1
THAI NGUYEN UNIVERSITY
THAI NGUYEN UNIVERSITY OF AGRICULTURE AND
FORESTRY
HOANG THI MINH THU
STUDYING ON FARMING TECHNIQUES FOR
POTATO PRODUCTION IN WINTER CROPS IN THAI
NGUYEN
Field of Research: Crop Science
Code: 9.62.01.10
PHD THESIS SUMMARY IN CROP SCIENCE
THAI NGUYEN - 2019
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This study was completed at:
THAI NGUYEN UNIVERSITY OF AGRICULTURE AND
FORESTRY
Supervisors: Pro. Dr. Tran Ngoc Ngoan
Assoc.Pro. Dr. Tran Van Dien
Examiner 1:...............................................................................
Examiner 2:...............................................................................
The thesis will be defending before the board of grassroots
level
Meeting at: Thai Nguyen University of Agriculture and
Forestry - Thai Nguyen University
At.. ... .. hours ... days ... .. month .. 2019
Refer at:
- National Library
- Learning Resource Center - Thai Nguyen University
- Library of Thai Nguyen University of agriculture and
Forestry
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PUBLICATIONS INCLUDED IN THIS THESIS
1. Hoang Thi Minh Thu, Duong Thi Thu Huong, Nguyen Thi
Nhung, Tran Ngoc Ngoan, (2018). Potato varieties selection from
imported sources in Thai Nguyen province in 2015-2016. Vietnam
Agricultural Science and Technology Magazine. No. 2 (87), p. 5964.
2. Hoang Thi Minh Thu, Duong Thi Thu Huong, Nguyen Thi
Nhung, Tran Ngoc Ngoan, (2018). The effect of potassium levels on
growth, development, yield and quality of KT1 potato variety.
Vietnam Agricultural Science and Technology Magazine. No. 9
(94), p. 69-73
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INTRODUCTION
1. Thesis imperiousness
Potato (Solanum tuberosum) is food crops of many European
countries and potato is also staple food crops in some countries
(Duong Hong Dat, 2005) [7]. Potato tubers contain 20% of dry
matter, including 80-85% of starch, 3-5% of protein and some other
vitamins (Nguyen Van Thang and Bui Thi My, 1996) [38].
Thai Nguyen is a midland province in the northern
mountainous region of Vietnam with a natural area of more than
3562.82 km2 and a population of about 1.2 million people (Thai
Nguyen Statistical Office, 2017) [4] . Thai Nguyen's potato
consumption market is very large due to its large population and
there are many universities, colleges, military camps and Sam Sung
Company located in the area. Although the demand for potatoes is
large, most of the province's potato consumption is imported from
other provinces and China and the output of potatoes in the province
is still low to meet the consumption of people demand.
The weather in winter crop in Thai Nguyen is very suitable for
the growth and development of potatoes, with the average
temperature from 16.6 to 25.50C; rainfall from 0.3 to 322.5 mm; the
average humidity is 72-75%. In recent years, potatoes have been
included in the winter crop structure, the province has many policies
to support the development and expansion of potato area, hence,
potatoes have occupied an important position in the development of
winter crop growing in Thai Nguyen province, the province has
good potential to expand potato area. However, the potato
cultivation area in the province is decreasing, the main reason is due
to the lack of good potato varieties for farmers, mainly cultivating
Chinese varieties with poor quality, much pests and diseases
infection and low yield. Futhermore, potato quality is not
guaranteed, especially farming techniques such as: crop season,
density, fertilizer, watering, ridging are not appropriate. Therefore,
in order to expand potato area in winter crop in Thai Nguyen, it is
necessary to have comprehensive and extensive research on variety
selection techniques to farming techniques. Thus, we carried out the
5
topic "Studying on farming techniqes for potato production in
winter crops in Thai Nguyen province".
2. Objectives of the study
- Assessing the status of potato production to identify the
limitation factors of potato yield in Thai Nguyen province.
- Identifying potato varieties with high yield and good quality
in accordance with winter crop conditions in Thai Nguyen.
- Identifying appropriate farming techniqes for potatoes in
winter crop conditions in Thai Nguyen province to supplement and
completing intensive farming for potatoes in Thai Nguyen province
contributed to expand the potato area of in the field of two rice
crops.
