Tóm tắt: Nghiên cứu sinh thái vùng trồng rau ở Thường Tín, Hà Nội và đề xuất một số nội dung Giáo dục môi trường cho trẻ mầm non

MINISTRY OF EDUCATION AND TRAINING
HANOI NATIONAL UNIVERSITY OF EDUCATION

NGUYEN HA LINH

ECOLOGICAL RESEARCH ON THE VEGETABLE GROWING
AREAS IN THUONG TIN, HANOI AND PROPOSE SOME
ENVIRONMENTAL EDUCATION CONTENTS
FOR PRESCHOOL CHILDREN

MAJOR: ECOLOGY
CODE: 9420120

THE DOCTORAL DISSERTATION SUMMARY

HANOI - 2024

The research project is completed at:
Falcuty of Biology - Hanoi National University of Education

Science instructor: 1. Associate Professor, PhD. Mai Sy Tuan
2. Assoc. Prof. PhD. Nguyen Thi Hong Lien

Review 1: Prof. PhD. Tran The Bach
Review 2: Institute of Ecology and Biological Resources
Review 3:
Prof. PhD. Nguyen Trung Thanh
VNU University of Science

Prof. PhD. Hoang Van Sam
Vietnam National University of Forestry

The thesis will be reviewed by the Council of Thesis Evaluation at Hanoi National
University of Education

at...on .......hour..., date... month... 2024.
.

The thesis can be found at:
- National Library, Hanoi
- Library of Hanoi National University of Education

LIST OF PROJECTS THAT HAVE BEEN ANNOUNCED

1. Nguyen Thi Luyen and Nguyen Ha Linh (2020), “Using the ecological
environmental education for preschool children”, HNUE Journal of Science, Vol 64,
Issue 4B, 98 – 110.
2. Nguyen Ha Linh and Nguyen Thi Hong Lien (2022), “Diversity of wild medicinal
plants in the vegetable cultivation areas in Thuong Tin district, Hanoi City”, HNUE
Journal of Science, Natural Sciences,Vol 67, Issue 3, 109 – 123.
3. Nguyen Ha Linh and Nguyen Thi Luyen (2022), "Organizing experiential activities
to explore biological diversity in vegetable gardens for preschool children", HNUE
Journal of Science, Vol 67, Issue 4A, 247 – 259.
4. Linh Ha Nguyen, Hong Lien Thi Nguyen, Mai Ngoc Le et al (2024), “Exploring the
Distribution of Mecardonia procumbens (Miller) Small in Select Regions of Hanoi
Region”, Asian Journal of Plants Sciences, Vol 23, Issue 1, 61 – 68.

INTRODUCTION
1. Background

Vegetables are essential food in people’s daily diet. Vegetable production in thse

world and Vietnam has increased gradually over the years, catering the population rise.
In Hanoi, the total vegetable growing areas is more than 33.6 thousand hectares (2022)...
Many studies about vegetable growing areasin Hanoi have been carried out in Gia Lam,
Thanh Tri, Dong Anh districts… They focus on assessing the impact of vegetable
growing on soil, water and air quality; and pest management..., not paying enough
attention to the impact of vegetable growing methods on local ecological factors.

Thuong Tin is one of the largest vegetable growing areas in Hanoi, the main
products are spices, and leafy vegetables of the Brassicaceae and Cucurbitaceae. In
recent years, organic vegetable production has become a trend and is encouraged
to expand in scale and area because of its quality safety for users and brings high
economic value to farmers. In Thuong Tin vegetable growing area, the farmers
have two methods of cultivating vegetables: traditional vegetable cultivating and
organic vegetable cultivating. The basic difference between these two methods is
the (non)usage of chemicals (chemical fertilizers, plant protection chemicals…) in
farming. This can lead to various impacts on the natural environment. However,
research on the ecology of Thuong Tin vegetable growing areas, Hanoi is still
limited. Comprehensive research on abiotic and biotic factors has almost not been
conducted. Therefore, it is necessary to study the ecology of Thuong Tin vegetable
growing areas. Besides, it is needed to evaluate the impact of vegetable growing on
ecological factors as a foundation for building sustainable organic agriculture.

Forstering organic agriculture is one of the world's 17 sustainable development
goals. Sustainable development is expressed in economics, society, environment.
Environmental Education is an effective method to sufficiently implement sustainable
development goals. Many studies have shown that Environmental Education needs to
be implemented right from the preschool age. In Vietnam, Environmental Education is
implemented at all levels in the national education system, including the preschool
level. The organization and implementation of educational programs at preschool
educational establishments is based on the national early childhood education

curriculum issued by the Ministry of Education and Training. In the implementation
process, teachers need to exploit educational content appropriate to the actual
conditions local contexts. This helps preschool activities to be regionally specific to
maximize children's life and experience, creating conditions for children to consolidate
and acquire knowledge. For Environmental Education, this is meaningful because using
materials from the context and environment where children live and study as a means
of teaching; Exploiting educational content about local environmental issues will help
children understand the need to protect the environment right around them, not just
protecting beautiful scenes or famous places in other places.

However, environmental education for preschool children in Vietnam is not fully
effective due to many reasons: mainly lack of space to organize activities, educational
content is still generally theoretical, limited reference sources, and implementation

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instructions. In vegetable growing areas, vegetables are close and familiar objects to
children. Exploiting and using the results of ecological research in vegetable growing
areas to propose some environmental education content for preschool children
contributes to improving the effectiveness of environmental education. Besides, this
helps children to love their homeland and respect labor products.

For the above reasons, the thesis "Ecological research on the vegetable growing areas
in Thuong Tin, Hanoi and propose some environmental education contents for preschool
children" was carried out.
2. Research objectives
2.1. Providing data on the differences in some abiotic and biotic ecological factors in
vegetable growing methods in Thuong Tin, Hanoi, as a basis for the development of
organic agriculture, contributing to sustainable development Thuong Tin vegetable
growing areas.

