Ảnh hưởng của phân bón đến độ phì nhiêu đất đỏ bazan và năng suất cà phê ở cao nguyên di linh, lâm đồng tóm tắt luận án (tiếng anh) (1)

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PREAMBLE
1.1 The urgency of the topic
Reddish brown soil developed on basalt (Rhodic Ferralsols - FRr), which is relatively high in natural
fertility due to its thick, spongy, total organic matter and total phosphorus at a rich level, total nitrogen on a decent
level. This type of soil is suitable for growing perennial trees of high economic value such as coffee, tea, pepper
and fruit trees. In Lam Dong province, there are 212,049 ha of basalt reddish brown soil, distributed mainly in Di
Linh Plateau (182,818 ha).
By 2015, there be 157,307 ha of coffee in Lam Dong province, concentrated in the Di Linh plateau with an
area of 140,482 ha (accounting for 89.3% of the provincial coffee area), mainly Coffea canephora Pierre),
accounting for about 95% of the area.
The productivity of Vietnamese coffee over the last 10 years has always reached an average of 2 tons/ha,
Which is the highest in the world, with typical places reaching 5 – 6 tons/ha, special is 9 – 10 tons/ha.
Contributing to the above results are many technical factors (seedling, care, irrigation, plant protection), but
fertilizer is still a decisive factor.
Coffee is a perennial plant grown on high land so that, along with the high nutritional requirements of N, P,
K, organic fertilizer plays an important role in creating a stable and efficient intensive environment. For that
reason, there have been many studies on the effects of inorganic fertilizer N, P, K and organic fertilizer on yield
and quality of coffee in the Central Highlands. Typical works of Truong Hong and Ton Nu Tuan Nam, 1999; Y
Kanin Hdok, 2005; Trinh Cong Tu, 1996; Le Hong Lich, 2000; Ho Cong Truc and Pham Quang Ha, 2004, Nguyen
Van Minh (2014), Nguyen Van Bo (2016), ... However, these studies are concentrated in Dak Lak, Gia Lai. So far,
there have not been any researches that thoroughly concern the relationship between fertilizer and soil fertility. In
Lam Dong province, there is very little research on the nutritional management of coffee, especially in the Di Linh
highlands, where the characteristics of the climate and the history of land formation are characterized. Late
Cenozoic volcanic eruptions have markedly different soil properties compared to the same basalt red soils in other
provinces in the Central Highlands.
A recent survey on the use of fertilizer in coffee in Lam Dong shows that many issues have become a
challenge for sustainable coffee production. First of all, most of farmers use fertilizers which are lacking in
science, fertilizing very high in quantity and unbalanced in proportion. For nitrogenous fertilizer, more than 40%
of households over 500 N kg/ha/year (highest 897 kg N), With phosphorus fertilizer, 53% of households over 300

kg P2O5/ha/year (highest 620 kg P2O5). As for potassium, the average amount of fertilizer applied by farmers is
quite reasonable (average 299 – 317 kg K2O/ha/year), although there are still some households applying too much
potassium. Compared to the average yield in Lam Dong (3.6 tons/ha), the amount of nitrogen and phosphorus
wasted annually is very large. The inorganic inorganic fertilizer application rate is also severely imbalanced. In
most farmers, the application rate is N: P 2O5: K2O = 1.38: 1.0: 0.94. This is reducing the efficiency of fertilizer use,
reducing plant health, increasing pests and causing environmental pollution.
Secondly, organic fertilizers for coffee vary greatly from 0 - 45 tons/ha/year, 2 – 3 years of application one
time. In fact, the demand for organic fertilizers is increasing, but the ability to provide locally just limited to just


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shoddy, the situation of using fresh manure (pig, cow, chicken, ...) is still popular as a source of pollution for both
people and the environment. Therefore, research on the use of high quality compost to offset the need for organic
fertilizer is essential.
A long process of using fertilizers for unprofitable coffee on the one hand reduces the efficiency of fertilizer
use, reducing the productivity and quality of coffee, resulting in low economic efficiency, on the other hand, The
soil fertility of basalt red soil in the Di Linh plateau was reduced, with the content of OM, Ca 2+, Mg2+ decreasing,
acidification (pHKCl 3.53 – 4.67 ), the amount of Al3+ and SO42- in the soil tends to increase and contribute to the
emergence of diseases for coffee (Lam Van Ha, 2016).
On the urgent need for a comprehensive and systematic study on the relationship between soil – fertilizer –
soil ecological environment for sustainable coffee cultivation in the context of climate change, research topics
“The effect of fertilizers on fertility of basalt red soil and coffee productivity in the Di Linh Plateau in Lam
Dong Province” was investigated.
1.2 The scientific and practical significance of the topic
- Provides new information on fertilizer relationships - fertility - ecology of basalt reddish brown soil in Di
Linh plateau. To supplement the scientific basis in the strategy of managing balanced and appropriate fertilization
between inorganic fertilizers and organic fertilizers, contributing to the improvement of fertilizer use efficiency
and improvement of fertility of baslt reddish brown soil for intensive farming sustainable coffee trees.
- Contribute some technical solutions to use fertilizer in coffee production in the direction of increasing
economic efficiency and improving fertility of basalt reddish brown soil in the strategy of using and protecting the

sustainable land resources of the Lam Dong province.
1.3 Objectives of the study
1.3.1 Assessment of the effect of compost, nitrogen and phosphorus fertilizers on soil fertility of coffee plantations
in Di Linh plateau, Lam Dong.
1.3.2 Evaluation of the effect of compost, nitrogen and phosphorus fertilizer on the yield of ground coffee in basalt
reddish brown soil.
1.3.3 Sustainable coffee production model in basalt reddish brown soil in Di Linh plateau, Lam Dong.
1.4 Object and scope of research of the project
- The dose of nitrogenous fertilizer; phosphorus fertilizer and compost to the fertility of reddish brown soil
development on basalt rock in the Di Linh plateau has intensified coffee trees for many years.
- The dose of nitrogen fertilizer; phosphorus fertilizer and compost to coffea Canephora Pierre yielded
Truong Son 1 (TS1).
1.5 Limit the research of the topic


