1

Adaptability and nut yield of macadamia in

Northwest Vietnam and recommendation of suitable

clones for commercial planting

AFLI Technical Report No. 5

SUMMARY

This survey in adaptability and nut production of macadamia germplasm in the Northwest

region of Vietnam was undertaken as a component of the project “Agroforestry for

Livelihoods of Smallholder Farmers in North-West Vietnam”, funded by the Australian

Center for International Agricultural Research (ACIAR).

Objectives of the survey were to better understand adaptability, growth and nut yield of

macadamia and clonal variation in these traits, information that will support sustainable

development of this species in the Northwest region.

The study evaluated seven macadamia plantations in the Northwest region. Macadamia

shows good adaptability and reasonable nut yields in several different locations 300-700

metres above sea level. A clone trial at Mai Son, Son La Province, tested six selected

clones and two controls (unimproved seedlings, and cuttings from selected superior

seedling trees). Significant differences in annual nut yield were recorded in two successive

years over the period 2011-12. Clones OC, 246 and 816 had the highest yields of the six

clones tested, with mean ranging from 2 to 6 kg per tree. Nut yields were higher in 2011

than in 2012. Clones 246 and OC maintained the highest consistent nut yields during these

two years. Clone 842 had high nut yield in 2011 but its yield significantly decreased in

2012. Clone 816 had intermediate nut yield and remained stable over the two years. We

suggest that clones OC, 246 and 816 should be planted in mixture to maintain sustainable

yield as well as ensuring maximum cross-pollination. Recommendations on suitable

climatic conditions for planting macadamia are presented, and management issues in

macadamia plantations with respect to the Northwest conditions are also discussed.

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ACKNOWLEDGEMENTS

I would like to express my sincere thanks to ICRAF-ACIAR project “Agroforestry for

Livelihoods of Smallholder Farmers in North-West Vietnam” for giving me an opportunity

to conduct this intensive study. My personal thanks to Dr. Delia Catacuntan and Dr. Hoang

Thi Lua at ICRAF Ha Noi for supporting during this study. My sincere thanks to Mr. Tan

Van Phong and Mr. Ha Van Tiep at North West Forestry Science Centre of Vietnam

Academy of Forest Science for supporting me during the survey. I would like to thank my

colleagues in Institute of Forest Tree Improvement and Biotechnology, Vietnam Academy

of Forest Science for helping during data collection, analysis and commenting during the

work. Finally, my special thanks to Dr. Chris Harwood at CSIRO Sustainable Ecosystems,

Australia for his valuable comments and suggestions in successive drafts of the report.

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ABBREVIATIONS a.s.l above sea level – refer to absolute altitiude of a location

CV Coefficient of phenotypic variation

Dgl Diameter at ground level of a tree

Dcr Diameter of crown of a tree

Fpr Probability of difference between treatments in Fisher-test. Treatments differ

significantly if Fpr < 0.05

Ht Total height of the tree

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TABLE OF CONTENTS

INTRODUCTION ................................................................................................................. 5

STUDY OBJECTIVES ......................................................................................................... 7

METHODOLOGY ................................................................................................................ 8

RESULTS ............................................................................................................................ 10

Growth and nut yield of macadamia in the Northwest region ............................................. 10

Clonal variation in growth characters in the clonal trial ..................................................... 12

Clonal variation in nut yield in the clonal trial .................................................................... 12

Clonal variation in the clonal archieve ................................................................................ 14

DISCUSSION ...................................................................................................................... 14

Adaptability and productivity of macadamia in the Northwest ........................................... 15

Variation in growth characters and nut production ............................................................. 17

Management issues for macadamia plantation in the northwest ......................................... 18

CONCLUSIONS AND RECOMMENDATIONS .............................................................. 21

REFERENCES .................................................................................................................... 22

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INTRODUCTION

Macadamia is the common name of nine tree species belong to genus Macadamia, family

Proteaceae. Among these nine species, only two, Macadamia integrifolia Maiden &

Betche and Macadamia tetraphylla L. Johnson have commercial value. These two species

have their natural distributions in coastal southeast Queensland and northeast New South

Wales, Australia. The other species are not edible because of their bitter taste (Mast et al.