- Building a model of intensive potato production with high
yield and economic efficiency in two rice crops.
3. Materials and research scope
3.1. Materials
- Potato varieties: Selecting potential potato varieties including
8 imported potato varieties through the experiments of winter crop in
2-crop field in Thai Nguyen province.
- Studying on farming techniques for potato production in
winter crop including density, crop season, fertilizer, watering and
ridging.
3.2. Research scope
- Studying on some characteristics of varieties and farming
techniques for potato production in Thinh Duc commune, Thai
Nguyen City and Phan Me commune, Phu Luong district.
- Model of experimental production in Phan Me commune,
Phu Luong district and Thinh Duc commune, Thai Nguyen City,
Thai Nguyen province.
4. New contributions of the study
- Identifying the KT1 potato variety with good prospect
showed average growing period, good growth and development, low
pest infection, high yield (31 - 32 tons/ha), good quality and it is
appropriate for fresh food and processes.
- Identifying appropriate farming techniques for KT1 potato
varieties winter crop in Thai Nguyen. The best sowing time was
6
from November 1 to November 10. The appropriate mineral
fertilizers levels were 15 tons of manure + 180kg N + 180 kg of P 2O5
+ 180 kg K2O/ha with planting density of 5 clusters/m 2, while the
suitable potassium levels were 15 tons of manure + 150 kg N + 180
kg K2O + 150 kg P2O5/ha. The appropriate micro-organic fertilizers
levels were 15 tons of manure + 150 kg N + 150 kg P 2O5/ha + 150
kg K2O/ha showed the highest yield and economic efficiency. The
additional watering was 3 times (15 days after sowing, 45 days after
sowing, 75 days after sowing). Ridging 2 times/crop (15 days after
sowing and 45 days after sowing).
5. Scientific and practical significance
5.1. Scientific significance
- The results obtained from experiments identified varieties
and farming techniques which were a scientific basis to complement
the technical process of potato production in Thai Nguyen province.
- Study results can be used for reference in teaching and
researching potato varieties.
5.2. Scientific and practical significance
- The study results were the basis for selecting good potato
varieties with high yield and good quality in accordance with the
winter crop on two rice crop fields in Thai Nguyen province.
- Supplementing scientific arguments to select suitable
imported potato varieties and building up the process of potato
production in winter crop in Thai Nguyen province.
CHAPTER 2
MATERIALS, CONTENTS AND RESEARCH METHODS
2.1. Research materials
The study included 8 potatoes varieties tested in different
ecological conditions.
2.2. Research contents
2.2.1. Surveying the current status of potato production and
determining limitation factors to potato production in Thai Nguyen
province
2.2.2. Studying on the growth and development of 8 potato varieties
in winter crops in Thai Nguyen
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2.2.3. Studying farming techniques for KT1 potato variety in winter
crops in Thai Nguyen
2.2.4. Building a model of potato production in winter crops in
2017 in two rice crop fields in Thai Nguyen
2.3. Research methods
2.3.1. Survey method to assess the status of potato production in
Thai Nguyen
2.3.2. Research methods of field experiments
* Research location:
The experiments were conducted in Phan Me commune, Phu
Luong district and Thinh Duc commune, Thai Nguyen City, Thai
Nguyen province.
* Experimental land:
The study was conducted in the sandy loam fields: pH = 5,38;
humus = 1.58%, N = 0.146%, P2O5 = 0.116%, K2O = 0.82%, P2O5 dt
(mg/100g) = 8.78, K2Odt (mg/100g) = 8.51.
* Experimental design
- Experiment 1: The growth and development of some potato
varieties in winter crops in 2015 and 2016 in Thai Nguyen.
- Experiment 2: The effect of crop seasons on growth and
yield of KT1 potato variety in winter crops in 2016 and 2017 in
Thai Nguyen.
- Experiment 3: The effect of planting density and mineral
fertilizer on potato growth and yield of KT1 potato variety in
winter crops in 2016 and 2017 in Thai Nguyen.
In which: Manure was 15 tons
P1:
P2:
P3:
P4:
120 kg N + 120 kg P2O5 + 120 kg K2O
150 kg N + 150 kg P2O5 + 150 kg K2O (control)
180 kg N + 180 kg P2O5 + 180 kgK2O
210 kg N + 210 kg P2O5 + 210 K2O
M1: 44 clusters/m2
M2: 55 clusters /m2
M3: 66 clusters /m2
- Experiment 4: The effect of planting density and microbial
organic fertilizer on potato growth and yield of KT1 potato variety
in winter crops in 2016 and 2017 in Thai Nguyen.
