Volume 7
Issue 2
Forestry
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume7/issue2/forestry/art-10.html
INFLUENCE OF FOREST SLOPE ROAD ON WATER STORAGE IN ADJOINING SOILS
Janusz Goł±b
There were undertaken researches describing quantitative changes of water storage in wayside zone soils, as well as the differences in storage, caused in this zone by cut of water-bearing layers connected with the road excavations. It was assumpted, that studying the water storage in land profiles suitably situated in relation to road course, it is possible to establish the road draining effect. Near the same road three transverse sections were chosen, on each of them three land profiles. And in separate layers the moisture sensors were placed. The moisture, measured on improved conductometric method, was according to original methodology by Kucza and Suliński counted on water storage in profile layers dimension. Measurements were taken in Beskid Śląski forests in vegetative period of 1999 year (27. III – 29. X) once a week. Separate measuring session with everyday observations lasted for eight days (7-14. VIII. 1999r). Researches were conducted in the same places, utilizing the same measur
Key words:
water balance; the water storage in soil; forest slope road; drainage of a slope..
INTRODUCTION AND AIM
The forest slope roads are in mountain forestry very essential part of the communication net however road location in excavation itself causes that the road takes over a water leaking from sectioned water-bearing layers. This water led directly to streams avoids the retention-active part of forest surface situated directly below road. This accelerates considerably the water outflow from drainage area and reduces the part of forest in water outflow regulation [2, 3]. Building right arrangement of culverts or spillways reduces meaning of road draining effect, however the water outflow from these devices on slope is punctual and arrangement of water relations of this part of slope is not reproduced to state from before road building.
It was an assumption made on the beginning of works that the wayside zone of slope has disturbed water relations. The excavation of water-bearing layers dries off the slope lying over the road. Meanwhile the part of slope below the road is detached from the tributary of water flowing down intercoated way. These disturbances can also be result of a gap formed in stand, which differentiates the quantity of energy reaching stand interior on the edge of hatches in comparison with interior in full density. It was assumed that the influence of road on water relations could be seized by locating the investigative profiles in zone of 30 meters both sides from edge of road track-way. Because of technical and financial regards it wasn’t possible to establish verifying investigative profiles beyond the area of expected road influence. In order to interpret the dynamics of water storage by keeping the rule quasi ceteris paribus, the efforts were made to eliminate some of plenty factors having an effect on water balance.
As an object of investigations were accepted the water relations in soils adjoining to road belt, formed under influence of cut of soil cover and bedrock by the road excavation.
The object of investigations one should consider in two aspects. The first concerns the drainage of water flowing down subterraneously as well as the interception by road excavation of water flowing down on the surface and diversion collected or by spillways (and culverts) on a slope below the road, or on road crown parallel to its axis. The object of investigations links directly to results of these processes that is water storage in soil.
The second aspect concerns the soil water storage dynamics as a biotope factor. The hydrogeological conditions are, beside of meteorological conditions over the tree crowns, decisive about external conditions of the formation of forest assemblages water balance [6]. The steady drainage of soil cover should doubtlessly influence on conditions creating definite water relations in soils connected with gravitationally flowing down water occurrence. One should however underline, that in conditions of excess of precipitation in relation to atmosphere water receiving ability the accessibility of water for the tree roots means comparatively less for optimal water relations shaping in soils.
The main aim of investigations is verification of thesis that the deeply cut slope roads create the slope water-bearing layers draining system and cause the water relations disorder in the soils adjoining to track-way. In steady external conditions the position of soil profile in relation to the road should be a factor formatting these distortions size even when as years go by after building the road the new arrangement of water relations in wayside zone undergo a stabilization.
METHODS
Description of investigations area and measuring profiles
In 1997 year Department of Forest Engineering of Cracow Agricultural University built on area of Dupniański stream catchment (Nadle¶nictwo Wisła) measuring devices to investigate the water balance of chosen spruce stands as well as whole drainage area. So that the investigations area is the object of specialistic descriptions [1, 9], here (tab. 1) the only basic information was quoted.