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The research focused on the effect of N fertilizer, P fertilizer and compost to some physical, chemical and
biological properties of basalt reddish brown soil associated with fertility, soil environment and coffee productivity
of Di Linh plateau, Lam Dong.
1.6 New contributions of the topic
- Determine the importance of nitrogenous fertilizer, phosphorous fertilizer and compost to the fertility and
ecology of basalt reddish brown soil.
- Proposed measures to use nitrogenous fertilizer, phosphorous fertilizer and compost for high-yielding
coffee to stabilize coffee productivity in Lam Dong province.

CHAPTER I OVERVIEW OF DOCUMENTS
1.1 Soil fertility
1.1.1 Soil fertility and soil fertility considerations
1.1.2 Main elements of soil fertility
1.1.3 Criteria for soil fertility assessment

1.1.3.1 Physical indicators
1.1.3.2 Chemical criteria
1.2 The role of organisms in the fertility of agricultural land
1.3 Fertility characteristics of red soil developed on basalt
1.3.1 Formation and distribution of red soil developed on basalt in Vietnam
1.3.2 Physical, chemical and biological properties of red soils developed on basalt
1.3.3 Evolution of soil fertility basaltic Central Highlands coffee growers
1.3.3.1 Physical properties
1.3.3.2. Chemical properties
1.3.4 Characteristics of basalt reddish brown soil in the study area
1.4 The role of fertilizers in crop yield and soil fertility
1.4.1 The concept of fertilizer and the role of fertilizers in agricultural production
1.4.2 The role of nitrogen, phosphorus, potassium fertilizers with the productivity of ground coffee and soil
fertility
1.4.2.1 Ecological characteristics of coffee trees
1.4.2.2 The role of nitrogen fertilizer (N) in coffee plantations


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1.4.2.3 The role of phosphorus fertilizer (P) in coffee plantations
1.4.2.4 The role of potassium fertilizer (K) in coffee plantations
1.4.2.5 Effects of nitrogen, phosphorus and potassium fertilizers to soil fertility
1.4.3 Organic fertilizers, the role of organic fertilizers in crop yields and fertility
1.4.3.1 Main sources of organic matter added to the soil
1.4.3.2 Role of organic fertilizer

CHAPTER II. CONTENT AND METHODOLOGY
2.1 Research content
2.1.1 Contents 1: Survey and assessment of fertilizer use status of coffee farmers in Di Linh plateau, Lam Dong
province.

2.1.2. Content 2: Study on the effect of compost, nitrogen fertilizer and phosphorus fertilizer on soil fertility of
basalt reddish brown soils in Di Linh plateau, Lam Dong province.
2.1.3. Content 3: Study on the effect of compost, nitrogen fertilizer and phosphorus fertilizer to coffee yield on the
basalt reddish brown soil of Di Linh plateau, Lam Dong province.
2.1.4 Content 4: Develop a demonstration model for sustainable coffee production on the basalt reddish brown soil
of Di Linh Plateau, Lam Dong Province.
2.2 Characteristics of climate in the study area
Di Linh Plateau has a height of 800 m above sea level. Monsoon tropical climate: rainy season (from May to
November) and dry season (from December to April). The average temperature is 18 - 27 0C, the rainfall is 1,750 3,150 mm/year, the relative humidity is 85 - 87%.
2.3 Study Materials
2.3.1 Soil and experimental site
The basalt Reddish brown soils (Rhodic Ferralsols), slope ± 4 0, thick layer > 120 cm in Dan Phuong
commune, Lam Ha district; Forest soil was collected in Tan Thanh commune, Lam Ha district.
2.3.2 Crops: Coffea Canephora Pierre is grafted with TS1 seedlings, 15 years old; age of grafted trees is 3 years;
density of 1,100 trees/ha.
2.3.3 Fertilizer
Inorganic fertilizers: urea fertilizer, FMP, potassium chloride and compost.
2.3.4 Study time: from April 2012 to December 2015.
2.4 Research methodology


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2.4.1 Survey, interview farmers on pre-printed information sheets.
- The survey sites include 3 districts of Lam Ha, Di Linh and Bao Lam. The total number of questionnaires
was 135; Survey on area, productivity and actual use of fertilizer for coffee.
2.4.2 Method of field experiment arrangement
- The three-factor experiment was arranged in Split - Plot Design with 3 replications in which large plots
consisted of two treatments (compost and non compost), small plots with 4 levels of nitrogen (250, 320, 390 and
460 kg N/ha), 3 levels of phosphorus (100, 150 and 200 kg P 2O5/ha) on K fertilizer basis (350 kg K 2O/ha). Each
small plot has an area of 81 m2 (equivalent to 9 coffee trees) and large area of 3.600 m2.