In which:
M1: 4 clusters/m2
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M2: clusters /m2
M3: clusters /m2
* Standar: 150 kg N + 150 kg P2O 5 + 150 kgK 2O
P1: 15 tons of manure + standar
P2: 1.200 kg of Song Gianh organic fertilizer + standar
P3: 1.200 kg of Que Lam organic fertilizer + standar
P4: 1.200 kg Tien Nong organic fertilizer + standar
P5: 1.200 kg of Trun Que organic fertilizer + standar
- Experiment 5: The effect of potasium levels on the growth
and yield of KT1 potato variety in winter crops in 2016 and 2017 in
Thai Nguyen
In which:
Treatment 1:
Treatment 2:
Treatment 3:
Standar + 120 kg K2O/ha
Standar + 150 kg K2O/ha
Standar + 180 kg K2O/ha
Treatment 4:
Treatment 5:
Standar + 210 kg K2O/ha
Standar + 240 kg K2O/ha
* Standar: 15 tons of manure + 150 kg N + 150 kg P2O5
- Experiment 6: The effect of watering times on the growth
and yield of KT1 potato variety in winter crops in 2016 and 2017 in
Thai Nguyen
Irrigation methods (following the instructions of Nguyen Van
Thang et al, 1996 [40]): Watering 1/2 - 2/3 of the trench, soaking for
4 - 6 hours depending on soil moisture, ensuring enough moisture of
80% then removing shallow.
- Experiment 7: The effect of ridging times on the growth
and yield of KT1 potato variety in winter crops in 2016 and 2017 in
Thai Nguyen
2.3.3. Building a model of potato production in winter crops
- Location: Phan Me commune, Phu Luong district and Thinh
Duc commune, Thai Nguyen City, Thai Nguyen province.
- Size: 3.000 m2/1 model, there were 2 models in each location
(Model 1: KT1 variety + farming techniques from the research
results of the project; Model 2: Solara variety + farming techniques
of farmers). The total model size in 2 communes was 12.000 m 2.
- Duration: Winter crop season in 2017
2.4. Monitoring methods
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- According to QCVN 01-59-2011/BNNPTNT National
technical regulation on cultivation value testing and use of potato
varieties.
- According to the instructions of Root Crop Research and
International Potato Center.
* Technical process applied: (variety testing process)
2.5. Data analysis
The experimental design and data analysis followed the
guidance of Do Thi Ngoc Oanh et al, (2012) [27]. Pham Chi Thanh,
(1988) [37]. Using SAS 9.1 software and IRRISTAT 5.0 software,
[95], [120].
CHAPTER 3
RESULTS AND DISCUSSION
3.1. Natural, economic and social conditions affected potato
production and potato production situation in Thai Nguyen
3.1.2. Status of potato production in Thai Nguyen
For many years, maize is the main crop in the winter crop (in
2015, the province had planted 15.762 hectares, accounting for
52.45% of winter crop). Potatoes have just put into the crop
structure, so the area was very small (in 2015: 511 hectares),
accounting for 1.42% of the total area of winter crops and 2.8%
compared to winter maize crop.
Table 3.2. Winter crop structure in 2015 in field land in Thai
Nguyen province
Size
Income
Production
(Milion
ha
Rate (%)
(ton)
VND/ha)
Maize
15.762
52.45
79.053
11.5
Potato
511
1.42
6.965
45.83
Sweet potato
4.260
14.16
27.848
14.00
Vegetables
9.544
31.73
231.169
Total
30.077
100
345.035
(Thai Nguyen Department of Agriculture and Rural Development,
2017)[30]
Crop
10
Although the production area was limited, potato cultivation
brought a high income, net profit was 45.83 million VND/ha which
was 4 times higher compared to winter maize crop and 3.2 times in
comparision to sweet potato. According to farmer opinions, potatoes
require much higher investment than other crops, plants do not
actively source varieties and they show difficulty management than
other winter crops, so the plant has not really encouraged producers
and not yet established concentrated production areas.