| Table 1. Climatic and geological characteristics of the research region [4, 7, 8, 10] |
|
geographical region [4] |
Beskid ¦l±ski |
|
climatic region [4] |
Carpathian |
|
ground [4] |
marls, limestones, sandstones, conglomerates |
|
annual precipitation (inside winter half-year) [10] |
1200 mm (400 mm) |
|
annual precipitation for the catchment top point [8] |
1077 mm |
|
annual precipitation for the catchment lowest point [8] |
986 mm |
|
time of lying of the snow-cover [10] |
120 days |
|
average annual air temperature [10] |
+ 5,5 ° C |
|
average annual terrain evaporation (Konstantinow meth.) [10] |
515 mm |
|
potential evapotranspiration (Thornthwaite method) [7] |
585 mm |
|
average multiyear specific run-off [10] |
23 l * s -1 * km -2 |
Influence of stand factors and some external factors on balance dimensions were to be minimized by locating the places of measurement in possibly similar stands, near the same road, in small distance from each other, arranged equal way on transverse section in relation to road course. In Le¶nictwo Bukowiec forests three transverse sections were chosen, on each of them three land profiles. Their location was shown on fig. 1. Stands description was set down in tab. 2, technical parameters of roads as well as description of terrain in wayside zone was put in tab. 3, however the layers in profiles characteristic in tab. 4.
| Fig. 1. Scheme of ground profiles localization in cross-sections |
 |
| Table 2. Characteristics of stands around research profiles. (r = 10 m; convert to 1 ha) |
|
profile |
|
|
n |
Eg |
supplementary description |
|
C1 |
37.52 |
46.9 |
255 |
0.0687 |
part of the area from the slope edge (circa 50%) without the main stand, covered by the undergrowth and saplings: Picea (h=0.5-3m), indiv. Betula (h=2–3m), indiv. Fagus (h=2–4m); ground cover: Vaccinium myrtillus |
|
C2 |
36.33 |
34.3 |
414 |
0.1307 |
part of the area (circa 70%) covered by the undergrowth and saplings: Picea (h=0.5-0.8m), indiv. Betula, Fagus, Sorbus; ground cover: Vaccinium myrtillus |
|
C3 |
37.32 |
32.6 |
446 |
0.1355 |
part of the area (circa 50%) covered by the undergrowth Picea (h=0.3-0.5m), indiv. Sorbus; ground cover: Vaccinium myrtillus, Senecio, Petasites, graminae |
|
D1 |
34.43 |
38.1 |
318 |
0.0842 |
part of the area from the slope edge (circa 45%) with thin main stand, covered undergrowth and saplings: Picea (h=0.3-1m), indiv. Picea (h=2-5m), Betula and Fagus (h=1–6m), indiv. Sorbus (h<1m); ground cover: Vaccinium myrtillus, graminae |
|
D2 |
36.84 |
42.6 |
286 |
0.0820 |
circa 90% of the area covered by the undergrowth and saplings: Picea (h=0.3-1.5m), indiv. Picea (h=4m), indiv. Abies (h=0.2m), indiv. Fagus (h=0.7–5m), indiv. Betula (h=1.5m.), indiv. Sorbus (h=0.3-1.5m.); ground cover: Vaccinium myrtillus |
|
D3 |
37.33 |
39.7 |
318 |
0.0875 |
circa 5% of the area covered by the undergrowth and saplings: Picea (h=0.3-0.8m), indiv. Fagus (h=0.5–5m), indiv. Sorbus; ground cover: Vaccinium myrtillus |
|
E1 |
33.81 |
39.2 |
382 |
0.0932 |
part of the area from the slope edge (circa 20%) covered by the compact undergrowth and saplings: Picea (h=2-3m), Fagus (h=0.5–6m), indiv. Abies (h=0.2–6m), indiv. Sorbus (h=2m); ground cover: Vaccinium myrtillus |
|
E2 |
28.67 |
33.3 |
286 |
0.0560 |
with almost no ground cover, indiv. Picea (h=0.4-0.8m), indiv. Sorbus; ground cover: indiv. Pteropsida |
|
E3 |
38.57 |
41.3 |
191 |
0.0302 |
circa 20% of the area covered by the seedlings and undergrowth: Picea, Abies and Fagus (h<0.5m), indiv. Sorbus; ground cover: Vaccinium myrtillus |
where: C, D, E – cross-sections; 1, 2, 3 – TYPE of the ground profile;  – average height;  1,3 – average breast height; n – trees number; Eg – ground uncover coefficient |
