沙漠研究 22-1, 255 -258 (2012 )"ICAL 1 / DT X"

Journal of Arid Land Studies－Refereed Paper－

Effect of Tillage Methods on Productivity of Winter Wheat
in the Aral Sea Basin of Uzbekistan
Nurbekov AZIZ*1), M. SULEIMENOV2), T. FRIEDRICH3), F.TAHER4), R. IKRAMOV5) and N.NURJANOV6)
Abstract: Since achieving independence, Uzbekistan has made efforts towards developing its own market economy and put amajor emphasis on agricultural growth. During this transition, large and inefficient shirkat (cooperative) farms were dismantled andmuch smaller private farms were established. For development of this new type of farms, there are constraints associated withlimited potential and abilities in crop, tillage methods, soil fertility improvement and on-farm water management. There is an urgent
need to pilot changes in agricultural practices in the region in order to improve winter wheat productivity in the salt anddrought-affected region of Aral Sea Basin of Uzbekistan. A four-year experiment was conducted, to identify best options of different
tillage methods in winter wheat cultivation, at farmers’ field in Chimbay district, of Uzbekistan (N 42°57.091’, E 059°45.798’, 69 m
above sea level). Data analysis was performed using GenStat program. The highest yield was recorded in 2007 and yield ranged
between 2.23-2.87 t ha-1. It should be mentioned here that weather conditions in 2007 were favorable for winter wheat growth anddevelopment. The absolute highest yield was recorded in the no till treatment (2.87 t ha-1) in farmer 2 and 2.81 t ha-1 in farmer 1.
Statistical analysis shows that winter wheat yield was significantly affected by years (<0.001). The conventional tillage could bereplaced by no-tillage systems that increase yield and will likely improve soil properties in the long term.
Keywords: Conservation agriculture, No-till, Soil salinity, Tillage methods, Winter wheat

1. Introduction
Since achieving independence, Uzbekistan has madeefforts towards developing its own market economy and put amajor emphasis on agricultural growth. During this transition,
large and inefficient shirkat (cooperative) farms weredismantled and much smaller private farms were established.
For development of this new type of farms, there areconstraints associated with limited potential and abilities incrop, tillage methods, soil fertility improvement and on-farmwater management. There is an urgent need to pilot changes
in agricultural practices in the region in order to improve
winter wheat productivity in the salt and drought-affected
region of Aral Sea Basin of Uzbekistan. Degradation of soil
resources in the region is widespread and it is a direct threat tothe sustainability of agricultural production.
Dramaticchanges in soil management concepts are needed to counter thethreat. Conservation agriculture proposes options for such
positive changes through addressing a very broad variety ofissues related to soil management concepts, water resourcesmanagement and erosion control, mechanization and tillage,
mulching, etc.
Tillage is one of the important agronomic techniques inmost agricultural crops while no-till is the most modern tillage
technique which is a part of conservation agriculture. No-tillcontrols soil erosion because the plant material protects the soil
surface from high winds and rainfall and prevents loosening
and carrying away of soil elements. Thus, plant nutrients andsoil organic matter remain in the field where they are very
useful for crop production. Leaving at least some crop
residues in place can slow evaporation of precious soil
moisture. This effect is increased in a dry climate because
residues are slower to degrade. No-tilling also conserves soil
moisture, so more organic matter is produced, outweighing theinitial loss of feed or of income from its sale. The objectivesof this experiment were to see effect of different tillage
methods on productivity of winter wheat growth anddevelopment in the region of Aral Sea Basin of Uzbekistan.
Touchton and Jonson (1982) conducted an experiment on
the effect of 3 different methods of tillage and plantation on theyield of wheat and soybean. The 3 tillage methods included
chisel, Moldboard plow and no tillage. The results were thatthe yield of soybean in the 2 mentioned tillage methods didn'tdiffer, but yield of wheat in case of Plow with Chisel Plow wasless than Moldboard plow.
Cox (1986) studied the effect of different methods ofpreparation of soil and 2 different types of wheat seed on the* Corresponding Author: a.nurbekov@cgiar.org
P.O. Box 4564, Tashkent, Uzbekistan; Tel: +998-90-3485425; Fax: +998-71-1207125
1) Central Asia and the Caucasus Regional Office, International Center of Agricultural Research in the Dry Areas, Tashkent, Uzbekistan 12) International Maize and Wheat Improvement Center (CIMMYT), Astana, Kazakhstan 25) Central Asian Research Institute of Irrigation, Tashkent, Uzbekistan

