THE EFFECT OF PREVIOUS CROPS ON THE
CELLULOSE DECOMPOSITION ACTIVITY OF THE
SOIL
Schmidt R., Kerekes G., Szakál P., Kalocsai R., Giczi
Zs., Szlovák G.
University of West Hungary
Mosonmagyaróvár
Nutrients in the soil take part in a continuous transformation
process.
The decomposition of organic materials is done by different
groups of soil microorganisms.
Environmental parameters in the soil are changing rapidly
and the dominating groups of microorganisms vary with time
also very quickly determining of the end products of the
transformation processes.
Plant residues are the substrates of the decomposition
processes and also modify the environment where these
processes take place.
In this experiment we studied how the different plant residues
modify the cellulose decomposition activity of the soil.
According to the common belief we supposed that legume
plants have a more favourable effect on microbiological
activity and promote more intense cellulose decomposition.
Methods
The aim of the experiment was to study the effect of different previous crops
on the microbiological activity of the soil.
The experiment was carried out at the Experimental Station of the
Mosonmagyaróvár Faculty of West-Hungarian University. The type of soil was
calcareous Danube alluvial soil.
The decomposition of cellulose, that indicates the microbiological activity of
the soil was studied by “Unger cellulose test method” (Szegi 1979).
SOYBEAN (Glycine max)
MAIZE (Zea mais)
HORSEBEAN (Vicia faba)
SUNFLOWER (Helianthus annuus)
The size of the experimental plots was 3 m2. The plant residues used in the
experiment were collected from an area of the same size as the experimental
plots, were dried and cut into pieces not longer than 20 mm. The prepared
material was spread evenly on the surface of the experimental plots and mixed
into the soil down to a depth of 200 mm.
Soil analysis results
pHH2O
8.05
P2O5 (mg/kg)
397.6
pHKCl
7.31
K2O (mg/kg)
112.13
KA
56
Na (mg/kg)
33.53
CaCO3 18.7
Mg (nKCl) (mg/kg)
Humus
Zn (mg/kg)
4.76
Cu (mg/kg)
7.02
41.93
Mn (mg/kg)
24.8
9.43
Fe (mg/kg)
21.06
Total N%
3.3
0.252
NO3- (mg/kg)
NO3-N (mg/kg)
222.13
The test sacks were placed into the soil on the next day to a depth
of 150 mm. Sampling started on the 10th of March, on the 90th
day from the date when the sacks were put into the soil. Samples
were taken in each month in four repetitions till October.
Month
Precipitation mm
Average temperature
December
20.4
-1.6
January
12.2
-0.4
February
49.1
0.7
March
18.8
7.2
April
63.8
11.6
May
49.8
16.0
June
98.3
18.4
July
67.6
21.2
August
50.8
19.2
September
27.9
18.2
October
27.4
10.7
Cellulose decomposition during the experimental period in the
case of the four plant species
5
4.5
Cellulose remained (g)
4
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
Sunflower
June
Soybean
July
Aug.
Maize
Sept.
Oct.
Horsebean
In the beginning the cellulose decomposition was the slowest in
the soil treated with soybean residues, but the speed of the
decomposition became faster by the end of the vegetation period
and altogether we could measure the less amount of cellulose
residue in the case of this treatment.
5
4.5
4
Cellulose remained (g)
The
highest
initial
decomposition
speed
was measured in the
case of sunflower, but
the tendency was quite
opposite comparing to
soybean tratments and a
significant amount of
cellulose residue was
measured at the end of
the experimental period.
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
Sunflower
June
Soybean
July
Aug.
Maize
Sept.
Oct.
Horsebean
The cellulose decomposition was slower in the soil treated with
sunflower residues than in the soil where maize residues were
incorporated. The amount of the remained cellulose was lower
in the maize treated plots during the whole experimental period,
except May, though this difference disappeared by October. By
the end of the experiment 80% of cellulose was decomposed in
both cases.
5
4.5
Cellulose remained (g)
4
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
Sunflower
June
Soybean
July
Aug.
Maize
Sept.
Oct.
Horsebean
In the beginning the residues of horsebean had the same
effect as that of maize residues. Around the end of the
experiment the decomposition speed decreased and the
highest amount of cellulose remained could be measured
in the soil of soybean treated plots. Altogether 30% of the
total amount of cellulose did not decompose till the 10th of
October.
5
4.5
Cellulose remained (g)
4
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
Sunflower
June
Soybean
July
Aug.
Maize
Sept.
Oct.
Horsebean
Cellulose decomposition in the soil treated with sunflower
residue
Cellulose remained (g)
4.5
4
y = -0,424x + 4,5461
R2 = 0,9764
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
June
July
Aug.
Sept.
Oct.
Cellulose decomposition in the soil treated with soybean
residue
Cellulose remained (g)
6
y = -0,685x + 5,547
R2 = 0,9653
5
4
3
2
1
0
March
April
May
June
July
Aug.
Sept.
Oct.
Cellulose decomposition in the soil treated with maize
residue
5
Cellulose remained (g)
4.5
y = -0,4718x + 4,4344
R2 = 0,9255
4
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
June
July
Aug.
Sept.
Oct.
Cellulose decomposition in the soil treated with horsebean
residue
Cellulose remained (g)
5
4.5
4
y = -0,4027x + 4,3115
R2 = 0,8911
3.5
3
2.5
2
1.5
1
0.5
0
March
April
May
June
July
Aug.
Sept.
Oct.
Conclusions
The experiment carried out did not prove unquestionably that
the residues of legume plants promote cellulose
decomposition – that symbolised soil microbiological activity
in the experiment – more efficiently than the residues of other
plants.
Our present results were also inconsistent with literature
regarding that common statement that the decomposition of
the residues of soybean is protected, slower than the
decomposition of other annual legume plants.