Dissertation for doctor of philosophy in agriculture study on the growth and development ability of some imported soybean varieties and cultivation techniques for prospect variety in thai nguyen

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MINISTRY OF EDUCATION AND TRAINING
THAI NGUYEN UNIVERSITY




XUYEN THI LUU




STUDY ON THE GROWTH AND DEVELOPMENT
ABILITY OF SOME IMPORTED SOYBEAN
VARIETIES AND CULTIVATION TECHNIQUES FOR
PROSPECT VARIETY IN THAI NGUYEN



Major: AGRONOMY
Code: 62 62 01 01



DISSERTATION FOR DOCTOR OF PHYLOSOPHY
IN AGRICULTURE

THAI NGUYEN - 2011

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RELATED PUBLICATIONS

1. Xuyen Thi Luu, Dep Thi Luan, Tam Minh Hoang (2008), “Effect of
planting season of soybean variety 99084 - A28 in Spring and Winter Crop
in Thai Nguyen”, Journal of Science and Technology, 3(47) - Vol. 2/2008,
Thai Nguyen University Press , pp: 29 - 32.

2. Xuyen Thi Luu, Dep Thi Luan, Tam Minh Hoang (2010), “Study on the
effect of planting densities on the growth and development of soybean
varieties 99084 - A28 in winter crops 2007 - 2008 in Thai Nguyen”, Journal
of Agriculture and rural development, October, 2010, Press of Sciences and
technology, 18 Hoang Quoc Viet, Hanoi; pp: 126 - 130.

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INTRODUCTION

1. Background

Soybean (Glycine max (L) Merr) is industrial and short growing - duration crop that
is multi-purpose plant with high economic value. Its products supply food for human
and livestocks; they are also materials for processing industry and high valueable for
exporting. Besides, soybean plants are short growing-time crops that are very suitable
for crop rotation, intercroping, crop overlaping with many other plants and soil
improvement crop (Dan The Ngo et al., 1999) [10].
Soybean is popularly planted in all seven ecological areas over Vietnam.
Northern midland and mountainous region has the biggest area (69425 ha) which
holds 37.01% the total area of soybean in Vietnam but the lowest yield (1.03 tons/ha).
There are many reasons for low yield of soybean in this region such as unavailability
of high-yielding soybean varieties, low investment and unreasonable cultivation
methods. It is noted that lack of high-yielding soybean varieties and suitable
cultivation techniques are the main limitation to soybean yield. The result of variety
investigation in 2003-2004 of Department of Crop Production, Ministry of
Agriculture and Rural Development (2006) [9] showed that: The Northern Midland
and Mountainous Region is one of three areas planting high percentage of local
varieties of soybean and low percentage of new soybean varieties (37.5 - 38.4% areas
with local soybean varieties).
In recent years, Vietnam has imported many good varieties; however their
adaptability to ecological region is very different. For that reason we carried out the
research titled:” Study on the growth and development ability of some imported
soybean varieties and cultivation techniques for prospect variety in Thai Nguyen”.
2. Research Objectives
- Selecting the imported soybean varieties that have good growth and
development, are suitable with the ecological conditions of Thai Nguyen.
- Determining some intensive cultivation techniques that are suitable for the
prospect variety.
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3. Scientific and reality significance

3.1. Scientific significance
The research intends to select imported soybean varieties and determining
suitable techniques for selected variety in Thai Nguyen. The research results laid the
pavement for developing some imported soybean varieties in Thai Nguyen.
The research selected prospect soybean variety from the testing imported
varieties, suitable for ecological environment in Thai Nguyen and determined the
technical methods suitable for selected variety in spring and winter in Thai Nguyen.
3.2. Reality significance
- The thesis found out the limitation and prospects for developing soybean
production in Thai Nguyen.
- Determining and providing some soybean varieties that have good growth and
development in spring and winter in Thai Nguyen.
- The study results from some technical methods for cultivating soybean contributed
on cultivation guideline improvement for soybean intensive farming in winter and
spring in Thai Nguyen.
- The using new and high yielding variety of soybean and new technical methods
resulted in higher economic efficiency, raising the incomes for farmers that planting
soybean and promoted the development of soybean production in Thai Nguyen.
4. New findings of the thesis
- Based on investigating, analyzing and assessing some advantages and disadvantages
effecting on production and results from research on selecting soybean varieties from
imported varieties and on determining some technical methods, the scientific basement
for developing soybean in winter and spring in Thai Nguyen was confirmed.
- Determined the growth and development ability of some soybean varieties in
spring and winter crop in Thai Nguyen and two high yielding varieties ĐT2000 and
99084 - A28 were selected. In winter crops, the average yield were from 1.71 to 1.77
tons/ha that were higher than the control variety DT84 by 0.38 to 0.45 tons/ha. In
spring crops, the average yield were from 2.16 to 2.24 tons/ha that were higher than
the control by 0.37 to 0.45 tons/ha.
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- Suggested some techniques for completing cultivation guideline for new soybean
variety (99084 - A28) with optimum planting time in spring crop is from 15th, February
to 6th, March and 5th to 25th, September in winter. The optimum density in spring was
35 plants/ha and 45 plants/ha in winter. The most suitable fertilizer combination was 5
tons of manure + 40 kg N + 80 kg P2O5 + 40 kg K2O + 300 kg of lime/ha.
- Trial of soybean planting in winter and spring in three places of Thai Nguyen
was successfully built and implemented. The trial locations are Trang Xa Commune -
Vo Nhai District, Hoa Thuong Commune - Dong Hy District and Son Cam
Commune - Phu Luong District with the variety 99084 - A28 and new technical
methods that got the yield from 2.54 to 2.83 tons/ha, raising by 52,8 - 53,9%
compared to the control in winter; 2.32 - 2.75 tons/ha raising by 52,6 - 63,5% than
the control; the interest were from 20.2 to 24.5 millions VND/ha in spring and 20.3 to
23.3 millions VND in winter.
5. Thesis structure
The dissertation was fulfilled with 102 pages, 31 tables, 3 figures and 2
diagrams. Beside the introduction, the dissertation was divided into 3 chapters where
chapter 1: Literature review (25 pages); chapter 2: Research content and methods (13
pages); chapter 3: Results and discussion (58 pages), Conclusion and suggestion (2
pages) and 55 pages for appendices. The dissertation used 115 references in Vietnamese
and 58 references in English.