2008).

The two edible macadamia species have woody nuts, with a kernel-to-nut weight ratio

ranging from 30 to 50%. Kernel contains 71-80% fatty oil. Kernel are widely used in the

confectionary industry for high-value products or can be roasted to eat directly (Cavaletto

1981; Stephenson 2005).

According to Nguyen Cong Tan (2008), macadamia kernels have high nutrient content

with unsaturated fatty acid predominating (78.2%), followed by carboydrate (10%),

potassium (0,37%), phosphorus (0.17%) and magnesium (0.12%). Fatty oil content of

macadamia is higher than that of ground nut and cashew nut. Thanks to its taste and high

nutrient content, macadamia is a high value agricultural product.

During the last two decades, macadamia has attracted great interest and been promoted

worldwide. By 2006, the global area of macadamia plantations had reached 112,000 ha,

equivalent to about 17 millions trees, with a total productivity of 120,000 tons of kernel per

annum (Hoang Hoe, 2008). Macadamia is widely planted in Australia (44,000 ha), United

States of America (23,600 ha in Hawaii), Brazil (3,300 ha), Kenya (12,500 ha), South

Africa (16,500 ha), Guatemala (6,200 ha), Thailand (1,500 ha) and China (5,000 ha).

Macadamia was first introduced to Vietnam in 1994 from unselected seed, with a few

seedlings planted by the Research Centre for Forest Tree Improvement (RCFTI) of the

Forest Science Institute of Vietnam (FSIV) at their field station at Ba Vi in Hanoi

Province. These first trees started to produce nuts in 1999 and some individual trees were

producing 7 kg of nuts per year by 2002.

In 2002, the Australian Macadamia Association transferred 9 clones (246, 344, 741, 842,

816, 849, 856, NG8 and Daddow) with high productivity and nut quality to RCFTI for

testing their adaptability, growth and yield in Vietnam. Two other clones (OC and A800)

were introduced from China. These clones have been tested in different locations in

Vietnam under a MARD funded research project “Testing of adaptability and nut

productivity and vegetative propagation of Macadamia in Vietnam” which commenced in

2002. Clonal trials of this species have been planted at Hanoi, Son La, Quang Ninh, Quang

Binh, Dak Lak and more recently in Lai Chau and Thanh Hoa provinces (Nguyen Dinh

Hai, 2010). Nut production has been reported to be high in DakLak province and low to

intermediate in other provinces (Nguyen Dinh Hai, 2010). In parallel with this research

project, from 2004 macadamia has also been planted commercially in Lang Son, Quang

Ninh, Son La and Nghe An provinces, using germplasm imported from China without

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prior testing of adaptability and productivity. The scale of planting has been small because

of a shortage of planting stock.

Flowering and nut production have been reported in some trials and pilot planting areas of

macadamia in the Northwest region. This data indicates that macadamia may be suitable

for planting there for nut production to improve farmer livelihoods. However, knowledge

of macadamia adaptability, nut production capacity, pests and diseases, cultivation

techniques and genetic differences in performance, which are critically important for

sustainable development of macadamia remains limited in this region.

This survey in adaptability and nut production of macadamia in the northwest region was

an activity of the research project “Agroforestry for Livelihoods of Smallholder Farmers in

North-West Vietnam” funded by the Australian Center for International Agricultural

Research (ACIAR). The project has the overall aim of improving the performance of

smallholder farming systems in North-West Vietnam through agroforestry.

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STUDY OBJECTIVES

Objectives of the survey were to provide better understanding about adaptability, growth

and yield of macadamia in the Northwest region for sustainable development of this

species. Specific objective of the survey were to:

(i) evaluate growth and nut yield of macadamia in plantations in the Northwest region;

(ii) evaluate clonal variation in nut yield of macadamia in the Northwest in existing

clonal trials there; and

(iii) review plant propagation and cultivation techniques that are current applied in

macadamia plantations in the northwest and nearby regions of Vietnam to

recommend the most appropriate techniques

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METHODOLOGY

The survey was conducted in macadamia plantations in different locations in the Northwest

region. Details of these plantations were described in Table 1.