3.1.2. The situation of using potato varieties and farming
techniques application of farmers
Table 3.3. Potato variety structure of farmers 2015
Variety
Rosagol
Diamant
Solara
China
Total
Household Implimenting
Numbers
Household
%
numbers
27
15.00
22
12.22
62
34.44
69
38,33
180
100
Yield
(tons/ha)
16.7
13.2
13.5
11.3
(Survey data of households in 2015; * Some households grew 2
varieties)
Table 3.3 showed that potatoes in Thai Nguyen were grown
mainly by varieties imported from China. In recent years, the
Department of Agriculture and Rural Development has introduced
Solara, Rosagol and Diamant varieties into production due to the
suitable price of tuber. Although, yields of other varieties imported
from China (varieties bought by traders, unknown origin) were
lower than those of Solara, Rosagol, Diamant, the price of tubers
was cheap so there are about 38.33% of households have been using.
Furthermore, those varieties were difficult to buy because they have
to register and have a limited amount (some farmers harvested crops
later than agricultural extension implementation) and the price was
higher than that of China varieties.
3.1.2.2. Favorable and unfavorable conditions of potato production
in Thai Nguyen province
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* Favorable conditions
- Climate and soil conditions are relatively suitable for the
growth and development of potatoes and the winter crop area is quite
large (potatoes have a short growth period of 80-90 days, prefer cold
under none pressure of crop seasons). The inland canal systems are
relatively adequate for irrigation and potato cultivation.
- Potato market in Thai Nguyen province is large and easy to
sell, many people are aware of the potato value, the income from
potatoes is also higher in comparison to other winter crops.
- Province and districts have policies to support variety prices,
fertilizers and instruct farmers on farming techniques. There are also
many new varieties with high quality.
* Unfavorable conditions
- Farmers have not updated farming techniques for potato
production, there are many farmers do not ridge, irrigate and the use
of fertilizers is incorrect, the sowing time is too early or too late, the
planting density is too sparse or too thick, unknow how to control
pests and diseases and untreated soil before sowing.
- Potato production is small, spontaneous and it has not yet
formed a concentrated production area, resulting in low price
potatoes in markets.
- There are unsuitable varieties, varieties mainly imported
from China with poor quality. Furthermore, varieties are infected
with pests and diseases and low yield.
- The cost of investment for potato production is high, the cost
of variety accounts for 50% of the total cost, while potato cultivation
requires higher farming techniques compared other winter crops
limited the expansion of potato crop area.
3.2. The growth and development of some winter potato varieties
in 2015 and 2016 in Thai Nguyen
3.2.2. The growth of some winter potato varieties in 2015 and 2016
in Thai Nguyen
Table 3.11. Growth of some winter potato varieties in 2015 and
2016
Treatment
2015
GD
(grade 3-7)
2016
CCV (%)
GD
(grade 3-7)
CCV (%)
12
KT1
K3
12KT3-1
KT9
Georgina
Concordia
Jelly
Solara (control)
TN
7
7
7
7
7
5
7
7
PL
7
3
7
5
5
7
7
7
TN
100
90.0
99.8
99.0
100
100
99.8
100
PL
100
80.0
99.8
99.8
100
99.0
99.8
100
TN
7
3
7
7
7
5
7
7
PL
7
3
7
7
5
7
7
7
TN
100
80.8
100
99.8
100
100
99.8
100
PL
100
80.0
99.8
99.8
99.0
100
99.8
100
Note: (TN: Thai Nguyen city; PL: Phu Luong district; GD: Growth
and Development; CCV: Canopy cover; Grade (3-7): Grade 3:
Poor; Grade 5: Medium; Grade 7: Good)
- Table 3.11 showed that the growth of the potato varieties
experimented in two locations in the winter crops reached from
medium to good (except K3 variety), in which KT1, 12KT3-1 and
Jelly varieties had good growth (grade 7) that was equivalent to the
control variety (Solara) in both experimental sites in 2015 and 2016.
- The canopy cover reached from 80 - 100%. In which KT1
variety reached the highest canopy cover (100%), that was
equivalent to the control variety in both experimental sites in 2015
and 2016. The remaining varieties had canopy cover ranged from 80
- 99.8%.
3.2.3.Morphological characteristics of potato varieties
Morphological characteristics are an important factor in
selection and breeding because it is related to the growth, yield and
quality of tubers. Results were presented in table 3.13.