CHAPTER 1: LITERATURE REVIEW

1.1. Soybean production status in Vietnam and in the world
1.1.1. Soybean production in the world
The data collection from Dan The Ngo et al., (1999) [10], Duc Van Hoang
(1982) [23], FAO Statistic Database, 2009 [75] showed that the soybean production
of the world has increased rapidly in area - yield and output. In the period of 1963 -
1964, the planting area of soybean over the world was 27.3 millions hectare and

increased to 96.87 hectare in 2008. In 1960 the yield of soybean over the world was
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only 1.20 tons/ha but increased to 2.384 tons/ha in 2008, by 98.87% compared to
1960. The output in 1960 was 26.00 millions ton and 230.95 millions ton in 2008,
increased 8.85 times.
1.1.2. Production of soybean in Vietnam
According to Dan The Ngo et al., 1999 [10], Thieu Van Pham, 2006 [44],
soybean has been grown in Vietnam for a very long time but the area was only 32000
ha (1944) and yield was very low (0.41 tons/ha). In recent years, the soybean has
developed rapidly in both area and yield. In 1995, the soybean area of whole country
was 121.1 thousands hectare; it increased gradually through the years and got 191.5
thousands hectare in 2008.
In 1995, the yield of whole country was 1.03 tons/ha and continuously increased
through the years and reached the highest in 2007 at 1.47 tons/ha. Although there
were some changes in area and yield, the output increased gradually through the
years. In 1995, the output of whole country was 125.5 thousands tons and reached the
highest in 2005 at 292.7 thousands tons.
1.2. Status of soybean research
1.2.1. Research on soybean over the world
The 1st international soybean variety evaluation experiment (ISVEX) in 1973
was conducted in ranges of 90 places in 33 countries representing for environmental
zone. Nowadays, the soybean research is received a great deal of attentions,
especially in developed countries that are big producers of soybean.Beside the
research on selecting and creating varieties, the scientist over the world still study on
technical methods such as planting time, density and fertilizer for soybean
production.
1.2.2. Soybean research in Vietnam
In the period of 2001 - 2005, Vietnam imported 540 samples of soybean
varieties from other countries that supplemented to collection of varieties and tested

9482 soybean variety samples; found out 83 samples of varieties that have precious
characteristics. In the period of 1985 - 2005, Vietnam created 15 samples of soybean
varieties by cross-breeding that were certified as national varieties (Long Dinh Tran
5

and Chinh Thi Nguyen, 2005) [35]. Creating and selecting by mutation treatment
method resulted in 4 national varieties (Vinh Quang Mai et al., 2005)[52].
Besides, scientists also studied on technical methods such as planting time, density
and fertilizer. Research of some authors such as Dan Thi Nguyen (1996) [11], Thieu
Van Pham, 2006 [44], Xiem Tu Nguyen and Phien Thai (1998) [56], Kha Minh Vo
(1996) [29], Hinh Tan Nguyen et al, (2006) [25], Truong Thi Tran et al, 2006 [46]
showed that: The actual amount of fertilizer required depended on season, soil types, the
previous plants and varieties. Hence, there is no fertilizer combination for all of different
seasons, regions and soil types.

CHAPTER 2: REASERCH CONTENTS AND METHODS

2.1. Materials
The experiment included 10 varieties of soybean: ĐT12, TQ, VX92, VX93,
ĐT2000, 95389, CM60, 99084 - A18, 99084 - A28, DT84 (control). The whole
experiment was applied the same fertilizer combination of Lam Thao Super phosphorus
16,50%, Urea Nitrogen 46,0%, Chloride potassium 50,0%, manure and lime.
2.2. Contents
2.2.1. Survey for existing production of soybean in Thai Nguyen
2.2.2. Assessing growth and development of imported varieties of soybean in
Thai Nguyen
2.2.3. Determining some main technical methods for prospect variety 99084 - A28
(timing, density and fertilization)
2.2.4. Trial for testing newly developed techniques in farmer fields.
2.3. Methodology

2.3.1. Survey for existing production state of soybean in Thai Nguyen
- The data of climate and weather was collected in Hydro-meteorological station
in Thai Nguyen Province.
- Determining the texture and characteristic of soil conducting experiment and trials,
the soil samples was taken before carrying out the experiment (5samples/place).
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- Determining the status of soybean production in Thai Nguyen by collecting
secondary data and interviewing the staffs of Agricultural and rural development
Department of Thai Nguyen Province.
- Determining the status of soybean production in some districts, using
Participatory Rural Appraisal method (PRA), interviewing farmers by questionnaire
(Appendix 3).
2.3.2. Assessing growth and development of the imported soybean varieties in
Thai Nguyen
2.3.2.1. Experiment 1: Study on the growth and development of some imported
soybean varieties in spring and winter crops in 2004 and 2005 in Thai Nguyen
a/ Materials: 10 soybean varieties.
b/ Time and place: Soybean was sowed on 15th, February, 2004 and 18th,
February, 2005 in spring season and on 15th, September, 2004 and 17th, September,
2005 in winter crops in Thai Nguyen University of Agriculture and Forestry.
c/ Experimental conditions: The experiment was conducted in one rice crop
land, the soil texture is light, pHKCl = 4.85; Total Nitrogen = 0.11%; Total potassium
= 0.55%; Total phosphorus = 0.07%; Organic matter = 1.82%.
d/ Experimental design: Randomized Complete Block Design - RCBD with 3
replications. The plot area is 1.4m x 5 m= 7m
2
.
- Technical guideline: Based on the soybean variety testing guideline No. 10TCN
339 - 2002 (MARD, 2001) [4] and No. 10TCN 339 - 2006 (MARD, 2006) [38].

