light of 25.7 W irT2, and constant temperature of 25°C. Twenty-two millime-ters of irrigation water was applied weekly for three wetting/drying cycles. The time ofdisappearance of irrigation water at each cycle was recorded. Cumulative evaporationversus time of measurements were determined by periodically weighing each soil column.The soil moisture distributions at the end of the experiment (third cycle) were determined.The amount of water conserved (PWC) was calculated as the difference between cumu-

1 The use of the trade name Jalma is for the information of the reader and does not constitutean official endorsement of the product.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

Gel-Conditioned Layer and Water Movement 283

lative quantity of water applied (Q) minus cumulative evaporation (£), and expressed aspercentage of the former: PWC = (Q - E)/Q X 100.

Results and Discussion

For brevity, the 0.0, 0.2, 0.4, and 0.8% Jalma treatments (T) are referred to hereafter asToo, To2, T04, and Tog, respectively. The depths of treated layer of 0-0.05, 0-0.10, and0-0.15 m are denoted by D5, D,o, and D,5, respectively. The electrical conductivities ofwater used as 0.5, 2, and 4 dS nT1 are denoted by EC05, EC2, and EC4, respectively.

Infiltration

The times required for 22 mm of irrigation water to infiltrate into soil columns as affectedby the depths of Jalma-treated surface layer were recorded for three cycles at differentwater quality. Table 1 shows the infiltration time for the first cycle only. For EC05,generally the results indicated that the infiltration time significantly decreased with depthof Jalma application, except To 8. For quality of irrigation water containing EC2 and EC4,generally the results revealed that the depth of the treated layer had no significant effecton infiltration time, with exception of To 8 at EC2. Furthermore, this treatment caused arelatively higher infiltration time. This behavior may be attributed to the swelling effectof the increased Jalma application rate. The electrical conductivity of 2 dS irf' did notsufficiently suppress the swelling effect. The effect of Jalma was predominant on the top0.05 m for T o 2 and T04 .

Table 1 shows the effect of Jalma rate on infiltration time using different quality ofirrigation water. The results indicated that the infiltration time significantly increased with

Table 1Time Required (s) by Water to Infiltrate Soil Columns as Affected by Jalma

Application Rate, Gel-Treated Layer Depth, and Water Quality for the First Cycle

Depth of TreatedLayer (cm)

0-50-100-15LSD005

0-50-100-15

LSD0.0S

0-50-100-15

LSDo.os

None

61.361.361.3NS

52.652.652.6NS

52.652.652.6NS

Rate of Application

2

EC = 0.5 dS nT1

43.339.337.65.01

EC = 2 dS irT1

35.335.633.3NS

EC = 4 dS nT1

35.035.033.6NS

(mgj

4

42.344.039.64.4

32.635.331.6NS

34.033.332.6NS

r1 soil)

8

233.3250.0240.0

NS

50.060.068.312.47

54.055.351.3NS

LSDo.05

28.424.6816.24

6.607.566.73

4.645.455.86

Note. NS, not significant.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

284 A. A. Shalaby

increasing of Jalma rate. Also, the results revealed that the time of infiltration significantlyincreased by approximately fourfold at To 8. The infiltration time decreased for any depthof Jalma treated layer at To 0 to To 4. This decrease, due to the Jalma treated layer, causedthe improvement of aggregates stability (Al-Omran et al. 1987), and thus promoted theinfiltration rate. However, the higher Jalma rate (To 8) increased the infiltration time at anygiven Jalma-treated layer. It seems that To g markedly increased swelling and conse-quently increased the time of infiltration into soil columns (Al-Omran et al. 1987).

A comparison of the effects of water quality on infiltration time showed that the Jalmaapplication gave lower infiltration times at EC2 and EC4 than tap water for all treatments.This decreased effect of Jalma may be attributed to the nature of synthetic conditioner(Johnson 1984; Al-Darby et al. 1993) when salt solution was used in irrigation. In addi-tion, increased salt concentration reduced swelling of soil and consequently increasedinfiltration rate and decreased infiltration time compared to tap water.