| Table 3. Slope road parameters and adjacent terrain description |
|
cross-section |
position with regard to road *) |
slope |
Height |
surface |
longitudinal declivity |
Crosswise |
Width |
Depth |
|
C |
n |
42 % |
2.3 m |
hard |
1.3 % |
1.0 % |
6.7 m |
0.3 m |
|
p |
35 % |
5.5 m |
||||||
|
D |
n |
39 % |
1.8 m |
hard |
1.0 % |
0.2 % |
5.4 m |
0.1 m |
|
p |
45 % |
4.6 m |
||||||
|
E |
n |
42 % |
2.4 m |
hard |
3.2 % |
3.8 % |
5 m |
0.1 m |
|
p |
45 % |
4.5 m |
| *) - n – slope up to the road, - p – slope under the road. |
| Table 4. Selected physical characteristics of appearance grounds in profiles |
|
profile |
layer |
type of the ground according to |
volumetric density |
specific density |
hi |
ni |
wr i |
fr >2mm |
wred i |
|
Pk max i |
|
C1 |
pr m1 m2 |
P“pi” Pg G |
0.56 1.20 1.32 |
2.33 2.62 2.62 |
100 200 350 |
0.76 0.54 0.50 |
166.5 45.1 37.4 |
6 18 37 |
0.94 0.82 0.63 |
35.8 5.5 4.8 |
54.6 44.1 41.2 |
|
C2 |
pr m1 m2 |
P“pi” P“pi” Pg |
0.32 1.54 1.42 |
2.10 2.64 2.66 |
50 250 400 |
0.85 0.42 0.47 |
337.7 27.0 32.8 |
6 18 37 |
0.94 0.82 0.63 |
40.3 3.6 4.5 |
62.2 34.4 38.2 |
|
C3 |
pr m1 m2 |
P“pi” “Pi”p Pg |
0.66 1.44 1.43 |
2.52 2.63 2.63 |
100 150 450 |
0.74 0.45 0.46 |
118.9 31.6 32.0 |
6 18 37 |
0.94 0.82 0.63 |
14.3 4.0 3.7 |
57.0 37.9 38.4 |
|
D1 |
pr m1 m2 |
P Pg P“pi” |
0.53 1.30 1.25 |
2.26 2.62 2.60 |
50 100 300 |
0.77 0.50 0.52 |
256.6 38.7 41.3 |
6 18 37 |
0.94 0.82 0.63 |
34.0 5.0 5.3 |
56.5 41.8 42.9 |
|
D2 |
pr m1 m2 |
P Pg P“pi” |
0.84 1.27 1.43 |
2.53 2.65 2.63 |
100 150 350 |
0.67 0.52 0.46 |
95.4 41.0 31.9 |
6 18 37 |
0.94 0.82 0.63 |
15.5 3.6 3.5 |
50.8 43.5 38.5 |
|
D3 |
pr m1 m2 |
P“pi” Pg P“pi” |
0.69 1.25 1.24 |
2.42 2.62 2.63 |
200 200 250 |
0.71 0.52 0.53 |
111.7 41.6 42.3 |
6 18 37 |
0.94 0.82 0.63 |
19.8 4.9 4.0 |
52.9 43.1 43.9 |
|
E1 |
pr m1 m2 |
P“pi” Pg G |
0.49 1.27 1.30 |
2.23 2.62 2.61 |
50 150 350 |
0.78 0.52 0.50 |
187.2 40.9 38.8 |
6 18 37 |
0.94 0.82 0.63 |
35.9 5.3 5.6 |
57.6 42.6 41.6 |
|
E2 |
pr m1 m2 |
P“pi” P“pi” Pg |
0.59 1.30 1.44 |
2.49 2.62 2.63 |
100 300 400 |
0.76 0.50 0.45 |
175.2 38.9 31.6 |
6 18 37 |
0.94 0.82 0.63 |
18.4 6.2 4.1 |
58.7 41.3 37.9 |
|
E3 |
pr m1 m2 |
Pg Pg G |
0.77 1.12 1.16 |
2.53 2.53 2.60 |
80 150 450 |
0.70 0.56 0.55 |
137.3 49.8 47.8 |
6 18 37 |
0.94 0.82 0.63 |
22.4 6.4 4.5 |
52.9 45.4 45.7 |
where: C, D, E – cross-sections; 1, 2, 3 – TYPE of the ground profile; org, m1, m2 – organic and mineral layers of the profile; hi – layer thickness; ni – layer porosity; wr i – layer maximal humidity; fr >2mm – percentage of the fraction up to 2 mm in the layer; wred i – layer reduction coefficient with regard to for share of the fraction up to 2 mm;  om i – mean content of organic components in the layer; Pk max i – maximal porosital capacity of the layer [5]. |
Way of the water storage enumerating in soil
Water storage in edifying the profiles soil layers were counted on the moisture measured with conductometric method, applied and improved in Department of Forest Engineering of Cracow Agricultural University by Kucza and Suliński. Original counting methodology (mentioned scholars' authorship), applied in storage calculations came into being during over ten years of investigations in different soils and at present is being prepared to publication. Only final formulae of calculation were quoted here. For individual layer of soil in profile the water storage is counted on basis of following formula:
 |
where:
Zi - water storage in the profile layer [mm]
hi - layer thickness [mm]
ni - ground porosity in the layer
Sri - ground humidity degree of the layer
wred i - layer reduction coefficient with regard to for share of the gravel and stone fraction
In order to count the water storage in whole profile one should add up storage in layers.