The planting density was 35 plants/m2, the distance between lines was 35 cm
and between plants was 8.2 cm.
The applied fertilizer combination was 5 tons of manure + 30 kg N + 60 kg P
2
O
5

+ 30 kg K
2
O + 300 kg lime/ha.
e) Research monitoring indicators and method: The monitoring indicators and
method were carried out based on the soybean variety testing guideline No. 10TCN
339 - 2002 (MARD, 2001) [4 ] and No. 10TCN 339 - 2006 (MARD, 2006) [38].
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2.3.2.2. Experiment 2: Testing some prospect varieties of soybean in spring, 2006 in
Thai Nguyen
a/ Research sites: Trang Xa Commune - Vo Nhai District, Hoa Thuong Commune - Dong
Hy District, Son Cam Commune - Phu Luong District.
b/ Materials: 3 prospect varieties were selected through 4 testing seasons
(VX93, 99084 - A28, ĐT2000) and DT84 (control). The testing area is 500m
2
for
each variety in each place.
c/ Experiment conditions: The experiment was implemented on one rice-crop
land with light texture of soil. The chemical properties of soil in experiment places
are shown below:
Table 2.2. The chemical properties of soil in experiment sites
Indicators Dong Hy Vo Nhai Phu Luong
pHKCL 4.6 4.5 4.3

N (%) 0.11 0.10 0.11
P
2
O
5
(%) 0.13 0.15 0.11
K
2
O (%) 0.73 0.62 0.67
OM (%) 1.92 1.74 1.85
(The soil was sampled in 2005)
The dosage of fertilizer and other experimental procedure are as the same as
experiment 1.
2.3.3. Studying some main technical methods for the prospect soybean variety
99084 - A28
2.3.3.1. Experiment 3: Determining the planting time for soybean variety 99084 -
A28 in spring and winter in Thai Nguyen.
a/ Time and place: Spring and winter crops in 2005 and 2006 at Thai Nguyen
University of Agricultural and Forestry.
Table 2.3: Sowing date of the treatments
Spring crop Winter crop
Treatment
2005 2006 2005 2006
Date 1 5/2 5/2 5/9 5/9
Date 2 15/2 15/2 15/9 15/9
Date 3 25/2 25/2 25/9 25/9
Date 4 7/3 6/3 5/10 5/10
Date 5 17/3 16/3 15/10 15/10
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b/ Experiment design: Randomized Complete Block Design - RCBD with 3
replications. The plot area is 2.8m x 5m = 14 m
2
.
c/ Experiment condition, fertilizers, densities and other technical methods were
similar to the experiment 1.
2.3.3.2. Experiment 4: Determining the planting density of soybean variety 99084 -
A28 in spring and winter crops in 2007 - 2008 in Thai Nguyen.
a/ Time and place: In spring and winter crops in 2007 - 2008 at Thai Nguyen
University of Agriculture and Forestry.
b/ Testing densities:
+ Density 1: 25 plants/m
2
(distance between lines: 35cm; distance between
plants: 11,4 cm)
+ Density 2: 35 plants/m
2
(distance between lines: 35cm; distance between
plants: 8,2 cm)
+ Density 3: 45 plants/m
2
(distance between lines: 35cm; distance between
plants: 6,3 cm)
+ Density 4: 55 plants/m
2
(distance between lines: 35cm; distance between
plants: 5,2 cm)
+ Density 5: 65 plants/m
2
(distance between lines: 35cm; distance between

plants: 4,4 cm)
2.3.3.3. Experiment 5: Determining the optimum N-fertilizer rate for soybean variety
99084 - A28 in spring, 2007 - 2008 in Thai Nguyen.
Fertilizer base: 5 tons of manure + 60 kg P2O5 + 30 Kg K2O + 300 kg lime/ha.
a/ Time and Place: Spring, 2007- 2008 at Thai Nguyen University of Agriculture
and Forestry.
b/ Experiment design: Randomized Complete Block Design - RCBD with 5
treatments, 3 replications. The plot area is 2.8m x 5m = 14 m
2
.
+ Treatment 1: Base + 20 Kg N
+ Treatment 2: Base + 30 Kg N
+ Treatment 3: Base + 40 Kg N
+ Treatment 4: Base + 50 Kg N
+ Treatment 5: Base + 60 Kg N.
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c/ Experiment condition: As the same as the experiment 1.
d/ Indicators and monitoring method: Growth duration, plant height, the leaf area
index, pest and disease, lodging resistance ability, yield components, yield and calculation
for treatment economic efficiency.
2.3.3.4. Experiment 6: Determining the optimum P-fertilizer for soybean variety
99084 - A28 in spring crops in Thai Nguyen.
Base Fertilizer: 5 tons of manure + 30 Kg N + 30 Kg K
2
O + 300 kg lime/ha.
a/ Time and place: Spring, 2007-2008 in TUAF.
b/ Experiment design and monitoring method: As the same as experiment 5.
c/ Experiment conditions: As the same as experiment 1.
+ Treatment 1: Base + 40 Kg P

2
O
5
;
+ Treatment 2: Base + 60 Kg P
2
O
5
.
+ Treatment 3: Base + 80 Kg P
2
O
5
;
+ Treatment 4: Base + 100 Kg P
2
O
5
.
+ Treatment 5: Base + 120 Kg P
2
O
5
.
2.3.3.5. Experiment 7: Determining the optimum K-fertilizer for soybean variety 99084
- A28 in spring crops in Thai Nguyen.
Base fertilizer: 5 tons of manure + 30 Kg N + 60 Kg P
2
O
5

+ 300 kg lime/ha.
a/ Time and place: Spring crops, 2007 - 2008 in TUAF.
b/ Experiment design, norms and monitoring methods: as experiment 5.
c/ Experiment condition: As the same as the experiment 1.
+ Treatment 1: Base + 20 Kg K
2
O
+ Treatment 2: Base + 30 Kg K
2
O
+ Treatment 3: Base + 40 Kg K
2
O
+ Treatment 4: Base + 50 Kg K
2
O
+ Treatment 5: Base + 60 Kg K
2
O.
2.3.3.6. Experiment 8: Determining the optimum fertilizer combinations for soybean
variety 99084 - A28 in spring crops in Thai Nguyen
Experiment included 7 treatments which are selected as the highest yield and
economic efficiency in experiments 3,4,5,6,7.
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a/ Time and place: Spring, 2009 in TUAF.
b/ Experiment design: RCBD with 7 treatments, 3 replications. The plot area is
2.8m x 5m = 14,0m
2
.
Fertilizer base was 5 tons of manure + 300 kg lime per hectare. The rates of N, P