Evaporation

The effects of Jalma treatment on cumulative evaporation (£) vs. time (0 relationships areshown in Tables 2-4 and Fig. 1. For tap water, it was evident that a surface Jalmatreatment of 0.05 m was effective in reducing evaporation for each cycle. During the threecycles the To 4 treatment at a depth of 0.05 m gave a lower value than the other treatments.However, increasing the Jalma rate to 0.8% slightly increased cumulative evaporation. Asmentioned in a previous study (Al-Omran et al. 1987), the influence of Jalma on cumu-lative evaporation at the 0.05-m surface layer may be due to its effects on aggregation andswelling. Both phenomena affect infiltration, redistribution, and capillary rise, which inturn influence the cumulative evaporation. Generally, increasing the depth of the treated

Table 2Intermittent Cumulative Evaporation from Soil Column as Affected by Jalma

Application Rate and Gel-Treated Layer Depth for Tap Water


0-50-100-15

LSDo.05

0-50-100-15LSD005

0-50-100-15LSD005

Jalma

None

17.2817.2817.28NS

36.8336.8336.83NS

56.7956.7956.79NS

Application

2

Cycle 113.9917.4516.731.021Cycle 2

30.7435.4736.26

2.086Cycle 3

49.1753.4555.48

2.790

Rate (mg g '

4

10.5016.8116.150.975

24.4435.3435.68

2.761

41.5851.4255.114.849

soil)

8

12.0814.7714.470.894

25.2029.7529.95

1.678

39.2544.9344.56

2.479

LSDo.05

0.8440.8091.0931.093

1.4382.4711.808

1.8193.842.702


Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14



Application Rate and Gel-Treated Layer Depth for Irrigation Water for EC 2 dS m"1


0-50-100-15LSDa05

0-50-100-15LSD0o5

0-50-100-15LSD005

Jalma

None

16.5616.5616.56NS

34.8934.8934.89NS

54.4854.4854.48NS

Application

2

Cycle 111.6817.3017.170.850

Cycle 227.7235.8736.97

1.400Cycle 3

46.4554.8757.98

1.978

Rate (mg ,

4

8.7117.7916.471.619

20.6838.4836.842.628

40.3960.0558.542.114

g"1 soil)

8

10.2416.6116.06

1.125

22.3835.7934.92

1.595

39.5756.1655.42

0.843

LSD005

1.5430.7591.067

2.7211.5101.414

2.3721.9721.742


layer to 0.10 or 0.15 m increased cumulative evaporation for all treatments (Fig. 1A). Theresultant evaporation depended on rate of Jalma application, the depth of the Jalma-treatedlayer, and water quality. Figure 1A illustrates the effect of Jalma-treated layer depth oncumulative evaporation vs. the time relationship for tap water at a Jalma application of0.4%. Treatment T0 4 was selected because it proved to be the optimal treatment for waterconservation of sandy soils (Al-Omran et al. 1987). It was evident that E value wassignificantly lower when Jalma was applied at the top 0.05 m of the soil, and increasingthe layer depth was not effective in suppressing evaporation. At the end of the first cycleD5 had a lower E value than the control or the other treatments. The data suggest thatbeneficial effects of Jalma became more pronounced with increased drying and wettingcycles. At the third cycle it was evident that the application of Jalma at 0.10 or 0.15 msuppressed evaporation in comparison to the control treatment. At the end of the thirdcycle, E ranked as follows: Do > D15 > D10 > D5. The deeper the Jalma-treated layer (D15),the more water was retained at the layer, and consequently the higher was E. The reduc-tion of evaporation at D5 treatment may be attributed to higher amount of water retainedbelow it, due to reduced capillary rise.

For water quality of EC2, Table 3 shows the effect of Jalma rate and depth of theJalma-treated layer on cumulative evaporation. The results indicated that Jalma treatmentsat 0.05 m were effective in reducing evaporation at each cycle. Figure IB illustrates theeffect of the Jalma-treated layer on E at To 4. It is evident that evaporation significantlydecreased when Jalma was applied at the top 0.05 m of soil column. Increasing the depthof the treated layer did not suppress evaporation. At the end of the third cycle, evaporationranked as follows: D10 > D15 > Do > D5. Table 4 and Fig. 1C show the effect of waterquality at EC4 and the rate of Jalma application at different Jalma-treated layer depths on

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

286 . A. A. Shalaby


Application Rate and Gel-Treated Layer Depth for Irrigation Water of EC 4 dS m"1


0-50-100-15LSD005

0-50-100-15

LSDQ.OS

0-50-100-15LSD005

Jalma

None

16.2616.7016.26NS

34.7434.7434.74NS

54.6654.6654.66NS

Application

2

Cycle 112.2416.6016.840.728

Cycle 228.7934.1436.28

1.997Cycle 3

47.4152.3156.45

3.01

Rate (mg g '

4

8.9616.7217.150.551

22.6536.3738.470.882

43.0356.2159.30

1.964

soil)

8

9.5215.7915.710.482

24.0633.5133.934.345

42.3553.8654.35

5.612

LSD0.05

0.6420.4960.325

3.0792.3790.905

3.9393.5671.325


E. To 4 at a depth of 0.05 m clearly gave reduced evaporation. Table 5 shows the effectof water quality and Jalma rate on cumulative evaporation at the third cycle at differentdepths of the treated layer. In general, the data indicate that increasing the depth of Jalmatreated layer did not reduce cumulative evaporation. Adding saline water would increasecumulative evaporation. The data also indicate that increasing Jalma rate would suppressevaporation with increased number of drying/wetting cycles. The thinner the Jalma-treatedlayer, the higher was the amount of water retained below it, due to reduced capillary rise,and the lower was the evaporation. The significant effect of water quality on cumulativeevaporation may be attributed to the nature of synthetic polymers. When salt solution wasadded the polymers did not retain water at the soil column and did not permit the waterto evaporate easily compared to tap water (Al-Darby et al. 1993).