The variable factor for soil layer, dependent from value of current humidity is here the humidity degree, which is being enumerated according to formula:
 |
wi - ground layer humidity,
wr i - maximal ground layer humidity
Individual indispensable factor values to calculate of storage (except current humidity) for every layer of investigative profiles were shown in tab. 4.
RESULTS
The size of water storage in soil basic on weekly measurements
The example of research results statement for one section was put in tab. 5 as well as on fig. 2. Soil water storage isoline was interpolated on fig. 2C with the criging method according to values measured on three depths in profile, and then counted on the soil layer of 1 cm.
| Table 5. Water storage [mm] according to measure in the vegetative season 1999 in layers on the cross-section D and selected hydrological parameters of the catchment |
|
date |
marked out |
D1 |
D1 |
D1 |
D2 |
D2 |
D2 |
D3 |
D3 |
D3 |
P |
e |
Q |
|
27 III |
1 |
9.7 |
29.6 |
69.8 |
43.8 |
33.4 |
73.7 |
63.6 |
55.7 |
54.1 |
34.0 |
2.18 |
18.5 |
|
6 IV |
8.6 |
23.6 |
70.7 |
37.2 |
33.3 |
73.7 |
63.8 |
61.2 |
56.6 |
3.4 |
4.58 |
46.8 |
|
|
15 IV |
9.2 |
26.2 |
66.3 |
36.3 |
29.7 |
73.4 |
58.4 |
53.6 |
52.6 |
18.4 |
2.24 |
12.3 |
|
|
23 IV |
10.3 |
34.4 |
72.6 |
43.0 |
36.1 |
74.1 |
64.7 |
57.6 |
54.5 |
37.8 |
4.71 |
9.6 |
|
|
29 IV |
9.3 |
25.1 |
71.2 |
43.3 |
36.9 |
73.3 |
67.4 |
56.5 |
54.4 |
12.8 |
1.53 |
6.0 |
|
|
7 V |
8.8 |
23.9 |
71.8 |
41.2 |
33.4 |
72.2 |
64.3 |
57.8 |
54.5 |
13.8 |
5.02 |
6.2 |
|
|
14 V |
8.9 |
21.3 |
71.3 |
44.8 |
38.5 |
75.4 |
67.4 |
60.6 |
57.3 |
38.0 |
3.21 |
5.0 |
|
|
21 V |
8.9 |
23.3 |
71.3 |
42.5 |
37.6 |
74.9 |
68.1 |
59.3 |
55.2 |
24.4 |
4.42 |
5.9 |
|
|
27 V |
7.9 |
19.6 |
70.1 |
41.5 |
31.5 |
74.2 |
68.1 |
58.6 |
54.7 |
3.8 |
5.06 |
3.8 |
|
|
mean water storage in the period |
9.07 |
25.22 |
70.57 |
41.51 |
34.49 |
73.88 |
65.09 |
57.88 |
54.88 |
||||
|
4 VI |
2 |
7.0 |
15.0 |
72.5 |
38.4 |
36.7 |
72.7 |
68.9 |
60.6 |
55.1 |
34.0 |
5.82 |
6.1 |
|
11 VI |
9.0 |
19.2 |
72.5 |
45.1 |
38.0 |
76.0 |
66.5 |
61.0 |
56.2 |
36.6 |
3.26 |
8.2 |
|
|
18 VI |
9.4 |
21.6 |
72.3 |
44.3 |
37.7 |
76.6 |
67.1 |
60.6 |
56.3 |
58.0 |
0.91 |
9.5 |
|
|
25 VI |
9.8 |
24.1 |
72.0 |
43.5 |
37.5 |
77.1 |
67.8 |
60.2 |
56.4 |
80.0 |
1.35 |
50.4 |
|
|
2 VII |
8.4 |
20.0 |
71.1 |
40.6 |
36.3 |
77.1 |
69.8 |
62.1 |
56.2 |
0.8 |
5.60 |
22.5 |
|
|
9 VII |
9.0 |
15.0 |
72.9 |
44.4 |