- Demonstration models were located at two sites: each of the three treatments: farmer control, NPK
treatment and NPK treatment with compost. The area of each model is 1.5 ha, each treatment is 5,000 m 2 and the
density is 1,100 coffee trees/ha.
+ Model 1: Dan Ha Village, Dan Phuong Commune, Lam Ha District, Lam Dong Province.
+ Model 2: Hamlet 7, Phuc Tho commune, Lam Ha district, Lam Dong province.
Table 2.1 Compost, nitrogen fertilizer and phosphorus fertilizer in treated treatments
(on the basis of 350 kg K2O/ha/year).
Treatment (NT)

Compost

P2O5

(tons/ha)

N
(kg/ha)

NT1

0

100

250

NT2

0

100

320

NT3

0

100

390

NT4

0

100

460

NT5

0

150

250

NT6

0

150

320

NT7

0

150

390

NT8

0

150

460

NT9

0

200

250

NT10

0

200

320

NT11

0

200

390

NT12

0

200

460

NT13

10

100

250


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NT14

10

100

320

NT15

10

100

390

NT16

10

100

460

NT17

10

150

250

NT18

10

150

320

NT19

10

150

390

NT20

10

150

460

NT21

10

200

250

NT22

10

200

320

NT23

10

200

390

NT24

10

200

460

2.4.3 Method of application
- Compost is applied in June, buried in the soil. Fertilized phosphate fertilizer is applied 100% at the end of
April - early May, spread in the basin 30 cm, mixed with soil.
- Urea and KCl fertilizers are mixed in the right proportion of 4 times/year (between dry season; early; mid
and late rainy season). Apply in the basin from the original 30 cm, mixed into the soil.
2.4.4 Caring techniques as directed by 10 standards of the Ministry of Agriculture 478 - 2001.
2.4.5 Method of soil sample collection
2.4.5.1 Earthworms sample (collected in May, July and October of 2014):
According to the method of Fender and McKey-Fender (1990), the number of samples 72
2.4.5.2 Soil sample for microbial density assessment (collected in October 2014):
According to TCVN 7538-6: 2010, sample number 72
2.4.5.3 Soil samples for physical and chemical evaluation (collected in November 2014):
Soil samples for density, porosity and durable solid wastes were collected according to TCVN 5297: 1995
and TCVN 7538-2: 2005 with specialized kits. Soil samples for analysis of some chemical criteria were collected
according to TCVN 5297: 1995 and WASI on coffee cultivated soil, number of samples 72.
2.4.6 Soil analysis methods:
Soil physical, soil chemical and soil biological (pH, SOM, CEC (cation exchange capacity), Ca 2+, Mg2+,
Al3+, total microorganism, nitrogen fixation, P-decay, cellulose decay) were analyzed according to TCVN and Soil,
Fertilizer and Plant Analysis Manual of the National Institute for Soils and Fertilizers (1998).


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2.4.7 Sampling: Coffee Productivity and Economic Efficiency Calculation:
Farmers and economic efficiency were collected from the second year of field trials and monitored
continuously for 3 years (2013, 2014 and 2015).
2.4.8 Statistical processing method:
Data collected were analyzed for variance (ANOVA) and mean values tested according to LSD (the smallest
difference) with α ≤ 0.05 using IRRITAS version 5.0 software. Correlation between factors analyzed by XLSTAT

2012 and Microsoft Office Excel 2010. Principal Component Analysis (PCA) was used to analyze relationships
between physical, chemical and biological study with fertility and fertility.

Chapter III. RESEARCH RESULTS AND DISCUSSION

3.1 Current status of coffee cultivation of farmers in Di Linh plateau, Lam Dong province
3.1.1 Size of area and yield of coffee
The average yield of coffee beans in the three districts of Lam Ha, Bao Lam and Di Linh was 3.6 - 3.7
tons/ha. However, there is a great variation in coffee yield of farmers, ranging from < 2.0 tons/ha to > 5.0 tons/ha.
In all three districts, the percentage of farmers receiving yield ranged from 3.1 to 4.0 tons/ha, accounting for the
majority (55.7%).
3.1.2 The actual use of inorganic fertilizer for Canephora coffee
3.1.2.1 The amount of fertilizer N, P, K
- Nitrogenous fertilizer: The application of coffee to farmers in three districts (Lam Ha, Di Linh and Bao
Lam) has a great variation. Nitrogen levels range from 196 - 897 kg N/ha/year, average 448.5 kg N/ha/year.
Compared to the WASI recommendation (N = 300 kg N/ha for yield), the average N fertilizer application for
coffee in all three districts was 118- 166 kg N/ha, up to 77% of N households.
- Phosphorous fertilizers: The phosphorus level is 105 - 620 kg P 2O5/ha/year, average is 324.1 kg
P2O5/ha/year. Compared with WASI recommendation (P2O5 fertilizer level of 3 - 4 tons/ha, 80 - 100 kg
P2O5/ha/year), the amount of phosphorous fertilizer applied to all 3 districts is higher than 212 - 293, 5 (kg
P2O5/ha/year), up to 97.0% of phosphorous fertilizer application.
- Potassium fertilizers: Low potassium levels of 80 - 900 kg K 2O/ha/year, average 305.8 kg K2O/ha/year.
Compared with WASI (K2O application rate for yield 3 - 4 tons/ha, 250 - 300 kg K 2O/ha/year, 36.3% excess
potassium).
Farmers applied high NPK fertilizers, but yield did not increase, fertilizer application was not effected,
resulting in waste of fertilizer and low economic efficiency.


