[3] DEVELOPMENT OF lliE MElliOD USED TODETERMINE lliE DEGREE OF A SOILS'

WATER-REPEllENCE

SECTION [3] DEVELOPMENT OF THE METHOD USED TO DETERMINE THE DEGREEOF A SOILS' WATER-REPELLENCE

OBJECTIVE

[1] To identify possible improvements to an existing method of determining the

relative degree of soil water repellence.

[3.1] INTRODUCTIONNwnerous methods have been employed by researchers world-wide to quantify the

water-repellent properties of soils (Hammond & Yuan, 1969; Letey, 1969; Nakaya et al.,

1977; King, 1981; Wallis et al., 1991). The method developed by King (1981), clearlyidentified the possibility that a soil can be ascribed a relative value of water-repellence, corresponding to the molarity of an aqueous ethanol solution which, whenapplied to the dried soil surface, penetrates within a predetermined time interval.

This method provided rapid determination of water-repellence, a factor which was

very important when considering the quantity of samples to be assessed in thefollowing studies. However it was apparent that on some soils or on samples fromsome courses, general maintenance practices were contributing to the variationobserved between replicates using this method.

The cross-sectional profile of soil cores removed from UK golf greens and othermanaged amenity turf areas were far from uniform. On cores from golf greens,

evidence of aeration through hollow tining or other similar practices was clear and theinfill of these tine holes with topdressing material or improved root growth wasapparent. Changes in soil structure across the profile at any given depth and localised

increases in organic matter (root material), drastically affected the molarity of aqueousethanol required to penetrate the samples at random locations across the profile.

Since the objective of the analysis was to determine the inherent degree of water-

repellence of the soil itself and not the obviously repellent nature of accumulations of

organic matter, it was decided to amend the method of King (1981) to minimise thisobserved variation produced as a direct result of management practices.

[3.2] MATERIALS AND METHODS

Two sites were selected for this study; Ganton Golf Course (NGR SE 981778) and

Shipley Golf Course (NGRSE 109380). Ten SO mm diameter soil cores were removedto a depth of 80 mm from each of the three distinct zones of a Marasmius oreadesfairy ring (Section 6); the inner, dead and outer zones. The rings selected for inclusion

in this study were located on the practice areas of both courses.

Soil cores were air-dried at 20°C for 4 days, after being halved across the diameter ofthe core through the depth of the sample. Once air-dried, the cores were marked at20 mm depth intervals from the surface of the profile to a depth of 60 mm. At each

depth interval, a range of aqueous ethanol solutions with a molarity ranging from 0 Mto 7 M (Appendix I), were applied to the surface as 36 J.ll droplets dispensed from aPasteur pipette. The time interval required for their penetration into the profile wasrecorded. The concentration of aqueous ethanol was adjusted until the lowestconcentration which penetrated the soil in less than 10 seconds was determined. Themolarity of the aqueous ethanol solution which fulfilled these criteria was recorded asthe MEDvalue for that soil. Ten replicate drops of each ethanol solution were placed

on the soils' surface and the mean penetration time was used to determine the finalMEDvalue.

On completion of this analysis on the intact soil cores, each core was cut at 20 mm

depth intervals to a final depth of 60 mm. The core sections were then milled and

sieved to s 1.3 mm particle size to remove as much of the root material as possiblefrom the samples. The sieved soil was placed in the lid of a 90 mm diameter plastic

Petri dish and levelled using the Petri dish base. Once levelled, the application of

aqueous ethanol solutions to the soil was repeated; 10 drops of each selected aqueousethanol solution at each depth interval. The penetration time was again recorded andthe mean value used to determine the aqueous ethanol concentration whichpenetrated in less than 10 seconds. This second MEDvalue was recorded for themilled soil. Following the MEDassessments on milled soils the samples were used to

determine the corresponding percentage organic matter content (Section 4.2.11).

[3.2.1] Statistical analysis

Percentage data recorded for soil organic matter content, was analysed using analysis

of variance. All data were subjected to arcsin transformation prior to analysis but forease of interpretation, transformed data have not been presented. MED valuesobtained in this study have been analysed by analysis of variance and also expressed

graphically in two ways. The mean MEDvalue and corresponding SEDvalues havebeen plotted for each zone and depth interval through the soil core for each fairy ring.The recorded MED values for each individual core and the corresponding mean

penetration time of the aqueous ethanol solution have been plotted against each otherfor each depth interval for each of the representative soil samples.

Depth(mm)

[3.3] RESULTS

The MED values ascribed to the individual soil samples (intact and milled soilrespectively) with depthj of each of 10 replicate cores taken from the inner, dead and

outer zones of a M. oreades fairy ring sampled at Ganton golf course, are given in

Appendix II. These tables also indicate the mean penetration time (seconds) of10 replicate drops of the stated aqueous ethanol solution and the standard error of

the mean penetration times recorded.

The mean MEDvalues obtained for both intact and milled soil cores taken from the

inner, dead and outer zones of a M. oreades fairy ring at Ganton golf course, areshown in Table 21. The PLSD(p s; 0.05) values and the standard error of the mean

MEDvalues are also given in Table 21.