Table 1. Macadamia plantations evaluated in the study

Location Elevation

(m asl)

Total

area (ha)

Age

(years)

Plantation type

Mai Son, Son La 600 1 8 Clonal trial

Mai Son, Son La 600 0.3 8 Clonal archive

Chieng Sinh, Son

La city, Son La

670 0.5 8 Household plantation

Pung Tra, Thuan

Chuan, Son La

550 n.a. 8 Home garden

Muong Lay, Dien

Bien

270 n.a. 8 Home garden

Dien Bien city 500 n.a. 8 Home garden

Tan Uyen, Lai

Chau

570 1 3 Commercial plantation

n.a. = not available

The clonal trial of macadamia in Mai Son district, Son La province was planted in August

2004 by RCFTI in collaboration with the North West Forestry Science and Production

Centre. The trial tests 6 grafted clones of macadamia namely OC, A800, 246, 816, 842,

849, one control of unselected seedlings and a second control of a mixture of newly

selected clones from Ba Vi, Hanoi, propagated by stem cuttings. The trial design is a

randomized complete block design with 8 replicates and single tree plots of most

treatments, although the controls and clone OC were better-represented. The clonal archive

of macadamia at Mai Son was established in July 2004 by the Son La Centre of Plant,

Livestock and Fisheries Germplasm in Mai Son district. It includes clones OC and 246.

Both trials are located at elevation about 600 m a.s.l on ferralitc silty loam soil with pH of

4.8. The total rainfall in the area is about 1400 mm with most rain falling from April to

September and mean annual temperature is 220C. Both plantations were planted at a

spacing of 7 m x 7 m and received 50 kg of composted cattle manure and 500 g of NPK

fertilizer per tree at planting in a pit of 80 x 80 x 80 cm. The clonal trial additionally

received 500 g of NPK fertilizer per tree at age 2 years.

The household plantation in Son La city was planted in 2004 by a farmer, Ms. Pham Thi

Trang, with grafts provided by Son La Forestry Extension Service. Clonal identities were

not recorded, the plantation is probably a mix of different clones. This plantation was

planted at spacing of 5 m x 5 m and no fertilizer was applied.

The plantation in Tan Uyen district, Lai Chau province was planted in 2009 and managed

by Minh Son Co. Ltd. Grafts of several clones were provided by a company in Ba Vi

district, Hanoi Province. The plantation was planted at a spacing of 5 m x 5 m. Twenty kg

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of cattle manure and 500 g NPK per tree was applied just before planting in a pit of 80 x 80

x 80 cm.

In these plantations, data collection was carried out in August – September 2012. The

following data were collected:

- Growth traits: diameter ground level (Dgl), height (Ht), crown diameter (Dcr)

- Total weight of nuts per tree

Nut yields in the clonal trial at Mai Son were also recorded in 2011.

Data collected in the clonal trial at Mai Son were then analysed by ANOVA Single Factor

using DataPlus 3.0 (CSIRO) and Genstat 12 (VSN International) whereas data collected

from clonal archives were analysed by ANOVA Single Factor model in Microsoft Excel

2007. The analyses tested the significance of differences between treatments (clones and

controls) in growth traits and nut production

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RESULTS

Growth and nut yield of macadamia in the Northwest region

Results of investigation in macadamia plantations in the Northwest are presented in Table

2. All plantations investigated were planted as grafted trees (except for the control

treatments in the clonal trial) but clone identity was unknown except for the clonal trial and

clonal archieve in Mai Son district, Son La province. Macadamia plantations planted in

2004 in the Northwest showed good growth with mean height at eight years ranging from

4.2 to 5.0 m and crown diameter from 3.8 to 5.5 m. All six eight-year-old plantations

produced nuts, with average nut yield ranged from 1.9 to 4.2 kg per tree. The plantation

managed by Minh Son company in Tan Uyen district, Lai Chau province was 3 years old

at the time of investigation and showed very good growth with average height of 2.9 m and

crown diameter of 2.3 m but no nut production was recorded in the plantation. However,

we were told that flowers had been recorded on some trees in January 2012.

