CONTENT Vol. 2 - Humus.ru

15th IHSS Meeting- Vol. 2
compared to virgin ones, the same geographical relationships of humus accumulation can be
observed. Therefore, losses of humus as well as its supply increase from Albeluvisols (soils of
Podzol type) to Albic Luvisols (soils of Grey forest type) and then to Luvic Chernozem (soils
of Chernozem type), later, in Kastanozems/Calcisols (steppe chestnut soils), humus losses
decrease (Table 1). From response of these soils to ploughing and their subsequent utilization
one should expect to note that chernozems are the least ecologically resistant soils. It
contradicts to generally accepted conceptions as concerns these soils. In reality, there is no
contradiction, if to take into account the fact that in chernozems more than half of humus
losses arise from erosion processes. As for the soils under irrigation, here the losses at the
expense of irrigation erosion are especially revealed.
Soil, location
Epigenic
Albeluvisols,
taiga (soils
of Podzol type)
Albic Luvisols,
forest steppe
(soils of Grey
forest type)
Luvic Chernozem,
forest steppe
(leached
chernozems)
Luvic
Chernozem,
steppe
(ordinary
chernozems)
Kastanozem/
Calcisols, steppe
(chestnut
soil)
Table 1. Some characteristics of humus and humic acids
Humus,
t per ha
in 1 m
layer
147.6
135.9
215.9
186.8
395.7
308.6
(265.2*)
370.5
280.9
177.8
168.5
(158.2*)
Losses of
humus, %
of total
content, %
8 1.7
1.3
14 1.9
1.4
22
(33*)
HA/FA
2.4
1.7
(1.5*)
24 2.2
5.2
(11.1*)
1.8
1.8
1.4
(1.2*)
CEC,
cmol c /kg
HA
340
300
430
380
490
440
(410*)
500
450
470
420
(400*)
Decrease
in CEC,
%,
Some indices of HA
12 39
24
12 37
28
11
(16*)
С of hydro-
lyzate,% of
total mass
of HA %
32
24
(17*)
10 33
11
(15*)
24
25
25
(20*)
DA,
23
28
20
31
%
29
39
(39*)
27
36
25
35
(35*)
Note: above line – virgin land, below line – plough land, * - under influence of 13-year
irrigation
С/N
16.1
20.9
17.7
21.8
16.9
22.8
(24.2*)
16.5
23.0
17.3
21.3
(23.1*)
Vol. 2 Page - 35 -