2.2. From research results on some abiotic and biotic ecological factors in Thuong Tin
vegetable growing area, Hanoi, some environmental education contents for preschool
children are proposed.
3. Research content
3.1. Research on the characteristics of some abiotic and biotic ecological factors in
Thuong Tin vegetable growing area and evaluate the effectiveness of environmental
protection, sustainable development of different vegetable growing methods in the
study area.
3.2. Using practical research results in Thuong Tin vegetable growing area, propose
some environmental education contents for preschool children.
4. Scientific hypothesis

Different methods of growing and using vegetable soik in Thuong Tin vegetable
growing areas, have created differences in abiotic and biotic ecological factors. It is possible
to select and exploit the results of ecological research on vegetable growing areas in Thuong
Tin, Hanoi to propose some environmental education content for preschool children.
5. Significance of the research
5.1. Scientific significance

The thesis provides scientific data and explanations about the differences in
abiotic and biotic ecological factors in different vegetable growing methods in Thuong
Tin vegetable growing area, Hanoi.
5.2. Practical significance

The research results are the basis for state management agencies to make
planning and plans for the sustainable development of vegetable growing areas in
Thuong Tin district, Hanoi.

Improve the effectiveness of environmental education for preschool children
through proposing environmental education content, associated with local practice.

6. Arguments
6.1. Traditional vegetable growing and organic vegetable growing have different effects
on the local environment, including the soil environment and biome. From the research
results obtained, planning solutions can be proposed to expand the scale of

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environmentally friendly vegetable growing methods and develop sustainable organic
agriculture.
6.2. Environmental education needs to start from preschool age, in which priority
should be given to exploiting content that is specific to the characteristics of where
children live and study in order to maximize their living capital. In vegetable growing
areas, vegetables are close and familiar objects to children. Therefore, using the results
of ecological research in vegetable growing areas to propose some environmental
education content for children will contribute to improving the effectiveness of
environmental education in local preschools.
7. New contributions of the thesis
7.1. For the first time, this research investigates abiotic ecological factors combined
with biotic ecological factors in vegetablegrowing areas. Provide scientific data on
environmental ecology in Thuong Tin vegetable growing area: soil properties
(mechanical composition, physical and chemical properties of soil); characteristics of
wild plants, soil and above-ground animals).
7.2. Assessed the impact of vegetable growing methods on ecological factors: soil, wild
plants, and soil animals in Thuong Tin vegetable growing area, Hanoi.
7.3. Discovered of the genus Mecardonia Ruiz & Pav., species Mecardonia procumbens
(Miller) Small, supplementing the Vietnamese flora.
7.4. For the first time, using the results of ecological research on vegetable growing
areas to propose some environmental education content for preschool children.
8. Structure of the thesis

In addition to the introduction, conclusions and recommendations, references and
appendices, the thesis includes 3 chapters:

Chapter 1: Overview
Chapter 2:Research objects and methods
Chapter 3: Research results and Discussion

CHAPTER 1. OVERVIEW
1.1. The role of some ecological factors on the structure, yield, and quality of
vegetables
1.1.1. Abiotic factors
1.1.1.1. Light

Light is an indispensable condition for photosynthesis in plants, affecting the
morphology, yield, and quality of vegetables. synthesis of phytochemicals. The content
of dry matter, protein, K, Ca, Mg, ascorbic acid, lutein, beta-carotene, sugar in many
vegetables changes when grown under different lighting conditions. The content of
lutein and beta-carotene in spinach and the content of sugar and ascorbic acid in lettuce
and tomatoes increased as light intensity increased. Low light intensity weakens young
shoots or increases nitrate accumulation; slows down flowering; Reduces fruit set rate
and fruit size; Reduced nutritional quality reduces market price (Czeczko, 2013),
(Rouphael, 2012), (Ministry of Agriculture and Rural Development, 2021).
1.1.1.2. Temperature

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Temperature is an important factor that contributes to regulating the growth and
development of plants. Lin et al (2010) reported that increased temperatures can be
beneficial for vegetables provided they do not exceed a critical threshold. Temperatures
exceeding the critical level will affect morphological characteristics and physiological

activities, thereby reducing the yield and quality of grown vegetables. Improper
temperature also reduces the "deliciousness" of vegetables. . Plants that are stressed by
heat and drought reduce their resistance to pests and diseases.
1.1.1.3. Water

Water is an essential factor for the life of organisms, determining crop
productivity and quality. Different vegetables have different soil moisture needs and
this need can change depending on the growing period (Ta Thu Cuc, 2005). Humidity
also affects the quality of vegetables when harvested. Too high humidity makes stems
and leaves weak, reducing resistance to adverse conditions; Reduces crispness and
sweetness, making it difficult to preserve and transport. However, when the air
humidity is too low, vegetable plants will lose water quickly due to evaporation, which
can cause wilting and death of the plant (Ministry of Agriculture and Rural
Development, 2021).
1.1.1.4. Soil

Among all types of soil, loam soil is suitable for most crops and vegetables. On
loamy soil, they will grow and develop better, cultivating it with less effort and cost but
still ensuring good productivity (Nguyen Duy Lam et al., 2019). Soil pH from 5.5 to
7.0 is suitable for most vegetable crops (Ronen, 2016). Cultivated soil has less
accumulated OM content than uncultivated soil; the longer it is cultivated, the greater
the decrease in OM (VandenBygaart, et al, 2013). The way that soil is exploited and
used will affect the OM and N content in the soil(Mikhailova et al, 2000).

The availability of chemical elements in the soil determines the yield and quality
of crops, affecting the development of resistance to pests and diseases in vegetables.
The chemical elements necessary for vegetables are divided into 3 groups:
macronutrients, secondary elements and microelements based on the needs of the plant.
It is necessary to periodically add nutrients to the soil to maintain the yield and quality
of vegetables (Czeczko, 2013).