Table 2. Growth and nut productivity of macadamia in some locations in the Northwest

Location Plantation

type

Age

(year)

Dgl

(cm)

Ht

(m)

Dcr

(m)

Average nut

yield per tree

(kg/tree, 2012)

Mai Son, Son La Clonal trial 8 13.5 4.9 5.0 1.9

Mai Son, Son La Clonal

archive

8 12.5 5.0 5.5 3.2

Chieng Sinh, Son

La

Household

plantation

8 12.5 4.5 4.2 2.8

Pu Trang, Thuan

Chau, Son La

Home garden 8 13.2 5.0 4.5 2.6

Muong Lay, Dien

Bien

Home garden 8 14.3 5.1 5.0 4.2

Dien Bien city Home garden 8 13.8 5.0 4.5 3.9

Tan Uyen, Lai

Chau

Commercial

plantation

3 6.5 2.9 2.3 0

Among the above plantations, the clonal trial and clonal archive in Mai Son and plantation

managed by Minh Son company in Tan Uyen district, Lai Chau province had fertilizer

applied and were weeded in the the first 2-3 years. In the clonal trial, macadamia was

grown over coffee and was starting to shade out the coffee at age 8 years. The two

plantations at Mai Son were planted at spacing of 7 m x 7 m. The trees in these two

plantations were generally healthy, canopies were not closed and fruits were found on the

lower branches of the crowns.

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The small householder’s plantation in Chieng Sinh commune, Son La city was planted in

2004 with a spacing of 5 m x 5 m, and grafts were provided by Son La Agriculture

Extension Service. There was no fertilizer applied prior to or after planting and no other

crops were planted underneath the trees. The trees were generally healthy with average

height of 4.5 m. Almost all trees bore nuts in 2012, with an average of 2.8 kg per tree.

However, in this plantation the canopy was already closed, lower branches had started to

die and fewer nuts were observed in the lower part of the crown.

There were three other home gardens planting of macadamia: one in Pu Trang commune,

Thuan Chau district, Son La province; one in Muong Lay district, Dien Bien province; and

one in Dien Bien Phu city, Dien Bien province with 2-4 trees. At the time of investigation,

the trees looked very healthy and had provided heavy fruit yields in 2012, estimated at 3.9

– 4.2 kg per tree.

Since 2011, some larger scale macadamia plantations have been established in the

Northwest including the following locations:

- Quai Toi commune, Tuan Giao district, Dien Bien province: 5 ha, planted in 2011

- Ta Leng commune, Dien Bien Phu city: 14 ha, planted in 2012

- Ban Bo commune, Tan Uyen district, Lai Chau province: 50 ha, planted in 2012

All plantations were planted using grafts provided by a company in Ba Vi district, Ha Noi

province. However, clonal identity was not maintained, as different clonal lines were

mixed in the nursery before delivery to the plantations. During the survey, all these

plantations showed high survival rates of more than 90% and good growth.

At the time of investigation, no pest and disease symptoms were recorded either in

nurseries or any parts of the trees e.g. stem, branch, leaf, flower and fruit in the plantation.

Macadamia in clonal trial in Mai Son mixed with Coffee

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Clonal variation in growth characters in the clonal trial

Growth characteristics of clones and control treatments at 8 years in the clonal trial at Mai

Son are presented in Table 3. All clones had high survival percentage (87.5 – 100%). There

were no significant differences between treatments in any growth parameters. The results

showed good adaptability of all clones, and the seedling and cutting controls.