52.5 |
77.3 |
70.1 |
63.7 |
57.1 |
54.6 |
6.44 |
7.8 |
|
|
16 VII |
9.5 |
23.4 |
72.7 |
44.3 |
44.5 |
77.2 |
66.9 |
62.3 |
55.3 |
37.6 |
2.04 |
8.7 |
|
|
23 VII |
8.1 |
17.0 |
74.0 |
45.3 |
38.0 |
78.6 |
73.8 |
63.9 |
58.0 |
25.4 |
6.41 |
7.4 |
|
|
30 VII |
5.7 |
15.0 |
72.0 |
46.7 |
36.3 |
76.8 |
68.3 |
63.3 |
55.3 |
1.2 |
3.81 |
5.0 |
|
|
mean water storage in the period |
8.43 |
18.92 |
72.44 |
43.62 |
39.72 |
76.6 |
68.8 |
61.97 |
56.21 |
||||
|
7 VIII |
3 |
5.2 |
14.1 |
63.9 |
29.0 |
26.2 |
70.6 |
68.2 |
62.6 |
55.0 |
5.6 |
6.34 |
3.1 |
|
14 VIII |
5.2 |
14.1 |
51.3 |
25.5 |
20.7 |
64.6 |
64.8 |
57.3 |
49.1 |
10.5 |
3.50 |
2.1 |
|
|
23 VIII |
5.2 |
14.4 |
39.6 |
25.4 |
20.0 |
63.8 |
68.1 |
58.3 |
51.0 |
9.5 |
2.45 |
2.1 |
|
|
30 VIII |
5.2 |
14.1 |
39.0 |
25.4 |
19.2 |
55.2 |
66.7 |
55.6 |
49.8 |
14.1 |
4.29 |
1.3 |
|
|
7 IX |
5.2 |
14.1 |
39.0 |
25.3 |
19.2 |
53.1 |
55.5 |
55.0 |
47.3 |
12.0 |
3.33 |
2.0 |
|
|
15 IX |
5.2 |
14.1 |
39.0 |
25.3 |
19.1 |
46.2 |
46.3 |
52.6 |
43.8 |
0.0 |
4.50 |
1.1 |
|
|
mean water storage in the period |
5.20 |
14.15 |
45.30 |
25.98 |
20.73 |
58.92 |
61.60 |
56.90 |
49.33 |
||||
|
24 IX |
4 |
5.2 |
14.1 |
39.0 |
25.5 |
19.1 |
48.1 |
43.7 |
43.1 |
40.2 |
0.0 |
4.19 |
1.1 |
|
1 X |
5.2 |
14.1 |
39.0 |
26.0 |
19.1 |
48.1 |
38.1 |
46.0 |
40.2 |
50.0 |
2.79 |
2.0 |
|
|
8 X |
5.2 |
14.1 |
39.0 |
29.9 |
19.3 |
55.1 |
41.7 |
53.5 |
42.6 |
46.0 |
1.45 |
3.0 |
|
|
15 X |
5.2 |
14.1 |
39.0 |
30.8 |
19.6 |
58.3 |
53.3 |
57.1 |
45.1 |
86.0 |
0.61 |
12.2 |
|
|
22 X |
5.2 |
14.1 |
39.0 |
31.0 |
21.5 |
62.2 |
55.1 |
55.8 |
47.0 |
19.8 |
0.75 |
14.2 |
|
|
29 X |
5.2 |
14.1 |
39.0 |
29.5 |
20.2 |
61.3 |
50.7 |
51.9 |
47.1 |
6.2 |
1.40 |
7.2 |
|
|
mean water storage in the period |
5.20 |
14.10 |
39.00 |
28.78 |
19.80 |
55.52 |
47.10 |
51.23 |
43.70 |
||||
| where: 1, 2, 3 – TYPE of the ground profile; org, m1, m2 – organic and mineral layers of the profile; P – weekly sum of the rainfall; e – weekly mean of deficit of the air humidity; Q – sum of the water outflow from the catchment. |
| Fig. 2. Graphic presentation of research results for the D1 profile |
 |
The size of soil water storage on basis of everyday measurements
Everyday researches were executed applying measuring apparatus used for simultaneously lasting weekly measurements. The aim of these researches was seizing the changes of storage in profiles, as reaction on current weather changes and influence of the vegetation.