1.1.2. Biotic factors
1.1.2.1. Soil organisms

Soil organisms include microorganisms and soil animals. The number and
composition of microorganisms are more diverse in the soil layer with a depth of 10 -
20 cm compared to the surface. This soil layer has appropriate moisture, accumulates
many nutrients, and is not directly affected. by sunlight (Naylor et al, 2022).

Soil animals are a group of animals whose lives are attached to the surface or
underground. They belong to many different taxonomic groups and are often divided
based on body size (Anderson, 1988). They include 3 groups: microfauna, mesofauna,
and macrofauna.

Earthworms improve the biological, chemical, and physical properties of soil
and act as indicator organisms for the degree of change, soil origin, soil properties, or

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soil pollution level (Ahmed et al, 2022). Burrowing activities of soil animals change
soil porosity, reducing compaction (Pisa et al, 2015). Many soil predators and groups
of parasitic soil insects are important in controlling root-eating invertebrates. Insects
such as beetles and flies are especially important in the decomposition of manure,
carrion, and fallen leaves, returning nutrients to the soil. Detritivores such as
nematodes, springtails, and millipedes etc. transform decomposing substances and
minerals into usable forms, closing the material cycle and increasing soil fertility (Stork
et al, 1992), (Gunstone et al, 2021). Soil insects also eat weed seeds, helping to reduce
the spread of weeds (Honek et al, 2003).
1.1.2.2. Weed

Weed management is a major challenge for vegetable growers, especially those

using organic methods. Vegetables vary in their sensitivity to weed competition
(Madden et al, 2021). In some cases, weeds are beneficial for vegetable crop
productivity, such as as alternative food, alternative vegetable hosts for leaf-eating
arthropods, and parasitic species (Araj et al, 2019). Weeds are the breeding ground and
residence of many types of vegetable pests, so their existence can be one of the reasons
why vegetables are more damaged by pests (Norris et al, 2005).
1.1.2.3. Vegetable pests and natural enemies

More than 70 families of Arthropods are considered crop pests. They eat leaves,
reducing leaf area; Some species suck sap from leaves, stems or roots; or is the main
vector of diseases that harm many vegetables (Inoue-Nagata et al, 2016),
(Shivalingaswamy et al, 2002). Increasing the abundance of natural enemies can reduce
the density of a common group of plant pests helping to increase crop productivity
(Cardinale et al, 2003).

In Vietnam, there are some studies on the composition of vegetable pests and
their natural enemies on some popular grown vegetables. Ho Thi Thu Giang (2002)
discovered 29 species of pests on Brassica vegetables and 77 species of natural enemies
in vegetable growing areas on the outskirts of Hanoi. Cao Hoang Yen Nhi et at (2014)
reported 34 species of Arthropods, including 17 species of pests, 17 species of natural
enemies on the biota of choysum, mustard greens, spinach, and amaranth in some
cultivated vegetable gardens.
1.2. Overview of vegetable planting and care techniques
1.2.1. Land preparation techniques before planting

Using machinery in plowing and cultivating helps improve soil structure,
promoting root development, higher earthworm population density, effective weed
control, and crop yields equal to or greater than with conventional tillage (France et al,
2017). However, frequent tillage is also detrimental to plants, increasing the risk of
erosion and nutrient leaching. There are many different ways to prepare the land before

planting, such as using herbicides to remove weed seeds; retain plant residue from
previous generations to create a source of organic matter before planting (Dao, 1998);
Use mulch with plastic film or straw, grass clippings, compost etc. (Zhao et al, 2014).
1.2.2. Seeds and sowing techniques

In ecological research, people are interested in the suitability of seeds to the

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environment and farming techniques. Currently, vegetable varieties with good
resistance to environmental harshness and changes in pests and diseases are of great
interest.(Perez et al., 2017) such as salt- and drought-resistant vegetable varieties that
are able to cope well with climate change (Abdou et al, 2013), (Sarker et al, 2020).Many
types of vegetables are grown from seedlings. The seedlings planted must be strong, big,
fat, sturdy, with straight roots, free from pests and diseases.
1.2.3. Planting season

Choosing the right time to plant vegetables for each variety will help improve
productivity and quality of harvested products and require less labor and care materials
(ICAR, 2006). Many vegetable growing regions around the world have changed sowing
dates to avoid impacts harmful effects of high temperatures during flowering and
harvesting to adapt to climate change (Singh et al 2013), (Olesen et al, 2011). Organic
vegetable farms are often equipped with protective systems such as net houses, and
greenhouses... so they can adjust and reduce adverse environmental conditions for
vegetable crops, so growing off-season vegetables is more suitable than farming.
traditional work (Tewari, 2007).
1.2.4. Arrange plants
1.2.4.1. Intercropping

Intercropping is an agricultural activity of growing two or more crops in the

same space and time, helping to increase productivity per unit of land area, reduce the
risk of crop failure, and control erosion, weeds, and harmful insects (Hugar et al, 2008).
In intercropping, it is necessary to choose the appropriate crop combination to be
compatible with factors such as density, root system, shade, and nutrient competition
(Ijoyah et al, 2012).
1.2.4.2. Rotational

Crop rotation is the rotation of crops so that the same crop is not grown in
consecutive seasons in one location, helping to minimize pests, reduce chemical use,
and support and contribute to increased soil fertility (Diacono et al, 2021), (Benicasa et
al, 2017), (Gabriel et al, 2012).