Table 3. Growth of 8 year old macadamia clones at Mai Son, Son La

Treatment Survival

(%)

Dgl (cm) Ht (m) Dcr (m)

Mean CV (%)

Mean CV (%)

Mean CV (%)

849 87.5 14.2 8.6 5.1 4.8 4.7 1.1

816 100 14.1 15.7 5.0 1.9 5.5 3.4

246 100 13.8 4.5 4.9 8.3 4.9 13.3

OC 100 13.7 4.7 4.9 7.6 4.9 9.5

A800 87.5 12.9 4.4 4.8 3.9 4.9 8.1

842 87.5 12.6 6.7 4.8 3.7 4.9 6.0

Control1

87.5 13.5 10.9 5.0 2.3 5.0 10.9

Control2

87.5 13.6 4.5 4.9 6.9 4.9 6.2

Grand Mean 13.6 4.9 5.0

Fpr

0.064 0.074 0.164

Control1: seedling; Control2: mix of cuttings from high yield selected trees in Ba Vi,

Hanoi

Clonal variation in nut yield in the clonal trial

Nut yield of macadamia in the clonal trial at Mai Son are presented in Table 4. There was a

strong decline in nut yield of most treatments from 2011 to 2012. The average yield across

the entire trial in 2011 was 3.3 kg per tree while the average yield in 2012 was only 1.9 kg

per tree. There were significant differences in nut yield among the genetic treatments (the

different clones and two controls) in 2011 and 2012 (Table 3).

There were also slight changes in rankings of treatments from 2011 to 2012. In 2011, the

best yielding clones were 246, OC, 842, 816, A800 and 849, and the seedling control

treatment yielded no nuts. In 2012, yields decreased in most treatments except clone 816

and the seedling control treatment, which displayed incrased yields. Although yields

decreased, clone OC, 246 and the cutting mixed of selected clones from Ba Vi (Control 2)

were highly ranked in both years. Clone 842 which ranked fourth in 2011 decreased to

sixth in 2012. Rankings of clones 246 and OC remained stable over the two years while

clone 816 remained stable in both ranking and yield over the two years. Clone 842 was the

least stable both in rank and yield. Clone 849 was the worst performer over the two years,

yielding virtually no nuts.

XX

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Table 4. Nut production of macadamia in the clonal trial at Mai Son

Treatment

Total

number

of trees

2011 2012

Number

of nut

bearing

trees

Average nut

productivity per

tree (kg/tree)

Number

of nut

bearing

trees

Average nut

productivity per

tree (kg/tree)

Mean CV (%) Mean CV (%)

842 6 5 3.2 31 2 0.6 67

849 6 0 0 0 3 0.2 21

816 10 8 2.3 13 8 2.5 16

A800 6 3 2.1 20 0 0 0

246 5 5 6.2 23 5 3.2 14

OC 17 17 5.6 32 15 3.6 23

Control1 15 0 0 0 12 1.9 43

Control2 14 14 6.9 56 10 2.9 34

Fpr 0.006 0.014

Mean 3.28 1.93

Control1: seedling; Control2: mix of cuttings from high yielding selected trees at Ba Vi,

Hanoi

XXXX

Clone 246 in Mai Son – Macadamia start shading out Coffee

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Clonal variation in the clonal archive

Table 5. Growth and nut productivity in clonal archive Mai Son, Son La

Clone Dgl (cm) Dcr (m) Ht (m) Nut Yield (kg/tree,

2012)

OC 12.4 4.3 4.6 3.3

246 12.6 4.2 4.4 3.1

Fpr 0.684 0.719 0.174 0.597

A total of 30 trees of the two clones OC and 246 were planted in the clonal archive in the

nursery of Son La Plant, Livestock and Fisheries in 2004. As shown in Table 5, the two

clones did not differ significantly in growth traits or nut yield. Mean productivity in 2012

was 3.1 – 3.3 kg of nuts per tree.

Macadamia in nursery in Son La Germplasm Centre

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DISCUSSION

Adaptability and productivity of macadamia in the Northwest

The high survival rate and reasonable nut production of macadamia in different locations

in Northwest Vietnam show that this species can be planted for nut production in this

region.