TABLE 21Mean MEDvalues obtained for both intact and milled soil cores taken from the inner,

dead and outer zones of a Marasmius oreades fairy ring at Ganton golf course

Mean MEDvalues for intact and milled soil cores from each zoneInner zone Dead zone Outer zone

Intact Milled Intact Milled Intact Milled

0-20 3.97 4.56 5.95 5.70 4.80 5.23

(0.18) (0.04) (0.17) (0.13) (0.20) (0.21)

20-40 2.64 4.45 5.70 5.80 3.97 4.78

(0.73) (0.03) (0.18) (0.21) (0.52) (0.37)

40-60 2.33 3.87 5.58 5.45 2.37 3.28

(0.47) (0.30) (0.12) 0.07) (0.86) (0.50)Zone PLSD(p~0.05) = 0.379Depth inteIVal PLSD(p~0.05) = 0.379Soil type PLSD(p~0.05) = 0.310Zone * soil type Pl.SD(p~0.05) = 0.537Zone * depth inteIVal PLSD(p~0.05) = 0.657Values in parentheses are the s.e.d. values.

The information shown in Table 21 indicates that with regard to the three zOlies of thering (irrespective of soil type), statistical analysis has identified that each zone (inner,

dead and outer) is significantly different from the other two. The dead zone is shownto have the highest MEDvalue and the inner zone the lowest. With regard to the depthinterval alone, each is significantly different from the other two. The 0-20 mm depthinterval is shown to have the greatest MEDvalue and the severity of water-repellence

decreases with increasing depth. Milled soils produce significantly higher values ofwater-repellence compared with intact soil cores. Significant interactions were alsoidentified between zone'" soil type and zone'" depth interval.

To identify specific differences in MEDvalues obtained with depth and between intactand milled soils, the results obtained from each zone of the ring sampled at Gantongolf course were analysed independently. The information is shown in Tables 22

to 24.

TABLE 22MEDvalues obtained at depth for intact and milled soil cores taken from the inner

zone of a Marasmius oreades ring at Ganton golf course

MEDvalue at each depth interval (mm) for intact and milled soilsReplicate 0-20number intact milled

1 4.25 4.502 3.50 4.503 4.50 4.754 3.75 4.755 3.25 4.506 4.25 4.507 4.50 4.758 4.25 4.509 4.50 4.5010 2.90 4.50

Depth interval PLSD(p~O.05) == 0.416Soil type PLSD(p~.05) = 0.509Depth interval * soil type (p~0.05) = NSDNSDNo significant difference

20-40intact milled2.80 4.502.20 4.504.25 4.502.10 4.502.60 4.502.70 4.503.50 4.502.10 4.502.00 4.252.10 4.25

40-60intact milled1.00 3.250.50 2.604.25 4.500.75 3.255.00 5.252.10 4.253.25 2.602.20 4.502.10 4.252.10 4.25

Analysis of soil samples taken from the inner zone (Table 22) indicate significantdifferences in MEDvalues determined, both between soil types and at depth throughthe soil profile. Milled soils produced significantly higher MEDvalues compared with

the intact cores and the 0-20 mm depth interval showed significantly higher MEDvalues compared with both the 20-40 mm and 40-60 mm intervals. Betweenthemselves, the lower two depth intervals were not significantly different.

MED values obtained from the dead zone (Table 23) identified no significantdifferences within the data set.

Results of analysis completed on soil from the outer zone identified a significantdifference between MEDvalues ascribed to samples at depth through the profile butnot between intact and milled soils and no significant interaction was observed(Table 24). The MEDvalues obtained at depth intervals 0-20 mm and 20-40 mm werenot significantly different from each other but were significantly higher than those

recorded for the 40-60 mm depth interval.

TABLE 23MEDvalues obtained at depth for intact and milled soil cores taken from the dead

zone of a Marasmius oreades ring at Ganton golf course

MID value at each depth interval (mm) for intact and milled soilsReplicate (}20number intact milled

1 5.75 5.502 6.50 5.503 6.50 5.754 5.50 6.755 5.50 5.506 6.50 5.507 5.50 5.508 6.75 6.009 5.50 5.5010 5.50 5.50

Depth interval PLSD (p~O.OS) = NSDSoil type PLSD (p~O.OS) = NSDDepth interval * soil type (p~O.OS) = NSDNSD No significant difference

20-40intact milled5.25 5.255.50 5.506.75 7.005.75 6.005.25 5.255.25 5.255.50 5.506.75 7.005.50 5.755.50 5.50

40-60intact milled5.25 5.255.50 5.506.50 5.505.75 5.505.25 5.255.50 5.255.50 5.505.75 6.005.50 5.505.25 5.25

TABLE 24MEDvalues obtained at depth for intact and milled soil cores taken from the outer

zone of a Marasmius oreades ring at Ganton golf course

MID value at each depth interval (mm) for intact and milled soilsReplicate (}20number intact milled

1 5.50 5.502 4.25 4.503 4.25 4.504 5.75 6.755 4.25 4.506 5.50 5.507 4.50 5.258 4.50 5.259 5.25 5.2510 4.25 5.25

Depth interval PLSD (p~O.OS) = 0.997Soil type PLSD (p~O.OS) = NSDDepth interval * soil type (p~O.OS) = NSDNSD No significant difference

20-40intact milled6.00 5.502.70 4.401.90 2.305.50 6.752.10 4.255.75 5.753.25 4.502.50 4.504.75 4.505.25 5.25

40-60intact milled5.50 4.500.25 2.100.00 1.505.75 5.500.25 2.105.50 5.750.00 2.601.20 3.500.00 1.505.25 3.75

Figures 4 to 9 represent the MEDvalues of each soil sample with depth (intact andmilled soils respectively), plotted against their respective mean penetration times.