Organic farming practices intercropping and crop rotation to limit pests and
ensure product quality; Limit the risk of nutrient loss in the soil. Currently, traditional
farming does not maintain monoculture farming systems because it reduces organic
matter content, reduces soil microbial activity, affects soil enzymes, and is very
susceptible to pest outbreaks. (Reynafarje et al, 2016).
1.2.4.3. Planting density

The spacing density of vegetable plants depends on the variety (morphological
characteristics, genetic characteristics of the variety), external conditions and growing
techniques. Planting density can affect plant height, number of leaves, fruit set rate,
fruit size... thereby affecting the yield of vegetables (Satodiya et al, 2015), (Nguyen
Minh Tuan et al, 2015). Vegetable yield reaches its maximum level when plants fully
utilize nutrients in the environment.
1.2.5. Use fertilizer

Fertilizer helps improve production and increase crop productivity, but if applied

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unbalanced, it will lead to consequences: low productivity, poor quality, easily
damaged during transportation and difficulty in preserving ,and negative affect on
human health and the environment. Organic fertilizers can be used as an alternative for
inorganic fertilizers to improve soil structure (Lema et al, 2013). Ullah et al (2008)
stated that applying only poultry fertilizer is more effective than applying only chemical
fertilizers. Using Trichoderma biological organic fertilizer combined with the
appropriate chemical fertilizer ratio can help achieve maximum efficiency in terms of
yield, quality, and fertilizer savings (Ye et al, 2020).
1.2.6. Pest care and management

Farmers often use pesticides to increase vegetable productivity. However, that
can affect consumers and vegetable growers themselves if the necessary protection
tools are not used. Overuse of pesticides can cause pest resistance, the reappearance of
harmful organisms, and pesticide poisoning, creating risks to human health and health.
affect the ecosystem (Yadav et al, 2015).

In addition to using pesticides, there are three main groups of interventions that
limit pests and have little impact on the environment, which are: using biological
control methods (Schreinemachers et al, 2015), (Tran Dinh Chien et al 2008), (Tran
Thi My Hanh et al., 2023); Grafting high-yielding seedlings onto disease-resistant
rootstock (Davis et al, 2008) and investing in protected farming systems
(Schreinemachers et al 2016).
1.2.7. Organic vegetable production

Organic farming is a system that eliminates the use of chemicals in farming and
replaces it with management networks that maintain and increase long-term soil
fertility, increasing organic matter content, easily digestible NPK, water, and the quality
of the environment (Rao et al, 2007), (Bhat et al, 2013). The difference in crop yields
in organic and conventional production systems is 20% depending on the crop type,

and region (De Ponti et al, 2012). Organically grown vegetables have higher sugar,
vitamin C, Fe, Mg, and P content; NO3- or energy metal content is significantly lower
and productivity is higher (Pradeepkumar et al, 2017), (Suja 2013).
1.3. The effects of vegetable growing on the natural environment
1.3.1. Effects on the soil environment
1.3.1.1. Effects organic matter content in soil

Soil used for farming results in less accumulated organic matter than uncultivated
soil; the longer it is cultivated, the more organic matter decreases.(VandenBygaart et al,
2003).Excessive chemical fertilization, especially nitrogen fertilizer, negatively affects
nitrogen-fixing bacteria Rhizobium sp. (Savci, 2012). Organic fertilizer increases organic
matter content, fertility, and sustainable structure of the soil (Dao, 1998).
1.3.1.2. Effects on the physicochemical properties of soil

Tillage activities help increase soil microorganisms' access to organic matter,
thereby increasing N release (Dao,1998). Chemical fertilizers hurts soil pH, changing
soil structure and soil microflora. Using only organic fertilizers and microbial fertilizers
helps improve water holding capacity, porosity, available NPK content, N fixers, P
solubilizers, and dehydrogenase activity in soil (Suja, 2013).

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1.3.1.3. Effects the content of elements in the soil
Regular use of N, P, K fertilizers along with manure will contribute to increasing

organic matter and N content in the soil compared to neighboring areas without crops
(Thomas et al, 1993). Using inorganic fertilizers for a period of time increases the
content of heavy metals (Nziguheba et al, 2008). In the Hanoi vegetable growing area,
the further south you go, the higher the metal content in the soil (Ngo Thi Lan Phuong,
2010). Vegetable growing soil in Gia Lam, Dong Anh, Thanh Tri has a content of

nutrients (N, P, K) in many places are at the poor level and in some places the content
of Zn, Pb, Cu exceeds the allowable limit (Tran Khac Hiep, 2008). Vegetable cultivation
soil in Tien Le, Hoai Duc is mostly contaminated with As and Cd (Nguyen Ngan Ha,
2016).
1.3.2. Effects on the water environment

Agricultural cultivation pollutes surface water and groundwater with pesticides
and fertilizers (Norse D., 2005), (Belmans et al, 2018.]which is mainly caused by
nitrogen fertilizer (Khan et al, 2018). Groundwater pollution due to agricultural
chemicals also depends on weather, climate, hydrology, and soil conditions in the
farming area (Srivastav et al, 2020).
1.3.3. Effects on the air

Using fertilizers and plant protection chemicals in agriculture is also one of the
causes of air pollution. Fertilizer production and nitrification of fertilizers create
greenhouse gases that cause global warming and damage the ozone layer. Applying
lime or fertilizing ammonium with urea can evaporate NH3 and change it into HNO3,
creating acid rain, destroying vegetation, and changing the habitat of aquatic organisms
(Savci, 2012).
1.3.4. Effects on living creatures
1.3.4.1. Effects on weed

Weeds cause damage to vegetables due to their vigorous reproduction, high level
of nutrient competition, and wide ecological niche. Growing organic vegetables has a
higher above-ground weed biomass than traditional growing vegetable method (Poudel
et al, 2002). Weed abundance was higher at the edge of the field than in the middle of
the field, and this difference was more evident in traditionally cultivated fields.
Monocotyledonous weed species often dominate the group of wild plants due to their
small size and high regeneration ability compared to Dicotyledonous species (Rydberg
et al, 2000),(Hyvonen et al, 2003).