2
O
5

and K
2
O (kg/ha) for each treatment are as follows:
+ Treatment 1: 30: 60 : 30 (Control);
+ Treatment 2: 30: 80 : 40
+ Treatment 3: 30 :100 : 50
+ Treatment 4: 40 : 80 : 40
+ Treatment 5: 40 : 80 : 50
+ Treatment 6: 40 : 100 : 40
+ Treatment 7: 40 : 100 : 50
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.3.4. Trials for testing soybean variety 99084 - A28 in spring, 2010 in Thai Nguyen

a/ Places: Trang Xa Commune - Vo Nhai District, Hoa Thuong Commune - Dong Hy
District, Son Cam Commune - Phu Luong District.
b/ The experiment conditions: As the same as the experiment 2.
- Trial 1: New variety + New technical methods (optimum sowing date, density
and fertilizer combination were determined in experiments 3, 4, 8).
- Trial 2: Old variety (DT84) + New technical methods
c/ Monitoring indicators: The farmers participated in conducting and evaluation of
the trials: Yield (tons/ha), economic efficiency of the trials (expenditure - outcomes)
and farmers’ acceptance to the new variety and technical methods.
2.4. Data analysis
- The survey information was analyzed by the software Excel 5.0 and SAS
program.
- The data from the field experiment was calculated, analyzed by the software

Excel 5.0, SAS and IRRISTAT programs.

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CHAPTER 3: RESULTS AND DISCUSSION

3.1. Nature condition and status of soybean production in Thai Nguyen
3.1.1. Climate condition of Thai Nguyen Province
Based on the ecology requirements of soybean and analyzed the weather and
climate in years conducting experiments it showed that: Although the climate and
weather in Thai Nguyen varieties complicatedly but it was still suitable for the growth
and development of soybean, in general. Therefore, it needs to be based on the climate
data to adjust the suitable planting season.
3.1.2. The survey results of existing soybean production in Thai Nguyen
3.1.2.1. The survey results
The area of soybean in recent years has continuously reduced. In 2003, the area
was 3656 ha, after 5 years it reduced by 36,6% and got to 2316 ha (2007). It got the
big reduce in 2008 (2000 ha). The yield of soybean in Thai Nguyen in recent years
has an increasing trend from 1.131 tons/ha to 1.403 tons/ha because some farmers
started to use new varieties.
Soybean have been planted in all districts and city in Thai Nguyen Province but
the planting area are mainly in Pho Yen, Phu Binh, Vo Nhai, Dong Hy district and Song
Cong town. Soybean has been planted in 2 main cropping seasons which are spring and
winter. 100% households interviewed planted spring soybean and 66.7 - 95.2%
households planted winter soybean. The number of households planted summer-autumn
soybean was very low (14.6 - 26.2%).
The using of old varieties in soybean production is one of the reasons for low
soybean yield. At investigated places, we realized that the variety DT 84 was still
popularly grown in 52.8% households. Some varieties have transferred to the production
recently such as AK03, DT9, DT96, ĐT80 planted by 20.8% of interviewing
households. The variety Cuc Luc Ngan was grown in Vo Nhai and Phu Luong District

by 29.2% and 25.7 % households, respectively.
Investigating in applying the technical methods for soybean production showed that
planting soybean mainly based on experiences (21.4 - 52.1%). The number of
households applying the old technical methods was also fairly high (31.4 -37.5%).
Almost households applied fertilizer unreasonably; the fertilizer rate for soybean was
still lower than the guideline. Investigating in the status of soybean pests and diseases
showed that the pests were mainly Bean pyramid (Lamprosema indicata Fabricius)
and Lima bean pod-borer (Etiella zinckenella Treitschke).
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3.1.2.2. Advantages and disadvantages to soybean production in Thai Nguyen
Investigating in advantages of soybean Production showed that the most optimum
factors are the easy-consuming products and the low investment; these are confirmed by
100% households in all investigated places. The other optimum factor is the land: 100%
households in Vo Nhai and Phu Luong District and 97.6% households in Dong Hy
District claimed that there were many areas that can be grown soybean, because the crop
may grow in many soil types. Besides, planting soybean can use labor at the beginning
of the spring crops. The fact that soybean crop is very easy to plant was the opinion of
66.7 - 85.7% households. They considered that soybean is easy to plant because it may
be grown in many soil types and may be grown with minimum tillage, even though no
tillage as in planting the winter soybean.
The investigating results showed that there were many disadvantages of soybean
production in Thai Nguyen. The main disadvantaged factors were lack of good varieties,
improved technical guidelines, pest and diseases and drought at the beginning of spring
crops and the end of winter crops.
3.1.2.3. Some solutions for soybean production in Thai Nguyen
- Study on determining the suitable varieties in Thai Nguyen Province and designing
good service for soybean seeds for soybean Production.
- It needs to have a policy that promotes soybean production through agricultural
extension activities: Opening training courses for farmers in technical methods for
soybean production, building suitable demonstration trials for each region.

- Extending and enhancing the cooperation with some scientific organizations
(VAAS, TUAF) in research and transferring technology in soybean production.
- Long-term plan for soybean production for development of planting area,
yield, output and marketing.
3.2. Results of assessing growth and development of the imported varieties of
soybean in Thai Nguyen
3.2.1. Results of assessing growth and development of the imported varieties of
soybean in spring and winter crops, 2004 - 2005 in Thai Nguyen
- Estimated yield (EY): The EY was low or high depending on the yield
components. In this experiment, the variety 99084 - A28 and ĐT2000 had the yield
components ranging from fair to good level; therefore these varieties had the highest
yield (2.72 tons/ha and 2.78 tons/ha in spring crops; 2.42 tons/ha and 2.21 tons/ha in
winter crops, respectively), significantly higher than the control at the confidence
interval of 95% in 2 crops. The variety VX93 and 95389 had the EY equivalent to the
control (DT84: 2.29 tons/ha in spring and 1.84 tons/ha in winter). Other varieties had
the EY significantly lower than the control at the confidence interval of 95%.
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Table 3.12. Yield of testing varieties
Estimated yield (tons/ha) Actual Yield (tons/ha)
Variety
VX VĐ VX VĐ
DT84 (control) 2.29 18.4 17.9 13.3
ĐT12 1.66 1.64 1.47 1.06
TQ 1.57 1.52 1.32 1.16
VX92 1.65 1.55 1.27 1.27
VX93 2.15 1.89 1.72 1.50
ĐT2000 2.78 2.21 2.16 1.71
95389 2.37 1.78 1.78 1.48
CM60 1.70 1.59 1.33 1.26
99084-A18 1.76 1.52 1.49 1.29