FIGURE4. MID values and mean penetration time at 0-20 mm depth for intact coresfrom Ganton golf course.

10

9 • inner zoneLI./!; 8 + dead zoneI- 6 outer zoneZ 7 •0--6 +I- ~C"ell: &: 5I- CLI./ " 4 •z ~ •••~~3Z 2C

6 +LI./1: 1

0 :f:+0 1 2 3 4 5 6 7

MEDVALUE

FIGURES. MID values and mean penetration time at 0-20 mm depth for milled coresfrom Ganton golf course.

10

LI./ 9~ 8I-Z 7 •0~~6C"ell: &: 5I- C

"LI./ ., 4 • inner zone •Z ~~~3 + dead zone • 6 +Z •C 2 6 outer zone •LI./ I 6.++1: 1

A 6+0

0 1 2 3 4 5 6 7MEDVALUE

FIGURE6. MEDvalues and mean penetration time at 20-40 rom depth for intact coresfrom Ganton golf course.

10 • •&./

9

~ 8 • inner zone.... + dead zoneZ 7 •0_6 • 6 outer zone- ~.... "1:1 •C c: 5Ol: 0.... ~ 4 6. 6&./~z_ ,.~ 3Z •c 2&./ 1 6 •J: •0

0 1 2 3 4 5 6 7MEDVALUE

FIGURE7. MEDvalues and mean penetration time at 20-40 rom depth for milled coresfrom Ganton golf course.

10

&./ 9~ 8 6 • inner zoneto- dead zoneZ 70 6 outer zone-- 6.... ~C"I:I 5Ol: c:to- 0 •&./u4Z"~~-3Z 2C&./J: 1 61 66* 6

00 1 2 3 4 5 6 7

MEDVALUE

FIGURE8. MEDvalues and mean penetration time at 40-60 mm depth for intact coresfrom Ganton golf course.

10

9 •LIJ • inner zone~ 8 + dead zonel- •Z 7 • 6 outer zoneCI • •--61-1/\

6""oC c 5Cl: 0I- Cot •L1J"4Zl/\L1J~

3 • •D. t 6Z 2oCLIJ •J: 1 •0

0 1 2 3 4 5 6 7MEDVALUE

FIGURE9. MEDvalues and mean penetration time at 40-60 mm depth for milled coresfrom Ganton golf course.

10

9 • inner zoneLIJ

~ • dead zone8I- 6 • 6 outer zonZ 7CI--6 A1-1/\oC"" A •Cl:~S A 6I- CotLIJ ., 4zl/\L1J~

3 •D.Z 2 6oCLIJ AJ: 1 • .f-

00 1 2 3 4 5 7

MEDVALUE

The information shown in Figures 4 to 9 demonstrate that in using milled soils, therange of ascribed MED values is generally reduced below that seen on intact cores.

The MEDvalues identified for milled soils are generally higher than those for intactcores but are only significantly higher in soil removed from the inner zone.

The values shown in Table 21 have been expressed graphically for comparisonbetween individual zones at each of the three depth intervals assessed (Figures 10, 11and 12).

FIGURE10. Mean MEDvalues obtained for both intact and milled soil take from theinner, dead and outer zones of a Marasmius oreades fairy ring at Ganton golf course ata depth of 0-20 nun.

1

oINNER DEAD

ZONEOUTER

• Intact soil coreEI Milled soil

FIGURE11. Mean MEDvalues obtained for both intact and milled soil take from theinner, dead and outer zones of a Marasmius oreades fairy ling at Ganton golf course ata depth of 20-40 nun.

7

6

~5

;;> • Intact soil core

~4 8 Milled soil

~3

:;: 2

1

0INNER DEAD OUTER

ZONE

• Intact soil coremJ Milled soil

6

~ 5

~ 4~~ 3

~ 2~

1

0INNER DEAD OUTER

ZONE

FIGURE12. Mean MEDvalues obtained for both intact and milled soil take from theinner, dead and outer zones of a Marasmius oreades fairy ring at Ganton golf course ata depth of 40-60 mm.

7

Table 25 indicates the overall mean values for organic matter content of soil samplestaken from the inner, dead and outer zones of a M. oreades fairy ring sampled at

Ganton golf course. The PLSDvalues (p;5;O.OS)and the standard error of the mean MED

values are also shown.

TABLE 25Mean levels of organic matter in soil taken from the inner, dead and outer zones of a

Marasmius oreades fairy ring at Ganton golf course

Depth Mean organic matter content(%) from zones(mm) Inner zone Dead zone Outer zone

0-20 26.73 9.26t 15.89(4.64) (0.47) (1.54)

20-40 6.51 6.32 7.51(0.40) (0.12) (0.20)

40-60 5.27 5.23t 5.79(0.18) (0.10) (0.08)

Zone PLSD(p~O.OS)= 2.706Depth PLSD(p~0.05) = 2.706Zone * depth PLSD(p~O.OS)= 4.686t Mean of 9 valuesValues in parentheses are the s.e.d. values

The information presented in Table 25 indicates that there is a significant difference

between the levels of organic matter present in soils taken from each of the threezones of the ring. Each zone possesses an organic matter content that is significantlydifferent from the other two. The dead zone has the lowest organic matter contentand the inner zone has the highest. With regard to depth interval, the soil from0-20 mm depth contains a significantly higher organic matter content compared with

the other two depth intervals. The lower two depth intervals are not significantly

different from each other.