1.3.4.2. Effects on the animals on the ground

Pesticides negatively affect terrestrial animal populations: decline in the number
of raptors, mammals... (Mahmood et al, 2016).Populations of beneficial insects such as
bees and beetles are also significantly reduced by broad-spectrum insecticides in
vegetable farming. Insects in organic vegetable farms are more numerous than in
traditional farming method (Pilling et al, 2006). Using pesticides has a negative impact,
causing imbalance and instability in nature because pesticides destroy harmful species
while also killing many beneficial species (Bueno et al, 2004).

Among agriculturally important beneficial organisms, natural enemies of

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arthropods are most notable because they contribute to reducing pest outbreaks (Bueno
et al 2017). Overuse of pesticides in farming seriously affects the natural enemies of
pests, often leading to the resurgence of pests, the appearance of secondary pests, and
strong drug resistance (Fernandes et al, 2010).
1.3.4.3. Effects on soil animals

The farming process causes significant effects on the lives of animals living in
the soil: reducing the density of Collembola arthropods (Endlweber et al 2005)and
adversely affecting the reproduction of earthworms (Panda et al (1999)), (Goulson,
2013). Earthworm populations often decline under continuous cultivation over long
periods of time (Curry et al, 2002). The density of Earthworm species increases when
plowing, the density of night-active Reptiles is often higher in the case of unplowed or
harrowed soil (Riley et al, 2008)). Pesticides and synthetic fertilizers are believed to be
the main factors leading to insect decline and are a growing threat to the environment
in general and the soil environment in particular.

Besides the negative impacts on soil animal groups, the farming process also has
positive impacts on their lives such as rotational farming, increasing earthworm density
and biomass (Riley et al, 2008). Biomass and earthworm density in organic farming
systems are higher than in other farming systems (Scullion et al, 2002).
1.4. Summary of Thuong Tin vegetable growing area, Hanoi

Thuong Tin district has favorable conditions to develop specialized vegetable
cultivation: (1) The entire district is a plain, built up by the Red River and Nhue River,
the soil is mainly loam and sandy soil suitable for many vegetable. (2) Convenient
irrigation system, abundant surface water system and ponds and lakes to store
water during the dry season. (3) The four-season climate is suitable for growing
many different types of vegetables. (4) Convenient and diverse transportation system
(road, railway, waterway), close to Hanoi inner city, so transporting products quickly
and easily.

Thuong Tin has about 545 hectares of safe vegetable areas (2022), concentrated
mainly in 3 communes Thu Phu, Ha Hoi, Tan Minh. The district's vegetable growing
model includes traditional vegetables, safe vegetables, and organic vegetables. These
models belong to two basic farming types: traditional vegetable growing (using
chemical fertilizers and plant protection chemicals); Growing vegetables organically
(absolutely no chemicals are used in farming).

Currently, the use of agricultural land in general and vegetable growing soil in
Thuong Tin still has many shortcomings. It has not yet been possible to consolidate
land and exchange plots, form large sample fields and bring grid electricity to the fields
in some communes, making it difficult to expand production scale. The structure of
shifting from rice cultivation to annual crops such as vegetables, ornamental plants, and
medicinal herbs brings significant economic efficiency, so Thuong Tin's agricultural
development orientation shifts from food production to annual crops, in Vegetables
have the largest area (Do Thi Duc Hanh, 2012), (Pham Thanh Son et al., 2023).

It can be seen that research on vegetable growing ecology in the world focuses
on four directions: (1) Abiotic factors (temperature, light, water, soil...) and (2) biotic

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factors (weeds, soil animals, pests, natural enemies) affect the structure, yield and
quality of vegetables; (3) Techniques for growing and caring for vegetable plants; (4)
Research the effects of vegetable growing on the soil, water, air environment and
biological communities (weeds, soil animals, pests, natural enemies). However, these
studies are often carried out in individual directions, without comprehensive results in
a specific vegetable growing area. There is very little data on wild plants, mainly on the
effects of weeds on vegetable productivity. Research on the effects of vegetable
growing on soil animals and their role in vegetable growing ecology is not rare, but
only focuses on earthworms, with very little scientific data on other soil animal groups.

In Vietnam, research on vegetable growing ecology often focuses on assessing
the impact of farming on soil and water environmental quality. The impact of vegetable
cultivation on wild plant species has almost no data. The effects of vegetable growing
on animals are mainly studied on pests and natural enemies, not paying attention to soil
animals. Data on vegetable growing areas in Hanoi often focus on long-standing
vegetable growing districts such as Thanh Tri, Gia Lam, Dong Anh... There is currently
no complete data on Thuong Tin vegetable growing areas. In previous studies, people
only studied in one commune because Thuong Tin was only one of the research sites
along with other vegetable growing areas in Hanoi.

Therefore, it is necessary to have ecological research as a basis for management
levels and people to improve knowledge and apply science to vegetable cultivation that
is productive, safe and protects the environment.
1.5. Environmental education for preschool children

“Environmental education is the process of purposeful, planned impact of
educators to form and develop in learners an understanding of environmental issues,
positive attitudes and behaviors to preserve the environment" (Hoang Thi Phuong,
2008).
1.5.1. Objectives, tasks, and content of Environmental education for preschool
children

The goal of Environmental Education is to restore environmental sustainability
and positive changes in learners' behavior. Environmental education in the early years
also focuses on hands-on education, through active engagement with nature. Based on
the Preschool Education program revised and issued in 2021, Environmental Education
for preschool children aims to: Form a symbol of the living environment, the
relationship between humans and the environment; Educating children to initially
consciously care about environmental issues and recognize their responsibility in
protecting the environment; Develop some skills to protect and preserve the
environment, behave positively in solving environmental problems, and initially have
age-appropriate environmental protection habits.
1.5.2. Content of Environmental Education for preschool children

The Early Childhood Education Program issued by the Ministry of Education
and Training is a framework program, schools can deploy content appropriate to the
actual situation in the locality to meet the requirements of the program. Therefore, the
content of environmental education at different units and schools may be different, but

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they all ensure the environmental education goals that the framework program is aiming
for. Many researchers have proposed appropriate content for environmental education
for typical preschool children such as Hoang Thi Phuong, Le Thanh Van, Nguyen Thi

Luyen, Nguyen Ha Linh...