Table 3.13. Morphological characteristics of potato varieties
Variety
KT1
K3
12KT3-1
KT9
Georgina
Plant
shape
Semistanding
Semistanding
Semistanding
Semistanding
Semi-
Tuber
shape
Tuber
periderm
color
Tuber
medulla
color
Dormant
bud depth
(grade 1-5)
Oval
Yellow
Yellow
3
Circle
Yellow
Yellow
5
Oval
Yellow
Yellow
3
Oval
Vilolet
Yellow
5
Flat circle
Yellow
Light
3
13
Concordia
Jelly
Solara
(control)
standing
Semistanding
Semistanding
Semistanding
Yellow
Circle
Yellow
Yellow
3
Oval
Yellow
Yellow
3
Oval
Yellow
Yellow
3
Note: (Dormant bud depth, grade 1; shallow; 3; average; 5; deep)
- Plant shape: Experimental potato varieties were semistanding plants that was similar to the control varieties (Solara).
- Tuber shape: potato varieties were flat to oval plants. In
which Concordia variety was circle, Georgina and K3 were flat
circle tubers, the remaining varieties were oval that was similar to
the control variety.
- Tuber periderm colors were yellow and violet. Among them,
KT9 was violet. The remaining varieties were yellow, which were
similar to the control variety.
- Tuber medulla colors were yellow and light yellow. In which
Georgina was light yellow. The remaining varieties were similar to
the control varieties.
- Dormant bud depth of potato varieties was from medium to
deep. In which K3 and KT9 were deep, evaluated at grade 5. The
remaining varieties were medium, evaluated at grade 3 that was
similar to the control variety.
3.2.5. Yield components and yieldd of winter potato varieties in
2015 and 2016 in Thai Nguyen
Yield is the actual product obtained on an area unit, this is a
synthetic characteristic that faithfully reflects the adaptation levels of
the variety in certain cultivation and ecological conditions. Results
were presented in tables 3.18 and 3.19
Table 3.18. Yield of winter potato crop varieties in Thai Nguyen,
2015
Unit: tons/ha
No
1
2
Variety
KT1
K3
Thai Nguyen
city
29.42bc
16.44e
Phu Luong
a
33.78
20.00d
Average
31.60a
18.22d
14
3
4
5
6
7
8
P
12KT3-1
KT9
Georgina
Concordia
Jelly
Solara (control)
Location
T
L
L*T
26.81c
27.26bc
27.36bc
17.28e
26.74c
16.38e
23.46b
CV (%)
LSD.0,05
T
L
L*T
29.88b
28.00bc
28.12bc
26.44c
29.38bc
27.22bc
27.88a
<0.01
<0.01
<0.01
6.21
1.87
0.93
1.87
28.35b
27.63b
27.74b
21.86c
28.16b
21.70c
Table 3.18 showed that the yield of experimental potato
varieties in 2015 ranged from 16.38 to 33.78 tons/ha. There was
highly significant interaction effect between variety and location
(PL*T <0.01). In the experiment, KT9, Georgina and Jelly varieties
had a stable yield in the two study sites. Yields of the remaining
varieties in Phu Luong were significantly higher in comparision to
Thai Nguyen city.
Table 3.19. Yield of potato varieties in winter crop in Thai
Nguyen, 2016
Unit: tons/ha
No
Variety
1
2
3
4
5
6
7
8
KT1
K3
12KT3-1
KT9
Georgina
Concordia
Jelly
Solara (control)
Location
T
L
L*T
P
CV (%)
Thai Nguyen
city
30.67
14.00
26.56
26.11
27.18
26.56
26.90
17.89
24.48b
Phu Luong
Average
33.39
25.56
28.94
27.94
27.78
26.28
28.83
26.78
28.19a
<0.01
<0.01
>0.05
14.11
32.04a
19.77d
27.75ab
27.02b
27.48b
26.41bc
27.88ab
22.33c
15
LSD.0,05
T
L
L*T
4.40
2.20
ns
Table 3.19 showed that yield of experimental potato varieties
in 2016 ranged from 14-33.78 tons/ha. There was no significant
interaction effect between the variety and location (PL*T > 0,05), so
the variation in yield of experimental potato varieties in the two
experimental sites was similar.