Because significant differences were identified between the three zones, the values

recorded for the organic matter content of the soil samples from each zone were

analysed independently. The actual levels of organic matter present within the milledsoil samples used for MEDdetermination are shown in Tables 26 to 28. An organic

matter content value is given for each of the 10 replicate cores removed from each of

the inner, dead and outer zones of a M. oreades fairy ring sampled at Ganton golfcourse and an overall mean value for the organic matter content of soil from eachdepth interval within each of the three zones is recorded.

With regard to the inner zone (Table 26), the soil organic matter content has been

shown to be Significantly greater within the 0-20 mm depth interval than that presentwithin either the 20-40 mm or 40-60 mm depth interval. The lower two depthintervals show no significant difference with regard to the respective organic mattercontents.

TABLE 26The organic matter content of soil cores taken from the inner zone of a

Marasmius oreades fairy ring at Ganton golf course

Depth Organic matter content of soil (%) from core number(mm) 1 2 3 4 5 6 7 8 9 10 Mean

0-20 37.50 57.50 25.27 42.38 21.01 23.48 19.00 11.89 15.14 14.10 26.73

20-40 7.01 9.63 6.03 6.66 6.66 6.35 6.58 5.60 5.05 5.56 6.51

40-60 5.51 6.11 4.98 5.72 5.09 5.31 5.95 4.74 4.28 4.96 5.27Depth interval PLSD(p~0.05) = 7.552

10

12.00

6.57

5.67

TABLE 27The organic matter content of soil cores taken from the dead zone of a

Marasmius oreades fairy ring at Ganton golf course

Depth Organic matter content of soil (%) from core number(mm) 1 2 3 4 5 6 7 8 9

0-20 9.45 8.29 10.56 8.62 7.72 7.77 8.89 10.03

20-40 6.82 5.58 6.40 5.85 6.48 6.32 6.16 6.34 6.70

40-60 5.45 4.95 4.85 5.11 5.16 4.96 5.25 5.66Depth interval PLSD(p~0.05) = 0.780t Mean of 9 values

Mean

9.26t

6.325.23 t

Within the dead zone of the ring (Table 27) there is a significant difference betweenthe organic matter content of the soil samples obtained at each depth interval. Thelevels of organic matter content decrease significantly with increasing depth throughthe profile.

TABLE 28The organic matter content of soil cores taken from the outer zone of a

Marasm;us oreades fairy Ii.ng at Ganton golf course

Depth Organic matter content of soil (96) from core number(mm) 1 2 3 4 5 6 7 8 9 10 Mean0-20 11.51 18.17 14.72 10.31 18.39 10.15 19.74 24.10 11.72 20.12 15.8920-40 6.69 8.06 7.38 6.90 7.68 7.06 8047 8043 7.32 7.08 7.5140-60 5.76 5.36 5.86 5.83 6.00 5.72 6.18 5.81 5.91 5045 5.79Depth interval PLSD(p~0.05)= 2.606

The information contained in Table 28 indicates that the organic matter content of thesoil sample obtained at 0-20 mm depth through the outer zone of the ring, issignificantly higher than that present in either of the lower depth intervals observed.

There is no significant difference between the 20-40 mm and the 40-60 mm depthintervals.

The mean levels of organic matter given in Table 25 have been expressed graphically(Figure 13) to show the difference between values obtained for each of the threezones.

FIGURE13. Mean levels of organic matter in soil taken from the inner, dead and outerzones of a Marasm;us oreades fairy ring at Ganton golf course.

35~30-

INNER DEADZONE

• Depth 0-20 mm~ Depth 20 - 40 mmm Depth 40 - 60 mm

OUfER

The location of active mycelium observed after incubation of the soil samples inhumid chambers is shown in Table 29. It can be seen that no active fungal myceliumis present in soil samples taken from the apparent inner zone of the M. oreades ring,but that the fungal mycelium is present in soils taken from both the dead and the

outer zones. The presence of fungal mycelium in the soil samples from the outer

zone may affect the relative MEDvalues ascribed to these soils but for the purpose ofthis assessment, a comparison between milled and unmilled soils can still be

completed and is still valid. This identifies the difficulty of sampling from a naturalbiological system using only the above ground symptoms of the fungal presence as

reference.

TABLE 29Location of active mycelium on soil cores taken from three zones of a

Marasmius oreades ring at Ganton golf course

Depth interval (mm) within each sample zoneReplicate Inner zone Dead zone Outer zonenumber 0-20 20-40 40-60 0-20 20-40 40-60 0-20 20-40 40-60

1 + + + + + +2 + + +3 + + +4 + + + + + +5 + + +6 + + + + + +7 + + + + +8 + + +9 + + + + + +10 + + + + +

+ Activemycelium present- No active mycelium present

The MED values ascribed to the individual soil samples (intact and milled soilrespectively) with depth, of each of 10 replicate cores taken from the inner, dead andouter zones of a M. oreades fairy ring sampled at Shipley golf course, are given in

Appendix II. These tables also indicate the mean penetration time (seconds) of10 replicate drops of the stated aqueous ethanol solution and the standard error ofthe mean penetration times recorded.

Analysis of the complete set of MEDdata recorded for the soil samples removed from

the ring at Shipley golf course, indicates that there are significant differences betweenthe three zones (inner, dead and outer) and the soil type (intact and milled). Inaddition, the interactions between zone 1< soil type and zone 1< depth interval also

indicate significant differences.