Although there are many different ways to propose environmental education
content for preschool children, the authors agree on 4 basic content groups including:
(1) Environmental symbols: invaluable ecological factors. born; creature; The
relationship between an organism and its environment is expressed in the law of its
adaptation during development. (2) Environmental benefits: The role of environment
for humans and other organisms. (3) Environmental pollution: the reality of the
environment or its components being reduced in quality and quantity; (4)
Environmental protection: ways to keep the environment green, clean, and beautiful;
Protect/use natural resources economically. Environmental education content needs to
be close, easy to understand, and suitable for children's cognitive abilities at each age,
avoiding approaching the content from an adult's perspective instead of from a child's
perspective.
1.5.3. Organizational forms and methods of environmental education for preschool
children

Environmental Education: It is not a specialized activity in preschools, but is
carried out from the perspective of integrating Environmental Education content into
appropriate activities in schools. In general, the integrated perspective of environmental
education is based on the idea of fostering children's ability to use the knowledge they
have acquired in real situations to solve environmental problems, following their
abilities, thenforming the capacity to act for the environment (Nguyen Thi Luyen,
2018), (Nguyen Ha Linh, 2019).

Many research projects have proposed methods and measures for environmental
education for preschool children (Le Thanh Van, 2006), (Hoang Thi Phuong, 2008),
which emphasizes the effectiveness of Environmental Education for children through
experience. Educational content is linked to children's real life and experiences that help
them connect their own existing experiences with new experiences; Compare and

contrast with ethical standards about the environment, thereby forming environmental
protection behavior (HoangThi Phuong et al., 2018), (Nguyen Ha Linh, 2019).
1.5.4. Environmental education is based on local practical contexts

Context-based education has been implemented in schools in many developed
countries in the world and Vietnam. Based on the Education Program Kindergarten
issued by the Ministry of Education and Training, Departments and Offices of
Education guide preschool educational establishments to develop school year plans and
organize implementation; Develop education and training appropriate to culture, local
conditions, schools, and children's abilities and needs. Normally, in educational topics,
preschool teachers will choose topics that are close and familiar to children in order to
promote children's life skills and experiences with daily life. This is even more
important for Environmental Education because people are motivated to protect places
that are meaningful to them, especially the places where they were born and raised.

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Using educational content related to objects in the environment around children
strengthens and nurtures awareness of protecting the environment where they learn and
live (Kudryavtsev, 2012). Children are aware of the need to protect the environment
right around them, not just protecting beautiful scenes that are very far away or that
they have never even come into contact with (Levi D and Kocher S, 1999)]. Therefore,
exploiting content about the local context to carry out Environmental Education
activities is necessary. It helps the connection between the familiar and the new is the
driving force that motivates learners to learn and take action to protect the environment
in which they live. Thereby, contributing to improving the effectiveness of
environmental education in schools. For children in vegetable growing areas,
vegetables are close and familiar objects to them; Children may have relatives who
work as vegetable growers and be exposed to vegetable crops and vegetable fields from
a young age. Exploiting the results of ecological research in vegetable growing areas to

propose several environmental education contents for local children to help children
develop their own life and experience; Know how to love and protect your living
environment. Besides, this also contributes to forming in children love for their
homeland and appreciation for labor products.

CHAPTER 2. RESEARCH OBJECTS AND METHODS
2.1. Object and scope of the study
2.1.1. Research subjects
- Abiotic and biotic ecological factors in Thuong Tin vegetable growing area, Hanoi.
- Content of environmental education for preschool children
2.1.2. Research scope

The study was conducted in Thuong Tin vegetable growing area, Hanoi.
- For characteristics of vegetable growing areas: research on area, seasons,
vegetable crop structure, and vegetable growing methods.
- For soil: research physical and chemical indicators including: mechanical
composition; density; proportion; porosity; pH; electrical conductivity (EC); organic matter
(OM) content; total nitrogen, phosphorus, potassium content; easy-to-digest phosphorus and
potassium content; CEC adsorption capacity and exchangeable cations (K+, Na+, Ca2+, Mg 2+).
- For plants: investigate vascular plants growing wild in vegetable fields in terms of
species composition, life form, use value, and community structure according to habitat and
season.
- For animals: investigation of Mesofauna and Macrofauna; A group of animals
harmful to vegetables and their natural enemies belonging to the phylum Arthropoda
appear in vegetable fields
- Using the results of ecological research in vegetable growing areas to propose
some environmental education contents for preschool children.
2.2. Location and time of research
2.2.1. Sample collection location

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- Soil samples were collected from vegetable fields following traditional vegetable
growing methods, organic vegetable growing methods, and abandoned vegetable fields
in Thuong Tin district at the time after harvest.
- Quantitative samples of wild plants and soil animals are collected in soil sampling
fields. Samples of wild plants were collected at a time when vegetables were not yet
harvested; Samples of soil animals were collected when harvest had just been
completed, and farmers have not yet prepared for the new vegetable batches.
- Qualitative samples of wild plants, soil animals, pests, and natural enemies of pests
were collected from vegetable fields and abandoned vegetable fields at different times.
2.2.2. Sample collection time: from November 2021 to April 2023.
2.3. Research Methods
2.3.1. Field research methods
2.3.1.1. Soil research methods

Soil samples were collected according to instructions in TCVN 4046:1985. 18
mixed soil samples were taken from 18 vegetable fields in 03 habitats including: 6
samples taken from traditional vegetable fields, 6 samples taken from organic vegetable
fields and 6 samples taken from abandoned vegetable fields.
2.3.1.2. Methods of plant research