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- Ratio of fertilizer N: P2O5: K2O: The average rate of application of fertilizer, phosphorus and potassium by

farmers is generally unbalanced (N: P2O5: K2O is 1.38: 1: 0.94), in which the amount of nitrogen and phosphorus
was much higher than that of potassium and recommended (3: 1: 3).
3.1.3 The use of organic fertilizer for coffee
The number of households used organic fertilizer accounts for 61.5% of the total surveyed households; Of
which 53.0% of households used fresh manure; The number of households compost accounted for 27.7%. The
application of manure varies, ranging from 8.5 to 35 tons/ha, on average 16.8 tons/ha and applied every 2 - 3
years. For compost applied with volume 1.0 - 5.3 tons/ha/year, average 2.8 tons/ha/year.
3.2 Effect of continuous application of compost, nitrogen and phosphorus fertilizers to coffee plants to the fertile
of basalt reddish-brown soil Di Linh plateau, Lam Dong
3.2.1 Effect of continuous application of compost, nitrogen and phosphorus fertilizers to coffee plants to physical
properties
3.2.1.1 Effect of continuous apply compost to soil physical properties
Applying compost continuously for 3 years at the rate of 10 tons/ha/year showed that soil density did not
change; soil bulk density decreased by 10.2%; porosity increased by 7.5% and durable structure soil increased by
17.2% compared with no compost (statistically significant difference).
3.2.1.2 Effect of continuous apply nitrogen fertilizer to some soil physical properties
The effect of 3-year N fertilizer rates on the soil bulk density was not statistically different; The lowest soil
weights were 320 kg N/ha/year and highest at 460 kg N/ha/year. Porosity and durable structure soil were highest at
the application of 320 kg N/ha/year and lowest at 460 kg N/ha/year (statistically significant difference).
3.2.1.3 Effects of continuous apply phosphorus fertilizer to soil physical properties
Phosphorus fertilizer application on basalt reddish brown soil does not have much impact on improving
soil physical properties.
3.2.1.4 Effects of compost, introgen and phosphorus fertilizer doses to some soil physical properties
Inorganic fertilizers N and P combined with compost did not significantly affect the soil bulk density.
The interaction between phosphorus and compost: Apply 10 tons of compost with 100 kg P 2O5/ha/year
making the lowest bulk density (meaningful). The interaction between compost with nitrogen and phosphorus gave
the lowest soil weight (significant) in NT14 (320 kg N - 100 kg P 2O5 - 350 kg K2O + 10 tons of compost/ha/year)
0.98 g/cm3. Fertility and soil water consistency decreased in the treatment treatments with N, P without organic
fertilizer (NT1 - NT12) and lowest in treatments with N (460 kg/ha) irrespective of the dose P fertilizer and
increase in the combination treatments of inorganic fertilizer N, P with compost (NT13 - NT24). Incorporation of

inorganic fertilizer NPK and compost at an appropriate level (320 N - 100 P 2O5 - 350 K2O + 10 tons of
compost/ha/year) has improved some soil physical properties.


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3.2.2 Effect of continuous apply compost, nitrogen and phosphorus fertilizers to coffee plants on some soil
chemical properties
3.2.2.1 Effects of continuous apply for compost to soil pH dynamics
The effect of fertilizing and no compost on pH H2O through 2013, 2014 and 2015 is statistically significant.
Applying 10 tons of compost/ha/year, the pHH2O move through 2013, 2014, 2015 is increasing compared with no
compost on average 6%.
3.2.2.2 Effects of continuous apply for nitrogen fertilizer to soil pH dynamics
After four consecutive years of application of N fertilizers at different levels (250, 320, 390 and 460 kg N),
the pH of the soil was markedly changed with the application of N (460 kg N/ha/year) caused the pH to drop lower
than the soil before the experiment, which is most evident in the fourth year (2015) of the experiment.
3.2.2.3 Effects of continuous apply for phosphorus fertilizer to soil pH dynamics
pH increases at the rate of 200 kg P2O5/ha/year through 2013, 2014 and 2015, especially the highest in 2015,
applying the molten phosphate fertilizer in the long run has improved the pH of basalt reddish brown soil.
3.2.2.4 Effects of compost, nitrogen and phosphorus fertilizer doses to soil pH dynamics.
The correlation between nitrogen and organic matter significantly increased the pH significantly when
applied 10 tons of compost/ha/year with 320 kg N/ha/year.
The highest (significant) correlation between NT18 (320 N - 200 P 2O5 - 350 K2O + 10 tons of
compost/ha/year) was 6.3 and lower the highest in NT4 (460 N - 100 P2O5 - 350 K2O/ha/year) was 4.8.
3.2.2.5 Effect of continuous apply of compost to some soil chemical properties
Applying compost 10 tons/ha/year increased SOM, CEC, Nts, P 2O5, K2O, Ca2+ and Mg2+ respectively
(36.51%, 21.8%, 15.79%, 13, 91%, 23.53% 67.63%, 52.74% and 49.33%), with Al 3+ decreased by 2.4 times
compared with no organic application.
After 3 years of continuous fertilization with 10 tons of compost/ha, CEC, SOM, Nts, P 2O5, K2O, Ca2+ and
Mg2+ contents were significantly improved. For soil not fertilized with organic matter, SOM content in soil
decreased compared to soil before experiment.

3.2.2.6 Effects of continuous apply nitrogen fertilizer to Some Soil Chemistry
- Variation of CEC, SOM and Nts content in soil is very clear. Levels of N fertilizer (320 kg N/ha/year) for
coffee will increase CEC, SOM, Nts in soil. Applying too low or too high levels makes CEC, SOM and Nts in the
soil decrease and lowest at 460 kg N/ha/year.
The content of P2O5dt and K2Odt increased with N fertilizer application rate and reached the highest level at
N2 (320 kg N/ha/year) and lowest at N4 (460 kg N/ha/year). Ca 2+ and Mg2+ levels in soil were highest at N2 = 320
kg/ha/year (3.53 and 2.24 cmol/kg of soil) and lowest at N4 = 460 kg/ha/year.