Water Conserved

Table 6 shows the percentage of water conserved (PWC) at the end of the third cycleaffected by Jalma rate, depth of the Jalma-treated layer, and water quality. For tap water,the PWC ranked as follows: T o 8 > T 0 4 > T 0 2 > T o 0 at the three depths of the Jalma-treated layer. However, surface Jalma treatment D5 gave significantly higher PWC valuesat the different rates of Jalma than D10 and D15. The same trend was found for the othertwo water qualities, but the surface treatment of D5 had much higher PWC values. Theseresults indicate that surface application of Jalma at top 0.05 m significantly improvedwater conservation and that increasing the thickness of the Jalma-treated layer had nobeneficial effect on PWC.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14


60

60

40

30

20

10

0<

(A)

-

-

» 4- + +

" B

• g

4-

. 4-

i

D • * *

+ 4- ++ +

i

control0.16 m0.10 m

0.06 nt

0

1= 70\60

ap

oi

ai

ativ

50

40

30

20

10|

O

(B)

10 15 20 25

, ^ * * * 0.10 m* g 5 a Q o.is m

* •J , . • control

* ' ' '

? 0.06 m

10 15 20 25

70

60

50

40

30

20

10

Ol

(C)

•

B ® a

" + +

I

U (3 IB + "*"

D

1 i s § ,* 7 • 4-

• a o* ¥ *

, 4-4- +

0.16 m0.10 mcontrol

0.06 m

10 15TIME (DAYS)

20 25

Figure 1. Intermittent evaporation at 0.4% Jalma as affected by depth of surface-treated layer: (A)using tap water, (B) at EC 2 dS m"1, (C) at EC 4 dS m"'.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

288 A. A. Shalaby

Table 5Intermittent Cumulative Evaporation as Affected JalmaApplication Rate of Water Quality for the Third Cycle

EC(dS irf1)

0.524LSD005

0.524LSD005

0.524LSD005

Jalma

2

Depth49.1746.4547.41

2.93Depth

53.4554.8752.31

2.63Depth

55.4857.9856.45

2.25

Application Rate (mg g '

4

i 0-5 cm41.5840.3943.05

2.190-10 cm

51.4260.0556.214.62

0-15 cm55.1158.5459.30

2.10

soil)

8

39.2539.5742.35

NS

44.9356.1653.86

3.919

44.5655.4254.35

1.80


Table 6Percentage of Water Conserved as Affected by Jalma

Application Rate and Water Quality


0-50-100-15LSD005

0-50-100-15LSD0 05

0-50-100-15LSDo.05

None

13.9513.9513.95NS

17.4517.4517.45NS

17.1817.1817.18NS

Jalma Application Rate (mg g '

2

EC = 0.5 dS irT25.5019.0115.934.21

EC = 2 dS m"1

29.6216.8612.152.99

EC = 4 dS m"1

28.1620.7414.464.54

4

37.0022.0016.507.32

38.89.01

11.303.19

34.8814.8310.152.90

soil)

8

40.5031.8732.48

3.74

40.0414.9016.034.80

35.8318.3917.658.47

LSD005

2.765.804.10

3.603.002.65

5.955.402.00


Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14


8

6

4

2

0

(A)

V%

—i—i—i

*—H K-.

\

—i—t—

\v~^S

—1

0 .06 rn

•"N*. -0.10 m

\ _ controlu 0.16 m

—\ H—'1.25 3.75 7.5 12.5 17.5 22.5 27.5 32.5

*Coo•5

••-•

.52o•

.52 2

0<—I

(B)

1.25

1.25 3.75 7.5 12.5 17.5 22.5 27.5 32.5

8

6

4

2

0

(C)

j ,

r—\ 1 1 r-

1 K _0.05 m

\ \ \ controlV V \ . 0-10 mu v v 0.15 m

( 1 1 1 13.75 7.6 12.5 17.5 22.5 27.5

Depth of Soil Columns (cm)32.5

Figure 2. Soil moisture distribution at 0.4% Jalma as affected by depth of surface-treated layer: (A)using tap water, (B) at EC 2 dS rrT1, (C) at EC 4 dS m~'.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