Collect samples according to transects and standard plots (Hoang Chung, 2006).
Investigate and make statistics of plant species growing wild in fields and field edges.
-The 5 routes have a total length of more than 30 km through 10 communes and Hoang
Gia organic vegetable farms.
- Set up 50 standard plots of size: 20 m x 20 m, including the field edge area and
vegetable field area to determine the composition of wild plant species in the vegetable
growing area.
- Set up 90 plots which have size 1m x 1m in 18 fields to take soil samples. Count the

number of individuals of each species in that 1m2 plot to calculate the H' index. Collect
samples in 3 seasons.
- Samples are preserved at the Department of Botany Laboratory,Department of
Biology, Hanoi University of Education.
2.3.1.3. Soil Animal Research Methods
- Quantitative samples of soil animals: dig a hole with dimensions of 50cm x 50cm,
according to the depth corresponding to 3 distribution layers, each layer is 10cm thick,
use pints, clamps, or straws to collect all animal samples (Nguyen Van Thuan et al.,
2012).
- Qualitative samples of soil animals, pests, and natural enemies: collected
simultaneously around the quantitative sampling area and at plant sampling points.
- Samples are preserved in 70o alcohol solution and processed in the laboratory of the
Department of Zoology, Department of Biology, Hanoi University of Education.
2.3.2. Research methods in the laboratory
2.3.2.1. Methods of analyzing soil indicators
- Soil criteria were analyzed according to the guidance documents of the Institute of
Soil Agrochemistry (2011) at the Laboratory of the Department of Environmental

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Chemistry and the Center for Analysis and Technology Transfer, Institute of
Agricultural Environment.
- Each crop analyzes 18 mixed soil samples taken from 18 soil sample fields.
2.3.2.2. Methods for identifying and studying plants
- Identify samples according to the method of comparing morphological characteristics
based on documents written by Pham Hoang Ho (1999-2003).
- Correct scientific names based on the List of Vietnamese plant species (Nguyen Tien
Ban, 1997) and The plant list of the British Royal Botanic Garden
().
- Arrange families, genera, and species based on the Manual for searching and

identifying angiosperm families in Vietnam by Nguyen Tien Ban (1997) and
supplemented by Takhtajan (2009).
- Assessment of life forms according to Le Tran Chan (1999); classification diversity
according to Nguyen Nghia Thin (2007); Use value according to Tran Minh Hoi et al.
(2017), Vo Van Chi (2018) and actual surveys among local people.
2.3.2.3. Methods of identifying and calculating the quantity and biomass of animals
- Identify groups of soil animals and animals harmful to vegetables and their natural
enemies based on documents by Do Van Nhuong (2005), Nguyen Duc Khiem (2005),
Schileko (2007), Jocqué R (2007), Khuat Dang Long (2011), Nguyen Xuan Thanh
(2010).
2.3.3. Sociological investigation methods

Using interview method (Pham Van Quyet et al., 2021) to collect information
from 50 vegetable growers, 10 Plantation & Plant Protection Department officers and
cooperatives in Thuong Tin district using structured and semi-structured questionnaires
on structure, vegetable productivity, methods, the process of growing and caring for
vegetable plants and other related issues.
2.3.4. Data processing methods
- Indicators are calculated according to formulas and performed using Microsoft Excel
software.
- Statistical analysis in this study was performed in R language.

CHAPTER 3. RESEARCH RESULTS AND DISCUSSION
3.1. Results of investigating the characteristics of Thuong Tin vegetable growing
area, Hanoi
3.1.1. Vegetable growing area and season

Vegetable growing area varies by season, the largest vegetable growing area is
in the winter season, followed by summer crops, and the spring season has the lowest
vegetable growing area.The district's safe vegetable production area has an area of 545

hectares, concentrated mainly in Tan Minh, Ha Hoi, and Thu Phu communes. The
district has an organic vegetable production model at Hoang Gia farm (Le Loi
commune). Its area is about 2 hectares.
3.1.2. Structure of vegetable crops according to season

The structure of vegetable crops is diverse and changes seasonally based on

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natural characteristics, market demand, and farmers' farming practices and experiences.

Vegetables of the Brassicaceae family, Cucurbitaceae family and spice vegetables

(perilla, marjoram, basil...) have the largest growing area. Species with wide ecological

limits are grown all year round, such as Malabar spinach and spices. Vegetable species

with narrow ecological limits are often only grown during the growing season due to

their lack of economic efficiency: temperate vegetables such as cauliflower, kohlrabi,

cabbage, chrysanthemum... are grown in winter. winter-spring; Water spinach is grown

in the spring and summer. In addition to main-season vegetables, Thuong Tin plans to

grow some off-season vegetables such as coriander, lettuce, and tomatoes. Among

them, the largest area of off-season vegetables is tomatoes.

Leafy vegetables are the most grown vegetable group in all seasons for a number

of reasons: they have wide adaptability and can be grown all year round; The growing

time is short, an average of 25 - 40 days/generation, helping to handle crop shortages

and bringing high efficiency to vegetable growers.

3.1.3. Arrange plants
Farmers practice intercropping and crop rotation to take advantage of nutrients in

the soil; reduce the risk of crop failure; Control erosion, weeds, invasive insects and

bring high productivity on a cultivated area.

3.1.4. Methods of growing vegetables
Local vegetable production is divided into two basic methods: traditional

vegetable growing and organic vegetable growing. Under the same soil and climate

conditions; The quality of irrigation water and seed sources is guaranteed. The basic

difference between these two methods is whether or not chemicals are used (chemical

fertilizers, plant protection chemicals, growth stimulants...) during the process.

Vegetable planting and care program.

3.2. Characteristics of vegetable growing soil

3.2.1. Mechanical composition and physicochemical properties of soil

3.2.1.1. Mechanical components

According to Katsinski's mechanical grain level division table, vegetable

growing soil in Thuong Tin district is mostly in the loam soil group (14/18 sampling

points). 4 fields have sandy soil; however, the percentage of sand is not high (below

65%).