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- Al3+ content in soil increased with N fertilizer application rate and highest at N4 = 460 kg/ha/year was 0.37
cmol/kg soil. Thus, balanced N fertilizer in coffee cultivation is very important, helping regulate Al 3+ content to
safe level for plant roots.
3.2.2.7 Effects of continuous apply phosphorus fertilizer to some chemical properties
- The effect of the dosages of phosphorus to CEC, SOM, Nts, P 2O5, K2O, Ca2+ and Al3+ in soil difference was
not statistically significant. Mg2+ content increased with the application of phosphate fertilizer to the soil and
highest at P3 (2.07 cmolc/kg soil).
3.2.2.8 Effect of the dose of compost, nitrogen fertilizer and phosphorus fertilizer to some soil chemical properties
- The correlation between N, P and compost at the application rate (320 kg N - 150 kg P 2O5 - 350 kg K2O +
10 tons of compost/ha/year) had the highest CEC (mean) be 9 cmolc/kg of soil and the lowest level of fertilizer
application (460 kg N - 200 kg P2O5 - 350 kg K2O/ha/year), and the application rate (460 kg N - 150 kg P 2O5 - 350
kg K2O/ha/year) be 12.2 cmoles/kg of soil.
- The interaction between compost, nitrogen and phosphorus fertilizer concentrations in SOM, N in the
highest soil (significant) in NT14 (320 kg N - 100 kg P2O5 - 350 kg K2O + 10 tons compost) and the lowest in NT8
(460 kg N - 150 kg P 2O5 - 350 kg K2O/ha/year, not compost) and NT12 (460 kg N - 200 kg P 2O5 - 350 kg
K2O/ha/year, not compost).
- The interaction between inorganic N, P and compost (NT 13 - NT24) resulted in a C/N ratio of 10.3 - 16.9,
which was optimal during the supply, N mineralization for trees and humus accumulation for soil. In contrast, in
inorganic fertilizers N, P without compost (NT1 - NT12), the C/N ratio ranged from 9.3 to 11.9, indicating
significant mineralization humus in the ground is reduced.

- The highest content of P2O5dt in NT14 (320 kg N - 100 kg P2O5 - 350 kg K2O + 10 tons of compost) 14.8
mg/100g and the lowest in NT8 (460 kg N - 150 kg P 2O5 - 350 kg K2O + 0 tons of compost) is 9.2 mg/100g of soil.
The content of K2Odt in inorganic fertilizers N, P without compost (NT1 - NT12) ranged from 12.2 - 19.2
mg/100g of soil and in the combination treatments of inorganic N, P with organic fertilizer (NT13 - NT24) ranged
from 20.1 to 26.7 mg/100g of soil.
The Ca2+ content in the highest (significant) soil at NT22 (320 N - 200 P 2O5 - 350 K2O + 10 tons of organic
fertilizer/ha/year) was 4.26 cmolc/kg and the lowest in NT4 (460 N - 100 P 2O5 - 350 K2O/ha/year) was 1.45
cmolc/kg.
The content of Mg2+ in the highest (mean) in NT22 (320 N - 200 P 2O5 - 350 K2O + 10 tons of
compost/ha/year) was 2.75 cmolc/kg and the lowest in treatment NT4 (460 N - 100 P 2O5 - 350 K2O/ha/year) was
0.67 cmol/kg.
- The interaction between organic and protein fertilizers and Al 3+ concentration in the soil decreased the
lowest at the level of 320 kg N/ha/year combined with 10 tons of compost/ha/year and highest at 460 kg N/ha/year
without compost.


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- The correlation between doses of compost, nitrogen and phosphorus fertilizer to the highest level of soil
3+

Al in NT4 (460 kg N - 100 kg P2O5 - 350 kg K2O/ha/year) was 0.64 cmolc/kg of soil and In the NT21 (250 kg N
- 100 kg P2O5 - 350 kg K2O + 10 tons of manure/ha/year) was 0.09 cmolc/kg of soil. In general, inorganic
fertilizers combined with compost (NT13 - NT24) contained low soil Al 3+ content (0.09 - 0.22 cmolc/kg soil)
compared to those using inorganic fertilizer N, P not compost (NT1 - NT12: 0.23 - 0.64 cmolc/kg of soil).
3.2.3 Effect of continuous apply compost, nitrogen and phosphorus fertilizers to coffee plant density, size and
biomass of earthworms
3.2.3.1 Effect of continuous apply compost to density, size and biomass of earthworms
Applying 10 tons of compost/ha/year resulted in increasing density, size and biomass of earthworms (2.5,
2.6 and 7.6 times) compared with no organic fertilizers (difference was statistically significant) and also higher
than the soil before the experiment.