The measurements were executed two or three times a day, then one day measured values were averaged for every layer of all the profiles. Averages received this way were day storage and as such subjected to statistical analysis. The statement of summed data for whole profiles for whole eightdays' investigative period was put in tab. 6 and on fig. 3.
| Table 6. Water storage [mm] according to daily measure as average of storage values in layers and selected hydrological parameters of the catchment |
|
Date |
C1 |
C2 |
C3 |
D1 |
D2 |
D3 |
E1 |
E2 |
E3 |
P |
e |
|
7 VIII |
151.4 |
141.8 |
135.9 |
84.0 |
127.9 |
182.8 |
121.1 |
148.2 |
151.8 |
0.0 |
4.38 |
|
8 VIII |
146.3 |
134.2 |
134.0 |
84.0 |
128.2 |
180.1 |
117.2 |
148.4 |
156.9 |
1.5 |
4.05 |
|
9 VIII |
145.3 |
137.9 |
128.4 |
79.5 |
121.9 |
179.5 |
113.9 |
141.4 |
153.1 |
0.1 |
3.92 |
|
10 VIII |
140.1 |
136.5 |
126.1 |
78.5 |
120.5 |
181.3 |
111.7 |
140.3 |
153.4 |
1.1 |
3.18 |
|
11 VIII |
143.2 |
132.9 |
131.3 |
77.0 |
122.2 |
182.5 |
113.6 |
139.7 |
157.9 |
6.5 |
2.61 |
|
12 VIII |
137.8 |
133.2 |
130.0 |
75.4 |
119.7 |
178.7 |
112.0 |
138.5 |
151.7 |
0.3 |
2.87 |
|
13 VIII |
132.2 |
130.1 |
127.5 |
74.3 |
121.2 |
176.0 |
108.8 |
130.2 |
146.6 |
0.0 |
3.66 |
|
14 VIII |
130.4 |
128.7 |
126.8 |
70.7 |
112.1 |
171.2 |
106.9 |
128.7 |
140.5 |
0.1 |
4.84 |
| where: C, D, E – cross-sections; 1, 2, 3 – TYPE of ground profile; P – daily sum of the rainfall; e – daily mean of deficit of the air humidity. |
| Fig. 3. Graphic presentation of research results for the D cross-section |
 |
Statistical analysis of material from weekly measurements
The analysis of shown results of measurements was steered on main (from point of view of put thesis) question: if the position of investigative profile in relation to road has essential influence on size and dynamics of water storage in soil profile.
To achieve it there were four investigation schemes built and the hypotheses were tested with method of multifactorial variance analysis (using STATGRAPHICS 1.4 PL). Classifying factors according to which dependent variables were assembled to examining variances were: 1) three types of profiles, 2) three investigative sections, 3) three layers in every profile, 4) four investigative periods on which measuring year was divided since 27 III to 29 X 1999. Soil exposure factor was introduced to variance analysis as accompanying variable.
When analysing data there were undertaken attempts to include different classifying factors of drainage area water outflow in periods between measurements as well as thickness or maximum field water capacity of individual layers and whole investigative profiles. From variance analysis point of view these factors had not the essential influence on size and dynamics of soil water storage, therefore it was skipped in description of investigation results. This fact can be possibly connected to a picture of maximum values of field water capacities: in 27 layers separated from 9 investigative profiles these values were not exceeded during 30 measuring days. So investigative profiles administered large reserve of water capacity (fig. 2D) therefore there was no "cutting” the value of accumulated water storage, nor current increases after rainfalls.
Both the sizes of water storage and their increases were studied in two versions: 1) the isolated values after count on soil layer of 1 cm, 2) as totals for whole profile. The results of chosen analyses were assembled in tab. 7, 8 and 9.