290 A. A. Shalaby

Soil Moisture Profiles

Figure 2 shows the soil moisture profiles at the termination of the third evaporation cycleat the Jalma rate of 0.4%, as influenced by the depth of the Jalma-treated layer and waterquality. For columns with tap water, the profiles of Do, D5, D10, D I 5 showed drying zonesfollowed by transmission zones. At half column depth the moisture contents were rankedas follows: D5 > D10 > D,5 > Do (Fig. 2A). For D5 treatment, the water content wassubstantially higher than for other Jalma-treated layer depths, which agrees with theresults presented in Table 6 for water conservation. For columns with irrigation water ofEC2 and EC4, the soil moisture profiles are presented in Fig. 2B and 2C, respectively. Themoisture profile consisted of a drying zone at the surface, a transmission zone in themiddle, and a dry zone at the bottom for Do, D10, and DI5. For D5, the same figures showa drying zone at the surface, followed by a transmission zone to the bottom of thecolumns. The results indicate that the water content at the termination of the experimentwas substantially higher with D5 treatment compared to other treated layer depths, whichis in full agreement with the results in Table 6 for water conservation at the columns. Itcan be concluded that the use of synthetic conditioner (Jalma) in sandy soils at a rate of0.4% and the top 0.05 m of soil will reduce cumulative evaporation and increase thepercentage of water conserved mainly because of the aggregation effect, which enhancesthe infiltration for the tap water. This is also indicated by the soil profiles in Fig. 2.However, for saline water the use of Jalma was not effective in reducing cumulativeevaporation at different Jalma-treated layer depths, mainly because of the nature of thisconditioner when using saline water in irrigation. The results also indicate that increasingthe Jalma-treated layer depth had no beneficial effect on the percentage of water con-served at the soil columns.

References

Al-Darby, A. M., A. M. Al-Omran, and A. A. Shalaby. 1993. Influence of water absorption capacityof soil gel-conditioners. Journal of College of Agriculture, King Saud University 5:111-117.

Al-Omran, A. M. 1987. Evaluation of some irrigation water in central region of Saudi Arabia.Journal of College of Agriculture, King Saud University 9:363-369.

Al-Omran, A. M., M. A. Mustafa, and A. A. Shalaby. 1987. Intermittent evaporation from soilcolumns as affected by a gel-forming conditioners. Soil Science Society of America Journal51:1593-1599.

Al-Omran, A. M., M. A. Mustafa, A. M. Al-Darby, and A. A. Shalaby. 1991. Gel-conditionedbarriers for water management of sandy soils. Irrigation Science 12:7-12.

Black, C. A., ed. 1965. Methods of Soil Analysis, Parts 1 and 2. American Society of Agronomy,Madison, WI.

Chaney, H., and R. S. Swift. 1986. Studies on aggregate stability, II: the effect of humic substanceson the stability of reformed soil aggregates. Journal of Soil Science 37:337-343.

Cheshire, M. V. 1979. Nature and Origin of Carbohydrates in Soils. Academic, London.El-Hady, O. A., M. Y. Tayel, and A. A. Lotfy. 1981. Super gel as a soil conditioner, II: its effect

on plant growth, enzyme activity, water use efficiency and nutrient uptake. Acta Horticulturae119:257-265.

Helalia, A. M., and J. Letey. 1988. Polymer type and water quality effects on soil dispersion. SoilScience Society of America Journal 52:243-246.

Hemyari, P., and D. L. Nofziger. 1981. Super Sluper effects on crust strength, water retention andwater infiltration of soils. Soil Science Society of America Journal 45:799-801.

Johnson, M. S. 1984. Effect of soluble salts on water adsorption by gel-forming soil conditioners.Journal of Science of Food and Agriculture 35:1063-1066.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14


Miller, D. E. 1979. Effect of H-SPAN on water retained by soils after irrigation. Soil Science Societyof America Journal 43:628-629.

Mustafa, M. A., A. M. Al-Darby, A. M. Al-Omran, and M. Mursi. 1989. Impact of gel conditionerand water quality upon soil infiltration. Irrigation Science 10:169-176.

Tayel, M. Y., and O. A. El-Hady. 1981. Super gel as a soil conditioner, I: its effect on some soilwater relations. Acta Horticulturae 119:247-256.

Tisdall, J. M., and J. M. Oades. 1982. Organic matter and water stable aggregates in soils. Journalof Soil Science 33:141-163.

Dow

nloa

ded

by [

Cor

nell

Uni

vers

ity L

ibra

ry]

at 0

5:05

11

Nov

embe

r 20

14

impact of gel‐conditioned layer depths and water quality on water movement in sandy soils

Documents