3.2.3.2 Effect of continuous apply nitrogen fertilizers to density, size and biomass of earthworms
At the level of N2 = 320 kg N/ha, the highest worm infestation was observed in the months (5, 7 and 10)
as well as the worm size and biomass and lowest at 460 kg N/ha/year (statistically significant).
3.2.3.3 Effect of continuous apply phosphorus fertilizer to density, size and biomass of earthworms
Diluted phosphorus had almost no effect on the density of earthworms in basaltic reddish soil.
3.2.3.4 Effect of the compost, nitrogen fertilizer and phosphorus fertilizer dose to density, size and biomass of
earthworms
- The highest worm density was applied at the rate of 10 tons of compost/ha/year with 200 kg P 2O5/ha/year
and the lowest level was 200 kg P 2O5/ha/year without compost. The correlation between phosphorus and compost
was not statistically significant, applying 10 tons of compost with 150 kg P 2O5/ha/year gave the largest worm size
compared to the remaining and low levels. At the level of 150 kg P 2O5/ha/year without compost.
- The effect of the interaction between nitrogen and compost was significant at the level of 320 kg N/ha/year
with 10 tons of compost and lowest at the level of 460 kg N/ha/year without compost. The interaction between
nitrogen fertilizer and phosphorus fertilizer showed the highest (significant) level of application at 320 N with 100
P2O5 and lowest at 460 N with 200 P2O5.
- The effects of N, P and organic fertilizer were investigated. The results showed that NT22 treatment (320
kg N, 200 kg P2O5 and 10 tons of compost/ha) gave the best results on earthworm density through months (5, 7
and 10). The size and biomass of NT14 (320 kg N, 100 kg P2O5 and 10 tons of compost/ha) gave the best results.
3.2.4 Effect of continuous apply compost, nitrogen and phosphorus fertilizer for coffee plants to soil microbial
density
3.2.4.1 Effect of continuous apply compost to soil microbial density
Applying 10 tons of organic fertilizer/ha/year of microorganism density (total, nitrogen fixation,
phosphorus-decay and cellulose-decay respectively: 4.6x10 6 cfu/g, 7.6x104 cfu/g, 14.0x105 cfu/g and 7.4x104 cfu/g


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of soil) increased by 31.42%, 40.74%, 91.78% and 68.18% compared with not compost and compared with the
soil before the experiment.
3.2.4.2 Effect of continuous apply nitrogen fertilizer to soil microbial density
The total microbial density varies with the amount of N applied to the soil. The total microbial density was

highest at N2 = 320 kg/ha/year, 5.7x10 6 cfu/g and lowest at 460 kg/ha/year, 2.7x10 6 cfu/g. The highest nitrogen
fixation of N1 = 250 kg/ha/year was 8.4x10 4 cfu/g of soil and the lowest was N4 = 460 kg/ha/year, 4.7x10 4 cfu/g
of soil. The highest dissolved phosphorus-decay density at N1 = 250 kg N/ha/year was 1.6x10 6 cfu/g soil and
lowest at N4 = 460kg N/ha/year was 6.3x10 5 cfu/g soil. The highest cellulase-decay density was N2 = 320
kg/ha/year, 6.0x104 cfu/g soil and lowest was N4 = 460 kg/ha/year was 4.8x10 4 cfu/g soil. It was found that high N
(460 kg/ha/year) resulted in a decrease in soil microbial density.
3.2.4.3 Effect of continuous apply phosphate fertiizer to microbial density in soil
The effect of phosphate levels on total microbial population, microbial cellulose-decay was not statistically
significant. For the concentration of nitrogen fixing bacteria, microorganisms dissolved phosphorus in the soil is
significantly different. The highest dissolved phosphorus-decay density was applied at the rate of 100 kg
P2O5/ha/year at 1.4x106 cfu/g soil and lowest at 200 kg P2O5/ha/year at 8x105 cfu/g soil; The concentration of 100
kg P2O5/ha/year was 8.9x104 cfu/g and lowest at the rate of 200 kg P2O5/ha/year of 4.6x104 cfu/g of soil.
3.2.4.4 Effect of doses for compost, nitrogen and phosphorus fertilizer concentrations to soil microbial density
- The total microbial density was highest (NT4 (320 kg N - 100 kg P 2O5 - 350 kg K2O + 10 tons of
compost/ha/year) was 7.1 x106 cfu/g of soil and lowest in NT8 (460 kg N - 150 kg P 2O5 - 350 kg K2O/ha/year) is
2.1x106 cfu/g of soil. Nitrogen fixation was highest in NT17 (250 kg N - 150 kg P 2O5 - 350 kg K2O + 10 tons of
compost/ha/year) was 14.7x104 cfu/g of soil and lowest in NT8 (460 kg N - 150 kg P 2O5 - 350 kg K2O/ha/year) is
2.3x104 cfu/g of soil.
- The interaction between phosphorus and compost was highest (100 kg P 2O5) plus 10 tons of
compost/ha/year and the minimum is 200 kg P2O5 and no compost. The interaction between phosphorus and
nitrogen fertilizer doses was highest at the application rate of 100 kg P 2O5 plus 250 kg N/ha/year and lowest at the
application rate 150 kg P2O5 with 460 kg N/ha/year. The interaction between nitrogenous and compost
concentrations was highest at the application rate of 250 kg N and 10 tons of compost/ha/year. The lowest level
was 460 kg N/ha/year without compost.
- The interaction between compost, nitrogen and phosphorus fertilizer doses to the highest phosphorusdecay density in NT13 (250 kg N - 100 kg P2O5 - 350 kg K2O + 10 tons compost/ha/year) was 37x105 cfu/g of soil
and the lowest NT12 (460 kg N - 200 kg P 2O5 - 350 kg K2O/ha/year) was 4.9x105 cfu/g soil. The highest
(significant) correlation between nitrogen and compost was found at the level of 320 kg N with 10 tons of
compost/ha/year and lowest at the application rate 250 kg N and 460 kg N without compost.
- The correlation between the doses of compost, nitrogen and phosphorus fertilizer to the highest cellulosedecay density (significant) in NT14 (320 kg N - 100 kg P 2O5 - 350 kg K2O + 10 tons compost/ha/year) is 11x10 4
cfu/g and the lowest in NT12 (460 kg N - 200 kg P 2O5 - 350 kg K2O/ha/year) is 3.5x104 cfu/g. In general, the