The effect of experimental sites on yield showed that the
experimental potato varieties grown in Phu Luong had an average
yield of 28.19 tons/ha that was significantly higher compared to Thai
Nguyen city (24.48 tons/ha).
The effect of varieties on yield showed that K3 had the lowest
yield (19.77 tons/ha), it was lower compared to the control (Solara:
22.33 tons/ha). The remaining varieties showed higher yield than the
control. In which KT1 had the highest actual yield (32.03 tons/ha).
3.2.6. Quality factors of experimental potato varieties
- The dry matter contents of experimental potato varieties
ranged from 16.4 - 20.5%. In which KT1 had the highest dry matter
content (20.5%), the remaining varieties were similar or lower
compared to the control (Solara: 18.8%).
- Sugar contents ranged from 0.37 to 0.62%. Among 8
varieties, KT1 had the lowest sugar content (0.37%), while KT9 had
the highest sugar content (0.62%), the remaining varieties showed
similar sugar content to the control (Solara: 0.57%).
- The starch content ranged from 13.7 to 18.7%. In which,
KT1 had the highest starch content (18.7%), while Georgina and
Concordia varieties showed the lowest starch content (13.7 - 14%).
The remaining varieties had similar starch content in comparision to
the control (Solara: 16.3%).
- Vitamin C contents of experimental potato varieties ranged
from 14.8 to 19 mg/100g. In which, K3 and Concordia varieties had
similar vitamin C contents (Solara: 14.9 mg/100 g), while vitamin C
contents of the remaining varieties were higher compared to the
control.
16
Table 3.20. Quality analysis of potato varieties in Phu Luong,
2016
Content
Variety
KT1
K3
12KT3-1
KT9
Georgina
Concordia
Jelly
Solara
(control)
Dry
matter
(%)
20.5
17.2
18.9
18.0
16.5
16.4
18.9
18.8
Sugar
(%)
Starch
(%)
VTMC
(mg/100g)
0.37
0.56
0.57
0.62
0.52
0.57
0.56
18.7
15.0
16.3
16,5
13.7
14.0
16.8
16.0
15.4
17.0
18.0
18.3
14.8
19.0
0.57
16.3
14.9
After boiling
Taste
Friability
(grade1(grade 1-5)
5)
1
2
1
3
1
1
3
3
1
2
1
1
3
2
1
2
Analyzed at Field Crops Research Institute
- The friability of potato varieties ranged from 1 - 3. Among 8
varieties, KT9 and Jelly were less friability (grade 3), while the
remaining varieties boiled were evaluated at grade 1, they were
similar to the control.
- After boiling, the taste of 12KT3-1 and Concordia was very
good, evaluated at grade 1, they were similar to the control, while
K3 and KT9 varieties were evaluated at medium grade (3) and they
were equvalent to the control.
Research results determined that KT1 potato variety showed
good growth, low pest infection, high yield (31.6 - 32.03 tons/ha),
the rate of commercial tuber reached > 90% (in the 2 study sites).
The variety showed good quality and it was suitable for fresh food
consumption demand and processe in the market. This result was
consistent with the study of Trinh Van My, 2014 [25]. Therefore, we
selected KT1 variety to conduct farming techniques experiement.
3.3. The effects of farming techniques on growth and
development of KT1 potato variety
3.3.1. The effect of crop seasons on growth and development of
KT1 potato variety in winter crop 2016 and 2017 in Thai Nguyen
Table 3.22. The effect of crop seasons on growth of KT1 potato
variety in winter crops in 2016 and 2017 in Thai Nguyen
Crop
season
Sowing
date
2016
GD
(grade 3-7)
2017
CCV
(%)
GD
(grade 3-7)
CCV
(%)
17
TV1
TV2
TV3
TV4
21/10
01/11
10/11
20/11
TN
5
7
7
5
PL
7
7
7
7
TN
100
100
100
98.3
PL
100
100
100
98.3
TN
5
7
7
5
PL
5
7
7
7
TN
100
100
100
100
PL
100
100
100
98.5
Note: (TN: Thai Nguyen City; PL: Phu Luong; GD: growth and
development; Grade 3: Poor; Grade 5: average; Grade 7: good;
CCV: canopy cover)
The crop seasons affected the growth of KT1 potato variety.