However, to develop this species as a commercial fruit species in the Northwest, it is

important to understand the ecological requirement of macadamia. Macadamia is reported

by a majority of authors to display best growth at mean annual temperatures between 20°C

and 25°C with annual rainfall from 1500 mm to 2500 mm (Allemann & Young, 2006;

Quinlan & Wilk, 2005; Trochoulias & Lahav, 1982). Prolonged exposure to temperature

above 350C causes bud break and chlorosis, and to temperatures below 10

0C delays growth

(Trochoulias & Lahav, 1982). Macadamia is somewhat sensitive to frost, which will kill

young trees and damage flowers and foliage of older trees (Quinlan & Wilk, 2005) so

mean daily minimum temperature of the coldest month should be above 30C (Allemann &

Young, 2006). Table 6 shows climatic conditions of areas in Vietnam where macadamia is

reported to have good growth and nut production and recommended suitable climatic

conditions in other countries. Based on this information and using Vietmap which is

Vietnam climatic mapping program developed by Dr. Trevor Booth of CSIRO, the most

suitable regions for growing macadamia in Vietnam can be identified.

Table 6:. Climatic conditions of areas in Vietnam where macadamia is reported to

display flowering and nut production and recommended suitable climatic conditions in

other countries

Location or

Country

Mean annual

temperature

(0C)

Mean daily

maximum

temperature

of hottest

month (0C)

Mean daily

minimum

temperature

of coldest

month (0C)

Annual

rainfall

(mm)

Reference

NSW,

Australia

20-25 38 n.a 1200 -

2500

Quinlan &

Wilk (2005)

NSW,

Australia

20-25 30 – 35 10 – 15 n.a Trochoulias &

Lahav (1982)

New Zealand 16 – 25 29 3 n.a Allemann &

Young (2006)

Mai Son, Son

La

21.8 30.6 10.2 1440 Nguyen Trong

Hieu (1990)

Dien Bien Phu 21.8 31.5 11.2 1580 Nguyen Trong

Hieu (1990)

Krong Nang,

Dac Lak

23.1 33.9 17.1 1770 Nguyen Trong

Hieu (1990)

Ba Vi, Ha Noi 23.1 32.9 13.1 1840 Nguyen Trong

Hieu (1990)

Recommended

range for

planting

20 – 25 30 - 35 10 - 18 1400 -

2500

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macadamia in

Vietnam

Figure 1 shows areas with green color where climates are suitable for macadamia and areas

with red color where climates are unsuitable. Not all areas in the northwest are suitable for

macadamia. Some locations at high elevations in Lai Chau province such as Sin Ho, Phong

Tho and Muong Te districts and in Dien Bien province such as Tua Chua district have

average temperatures of the coldest month below 100C with absolute minimum

temperature sometimes falling to -50C (Nguyen Trong Hieu, 1990) so are therefore not

suitable for macadamia.

All three plantations assessed in Son La were located on flat land at elevations of 600-700

m a.s.l. Much of the land area in the Northwest region is at higher elevations. Growth and

yields observed in this study may not be applicable at higher elevations, where slower

growth and poorer yields may be expected. However, we suggest expanded testing of

macadamia in different areas in the northwest to establish upper altitudinal limits for good

growth across the region and better understand the factors affecting performance.

O’Hara (1957) suggest that macadamia plantations should be free from hot and dry winds

during the period of flowering and early nut formation, as exposure results in high abortion

of flowers and developing nuts. Plantation growers in the Northwest should be aware of

this information because some parts of the Northwest are affected by hot and dry wind

during the flowering months of January to April. Macadamia trees do not have a clearly

defined taproot and this makes young trees particularly sensitive to blow-downs in strong

winds (Quinlan and Wilk, 2005), although blow-downs have not been observed in

plantations in the Northwest to date.

Figure 1:. Areas (green color) that have suitable climatic conditions for

desired growing Macadamia in Vietam

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Selection of suitable soil type is also important for growing macadamia. Quinlan and Wilk

(2005) suggested that most soil types are suitable for the production of Macadamias,

provided they are well drained and have no restrictive layers in the top 1 m of the soil, and

that poorly-drained clay soils, saline soils, sulfur-rich soils and heavily laterized soil are

avoided. It is noteworthy that all six eight-year-old plantations inspected in our survey,

established across a range of sites and with varying rates of fertilizer application, grew well

and bore substantial nut yields with site mean yields in the range 2-4 kg per tree in 2012.