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inorganic fertilizers N, P combined with compost (NT13 - NT24) had higher density of microorganisms than those
of inorganic fertilizer N, P without compost (NT1 - NT12).
3.2.5 Analyze the relationship between physical, chemical and biological properties in soil
3.2.5.1 Relationship between soil organic matter content and some physical soil properties
- The correlation between SOM content with bulk density, porosity and durable structure soil of soil
aggregates in country, r coefficient is 0.94; 0.95 and 0.95 (P ≤ 0.01) show that this is a very tight correlation.
3.2.5.2 Relationship between soil organic matter content and some soil chemical properties
- correlation between SOM content with CEC, K 2O and Ca2+ in soil with r coefficient of 0.95; 0.94; 0.94 and 0.94
(P ≤ 0.01). This is a very strong correlation. The correlation between Al 3+ with pH and between CEC and K 2O
correlated r respectively to -0.91 and 0.96 (P ≤ 0.01). Correlation between Ca2+ with pH, CEC, total K2O, K2O and
Al3+ (aluminum toxicant) in soil with coefficient r of 0.90; 0.93; 0.92; 0.92 and - 0.92 (P ≤ 0.01). This is a very
strong correlation.
3.2.5.3 Correlation between some physical and chemical properties of soil with the density, size and biomass of
earthworms as well as the density of soil microorganisms
- The correlation between earthworm density with soil bulk density, porosity and durable structure soil with
coefficient r was 0.95; 0.95 and 0.98 (P ≤ 0.01). Between worm size with density, porosity and structure durability,
the coefficient r was - 0.94; 0.94 and 0.99 (P ≤ 0.01).
- The correlation between SOM and densities, size and biomass of earthworms was a very close interaction
with r: 0.95; 0.96 and 0.90 (P <0.01). Between pH and earthworm density, the correlation coefficient r = 0.83 (P ≤
0.05), indicating the soil pH significantly influences the growth of earthworms. Correlation between Ca 2+ content
with density, size and biomass of earthworms with r coefficient of 0.93; 0.93 and 0.81 with (P ≤ 0.01).
- Multiple linear correlation among the factors (density, bulk density, porosity, durable structure soil, CEC,
pH, total N, P2O5, K2O, total K2O, Ca2+, Mg2+, Al3+ as well as bulk density, earthworm and bulk density of
microorganisms in the soil) with the main component being organic content, the linearity of variables through the
F1 and F2 axes is 82.23%. Thus, it can be seen that the soil bulk density, porosity and durable structure soil in
physics; SOM, pH, CEC, Nts, K2O, Ca2+, Al3+ (chemical) and bulk density, size and birth worm masses as well as
total microbial density, cellulose decay microorganisms (soil SOM) have a close relationship in basalt reddish

brown soil, in which the SOM, pH and Ca 2+ are the most important factors - especially the content of soil organic
matter.
3.3 Effect of compost, nitrogen and phosphorus fertilizer to productivity of coffee
3.3.1 Effect of compost to coffee yield
- Apply 10 tons of compost/ha/year. The percentage of fresh fruit per crop in 2013 is reduced by 2.2%, the
crop in 2014 decreases by 6.7% and the crop by 2015 by 11.4%. No compost (statistically significant difference).
Increase of yield/ha in 2013 is 28.6%, in 2014 is 34.3% and in 2015 is 43.3% compared with no compost


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(statistically significant difference). In terms of compost efficiency, one ton of compost/ha/year increased yield by
123.6 kg/ha.
3.3.2 Effect of nitrogen fertilizer to coffee yield
- Effects of nitrogen fertiizer rates on fresh rates/kernel: The lowest annual season (2013, 2014 and 2015)
and the highest N4 level; yield coffee beans are also similar. The steady N fertilization (320 kg/ha/year) and
stability will tend to decrease when nitrogen fertilizer is applied at high doses.
3.2.3 Effect of phosphorus fertilizer to coffee yield
- The effect of P fertilizer doses on fresh rates/kernel in different seasons 2013, 2014 and 2015 is the lowest,
with the lowest P1 fertilizer rate and then the highest P3 fertilizers. The yield per hectare in the 2013, 2014 and
2015 seasons is not statistically significant.
3.3.4 Effect of compost, nitrogen and phosphorus fertilizers doses to coffee yield on basalt reddish brown soil
- The interaction between compost and nitrogen fertilizers was lowest in the application of 320 kg N with 10
tons of compost/ha/year and highest in the application of 460 kg N/ha/year not have compost. It is also the highest
rate of application of NPK fertilizer (320 kg N with 10 tons of compost/ha/year) and the lowest level of fertilizer
application is 250 kg N/ha/year. The correlation between P fertilizer and compost was highest at 100 kg P 2O5 with
10 tons of compost/ha/year and lowest at 100 kg P 2O5/ha/year without compost. The highest impact (P < 0.05) was
achieved at 150 kg P2O5 with 320 kg and lowest at 200 kg P2O5 with 250 kg N/ha/year.
- The effects of compost and inorganic N, P doses on the fresh rates/kernel over the 2013, 2014 and 2015
seasons are generally the lowest in the NT (320 N - 350 K 2O + 10 tons of compost/ha) and highest in NT (460 N 350 K2O/ha) without compost, regardless of phosphate fertilizer dose. The number of coffee beans/ha over the
years (2013, 2014 and 2015) is the lowest in NT1 (250 kg N - 100 kg P 2O5 - 350 kg K2O/ha/year) 3.43 tons and

highest in TN14 (320 kg N - 100 kg P 2O5 - 350 kg K2O + 10 tons compost/ha/year) 5.68 tons. The coffee is applied
in combination with fertilizer N, P and compost (NT13 - NT24) higher than the NT inorganic fertilizer (NT1 NT12) only.
3.3.5 Economic efficiency (profitability) of coffee production and proposed dosage, reasonable ratio of NPK for
coffee business in Di Linh plateau, Lam Dong province
In intensive coffee production with high yielding varieties to produce high profit/production costs in the
same area of basalt reddish brown soil in Di Linh plateau, Lam Dong province should apply the combination of
inorganic fertilizers with the application rate of 320 N - 100 P 2O5 - 350 K2O (kg/ha/year) + 10 tons of compost.
3.3.6 Analysis of correlation between coffee and some factors of fertility
- The correlation between coffee yield and density, porosity and durability of soil aggregates with
coefficients r: - 0.73; 0.73 and 0.86 (P ≤ 0.05).
- Correlation between coffee beans with CEC, SOM, total N, K 2O and Ca2+ content in soil with correlation
coefficient r: 0.79; 0.80; 0.74; 0.85 and 0.74 (P ≤ 0.05). This is a tight interaction.


