The Effect of Soil Conditioners on Water Movement through Lateritic Sandy Loam Soil
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J. Agronomy & Crop Science 159, 241244 (1987) 1987 Paul Parey Scientific Publishers, Berlin and HamburgISSN 0931-2250
Contribution from Rural Development Centre, IIT, Kharagpur, India
The Effect of Soil Conditioners on Water Movementthrough Lateritic Sandy Loam Soil
K. K. SEN and P. B. S. BHADORIA
Authors' address: K. K. SEN and Dr. P. B. S. BHADORrA, Rural Development Centre, Indian Institute ofTechnology, Kharagpur-721302/India.
With one table and 2 figures
Received December 2, 1986; accepted February 19, 1987
The latentic sandy loam soil of Gopali suffers by a high infiltration rate and percolation loss. The investigatedsoil was treated by four soil conditioners, CMC, PVA. Guargum and Lignosulphonate (LIG.) at 0.05 percent and 0.10 per cent concentration level. The infiltration of water at - 2 m bar pressure in horizontalcolumn of soil was studied. The experimental results indicate that the lignosulphonate has increased the timeby 30 % and 70 % to penetrate the 15 cm depth of soil column at 0.05 and 0.10 per cent concentration level,respectively. In the case of PVA, increase of time was 18 per cent and 33 percent at these the concentrationlevel. Guargum at high concentration level increased the time by 31 per cent to penetrate the same depth ofsoil. Whereas CMC at high concentration reduced the time by 8 per cent. Similar trends were found in case ofvolume of water penetration and infiltration rate of treated soil.
IntroductionThe major objective of applying soil con-ditioner to soils is to improve or modify thenormal water regime in the soil profile throughalternation of water retention and transmissionproperties of the soil. The application oforganic adhesives as conditioners leads to arather complex change of different physicaland physicochemical properties of solid-liquidsystem in the soil. In fact through soil condi-tioning, not only size distribution of aggre-gates and the porous system changes, but alsothe properties of solid-liquid interface.
In case of water entering the soil at nearlyatmospheric pressure, the three parameters areof interest, the soil water diffusiviry, the com-ulative infiltration and the distance that waterpenetrates into the soil (NIELSON et al. 1962).Many researchers have dealt with the effect ofchemical products on water movementthrough soil. Laboratory studies conducted by
et al. (1962) indicated that wettingagent can increase infiltration rate of hydro-phobic soil, but either have no effect or adverseeffect on soils which are not hydrophobic.KiNjE (1967) observed that treatments withkrillium (HPAN-VAMP) and PVA increasedthe infiltration rates. In a loam sand and a finesandy loam, krillium and PVA reduced theinfiltration rate, where as in a clay loam soil theinfiltration rate increased. GREENLAND (1963)has suggested that the adsorption of unchargedpolymer molecules results in a lining of the soilpores. This would stabilized the aggregates anda lining of soil pores might have some effect onflow properties of soil. Experiments conductedby VERPLANCKE (1973) indicated that the infilt-ration for a bitumen treated soil was lowerthan untreated soil and that a treatment withPAM and PVA increased the infiltration rate.VERPLANCKE et al. (1975) similarly observedthat PAM, PVA and bitumen had markedly
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242 SEN and BHADORIA
CMCPV AGUARGUML I G
y = - 1 . 9 2 0 + 2.007X , r = 0.998y = - 3 .686 -t- 1.985X , r= 0.998y = -3 .717 +2.276X , r= 0.993
y = - 3 . 0 0 6 + 1.839X , r= 0 .996CONTROL
y =- 2.586-1-2.070X , r= 0.998
CM CPV AGUARGUMLI G
y = - 2 . 9 3 8y = - 2 . 5 9 0y = - 2 . 6 0 9
, r = 0.9931.77ix , r - 0 . 9 9 8] . 7 5 2 x , r : 0 , 9 9 6
y = - 3 . 6 6 8 + 1 . 6 3 5 x , r = 0.995
CMCPVAGUAR SUMLl GCONTROL
0I n f i l t r a t i o n t i m e , ( m i n )
Fig. 1. The position of the wetting front as a function of a square root of the infiltration time for control andtreated soils (A) Ci-concentration level of treatment (B) C^-concentration level of treatment
reduced the infiltration rate in coarse texturedsoils, but PAM and PVA had reversed effecton fine textured soil. HARTMAN and VER-PLANCKE (1975) found that the infiltration ratesof clay loam soil was increased by PAM +Glyoxal treatment. VLEESCHAUWER et al. (1979)also found the similar trend by PVA, PAM andbitumen on different textured soil.
Lateritic soil is known to have a very highrate of infiltration and percolation. Any prac-tice that would alter porosity and aggregatestability might reduce the high infiltration rate.The present investigation attempts the watermovement under different levels of concentra-tion of various soil conditioners in lateriticsoil.