3) Food and Agriculture Organization of the United Nations (FAO) Rome, Italy

6) Karakalpak Branch of Uzbek Scientific Production Center for Agriculture, Tashkent, Uzbekistan4) FAO Sub regional Office for Central Asia (FAO/SEC), Ankara, Turkey

amount of yield. In that study, different methods of soil
preparation included the conventional method of the region
with keeping the vegetative remains in the field with plowing
and tillage and without plowing or tillage. From the view
point of the amount of yield no significant difference wasobserved between treatments.
2. Materials and Methods
This experiment was conducted at the two demonstrations
farms of Chimbay district, Autonomus Republic ofKarakalpakistan, Uzbekistan. High-sensitivity GPS receiver
eTrex Vista®HCx used to obtain GPS coordinates of theresearch site and the coordinates are 42º58’19.71’’ N and
59º50’38.30’’. The soil type is medium-loamy, low inorganic matter (<0.612-0.617%). The method of Mishustin,
et al. (1968) was used to assess soil fertility and todetermine the soil biological activity. The soil ofexperimental site is rather dense with the bulk density
fluctuating between 1.4 and 1.6 g/cm³. The highest bulk
density was noted in the depth of 20-40 cm. The soil ofexperimental site is rather dense with the bulk density
fluctuating between 1.4 and 1.6 g/cm³. The highest bulk
density was noted in the depth of 20-40 cm. The irrigatedareas of the experimental site are considered to be of slightly
saline soil and the value of soil salinity fluctuates from 0.199%
to 0.637%. The content of Cl ranges from 0.03 to 0.065%,
which is close to maximum allowable concentration (0.04%)
for these conditions. All soil parameters were analyzed by
the method developed in Uzbek Research Institute of Cotton(UzRIC, 1973).
Winter wheat variety Dostlik was sown in the experiment.
The experiment was initiated in the autumn of 2004 and winterwheat was planted in the first year in the beginning ofNovember and harvested at the end of June, and following
years the winter wheat planted in mid of October. No-tillsowing had not been practiced at any of the sites prior to theexperiment. Seed was placed with 4 cm of soil cover in alltreatments. Fertilizer rate was held constant for all treatments
each year.
Tillage treatments include conventional tillage or plough(CT), minimum tillage with chiseling (MTC), minimum tillage
with disking (MTD), and no-till (NT) respectively. Winterwheat seeding rate was 200 kg ha-1 for each treatment throughthe experimental years.
The experiment was laid out in randomized complete block
design. Plot size was 200 m2 (25×8 m). Field observations
were recorded on plant height, TKW, grains per spike and yield.
Biometrical analysis of winter wheat was done according to themethods developed by State Variety Testing Commission ofAgricultural Crops (SVTCAC, 1970).
The data wasstatistically analyzed using GenStat program 11 edition.
The climate of experimental site is severe continental with
hot summers and cold winters. The average summer
temperature is 30ºC often surpassing 45°C; the average wintertemperature in January is about -5°C, with absolute minimum
as low as -40°C. According to the long term data of theChimbay Meteo Station, located in Chimbay district ofUzbekistan, the mean long-term precipitation is 110 mm,distributed as 18 mm in fall (September- November), 60 mm inwinter (December-March), 24 mm in spring (April-May), and8 mm in summer (June-August).

3. Results and Discussion
Humus content was higher with no-till wheat in the
0-10 cm depth, but lower at the 10-15 cm depth in Table 1.
This is explained by well known fact of differentiation ofsoil fertility as a result of conservation tillage when soil is
not turned up.
Overall, the no-till treatment hadsignificantly more organic matter.
There was a small, but significantly lower pH in the top
10 cm of the no-till system (Table 1). This is to be
expected since all the nitrogen is placed on the soil surface
and the nitrogen acidifies the soil. The tilled plots mixed
and diluted this effect. Various research experiments also
investigated the impact of different tillage systems on soilorganic matter. Mohanty et al. (2007) reported that
regression analyses between crop yield and soil organic
matter values for tillage and crop residues in rice-wheat
systems revealed that both crops showed a positive yield
response to increased levels of organic matter. There isgeneral agreement that reduced tillage can increase soilorganic matter. There are three kinds of organic matter insoil: the visible root system, the partly decomposed remainsof plants, and the well decomposed organic matter,commonly called humus (Mirzajanov 1971). Humus is
usually well mixed with the soil and adds structuralstability.
ANOVA (analysis of variance) shows that winter wheatyield was significantly affected by years (<0.001). There wasTable 1. Soil chemical parametres in the different tillage systems(2004-2008).
2004
Soil characteristicsCT

MT C2008

MT DNTCTMT C

MT DNTHumus content (%)

0.612

0.612

0.612

0.612

0.612

0.613

0.613

0.617

Nitrogen (%)

0.0450.045

0.045

0.045

0.045

0.046

0.046

0.049

Phosphorus (%)

0.141

0.141

0.141

0.141

0.141

0.142

0.142

0.151

N-NO3, mg/kg

12.87

12.87

12.87

12.87

12.87

12.87

12.88

12.93

P2O3, mg/kg

27.87

27.87

27.87

27.87

27.87

27.85

27.85

28.14

K2O, mg/kg

291291

291

291

291

292

293

299

77777

7.1

7.1

7.2

pH

These findings can showed that if we use no-till practices in
winter wheat cultivation it allows us to get stable yield acrossthe years and it also give us a buffer zone climate change issues
in the Aral Sea Basin.