| Table 7. Results of hypothesis tests concerning to relations between water storage in examining profiles and their position to the road (with the storage accounting distribution inside profiles) |
|
explained dependent variable: Z¢ 810 |
impact of the |
|||||
|
Variability |
Squares |
Degrees |
Mean |
F test values |
Significance |
|
|
accompanying variables |
||||||
|
Eg 810 |
24.418 |
1 |
28.418 |
113.15 |
0.0000 |
significant |
|
(Eg 810)2 |
26.2053 |
1 |
26.2053 |
104.34 |
0.0000 |
significant |
|
main factors |
||||||
|
cross-section810 |
36.7208 |
2 |
18.3604 |
73.11 |
0.0000 |
significant |
|
profile810 |
35.8792 |
2 |
17.9396 |
71.43 |
0.0000 |
significant |
|
layer810 |
35.9833 |
2 |
17.9916 |
71.64 |
0.0000 |
significant |
|
period810 |
94.4531 |
3 |
31.4844 |
125.36 |
0.0000 |
significant |
|
rest |
200.414 |
798 |
0.251145 |
|||
|
total |
395.492 |
809 |
||||
| where: Z¢ - water storage in the profile layer recalculated to layer thickness 1 cm; Eg - soil exposure coefficient; 810 - analysed data number. |
| Table 8. Values of specific water storage means in classifying groups and results hypothesis tests concern of classifying factors impact |
|
Classifying |
mean values |
result of the differences significance test |
|
|
profile |
TYPE 1 |
1.75 |
TYPE 1 and TYPE 2 – insignificance means differences |
|
layer |
organic (org) |
1.80 |
all means are different |
|
cross-section |
C |
2.44 |
all means are different |
| Table 9. Results of hypothesis tests concerning to relations between water storage increments in examining profiles and their position to the road (with the storage accounting distribution inside profiles) |
|
explained dependent variable: “delta”Z¢ 810 |
impact of the |
|||||
|
variability |
Squares |
degrees |
Mean |
F test values |
Significance |
|
|
accompanying variables |
||||||
|
Eg 810 |
2.62*10-5 |
1 |
2.62*10-5 |
0.00 |
0.9803 |
insignificant |
|
(Eg 810)2 |
3.78*10-6 |
1 |
3.78*10-6 |
0.00 |
0.9925 |
insignificant |
|
main factors |
||||||
|
cross-section810 |
5.54*10-3 |
2 |
2.77*10-3 |
0.07 |
0.9358 |
insignificant |
|
profile810 |
1.94*10-2 |
2 |
9.69*10-3 |
0.23 |
0.7927 |
insignificant |
|
layer810 |
2.03*10-2 |
2 |
1.01*10-2 |
0.24 |
0.7844 |
insignificant |
|
period810 |
2.30077 |
3 |
0.766923 |
18.40 |
0.0000 |
significant |
|
rest |
32.1411 |
771 |
4.17*10-2 |
|
|
|
|
total |
34.5152 |
782 |
|
|
|
|
| where: “delta”Z¢ - water storage increments in the profile layer recalculated to layer thickness 1 cm; Eg - soil exposure coefficient; 810 - analysed data number. |
Verbalizing results assembled in these tables one may state that all classifying factors have essential influence on shaping the size of water storage in studied profiles Assembling isolated storage regarding to profiles’ position in relation to road show characteristic order. The smallest stores appeared in the closest to road excavation profiles (TYPE 1- tab. 8, fig. 1), basing on mathematical statistics the stores in the profiles TYPE 2 were the same (column 4 in tab. 8), the largest in profiles below road excavation (TYPE 3). This ascertainment is the most important in aspect of main aim of this work. Moreover the fact pays attention, that the moistest was the central part of profile what is different result from received for profiles on lowland. It is worth to underline influence of investigative profile adherence to one of three sections – initially it can be to admit that this is connected to slope exposure, that is with quantity of energy reaching over the tree crowns.
Described factors had no meaning for shaping of increases of isolated soil water stores value. This ascertainment bases on variance analysis assembled in tab. 9.
Statistical analysis of data from everyday measurements
The same hypotheses, formulated to reach the same cognitive aim were tested basing on 24 hours data. The hypotheses were tested by method of multifactorial variance analysis according to two schemes – taking into account the differences of stores in individual layers of profiles (216 data; counted the soil layer of 1 cm), and after adding up to value for whole profiles (72 data; without counting to layer of 1 cm).
The results of chosen analyses are assembled in tab. 10, 11 and 12.