This data is summarised in Table 30 and the PLSD(pS;O.OS)values and the standard

error of the mean MEDvalues are also shown.

3.93 4.85 0.00 0.13(0.56) (0.24) (0.00) (0.07)

4.53 5.18 0.00 0.00(0.41) (0.13) (0.00) (0.00)

5.17 5.36 0.00 0.00(0.09) (0.04) (0.00) (0.00)

0.00(0.00)

0.00(0.00)

0.08 0.08(0.08) (0.08)

0.03(0.03)

20-40

40-60

Depth(mm)

0-20

TABLE 30Mean MEDvalues obtained for both intact and milled soil cores taken from the inner,

dead and outer zones of a Marasmius oreades ring at Shipley golf course.

Mean MID values for intact and milled soil cores from each zoneInner zone Dead zone Outer zone

Intact Milled Intact Milled Intact Milled

0.00(0.00)

Zone PLSD(p~O.OS)= 0.208Soil type PLSD(p~O.OS)= 0.173Depth interval PLSD(p~O.OS)= NSDZone * soil type PLSD(p~O.OS)= 0.294Zone * depth interval PLSD(p~O.OS)= 0.361Values in parentheses are the s.e.d. valuesNSDNo significant difference

The results expressed in Table 30 show that with regard to the three zones of the ring,the MEn value is significantly higher for the dead zone compared with the other two.

The inner and outer zones are not significantly different from each other. Milled soilsshow a significantly higher value of water-repellence compared with intact soil cores.Analysis has also shown that the interactions zone .,. soil type and zone .,. depth

interval are also significant.

To identify specific differences in MID values obtained with depth and between intactand milled soils, the results obtained from each zone of the ring sampled at Shipleygolf course were analysed independently. The information is shown in Tables 31to 33.

MED values obtained from the inner zone (Table 31) identified no significantdifferences within the data set.

Analysis of soil samples taken from the dead zone (Table 32) indicate significant

differences in MID values determined, both between soil types and at depth throughthe soil profile. Milled soils produced significantly higher MEDvalues compared with

the intact cores and the 0-20 mm depth interval showed significantly lower MED

values compared with the 40-60 mm interval. The MED value ascribed to the20-40 mm depth interval, was not significantly different from either the 0-20 mm or40-60 mm depth values.

TABLE 31MEDvalues obtained at depth for intact and milled soil cores taken from the inner

zone of a Marasmius oreades ring at Shipley golf course

MEDvalue at each depth interval (mm) for intact and milled soilsReplicate 0-20 20-40number intact milled intact milled

1 0 0 0 02 0 0 0 03 0 0 0.25 04 0 0 0 05 0 0 0 06 0 0 0 07 0 0 0 08 0 0 0 09 0.75 0.75 0 010 0 0 0 0

Depth interval PLSD (pSO.05) = NSDSoil type PLSD (pSO.05) = NSDDepth interval * soil type PLSD (pSO.05) = NSDNSD No significant difference

40-60intact milledo 0o 0o 0o 0

o 0o 0o 0o 0

The information shown in Table 33 indicates that significant differences are presentbetween MEDvalues recorded for depth interval and the depth interval .,.soil type

interaction. The MEDvalues recorded at 0-20 mm depth interval are significantly

different from the 20-40 mm and the 40-60 mm depth intervals, but that the lower

two levels are not significantly different from each other.

TABLE 32MEDvalues obtained at depth for intact and milled soil cores taken from the dead

zone of a Marasmius oreades ring at Shipley golf course

MEDvalue at each depth interval (mm) for intact and milled soilsReplicate 0-20 20-40number intact milled intact milled

1 1.90 4.50 1.90 4.502 5.25 5.25 4.75 5.253 5.25 5.50 5.25 5.004 0.75 3.25 2.40 4.505 4.75 5.25 4.75 5.256 5.25 5.50 5.00 5.257 5.50 5.75 5.25 5.508 1.90 4.50 5.50 5.509 5.25 4.50 5.00 5.2510 3.50 4.50 5.50 5.75

Depth interval PLSD (pSO.05) = 0.629Soil type PLSD (pSO.05) = 0.513Depth interval * soil type PLSD (pSO.05) = NSDNSD No significant difference

40-60intact milled5.25 5.504.75 5.25

5.25 5.504.75 5.255.00 5.255.25 5.505.50 5.255.50 5.255.25 5.50

TABLE 33MEDvalues obtained at depth for intact and milled soil cores taken from the outer

zone of a Marasmius oreades ring at Shipley golf course

MEDvalue at each depth interval (mm) for intact and milled soilsReplicate 0-20 20-40number intact milled intact milled

1 0 0 0 02 0 0 0 03 0 0.50 0 04 0 0 0 05 0 0.50 0 06 0 0 0 07 0 0 0 08 0 0 0 09 0 0.25 0 010 0 0 0 0

Depth interval PLSD(p~0.05) = 0.057SoUtype PLSD(p~O.OS)= NSDDepth interval * soil type PLSD(p~O.OS)= 0.080NSDNo significant difference

40-60intact milledo 0o 0o 0o 0o 0o 0o 0o 0

o 0o 0

Figures 14 to 19 represent the MEDvalues of each soil sample with depth (intact andmilled soils respectively), plotted against their respective mean penetration times.