99084-A28 2.72 2.42 2.24 1.78
CV (%) 8.2 4.4 7.6 8.1
LSD (0.05) 0.383 0.179 0.284 0.252
(Data were averaged over tow years 2004, 2005. For data analysis in each season,
see appendices 8 and 13)
- Actual yield (AY): The AY of testing varieties ranged from 1.27 to 2.24
tons/ha (spring crops) and from 1.06 to 1.78 tons/ha (winter crops); whereas the
variety DT2000 and 99084 - A28 had the highest AY (2.16 tons/ha and 2.24 tons/ha
in spring and 1.71 tons/ha and 1.78 tons/ha in winter), higher than the control at 95%
confidence interval. The varieties VX93 and 95389 had the AY equivalent to the
control (DT84:1.79 tons/ha in spring and 1.33 tons/ ha in winter). Other varieties had
the AY significantly lower than the control at 95% confidence interval.
The results were similar to those reported by Dien Van Tran et al., (2008) [22],
Dung Trung Duong et al., (2010) [15].
3.2.2. Results of assessing growth and development of the prospect variety in spring
- 2006 in Thai Nguyen
Based on the results of 4 seasons ( 2 spring crops and 2 winter crops in 2004 -
2005), the 3 varieties VX93, ĐT2000 and 99084 - A28 had the AY and AY
equivalent and significantly higher than the control in all crops. We had intended to
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test these there varieties in spring crop - 2006 on 3 districts Vo Nhai - Dong Hy - Phu
Luong of Thai Nguyen Province.
The results in table 3.13 showed that, the growing duration of varieties in testing
places are 1-2 days different; the varieties had the growing duration ranging from 90 -
120 days which were similar to the results obtained in spring crops in 2004 - 2005.
Table 3.13. Growing duration and actual yield of prospect varieties in
spring, 2006
Growing duration (days) Actual yield (tons/ha)
Indicators

Variety
Vo Nhai

Dong Hy

Phu
Luong
Vo Nhai

Dong Hy

Phu
Luong
VX93 95 93 94 17.5 20.7 19.4
ĐT 2000 102 101 102 18.6 20.5 20.3
99084-A28 100 99 99 21.0 23.8 22.5
DT84 (Control) 91 90 90 15.5 18.6 17.3
Yield is the integration indicator reflecting the adaptation ability of varieties in
each ecological condition and resistance ability to each pests and environments. The
results showed that all varieties had AY higher than the control (DT84: 1.55 - 1.86
tons/ha). The AY in Dong Hy District was the highest (1.86 - 2.38 tons/ha), next to
was that in Phu Luong District (1.73 - 2.25 tons/ha) and the lowest was in Vo Nhai
District (1.55 - 2.10 tons/ha). In all 3 places, variety 99084 - A28 had the highest AY
ranging from 2.10 to 2.38 tons/ha, next to that of variety ĐT2000 reaching 1.86 - 2.05
tons/ha, and the lowest AY belonged to the variety VX93 (1.75 - 2.07 tons/ha).
The main advantaged characteristics of the prospect variety 99084 - A28 which
be confirmed by farmers in the experiment and field seminars were:
+ The high yield
+ Resistance to pests and diseases

+ Good seed outlook: big, round, light yellow colour and small hilum.
Based on the results above, we selected the variety 99084 - A28 to conduct some
research on technical methods serving for proposing the technical guideline for
cultivating new variety of soybean.
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3.3. Results from research on some technical methods for the prospect soybean
variety 99084 - A28 in Thai Nguyen
3.3.1. Results of determining the optimum sowing date for the soybean variety

99084 -
A28 in spring and winter crops in Thai Nguyen

Table 3.18. Effect of planting season on yield of variety 99084 - A28 in Thai Nguyen

(Data were averaged over two years: 2005, 2006. For data analysis in each season,
see appendices 17 and 22)
The EY of the variety 99084 - A28 in other planting dates had big variation. In
spring, the EY ranged from 2.67 to 30.4 tons/ha whereas the EY of PS3 was
equivalent to PS2 and PS4 and higher than PS1 and PS5, significantly at confidence
interval of 95%. In winter, the EY ranged from 1.06 to 2.44 tons/ha and reached the
highest in PS1.
The AY in spring crops ranged from 1.80 to 2.19 tons/ha in which the AY of
PS3 was equivalent to PS2 and PS4 and significantly higher than PS1 and PS5 at the
confidence interval of 95%. The AY in winter ranged from 0.69 - 1.57 tons/ha
whereas the highest AY was in PS1 and PS2 (1.57 - 1.53 tons/ha), significantly
higher than in other dates at 95% confidence interval. This result was line with that
reported by Thieu Van Pham (2006) [44], Dung Trung Duong et al., (2009) [14].
3.3.2. Results of determining the optimum density for soybean variety 99084 - A28
in spring and winter crops in Thai Nguyen.
The table 3.22 showed that, in all spring and winter crops, the different densities

resulted in different AY and EY. In spring, the EY ranged from 1.86 to 2.78 tons/ha,
the AY ranged from 1.66 to 2.50 tons/ha. In Spring, both and AY increased from
Planting date
Estimated yield
(tons/ha)
Actual yield (tons/ha)

Planting
season
SC WC SC WC SC WC
PS1 5/2 5/9 2.67b 24.4a 18.0c 15.7a
PS 2 15/2 15/9 2.86ab 23.0b 20.9ab 15.3a
PS 3 25/2 25/9 3.04a 18.7c 21.9a 12.2b
PS 4 6(7)/3 5/10 2.75ab 12.9d 20.0ab 8.3c
PS 5 16(17)/3 15/10 2.67b 10.6e 19.6b 6.9d
CV (%)