Table 2. Analysis of variance.
Source ofd.f.

variation

m.s.

v.r.

FYear

31369979

10.16

<.001

T

3697389

5.17

0.002

Year.Farm

4154692

1.15

0.339

Year.T

9115662

0.86

0.566

Year.Farm.T

1271690

0.53

0.889

Residual

96134858

Total

127

4. Discussion

Remarks: d.f - Degree of freedom; m.s – means square; v.r – varianceratio; F – F-test statistic.

not significant effect on yield between the treatments, year withfarm and treatments (Table 2). Our findings are in line with
Silvio Košutić et al. (2005) reports where grain yield of winterwheat among conventional, conservation and no-till treatments
did not significantly differ.
Winter wheat productivity was higher in the treatment withno till method compared to the other treatments (Table 3).
The results obtained by Abbas Hemmat and Iraj Eskandari(2004) are in line with the findings of the recent study. The
highest yield was recorded in 2007 and yield ranged between
2.23-2.87 t ha-1 over the treatments and farms. Weatherconditions in 2007 were favorable for winter wheat growth anddevelopment. The absolute highest yield was recorded in theno till treatment (2.87 t ha-1) in farmer 2 and 2.81 t ha-1 infarmer 1. The reason for slightly higher yields of no-till
winter grown is not clear at this time. There are a number ofchanges which take place in the soil with a true no-tillage
system. It can be explained that these increased yield resultsfrom improved soil water management in the no-till system,
which limits evaporative water loss and improves water
infiltration during the fallow period. This shows that winterwheat yield increased with tillage methods and across the years.
It should also be mentioned here that winter wheat grain
productivity with no-till method was steady increased acrossthe years except 2008 where severe cold winter observed.
Table 2. Effect of different tillage methods on grain yield of winterwheat, t ha-1.

The winter of 2008 was unfavorable to the winter wheat
growth and development and coldest than usual and withheavily snow cover during the season and daily temperature
felt down up to -45°C. It negatively affected the productivityof winter wheat entire experiment and, as a result, yieldproductivity was less compared to the observed in previousyear. In other years, yield productivity was high in all tillage
methods across the years and farms (see Table 3).
Tanaka’s findings (1989) on the comparison of the yield of
pea while using different tillage treatments including no tillage,reduced tillage and conventional tillage (Moldboard Plow)
support the obtained results in the present study as it wasindicated in their study that the yield difference for thementioned tillage treatments was not significant and even notillage showed a better yield trend.
Grain yields under direct drilling were similar to thoseobtained using the reduced-tillage system and superior to yields
obtained by conventional tillage system (Abbas and Iraj, 2004).
Hossein (2008) reported that grain yield of wheat was notaffected by seed density and types of tillage machine.
On the basis of primary findings of this research it can beconcluded that the year is one of the factor that has been
implicated as critical in determining winter wheat productivity
in the region.
Finally, our results emphasize the necessity of taking intoaccount the NT method in the cultivation of winter wheat in
the drought and salt-affected region to stabilize wheat
production in the region. Otherwise CT will be substantiallyreduced wheat yield and also soil fertility in the Aral Sea Basin.
Further investigations of the effect of NT are needed to assess
its effects in the longer term, specifically to monitor long-term
effect of conservation agriculture.

5. Conclusions

Year, t ha-1
TM/F

CT

2005

2006

2007

2008

F1

F2

F1

F2

F1F2

F1

F2

2.37

2.57

2.77

2.27

2.83

2.50

1.95

2.25MTC

1.88

2.12

2.37

2.37

2.23

2.44

1.93

2.15

MTD

1.91

2.17

2.42

2.37

2.25

2.41

2.10

2.13

NT

2.12

2.24

2.57

2.59

2.81

2.88

2.34

2.32

Year

<.001

In view of these results, specific conclusions for different
tillage methods on winter wheat cultivation in the Aral Sea
Basin are as follows:
Taking into account the slow decomposition of organic
manure and crop residue, it is too early to make general
conclusions but nevertheless the results obtained areencouraging. The humus content increased remarkably but theeffect of organic manure and crop residue on the soil fertility

should be further tested in the future.
Winter wheat yield was higher in the treatment involving
the no-till method compared to the other treatments. The
highest yield was recorded in 2007 and this yield ranged
between 2.23-2.87 t ha-1. Statistical analysis shows thatwinter wheat yield was significantly affected by year-specificeffects (<0.001).
The reason for slightly higher yields of no-till winter grown
is not clear at this time. There are a number of changes whichtake place in the soil with a true no-tillage system.
No-till method tested in the Aral Sea Basin proved to besuitable for local conditions and can provide similar or higher
crop yields but saving considerable resources including fueland labour.
It is the first step towards Conservation Agriculture
adoption and successful implementation. There are manyefforts ahead needed to ensure further success of Conservation
Agriculture, including training of farmers and specialists,
providing support to supply of necessary equipment andresources.

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