Sowing time from November 1 to November 10 (TV2 and TV3) in
Thai Nguyen City grew better than the remaining 2 crop seasons.
Meanwhile, sowing time from November 1 to November 20 (TV2,
TV3 and TV4) in Phu Luong grew better than crop season 1.
- The canopy cover of different crop seasons ranged from 98.3
to 100%. The canopy cover in crop season 4 experiment (sowing on
20/11) in Thai Nguyen city and Phu Luong district (2016) and Phu
Luong (2017) was <100% (98.3 – 98.5%). Meanwhile canopy cover
reached 100% in the remaining crop seasons. Thus, canopy cover of
different crop seasons in the experiments was high.
Table 3.27. The effect of crop seasons on yield of KT1 potato
variety in winter crop in 2016 and 2017
Unit: ton/ha
Crop
Season
TV1
TV2
TV3
TV4
Sowing
Date
21/10
01/11
10/11
20/11
P
CV(%)
LSD. 0,05
2016
TN
27.57
31.90
31.17
28.57
<0.05
5.47
3.26
2017
PL
28.03
31.47
31.80
29.10
<0,05
3,44
2.07
TN
27,50
31,17
31,00
28.27
<0.05
4.94
2.91
PL
28.83
31.33
31,17
28,80
>0,05
6.05
ns
Note: (TN: Thai Nguyen City; PL: Phu Luong)
Table 3.27 showed that yield of KT1 potato variety ranged
from 27.57 to 31.9 tons/ha (in 2016) and from 27.5 to 31.33 tons/ha
(2017). In which, TV2 and TV3 (in 2 study sites in 2016 and Thai
Nguyen in 2017) had higher yield in comparision to the 2 remaining
crop seasons (P<0.05), while there was no significant (P>0.05)
difference in yield among crop seasons in the winter crop in Phu
18
Luon, 2017. Thus, the best sowing time of KT1 potato variety was
from November 1-10 in Thai Nguyen City.
3.3.2. The effect of planting density and mineral fertilizer on
growth and development of KT1 potato variety in winter crops in
2016 and 2017 in Thai Nguyen
Yield of treatments ranged from 26.33 to 34.97 tons/ha (winter
crop in 2016) and from 25.23 to 34.65 tons/ha (winter crop in 2017).
There was no significant interaction effect between planting density
and mineral fertilizer to yield (P P*M > 0.05). The difference in yield
of treatments was due to the separate effect of planting density (P M
<0.01) and fertilizer levels (PP <0.01).
When planting density increased, yield increased. Meanwhile, when
fertilizer levels increased from P1 to P4, yields increased to P3 then
decreased at the same planting density. On the other hand, at the
same fertilizer levels, yield increased when increased planting
density from M1 to M3. Planting density which was suitable for
KT1 potato variety was from 5-6 clusters/m 2 on average of both
crops. Yields of both above planting densities were significantly
(P>0.05) higher in comparision to others and the P3 fertilizer levels
reached the highest yield among different fertilizer levels (P>0.05).
Planting density with the highest average fertilizer level was M3P3
with 6 clusters/m2 and mineral fertilizer application at the rate of 180
kg N + 180 kg P205 + 180 kg K20/ha achieved the highest yield with
31.72 tons/ha.
Table 3.35. The effect of planting density and mineral fertilizer
on KT1 potato yield in winter crops in 2016 and 2017
Unit: tons/ha
Fertilizer
2016
2017
M1
M2
M3
Average
M1
M2
M3
Average
P1
26.43
27,97
30.93
28.44c
25.23
27.25
29.37
27.29c
P2
26.93
31.35
31.47
29.92bc
26.55
31.24
31.94
29.91b
a
27.05
33.47
34.65
31.72a
26.11
30.76
31.89
29.59b
b
a
a
P3
27.33
33.60
34.97
31.97
P4
26.33
31.93
32.60
30.29b
b
a
a
TBMĐ
P
26,76
31.21
32.49
M <0.01
26.23
30.68
31.97
M <0.01
19
CV(%)