4.1 2.9 3.9 7.7
LSD(0.05)

0.319 0.110 0.217 0.250
16
treatment 1 and reached the highest value in treatment 2 (65plants/m2) (The EY got
2.78 tons/ha and the AY was 2.50 tons/ha), then gradually reduced and rapidly
reduced when the densities was 65plants/m2 (the EY was 1.86 tons/ha and the AY
was 1.66 tons/ha).
Table 3.22. Effect of densities on the yield of variety 99084- A28 in Thai Nguyen
Spring Winter
Norm

Treatment
Estimated
Yield
(tons/ha)
Actual Yield
(tons/ ha)
Estimated
Yield
(tons/ha)
Actual Yield
(tons/ ha)
T1 (25) 2.32c 1.95c 2.00c 1.46d
T 2 (35) 2.78a 2.50a 2.20b 1.62c
T 3 (45) 2.61b 2.30b 2.47a 1.90a
T 4 (55) 2.22d 1.90cd 2.34ab 1.78b
T 5 (65) 1.86e 1.66d 1.99cd 1.46d
CV (%) 0.9 1.5 2.4 2.5
LSD(0.05) 0.058 0.085 0.145 0.112
(Data were averaged over two years: 2007, 2008. For data analysis in each season,
see appendices 27 and 31)
In winter, both the EY and the AY increased basing on the raise of density from
Treatment 1 to treatment 3 (45 plants/m
2
), but then reduced even though the raise of
density. The EY ranged from 1.99 to 2.47 tons/ha, the AY ranged from 1.66 to 1.90
tons/ha and reached the peak of yield in treatment 3 at 45 plants/m
2
(the EY was 2.47
tons/ha, the AY was 1.90 tons/ha).

The planting densities affected on the growing and developing indicators of the
soybean varieties 99084 - A28 in spring and winter crops in Thai Nguyen. The high
densities caused an increase of some indicators such as the plant height, the leaf area
index, pest infected index. On the contrary, an increase of densities caused the short
growing duration, the low number of primary branches , number of filled pods/plant,
number of filled kernels/pod and 1000-kernel weight. The yield rose basing on the
increase of densities to a given point (35 - 45 plants/m
2
), then reduced when
continuously increased the planting densities (65 plants/m
2
). From the collected data,
the most optimum density for soybean variety 99084 - A28 in Thai Nguyen was 35
plants per m
2
in spring crop and was 45 plants/m
2
in winter. At these planting
densities, the AY was the highest.
17
3.3.3. Study on optimum N-fertilizer rate for the variety 99084 - A28 in spring in
Thai Nguyen
Table 3.24. Effect of N-fertilizer rate on yield and interest of the soybean variety
99084 - A28 in spring in Thai Nguyen
Norm


Treatment

Filled

pods/plant

(pods)
Filled
kernels/pod
(kernels)
1000-
kernel
weight (g)

EY
(tons/
ha)
AY
(tons/ ha)

Interest
(Millions
VND/ha)

1 (20N) 21.0d 1.86b 162.8cd 2.23c 1.93c 11.82
2 (30N) 24.7c 1.93ab 165.9b 2.76b 2.34b 17.89
3 (40N) 27.9a 2.00a 167.6a 3.28a 2.77a 24.23
4 (50N) 26.5b 1.95ab 165.8b 3.00ab

2.31b 17.17
5 (60N) 23.7cd 1.88b 163.3c 2.54bc

1.85cd 10.17
CV (%) 2.0 2.0 0.3 3.3 1.4

LSD (0.05) 1.40 0.10 1.3 0.248 0.087
(Data were averaged over two years: 2007, 2008. For data analysis in each season,
see appendices 34, 35, 46 and 47)
The table 3.24 showed that the number of filled pods/plant, number of filled
kernels/pod and 1000-kernel weight increased with an increase of N-fertilizer rate
from T1 to T3, then reduced when continuously increasing N rates.
Applying N-fertilizer at different rate got the different EY and the AY. The EY
were 2.23 - 3.28 tons/ha, the AY were 1.85 - 2.77 tons/ha. Treatment 3 (40 kg N/ha)
had the highest EY and AY, significantly higher than other treatments.
The economic efficiency analysis of applying N-fertilizer (appendices 46 and 47)
showed that the interest increased from the treatment 1 (11.82 millions VND/ha) to treatment 3
and reached the highest interest in Treatment 3 (40 kgN/ha) with 24.23 millions VND/ha,
then the interest gradually reduced wh en increasing the N-fertilizer rate; the lowest
interest was in treatment 5 (10.17 million VND/ha).
Based on the results from two cropping seasons we found that the applied N-
fertilizer rate affecting on most growth and development indicators of the soybean
variety 99084 - A28. The higher rate resulted in the longer growing duration, the
higher plant height, LAI and the level of Bean pyramid and Lima bean podborer. The
yield components and yield gradually increased from the treatment 1 (20 kg N/ha)
and reached the peak in treatment 3 and then gradually reduced. In short, for the
soybean variety 99084 - A28 in spring in Thai Nguyen with the fertilizer base of 5
18
tons of manure + 60 P
2
O
5
+ 30 K
2
O + 300kg lime/ha, the optimum N-fertilize rate
was 40 kgN/ha which had the highest AY and interest.

3.3.4. Study on the optimum P-fertilizer rate for the soybean variety in spring in
Thai Nguyen
The different P-fertilizer rates clearly effected on number of filled pods/plant,
1000 kernel weight of the soybean variety 99084 - A28. Different P-fertilizer rate
treatments significantly effected on different indicators at 95% confident interval and
the yield was obtained in treatment 4 and 5 (100 and 120 kg P
2
O
5
/ha).
Applying P-fertilizer at different rates affected on the EY and the AY of the
variety 99084 - A28. The AY ranged from 1.65 - 3.4 tons/ha and had the significant
differences among treatments. The higher rates of P-fertilizer clearly resulted in
higher EY. When increasing 20 kg P
2
O
5
/ha resulted in increasing yield of 0.22 - 0.53
tons/ha. The AY ranged from 1.42 - 2.78 tons/ha in which treatment 5 (120 kg
P
2
O
5
/ha) had the highest AY and significantly higher than treatment 1, 2, 3 at the
confidence interval of 95%.
Table 3.26. Effect of P-fertilizer rate on yield components and yield of the
soybean variety 99084- A28 in spring in Thai Nguyen
Norm