FIGURE14. MEDvalues and mean penetration time at 0-20 mm depth for intact coresfrom Shipley golf course.

765234

MEDVALUE

o

~ • inner zone

+ dead zone

+ A outer zone

~ +~

+ +~ • +~

- +=1=..1.

I I I I Io

10

9

8

FIGURE15. MEDvalues and mean penetration time at 0-20 mm depth for milled coresfrom Shipley golf course.

21

o

10

98

7

...,J:-I-Zo--6I-l/\c"~ c 5I- 0

()..., ., 4Z l/\~-3Zc...,J:

. A •• inner zone

+ dead zoneA. • A outer zone

.

++ *. + +:t:+

I I I I

o 234

MEDVALUE

5 6 7

FIGURE 16. MED values and mean penetration time at 20-40 mm depth for intactcores from Shipley golf course.

.inner zone• •

+ dead zoneA outer zone.

++ ++

+ + *+.

I I I' I

10

...,9~ 8I-Z 7Q--6I-l/\c"~ g 5I- ()"""4Z III...,-Do 3~ 2...,J: 1

oo 234

MEDVALUE

5 6 7

FIGURE 17. MED values and mean penetration time at 20-40 rom depth for milledcores from Shipley golf course.

o

10

9

8

7

- • inner zone

+ dead zone

• A outer zone

+., + ++oj +++.

I I I I I I

LI.II:-l-I:o--6I- IIIC"CIl: c 5I- 0LI.I C> 4I: ~~-3~ 2LI.II: 1

o 234

MEDVALUE5 6 7

FIGURE 18. MED values and mean penetration time at 40-60 rom depth for intactcores from Shipley golf course.

10

9 • inner zoneLI.I

~ 8 + dead zoneI- A outer zoneI: 7 +0--6I- IIIC"5CIl: CI- 0LI.I C> 4I: ~~-3I: 2CLI.I 1I:

00 1 2 3 4 5 6 7

MEDVALUE

FIGURE19. MEDvalues and mean penetration time at 40-60 mm depth for milledcores from Shipley golf course.

10

w 9 • inner zoneJ; 8 + dead zoneI-Z 7 A outer zone0~~6C"Ol:C5I- 00LI.I CII 4ZlA~'"'3Z 2cw

**I: 1

00 2 3 4 5 6 7

MEDVALUE

The Figures 14 to 19 show that in the case of milled soils, the range of ascribed MED

values is generally reduced below that seen on intact cores. However, analysis of the

data indicates that there is no significant difference between the MED values

determine for either intact or milled soils.

The values shown in Table 30 have been expressed graphically for comparisonbetween zones at each of the three depth intervals assessed (Figures 20, 21 and 22).

FIGURE20. Mean MEDvalues obtained for both intact and milled soil taken from theinner, dead and outer zones of a Marasmius oreades fairy ring at Shipley golf course ata depth of 0-20 mm.

7

6w::> 5 • Intact soil core..J« II Milled soil> 4cw:E 3z

2«w:E

1-r- -r-

0 INNER DEAD OUTERZONE

FIGURE21. Mean MEDvalues obtained for both intact and milled soil taken from theinner, dead and outer zones of a Marasmius oreades fairy ring at Shipley golf course ata depth of 20-40 rom.

7

6Intact soil core

~5 Milled soil

...J

~4

C 3UJ~Z 2US~ 1

0INNER DEAD OUTER

ZONE

FIGURE22. Mean MEDvalues obtained for both intact and milled soil taken from theinner, dead and outer zones of a Marasmius oreades fairy ring at Shipley golf course ata depth of 40-60 rom.

7

6w::J

5..J<t Intact soil core> 4 Milled soil0W:E 3z

2<tw:E 1

0 - -INNER DEAD OUTERZONE

Table 34 indicates the overall mean values for organic matter content of soil samplestaken from the inner, dead and outer zones of a M. oreades fairy ring sampled at

Curvularia spp. However, these fungi were also present in unaffected soils. Muchcircumstantial evidence points to the fungi as causal agents in dry patch development(Danneberger, 1987). In 1964, Bond & Harris confirmed the presence of fungal

mycelium or an extracellular organic material, coating individual soil particles in soils

affected by dry patch. This was supported by Bond (1964, 1968 & 1969a) and

Savage et al,. (1969a). An organic coating was proven to exist following observation ofindividual sand grains using the scanning electron microscope (SEM) (Bond &

Hammond, 1970). The presence of this organic coating and frequently associated

fungal hyphae on grains from areas affected by dry patch, has been substantiated by

several research groups (Miller & Wilkinson, 1977; Danneberger, 1987; Karnok &

Tucker, 1989). This organic coating as observed by SEMappears uniformly distributedon the surface of smooth sand particles, but on angular grains, the coating may bepatchy and uneven (Roberts & Carbon, 1971).

The occurrence of dry patch on golf greens has regularly been associated with thepresence of fairy rings or superficial fairy rings (Baldwin, 1989c). Certain

basidiomycete fungi which may cause symptoms commonly referred to as fairy rings

on fine turf, produce a dense water-repellent hyphal mat below the turf surface, whichseverely restricts water infiltration. During the development of fairy rings caused byMarasmius oreades, a bare zone becomes apparent on the turf surface. The death ofthe grass which leads ultimately to the appearance of bare patches, is caused at least

in part, by conditions which follow prolific subsurface mycelial growth of M. oreades.