Materials and MethodsThe study was conducted in lateritic sandy loam soilof Gopali (010 cm) having the sand 73 %, silt12 % and clay 15 %, water holding capacity 36 %(vol/vol). CEC 8.4 meq/100 g, pH 5.4, E.C. 0.85 mmhos/cm, organic carbon 0.41 % and total N0.059%.
Treatments included were two levels of concentra-tion viz. 0.05 % (C,) and 0.10 % (C.) and four typeof conditioners namely CMC (T,), PVA (T2), Guar-gum (T3) and Lignosulphonate (T4) with one con-
trol. The soil samples after being equilibrated to 0.5bar tension, were treated with polymers as men-tioned above. Samples were air dried and passedthrough 2 mm sieve. The sieved air-dried soils werecarefully packed at a bulk density of 1.5 g/cc in aperspex column, 16 cm long and 3.7 cm innerdiameter. The columns were positioned horizontallyon V shaped wooden stand. Small holes were drilled1 cm apart in the upper part of perspex column tomaintain atmospheric pressure in the entire colunm.Distilled water was introduced at the one end of thehorizontal column through a saturated, coarse (neg-ligible inpedance) fritted glass plate of 2 mm thick-ness. Water infiltrating into the soil column throughthis glass plate was maintained at a - 2 m barpressure (NiELSON et al. 1962). The horizontal infilt-ration trials were run until the wetting front reachedto a fixed distance of 15 cm. Soil-column was dis-mantled and the soil-moisture content was measuredat 1 cm interval depth using gravimetric method.Volume of infiltrating water and distance from thewater source to the wetting front were recorded withrespect to time.
Results and DiscussionThe distance of wetting front (x) was recordedas a function of time (t) and the relationshipbetween x and t'/^ was worked out (Fig. 1) andthe slope of the line referred as penetrability
The Effect of Soil Conditioners on Water Movement 243
0.0022 Q23 0.2i 0.2S 0 25 0.27 Q28 0.29 0 30 0 3t 0.32 033 a3i 0 35 0.22 023 0.2i Q25 0^6 0 27 0.26 0,2 9 0.30 0.31 0.32 0.33 0.3i 0.35
Water conicni tcnrcm'^)Fig. 2. The penetrability over the volumetric water content for control and treated soils (A) C]-concentrationlevel of treatment (B) C2-concentration level of treatment
which is proportional to infiltration rate.There is a positive correlation between x andi^^ in all the cases (r = 0.99). It can be seenfrom the Fig. 1 that the rate of advancement ofthe wetting from increases with guargum andCMC and decreases with PVA and LIG ascompared to control. Faster movement of wet-ting front may be attributed to the stabilizationof aggregate. GREENLAND (1963) has suggestedthat the adsorption of uncharged polymermolecule results in a lining of the soil pores.This would stabilized the soil aggregates andconsequently makes it resistance to slakingeasily. Contradictions to our finding, KINJE(1967) has found that PVA treatment in clayloam soil increases the infiltration rate. He alsopointed out that the increase of infiltration rateof treated soil could be attributed the lining ofsoil pores. However, either the breakdown ofaggregates and/or hydrophobic nature of theconditioners may be the reason for slower rateof advancement of wetting front.
The penetrability (k = x t'/^ ) was computedand plotted against water-content (Fig. 2).From Fig. 2 it is apparent that the X of thetreated and untreated soil mainly changes athigher moisture content. This may be attrib-uted the breakdown of aggregates which facesmaximum amount water passing through themfor maximum period of run. The slope of thelines of Fig. 1 shows the penetrability value.Penetrability (of water) was greater in guargum
treated soil, but when the soil treated withlignosulphonate the penetrability of water con-siderably slowed down by 21 per cent asagainst control. Therefore time required forwettmg front to reach a desired distance wasseveral time greater for lignosulphonate treatedsoil. However increased concentration of guar-gum has resulted in lowering the k value. Thiscould be associated to micelle function. PVAalso considerably reduced the X value by 4 percent and 14 per cent at these two concentrationlevel respectively. But CMC increases thepenetrability by 5 per cent at higher concentra-tion level.
Table 1 also indicates that the time requiredto wet 15 cm depth of soil column increased by30 per cent and 70 per cent at Ci and C2concentration level of lignosulphonate as com-pared to control. PVA which is less effectivethan lignosulphonate increases the timerequired by 18 per cent and 33 per cent at Ciand C2 concentration level respectively. How-ever guargum and CMC were not effective indecreasing infiltration at 0.05 per cent concen-tration. Increased level of concentration hasresulted in decrease the time by 8 per cent forCMC treated soil and 31 per cent for guargumtreated soil. Volume of water penetration in afixed time (36 min) and rate of infiltration arechanged in same fashion as the time required towet 15 cm depth. From this