Treatment
Filled
pods/
plant
(pods)
Filled
kernels/

pod
(kernels)

1000-
kernel
weight
(g)
EY
(tons/

ha)
AY
(tons/

ha)
Interest
(Millions
VND/ha)
Effc
iency
(kg
soybean/

kg P
2
O
5
)

1(40P
2
O
5
) 16,3
e
1,83
b
158,32
d
16,5
e
14,2
d
4,4 -
2(60P
2
O
5
) 20,3
d
1,87
b

161,63
c
21,4
d
18,5
c
10,6 22,0
3(80P
2
O
5
) 24,3
c
1,94
ab
163,25
b
28,1
c
24,0
b
18,5 28,0
4(100P
2
O
5
) 27,8
b
1,98
a

164,58
a
31,8
b
26,9
ab
22,6 15,0
5(120P
2
O
5
) 29,5
a
2,00
a
164,75
a
34,0
a
27,8
a
23,5 4,0
CV (%) 1,5 2,0 2,0 2,1 1,8
LSD(0,05) 1,01 0,07 1,21 1,52 1,12
(Data were averaged over two years: 2007,2008. For data analysis in each season,
see appendices 38, 39, 40, 48 and 49)
19
The efficiency of using fertilizer was specified by the interest. Taking in the
accounts of the experiment (appendices 40 and 49) showed that, applying the higher
P-fertilizer made the higher interest, ranging from 0.44 - 2.35 millions VND/ha. The

lowest interest in treatment 1 (40 kg P
2
O
5
/ha) at 0.44 millions VND/ha; the highest
interest in treatment 5 (120 kg P
2
O
5
/ha) at 23.5 millions VND/ha. The using fertilizer
efficiency showed that treatment 5 with highest P-fertilizer (120 kg P
2
O
5
/ha) made
the lowest efficiency reaching 4.0 kg seed/1 kg P
2
O
5
. Treatment 4 had the efficiency
of 15.0 kg seed/1 kg P
2
O
5
. Treatment 3 had the highest efficiency at 28.0 kg seed1kg
P
2
O
5
. The results above showed that on the fertilizer base of 5 tons of manure + 30N

+ 30K
2
O + 300 kg lime, the P-fertilizer rate should be applied was 80 kg P
2
O
5
/ha due
to the highest using efficiency.
3.3.5. Research the optimum K-fertilizer rate for the soybean variety 99084 -
A28in spring in Thai Nguyen
The different K-fertilizer rates had the positive increase with some norms such
as number of filled pods/plant, filled kernels/pods, 1000-kernel weight of the soybean
variety 99084 - A28. The number of filled pods/plant ranged from 19.8 to 29.1 pods.
The number of filled kernels/pods ranged from 1.8 - 2.01 kernels. The 1000-kernel
weight ranged from 154.0 - 165.6 g.
Table 3.28. Effect of K-fertilizer rates on yield and interest of soybean variety
99084- A28 in spring crop in Thai Nguyen
Norm



Treatment
Filled
pods/
plant
(pods)
Filled
kernels
/pod
(kernels)

1000-
kernel
weight
(g)
EY
(tons/

ha)
AY
(tons/ ha)

Interest

(Millions
VND/ha)

Effciency
(kg
soybean/
kg K
2
O)
1 (20K
2
O) 19,8
d
1,80
c
154,0

c
19,2
d
16,6
d
7,9 -
2 (30K
2
O) 23,4
c
1,87
bc
161,8
b
24,8
c
20,9
c
14,2 43,5
3 (40K
2
O) 27,3
b
1,92
b
164,6
ab
30,2
b
26,3

b
22,1 53,0
4 (50K
2
O) 28,6
ab
1,97
ab
165,5
a
32,6
ab
28,7
ab
25,6 24,5
5 (60K
2
O) 29,1
a
2,01
a
165,6
a
33,9
a
29,4
a
26,5 7,5
CV (%) 2,2 1,8 0,2 1,7 2,3
LSD(0,05) 1,57 0,09 1,09 1,33 1,56

(Average data in 2007, 2008. Data treatment every years; appendix 43, 44, 45, 50, 51)
20
The EY and AY increased following by increasing K-fertilizer rate applied and
reached the highest value in treatment 5 (60 kg K
2
O/ha). The EY ranged from 1.92 -
3.39 tons/ha. The AY ranged from 1.66 to 2.94 tons/ha. The data treatment showed
that both EY and AY of treatment 4 and 5 that had no significant differences but
significantly higher than treatment 1, 2.
To assessing the efficiency of applying K-fertilizer by taking into accounts
through 2 spring crops 2007, 2008 (appendix 50,51). Table 3.28 showed that rising
the K-fertilizer made the rising of interest. The interest ranged from 7.9 to 26.5
millions VND/ha and reached the highest value in treatment 5 (60 kg K
2
O/ha). The
efficiency of applying K-fertilizer on the base of 5 tons of manure + 30 kg N + 60 kg
P
2
O
5
+ 300 kg lime showed that treatment 3 with 40 kg K
2
O/ha gave the highest
efficiency at 53,0 kg seed/1kg K
2
O; treatment 2 with 30 kg K
2
O/ha had 43.5 kg
seed/1 kg K
2

O. When raising the K-fertilizer rate, the yield still raised but the interest
gradually reduced and lowest in treatment 5 at 7,5 kg seed/1 kg K
2
O.
3.3.6. Research the optimum fertilizer combination for the prospected
soybean variety
in Thai Nguyen
Table 3.30. Effect of fertilizer combinations on yield and interest of variety
99084-A28 in Thai Nguyen
Treatment
N:P:K
Fertilizer
Estimated Yield

(tons/ha)
Actual Yield
(tons/ha)
Interest
(millions VND)

1(Control) 30:60:30 2.42cd 2.08de 14.0
2 30:80:40 2.80c 2.33d 17.2
3 30:100:50 3.14abcd 2.58abcd 20.5
4 40:80:40 3.87a 3.05a 27.8
5 40:80:50 3.55ab 2.97ab 26.5
6 40:100:40 3.37abc 2.73abc 22.6
7 40:100:50 2.99 2.57abcd 20.1
CV (%) 13.5 12.4
LSD(0.05) 0.759 0.577
(Based fertilizer: 5 tons of manure + 300 Kg lime/ha)