M. oreades produces dense mycelial growth which spreads through the soil beneath

the turf and due to its water-repellent nature, creates a barrier which is impervious towater. It is due to this well documented example of fungal activity in turf, leading tothe formation of a water-repellent soil and ultimate plant death which has arousedspeculation that dry patch is associated with fungal activity (Smith & Jackson, 1981).

Superficial fairy rings (thatch fungi) are thought to be caused by Trechispora alnicola,Coprinus spp., or by many non-sporing basidiomycete fungi (Baldwin, 1990). The

dense, white fungal mycelium is usually found in the thatch layer of affected fine turf.It occurs in patches, rings and part-rings and where intense fungal activity hasoccurred, the depth of the thatch layer is often reduced leaving a surface depression(Baldwin, 1990). Where they occur, the random distribution of superficial fairy rings

on golf greens has often been considered to be associated with dry patch although noconclusive evidence has been produced to confirm this. In the development of both

fairy rings and superficial fairy rings, this mat of fungal hyphae can clearly be seen in

the soil profile or in the thatch layer respectively. However, in areas affected by dry

patch, this mycelium is not generally evident. It is possible that fairy ring fungi orrelated soil fungi may promote the development of water-repellence either directly,resulting in death of the fungus due to the dry conditions imposed, or by the

Shipley golf course. The PLSDvalues (p~0.05)and the standard error of the mean MEDvalues are also shown.

TABLE 34Mean levels of organic matter in soil taken from the inner, dead and outer zones of a

Marasmius oreades fairy ring at Shipleygolf course

Depth(mm)

0-20

20-40

40-60

Mean organic matter content(%)from zonesInner zone Dead zone Outer zone

16.13 13.52 18.13(0.38) (0.29) (0.29)12.70 12.00t 14.62t

(0.55) (0.16) (0.19)12.25it 1O.86t 12.65(0.45) (0.14) (0.18)

Zone PLSD(p~0.05) = 0.514Depth interval PLSD(p~0.05) = 0.514Zone * depth interval PLSD(p~0.05) = 0.890t Mean of 9 valuesit Mean of 8 values

Values in parentheses are the s.e.d. values

The data given in Table 34 shows that each of the three zones contains a level oforganic matter which is significantly different from that which is present in each of

the other two zones. The outer zone has been shown to contain the highest level of

organic matter and the dead zone the lowest. At each of the specified depth intervals,

analysis has shown that the soils organic matter content is significantly different. The0-20 mm interval contains the highest level of organic matter and the 40-60 mminterval contains the lowest. There is also a significant interaction betweenzone .,.depth interval ..

Because significant differences were identified between the three zones, the values

recorded for the organic matter content of the soil samples from each zone wereanalysed independently. The information is shown in Tables 35 to 37. An organicmatter content value is given for each of the 10 replicate cores removed from each ofthe inner, dead and outer zones of aM .. oreades fairy ring sampled at Shipley golfcourse and an overall mean value for the organic matter content of soil from each

depth interval within each of the three zones is recorded.

With regard to the inner zone (Table 35), the soil organic matter content has beenshown to be significantly greater within the 0-20 mm depth interval than that presentwithin either the 20-40 mm or 40-60 mm depth interval. The lower two depthintervals show no significant difference with regard to the respective organic mattercontents.

16.1312.70

12.34*

TABLE 35The organic matter content of soil cores taken from the inner zone of a

Marasmius oreades fairy ring at Shipley golf course

Depth Organic matter content of soil (%) from core number(mm) 1 2 3 4 5 6 7 8 9 10

0-20 15.11 15.30 15.16 16.27 16.45 15.63 17.64 15.03 18.70 15.9720-40 11.09 13.17 10.40 12.42 12.07 12.96 13.38 11.05 16.38 14.0540-60 10.94 12.92 10.64 11.30 12.66 12.08 14.45 13.04Depth interval PLSD(pSO.05)= 1.325* Mean of 8 values

Mean

Analysis of both the dead zone (Table 36) and the outer zone (Table 37) soil organic

matter content indicates that for both zones, the organic matter content of each of thedepth intervals is significantly different from the other two. In each zone, the highestlevel of organic matter is present within the 0-20 mm depth interval and the lowest ispresent within the 40-60 mm depth interval.

TABLE 36The organic matter content of soil cores taken from the dead zone of a

Marasmius oreades fairy ring at Shipley golf course

Depth Organic matter content of soil (%) from core number(mm) 1 2 3 4 5 6 7 8 9 10

0-20 12.53 13.41 13.54 12.47 15.32 14.69 13.09 13.40 13.90 12.8920-40 11.52 12.66 11.90 11.27 12.59 11.87 12.34 12.06 11.80

40-60 10.31 10.78 10.90 11.53 10.34 10.87 11.20 11.21 10.56Depth interval PLSD(pSO.05)= 0.598t Mean of 9 values

TABLE 37The organic matter content of soil cores taken from the outer zone of a

Marasmius oreades fairy ring at Shipley golf course

Depth Organic matter content of soil (%) from core number(mm) 1 2 3 4 5 6 7 8 9 10

0-20 18.53 18.13 18.27 18.01 20.00 16.72 17.92 17.45 18.94 17.2820-40 14.50 14.74 13.76 14.33 15.09 15.11 15.50 14.00 14.5540-60 12.36 12.91 11.68 12.66 13.34 13.47 12.82 11.86 12.97 12.46Depth interval PLSD(pSO.05)= 0.652t Mean of 9 values

Mean

13.5212.00t

1O.86t

Mean

18.1314.62t

12.65

The mean levels of organic matter given in Table 34 have been expressed graphically(Figure 23) to show the difference between values obtained for each of the threezones.