| Table 10. Results of hypothesis tests concern to relations between water storage in examining profiles and their position to the road |
|
explained dependent variable: Z72 |
impact of the |
|||||
|
Variability |
Squares |
Degrees |
Mean |
F test |
significance |
|
|
accompanying variables |
||||||
|
Eg 72 |
14406.4 |
1 |
14406.4 |
91.79 |
0.0000 |
significant |
|
(Eg 72)2 |
13694.1 |
1 |
13694.1 |
87.25 |
0.0000 |
significant |
|
main factors |
||||||
|
cross-section72 |
14099.3 |
2 |
7049.67 |
44.92 |
0.0000 |
significant |
|
profile72 |
34113.0 |
2 |
17056.5 |
108.68 |
0.0000 |
significant |
|
rest |
10201.7 |
65 |
156.949 |
|
|
|
|
total |
50685.1 |
71 |
|
|
|
|
| where: Z - water storage in the profile (sum of layer storage); Eg - soil exposure coefficient; 72 - analysed data number; |
| Table 11. Values of water storage means in classifying groups and results hypothesis tests concern of classifying factors impact |
|
Classifying |
mean values |
result of the differences significance test |
|
|
profile |
TYPE 1 |
1.49 |
all means are different |
|
layer |
organic (pr) |
1.52 |
all means are different |
|
cross-section |
C |
2.15 |
cross-section D and E – differences insignificant, |
| Table 12. Results of hypothesis tests concerning to relations between water storage increments in examining profiles and their position to the road |
|
explained dependent variable: “delta” Z72 |
impact of the |
|||||
|
Variability |
Squares |
Degrees |
Mean |
F test values |
Significance |
|
|
accompanying variables |
||||||
|
Eg 72 |
4.06059 |
1 |
4.06059 |
0.39 |
0.5435 |
insignificant |
|
(Eg 72)2 |
3.63113 |
1 |
3.63113 |
0.35 |
0.5654 |
insignificant |
|
main factors |
||||||
|
cross-section72 |
4.94858 |
2 |
2.47429 |
0.24 |
0,7912 |
insignificant |
|
profile72 |
2.63194 |
2 |
1.31597 |
0.13 |
0.8826 |
insignificant |
|
rest |
589.011 |
56 |
10.5181 |
|
|
|
|
total |
606.026 |
62 |
|
|
|
|
| where: “delta”Z - water storage increments in the profile (sum of increments in layers); Eg - soil exposure coefficient; 72 - analysed data number. |
Conducted on both sets of data (weekly and 24 hour) analyses give the coherent results confirming that all classifying factors have essential influence on water storage size shaping in studied profiles. In both cases assembling isolated stores referring to profile position in relation to road showed characteristic order. The smallest stores appeared in the closest to road excavation profiles (TYPE 1 - tab. 11; comp. tab. 8, fig. 1.), meanwhile the largest stores were observed in profiles TYPE 3, that means situated below road excavation (column 3 in tab. 11; comp. tab. 8).
Described factors had no meaning for shaping value of isolated soil water storage increments (tab. 12).
Despite of changing classifying factors in next analyses, every time results received were giving the same answer to set in work aim question.
The final composition of test results demonstrating the existence or lack of essential influence of classifying factors on studied storage sizes and its dynamics permitted to accept two deductions:
the influence of position of investigative profiles in relation to slope road on soil water storage size examined with fulfillment the principle quasi ceteris paribus is essential. The smallest water stores were found in profiles on slope above the road near excavation edge, the biggest amount of water had below road profiles,
the profile position in relation to the road has not the essential influence on observed dynamics of water storage.
CONCLUSIONS
Basing on analysis of investigations’ results one should infer, that:
Cutting of slope and bedrock with road excavation is effective with water storage value decrease in soil profiles in closer to road stands. This can be connected to long-lasting effect of land water drainage caused by the road excavation.
Logically, shaping of water storage value in soil is connected with increment sizes following rainfalls and as result of evaporation in rainless periods. Therefore the transformations of storage increments should suit to appropriate transformations of storage value. The fact, that investigative profiles position in relation to the road was not formative factor for increase values, can be translated twofold:
taking under attention the period of over ten years passed from building the road it is possible to admit that examined state was stabilized in new hydrogeological and forest stand conditions, that means, the storage increases are not subject to larger changes;
the scale of water storage increase transformations in result of drainage by the road excavation turned out smaller than "sensitivity” investigative method applied.
The influence of profile position in relation to road on soil water storage was examined with eliminating influence of other recognizable factors modeling the water relations of soils, including soil forest vegetation protection degree. However it is not possible to be sure that the applied coefficient of soil exposure fully reflects the conditions of transfer of solar radiation and wind speed reduction in stands in vicinity of gap formed after tree cut in borders of track-way.
Water storage decrease in profiles closest to the edge of excavation in relation to further laid does not exceed the excess of precipitation in relation to possible evaporation therefore it should not be effective with lowering the quality of forest stands.
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Janusz Goł±b
Department of Forest Engineering
Cracow Agricultural University
29 – listopada 46, 31-425 Cracow, Poland
e-mail: rlgolab@cyf-kr.edu.pl
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