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- Correlation between coffee consumption and density, size and biomass of earthworms with coefficient r:
0.83; 0.87 and 0.82 (P ≤ 0.01). Correlation between cellulose degrading microalgae in soils with coffee beans with
coefficient r = 0.75 (P ≤ 0.05).
3.4 Demonstration model of sustainable coffee production in the basalt reddish brown soil of Di Linh plateau, Lam
Dong province
- For treatment of NPK fertilizer (320 N - 100 P 2O5 - 350 K2O) compared with the control cost of production
investment decreased 1,056,423 VND (reduced mainly from the cost of fertilizer supplies). But economic
efficiency increased by 0.54 tons/ha (14.1%) and net profit increased 22,666,423 VND compared with control.
- For NPK + compost treatment (320 N - 100 P 2O5 - 350 K2O + 10 tons of compost), production investment
cost increased by 15,312,126 VND compared to control (cost increased mainly due to investment in compost and
harvesting, processing due to increased production). But the economic efficiency increased by 1.61 tons (42.2%)
and net profit increased 49,087,873 VND (profit margin 3.7) compared with the control.
- Comparison between NPK + compost treatment with NPK inorganic fertilizers treatment shows that the
application of NPK + compost increased production cost to 16,368,550 VND, but the economic effect increased
1.07 tons per hectare (24.5%) and increased profit to 26,431,450 VND (profit rate 2.0) compared to NPK

application.

CHAPTER IV. CONCLUSIONS AND RECOMMENDATIONS
4.1 Conclusion
(1) The actual application of nitrogen, phosphorus, potassium for coffee in the Di Linh Plateau, Lam Dong
fluctuations in quantity and imbalance in proportion. With an average yield of 3.6 tons/ha, there were 77.0% of
households applying nitrogen fertilizers, 97.0% of households fertilized phosphorus, 36% of households lacked
potassium and 48% of households over-potassium. The amount of compost applied varies from 1 to 5.3
tons/ha/year on average of 2.8 tons/ha; manure from 8.5 to 35 tons/ha, average 16.8 tons/ha (2 - 3 years fertilizer
once). Of which, 53% of the households use manure (chicken, pigs,…) that is not processed for coffee.
(2) Apply nitrogen fertilizer, phosphorus fertilizer and compost rationally increase soil fertility.
a) Appling 10 tons of compost continuously in 3 years has caused: soil porosity increased by 7.5%,
durability increased 7.2%, soil density decreased 10.2%, CEC, SOM , P 2O5, K2O, Ca2+ and Mg2+ increased
respectively: 21.8%, 36.5%, 12.9%, 64%, 48.3% and 31.5%; Al 3+ decreased by 2.4 times; Earthworm density, size
and biomass increased (2.5, 2.6 and 7.6 times); The total (68.2%, 31.4%, 40.7%, 91.8% and 68.2%) respectively
increased in microbial populations with no compost.
b) Fertilizer application at 320 kg N/ha/year to improve some physical and chemical properties of soil,
reduce the density, increase porosity and durability in the country, maintain pH H2O 5.7 - 6.0; increased CEC, SOM,


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total N, K2O, Ca2+ and Mg2+; decreased Al3+; increased density, size and biomass of earthworms; increased
microbial density (total, nitrogen fixation, phosphorus degradation and cellulose degradation).
c) Increasing fertilizer application rate of 100 - 200 kg P 2O5/ha/year only improved some pH, Ca 2+, Mg2+;
However, it does not affect the physical, chemical and soil properties as well as the coffee yield. Therefore,
applying 100 kg P2O5/ha/year for coffee is reasonable.
(3) The reasonable amount of fertilizer for ground coffee in basalt reddish brown soil of Di Linh plateau: 10
tons of compost with 320 N - 100 P 2O5 - 350 K2O (kg/ha/year), this application also improves the fertility of the
soil in the best way.
(4) The factors including density, organic matter, Ca 2+, pH, earthworm density and size, cellulose

degradation density were strongly correlated with soil fertility and coffee yield in basalt reddish brown soil.
(5) The treatment of 10 tons of compost combined with 320 N - 100 P 2O5 - 350 K2O (kg/ha/year) increased
the yield of 1.07 tons/ha of coffee, increased profit 26,431,450 VND (profit rate 2.0) compared with NPK
fertilizers (in the same dose); Compared with control farmers, yield increased 1.61 tons/ha, profit increased
49,087,873 VND (profit rate 3.7).
4.2 Recommendations:
(1) Application and dissemination of fertilizer level of 320 kg N - 100 kg P 2O5 - 350 kg K2O + 10 tons of
compost/ha/year in coffee growing business in basalt reddish brown soil Di Linh Plateau, Lam Dong provincen.
(2) It is necessary to continue to study the application of micronutrients fertilizers for coffee Canephora in
the Di Linh plateau.