21
Sufficient and balanced fertilizer application made an increase of yield components
such as number of filled pods/plant, filled kernels/pods, 1000-kernel weight causing an
increase of EY and AY of the testing soybean varieties. The EY ranged from 2.42 - 3.87
tons/ha. The AY ranged from 2.08 - 3.05 tons/ha where treatment 4 had the EY at 3.87
tons/ha and the AY at 3.05 tons/ha, significantly higher than other treatments at the
confidence interval of 95%.
The results of economic efficiency calculation showed that the different
fertilizer combinations gave different interest ranging from 14.0 - 27.8 millions
VND/ha in which all treatments had the higher interest than the control and the
highest was obtained in treatment 4 at 27.8 millions VND/ha.
In short, applying the fertilizer with 5 tons of manure + 40 kg N + 80 kg P
2
O
5
+
40 kg K
2
O + 300 kg lime/ha for the soybean variety 99084 - A28 gave the highest
yield and economic efficiency.
3.4. Soybean demonstration trials in some districts of Thai Nguyen Province
Table 3.31. Yield and interest of soybean in modules
Actual Yield
Season Place Module
(Tons/

ha)
Module 1 compared to
module 2 (%)
Interest

(Million
VND/ha)
1 2.55 63.46 20.3
Vo Nhai
2 1.56 5.5
1 2.75 54.49 23.3
Dong Hy
2 1.78 8.8
1 2.32 52.63 16.9
Phu Luong
2 1.52 4.9
1 2.54 56.86 20.2
Winter
2009
TB
2 1.62 6.4
1 2.67 53.45 22.1
Vo Nhai
2 1.74 8.2
1 2.83 52.97 24.5
Dong Hy
2 1.85 9.8
1 2.54 53.94 20.2
Phu Luong
2 1.65 6.8
1 2.68 53.45 22.3
Spring
2010
TB
2 1.75 8.3

* Notes: Applying new technical methods to 2 modules
Module 1: Using new variety (99084 - A28);
Module 2: Using old variety (DT84)
22
Table 3.31 showed that with application of new technical methods, soybean
variety 99084 - A28 (Module 1) had averaged yield higher than DT84 (Module 2) in
spring and winter crops. In winter, 2009 in module 1, the use of new technical
methods and variety made the averaged yield at 2.54 tons/ha while in module 2, the
use of the old variety made the yield only at 1.62 tons/ha. In spring 2010, the
averaged yield of module 1 were 2.68 tons/ha while the module 2 only had 1.75
tons/ha. Among places of building modules, the yield in Dong Hy District was the
highest (2.75 tons/ha in module 1 in winter and 2.83 tons/ha in spring). In Vo Nhai
district, the yield module 1 were 2.55 tons/ha in winter and 2.67 tons/ha in spring, the
lowest yield in Phu Luong district in module 1 (2.32 tons/ha in winter and 2.54
tons/ha in spring).
The yield of module 1 was higher than module 2 with the same applied dose of
fertilizer causing higher interest in module 1 than module 2. Taking in the accounts
(appendix 53) showed the interest in module 1 in all 3 places ranging from 16,9 -
23,3 millions VND/ha while the interest in module 2 was only 4.9 - 8.8 millions
VND/ha; the interest in spring in module 1 was 20.2 - 24.5 millions VND/ha while
the module 2 only had 6.8 - 9.8 millions VND/ha.
The comparison between 2 modules confirmed that using new variety and
applying new technical methods gave the much higher yield and economic
efficiency than using the old variety. From the above results, we can initially
confirm that the building modules of soybean production in winter and spring
2010 in Thai Nguyen have been succeeded. All farmers agreed that the soybean
variety 99084 - A28 with the new technical methods was very suitable with
climate and land conditions of the region and obtained much higher yield as well
as economic efficiency than the local varieties.
23

CONCLUSION AND DISCUSSION

Conclusion
1. The favorable factors for developing the soybean production in Thai Nguyen
were the favorable climate conditions and the large land resource. The fact that
soybean is easy to plant and its products are quickly consumed is the base for
development of the soybean production in Thai Nguyen.
The main disadvantaged factors in soybean production were lack of high
yielding varieties that suitable with ecological area and lack of suitable
2. The comparison results of 10 varieties in two spring crops and two winter
crops in 2004 and 2005 showed that there were two varieties ĐT2000 and 99084 -
A28 that had the estimate yield (EY) and Actual yield (AY) significantly higher than
the control variety at 95% confidence interval in all testing crops. The EY in spring
crops were 2.72 and 2.78 tons/ha, 2.21 and 2.42 tons/ha in winter crops. The AY in
spring crops were 2.16 and 2.24 tons/ha, 1.71 and 1.78 tons/ha in winter crops.
3. The optimum planting dates of 99084 - A28 variety in spring crop in Thai
Nguyen was from 15th, Feb. to 6th, Mar. With this planting date, the EY was from
2.86 to 3.04 tons/ha; the AY was from 2.09 to 2.19 tans/ha that were higher than
other periods of planting. The optimum planting dates in winter crop was from 5th,
Sep. (when harvesting winter rice) to 25th, Sep. With this planting date, the EY was
from 1.87 to 2.40 tons/ha and the AY was from 1.22 to 1.57 tons/ha that significant
higher than other studied periods.
4. The most suitable density for soybean variety 99084 - A28 that was planted in
spring crop was 35 plants/m2 and 45 plants/m2 in winter. At these densities, the EY
was 2.78 tons/ha in spring crop and 2.47 tons/ha in winter; the AY was 2.50 tons/ha
in spring and 1.90 tons/ha in winter, significantly higher than other densities tested.
5. Planting the soybean variety 99084 - A28 in spring crops with the fertilizer
combination of 5 tons of manure + 40 kg N + 80 Kg P2O5 + 40 Kg K2O +300 Kg
lime/ha was the most optimum due to both its highest yield (3.05 tons/ha) and its
highest interest (27.8 millions VND/ha).