LSD.0,05
P<0.01
P<0.01
M*P>0.05
M*P>0.05
5.29
5.57
M: 1.37
M: 1.42
P: 1.58
P: 1,64
M*P: ns
M*P: ns
Table 3.36 showed that treatments P3M2 and P3M3 had the
highest net profit (90.93 - 94.53 million VND/ha). Therefore, in Thai
Nguyen City, KT1 potato variety may grow with planting density of
5-6 clusters/m2 and the amount of mineral fertilizer from 180 N +
180 P205 + 180 K20/ha (P3) to 210 N + 210 P205 + 210 K20/ha (P4).
However, it recommended that we should use the treatment P3M2 to
reduce the cost because total income of this treatment was 2.5
million VND/ha less than the P3M3 treatment, while the total cost
was 3.4 million VND/ha less than the P3M3 treatment. On the other
hand, sparse planting was easier to tend plants, less pests and
diseases infection and bigger tubers. This result coincided with the
study of Truong Van Ho, 2010 [17] and Le Sy Loi [24].
Table 3.36. Economic efficiency of the planting density and
mineral fertilizer treatments for KT1 potato varieties in winter
crops in 2016 and 2017
No
Treatment
1
2
3
4
5
6
7
8
9
10
11
12
P1M1
P1M2
P1M3
P2M1
P2M2
P2M3
P3M1
P3M2
P3M3
P4M1
P4M2
P4M3
Total Income
(VND/ha)
2016
2017
132.25
126.15
139.90
136.25
151.95
146.85
134.80
132.75
156.75
156.20
157.40
159.70
136.75
135.25
168.15
167.35
174.35
173.25
131.75
130.55
159.55
153.80
163.10
159.45
Total Cost
(VND/ha)
70.370
73.770
77.170
71.936
75.336
78.736
73.012
76.412
79.812
74.553
77.953
81.353
Net Profit
(VND/ha)
2016
2017
61.88
55.78
66.13
62.48
74.78
69.68
62.86
60.81
81,41
80.86
78.66
80.96
63.73
62.23
91.73
90.93
94.53
93.43
51.19
55.99
81.59
75.84
81.74
78.09
Average price of potatoes: 5.000VND/kg
20
3.3.3. The effect of planting density and microbial organic
fertilizer on growth and development of KT1 potato variety in
winter crops in 2016 and 2017 in Thai Nguyen
Table 3.44. The effect of planting density and micro-organic
fertilizer on KT1 potato yield in winter crops in 2016 and 2017
Unit: tons/ha
Fertilizer
H1
H2
H3
H4
H5
Average
density
M1
27.23
26,70
25.53
25.30
25.57
26.07b
P
CV(%)
LSD.0,05
2016
M2
M3
31,77
32.87
28.13
30.13
27.97
29,47
27,17
28.07
27.40
29.57
28.49a
30.02a
2017
TBPB
30.62a
28.32b
27.66b
26.84b
27.51b
M1
27.17
26.43
24,97
24.97
25.16
25.74b
M <0.01
H<0.05
M*H>0.05
7.57
M:1.61
H: 2.08
M*H: 0.55
M2
30.47
28.93
27.43
26.63
27.33
28.16a
M3
32.83
29.43
29.07
27.73
28.77
29.57a
TBPB
30.16a
28.27b
27.16bc
26.44c
27.09bc
M <0.01
H<0.01
M*H>0.05
6.72
M: 1.41
H: 1.82
M*H: ns
Yield of KT1 potato variety among treatments ranged from
25.3 to 32.87 tons/ha (2016) and from 24.97 to 32.83 tons/ha (2017).
There was no interaction effect between planting density and microorganic fertilizer to yield (PM * H> 0.05). The differences in yields of
treaments due to separate effects of planting density (P M <0.01) and
the effect of micro-organic fertilizers (P H <0.01). In the experiment,
the planting density of M2 and M3 (5 and 6 clusters/m 2) yielded
from 28.49 - 30.02 tons/ha (in 2016) and from 28.16 to 29.57 tons/ha
(in 2017), they were higher than that of sparse density (M1: 25.74 26.07 tons/ha). The treatment with manure fertilization achieved
significantly (P>0.05) higher yield (2016: 30.62 tons/ha and 2017:
30.16 tons/ha) compared to micro-organic fertilizers.
Table 3.45. Economic efficiency of experimental treatments in
winter crops in 2016 and 2017
No
Treatment
Total Income
(VND/ha)
2016
2017
Total Cost
(VND/ha)
Net Profit
(VND/ha)
2016
2017
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