FIGURE23. Mean levels of organic matter in soil taken from the inner, dead and outerzones of a Marasmius oreades fairy ring at Shipley golf course.

3530

~u-25

~~20~z0815

~~lO~ 5

o

• Depth 0 - 20 mm~ Depth 20 - 40 mmEm Depth 40 - 60 mm

INNER DEADZONE

OUTER

The location of active mycelium observed after incubation of the soil samples inhumid chambers is shown in Table 38. It can be seen that the active fungal mycelium

is present only in soil samples taken from the apparent dead zone of the M. oreadesring. This observation was consistent for all 10 samples collected and at all depthintervals selected for study.

TABLE 38Location of active mycelium on soil cores taken from three zones of a

Marasmius oreades ring at Shipley golf course

Depth interval (mm) within each sample zoneInner zone Dead zone Outer zone

20-40 40-60 0-20 20-40 40-60 0-20 20-40 40-60+ + ++ + ++ + ++ + ++ + ++ + ++ + ++ + ++ + ++ + +

0-20Replicatenumber

12345678910

+ Active mycelium present- No active mycelium present

[3.4] DISCUSSION

Any method of analysis which is to be used to quantify a given characteristic must bereliably accurate and reproducible. In determining relative values which can beascribed to samples of water-repellent soil, it is important that inherent variation in

soil structure throughout the profile of the sample does not detract from the final

result. In soil samples taken from areas of managed amenity turf, the structure of theprofile can vary widely at any given point. Normal maintenance practices affect thecomposition and structure of the soil profile, either directly by the addition of topdressing material used to improve surface levels or indirectly by the stimulation ofroot growth into hollow tine holes introduced to aid surface drainage, reduce thatchdepth and to allow aeration of the sward.

Increased root density at certain points across the profile can directly affect anymeasurement of water-repellence completed on intact soil cores. The method of King(1981) used a range of concentrations of aqueous ethanol solutions to determinerelative values of water-repellence of intact soil cores which had been allowed to air-

dry at 20 C. This drying inevitably dried the root and other organic material within the

sample and produced, by the very nature of root composition, bands of higWy water-

repellent material. Application of certain aqueous ethanol solutions to the soil surface

(King 1981) as the means of determining severity of water-repellence varied greatly in

their time of penetration, depending upon whether the applied droplet was placed onthe soil itself or on an adjacent dried root mass.

For an accurate assessment of a soil s water-repellence, such strong variation between

replicate drops of the same solution was deemed to be unacceptable. Since the aim of

the analysis was to determine the relative severity of water-repellence of the soilparticles themselves and not of the accumulations of organic matter, the milling andsieving of the samples was justified through its removal of much of the root andthatch material. The 1.3 mm sieve diameter used for this operation allowed almostcomplete passage of the soil particles within the sample and exclusion of the bulk ofthe free organic matter.

Determination of MEDvalues for individual soil samples indicated relative degrees of

water-repellence irrespective of their method of determination. However, by millingthe soils, the variation around the mean MEDvalue is reduced, therefore providing arelative figure of greater confidence. The actual MEDvalue in itself is not a complete

assessment of the soils water-repellence. It is more accurate to identify both the MED

value and the mean penetration time of the specific concentration of aqueous ethanolapplied. The importance of this is that any given concentration of aqueous ethanolmay have widely varying mean penetration times across different soil samples, but as

long as the mean time is less than 10 seconds, each of the soils will be ascribed thesame MEDvalue. This may give a false impression that all of the ascribed soils havethe same degree of water-repellence. This discrepancy can be overcome by

incorporating the mean penetration time with the MID value in the presentation of theresults.

The expression of the data in this manner identifies a closer grouping of the actual

values from soils which have been milled prior to analysis. This is perhaps furtherevidence that the milling of soil samples prior to determination of relative levels ofwater-repellence is a much more reproducible analysis. The higher MED valuesascribed to soils sampled from the outer zone of the ring at Ganton golf course can beaccounted for by the presence of active fungal mycelium within the soil taken from

this zone. Identification of the different zones in the M. oreades ring can be difficultto achieve if relying on the above ground symptoms alone. However, for the purposeof this assessment, it is of little significance that soil taken from the apparent outerzone of the ring, contained active mycelium. The results of the analysis still allowedidentification of the improvement in reproducibility of data using milled soils.

At Ganton golf course, the soil samples provided higher values of MED when

compared with those from Shipley golf course. This result reflects the inherentdifference in soil type present on both sites. Soils from Ganton golf course contain ahigher proportion of sand compared with Shipley golf course and as such, provide a

lower surface area per given volume of soil on which the water-repellent material canbe deposited.

The information obtained from this study has identified the possibility that animprovement in the reliability of relative value of water-repellence (MEDvalues) can beachieved by milling and sieving the soil prior to analysis. The results indicate thatmilling of the soil generally increased the MID values ascribed to the samples, butvariation between replicate drops of individual aqueous ethanol solutions on soilsamples removed from comparable locations around a M. oreades fairy ring isreduced.

In further analyses requiring assessment of a soil s water-repellence, it is this

amended ~ethod of King (1981) which has been used.