3.2.1.2. Density, density and porosity

Soil Location 𝑿̅±SD Quality
min max evalutionaccording to
properties sample
[Institute of Soil
Agrochemistry, 2001]

RHC 1.08 ± 0.02 1.05 1.11 Typical arable soil

Density RTT 1.18 ± 0.03 1.14 1.21 The soil is slightly
compacted
(g/cm3)
RH 1.25 ± 0.03 1.23 1.30 The soil is slightly
compacted

Proportion RHC 2.62 ± 0.03 2.58 2.65

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(g/cm3) RTT 2.47 ± 0.05 2.41 2.53

RH 2.40 ± 0.05 2.32 2.45

RHC 58.64 ± 1.01 56.98 59.50 Farmland,
Very good

Porosity RTT 52.19 ± 1.08 51.79 53.47 Response cultivation
(%) layer requirements
Do not response

RH 48.03 ± 1.37 46.12 49.80 cultivation layer

requirements

(RHC: growing organic vegetables; RTT: growing traditional vegetables, RH:

abandoned vegetable fields)

Vegetable soil density in Thuong Tin gradually increases according to the

habitat: RHC < RTT < RH, soil density RHC is typical of cropland, RTT and RH soils

are slightly compacted. Proportion and porosity decrease gradually: RHC > RTT > RH.

RHC soil is good for planting, RTT soil responses the cultivation layer requirements,

RH soil does not responses the cultivation layer requirements.

3.2.1.3. Soil acidity

RHC soil has pH H2O ranging from 7.08 to 7.47, belonging to the neutral soil

group; RTT soil has pH H2O from 6.55 to 7.26, belong to the less acidic and neutral soil

group; RH soils has pHH2O from 5.79 to 6.49 belong to the less acidic soil group.

3.2.1.4. Electrical conductivity

All soil samples collected in the study area have EC values within the range of

EC values favorable for vegetable growth (0.2 - 1.2 mS/cm). RHC soil has the highest

EC, followed by RTT, RH soil has the lowest EC value because EC depends not only

on soil structure but also on the amount of fertilizer applied to the soil.

3.2.2. Nutrients in the soil

3.2.2.1. Organic matter content in soil

Organic matter (OM) content gradually decreases in the soil order RHC (2.31

%) – RH (1.86 %) – RTT (1.53 %). Compared with the evaluation criteria of the Water,

Fertilizer, and Crop Analysis Handbook (Institute of Soil Agrochemistry), the OM

content in RHC is at the high level; RTT and RH the OM content ranged from medium

to high level.

3.2.2.2. Macronutrients

Sampling Total (%) Digestible (g/100g soil)

location N P2O5 K2O P2O5 K2O

RHC 0.115 ± 0.011 0.206 ± 0.949 ± 0.129 29.92 ± 2.81 20.16 ± 3.93

0.018

RTT 0.101 ± 0.014 0.346 ± 0.737 ± 0.070 63.10 ± 11.39 14.34 ± 2.30

0.050

R.H 0.106 ± 0.008 0.155 ± 0.696 ± 0.055 18.62 ± 2.87 6.36 ± 1.26

0.024

Total nitrogen in RHC soil ranges from 0.103 - 0.125%, belonging to the soil

group with medium total nitrogen content, RTT soil has total nitrogen from poor to

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medium (0.086 - 0.122%). Total nitrogen in RH soil has values ranging from 0.098 to
0.118%, ranging from poor to medium level.

Total and digestible phosphorus contents decrease in the order: RTT > RHC >
RH. The soil of the study area is rich in phosphorus at all sampling points in both total

and digestible phosphorus when compared with the range of total and available
phosphorus content of Vietnamese soil. In particular, RTT soil has very high
phosphorus content, % P2O5 from 0.262 to 0.405% and easily digestible phosphorus
from 52.22 - 83.93 mg P2O5 /100g of soil. 5/6 sampled fields in RTT habitat in all 3
seasons had total phosphorus content higher than the upper limit of total phosphorus
content in Vietnamese alluvial soil (0.3%).

Total potassium and digestible potassium content decrease in the order RHC >
RTT > RH. RHC soil has a total potassium content of 0.773 to 1.102 % K2O (low to
medium), digestible potassium from 17.24 - 25.04 mg K2O/100g soil (medium to high).
RTT soil has a total K content of 0.632 - 0.813% K2O (K-low group); Digestible
potassium ranges from 11.12 - 16.89 mg K2O/100g average soil group). The total and
digestible potassium content of RH soil is in the K-low group.
3.2.2.3. CEC adsorption capacity and exchangeable cations

K+ Na+ Ca2+ Mg2+
% % %
Sampling CEC Content %
location compared Content compared Content compared Content compared
13.07 0.517 ± to CEC to CEC to CEC to CEC
RHC ± 0.101
RTT 3.96 0.546 ± 4.18 9.95 ± 76.13 1.69 ± 12.93
RH 0.44 0.137 0.60 0.31
11.87
0.368 ± 3.10 0.316 ± 2.66 9.43 ± 79.44 1.45 ± 12.22
± 0.059 0.050 0.50 0.23
0.80
11.06 0.163 ± 1.47 0.174 ± 1.57 8.80 ± 79.57 1.32 ± 11.93
0.032 0.049 0.57 0.15
±

0.60

Note: unit of measurement Cmol/kg soil (air dry)

The adsorption capacity of CEC and the content of exchangeable ions K+, Na+,

Ca2+, Mg2+ gradually decrease in the order RHC > RTT > RH. Cultivated soilis always

fertilized and supplemented with nutrients to feed plants, while wild field soil is not

fertilized, so the content of exchangeable ions is the lowest.

3.2.2.4. Content of some heavy metals and many pesticide residues

Analytic QCVN Analytical results (unit mg/kg)
TT al 03-MT:
RHC R.H RTT Analytical method
paramet 2015
ers

first Pb 70 24,26 29.49 41.30 TCVN 6649:2000

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