Variation in growth characters and nut production

The average productivity obtained across the surveyed plantations (2-4 kg per tree at age 8

years) is lower than recorded values in other areas in Vietnam at similar ages. Nguyen

Dinh Hai (2010) recorded average nut yield of 4.8 kg/tree (960 kg/ha) at age 6 years in

Krong Nang, Dak Lak province on fertile bazan soil, with the best clones (849, 741 and

246) yielding 7.2 kg/tree (1440 kg/ha). On a site of low fertility, with degraded and

shallow lateritic soil at Ba Vi, Ha Noi, average productivity reached 3.4 kg/tree (680

kg/ha) whereas best clones reached from 4.7 to 7.6 kg/tree at age 10 years (Mai Trung

Kien, personal communication).

Clones OC, 246 and 816 had the highest nut yield in Mai Son district with average nut

yield ranging from 2.5 to 3.3 kg per tree at both sites, equivalent to 500 – 660 kg/ha. Yield

variation between years in fruit trees is not uncommon as fruiting is collectively influenced

by many factors including year-to-year environmental differences.The lower nut yield in

2012 in the clone trial at Mai Son may have been due to hot and dry winds in Janurary

2012 when the trees were flowering (Mr. Ha Van Tiep, personal communication). The hot

and dry wind may have caused abortion of flowers, especially in clones for which peak

flowering was at the time of the winds. We were advised that clone 842 flowered in

January at the time of the dry winds and this may be the cause of the large reduction in

yield in this clone in 2012. Many areas in the Northwest are subjected to present of hot and

dry wind in December – February, therefore shelter belt trees around macadamia farms are

suggested to minimize hot and dry wind effects. We were also advised that the 2011 year

was conducive to heavy macadamia crops, because a cold winter led to synchronised

flowering of different clones, and spring rains were relatively light, so flowers were not

rain-damaged. We were also informed that winter weather conditions in the northwest vary

strongly from year to year. This should be taken into account when selecting clones for

farm planting and when forecasting long-term yields from plantations.

Macadamia is an outcrossing species. A farm planting requires more than one good clone

to enable cross-pollination, for high fruit yields. It is important to select compatible clones

with overlapping flowering time to ensure cross-pollination. However, our yield survey

shows that even very small plantings of as few as 2-3 trees in home gardens can give good

nut yields. Unfortunately, the clonal identity in these small home-garden plantings is not

known. It may be that some but not all clones can yield well under self-fertilization. Clonal

identities in these small plantings could be checked using molecular markers (SSRs) to

resolve this issue.

18

Commercial macadamia plantations in other countries attain much higher yields at greater

ages. For example, in northern New South Wales, Australia, average yields increase from

about 250 kg nuts per hectare in year 5 to 1000 kg per hectare in year 7 and 2000 kg per

hectare in year 10. However, such high yields are sustained by heavy and repeated

fertilizer application to orchards (Quinland and Wilk, 2005). It will be important to

continue to monitor the first macadamia plantations in the Northwest over the next 3 or so

years to see whether nut yields increase over time. Such increase will determine the

economic viability of macadamia as a cash crop. We suggest a fertilizer trial that applies

different rates of fertilizer to different replicates in the Mai Son clonal trial to examine the

effect of fertilizer application on nut yields.

Management issues for macadamia plantation in the northwest

Some successful commercial plantations have been established in the Central highlands

region of Vietnam. Fertile, well-structured bazan (red clay-loam) soils and level or gently

sloping terrain, ideal climatic conditions, and experience with intensive management of

coffee plantations would help to explain the success obtained there there.

Adoption of macadamia in the Northwest region on sloping land with poorer soils by

farmers who are poor and unfamiliar with intensive crop management techniques poses

major challenges. Among macadamia plantations planted in 2004 in the Northwest, the

clonal trial and clonal archieve which are managed by government institutes can be

considered as being intensively managed, with substantial fertilizer applied at planting and

good weed control. Small household plantations in Son La and Dien Bien provinces which

received less fertilizer and weed control were less intensively cultivated. Growth and initial

nut yield of those plantations were comparable although they were planted at different

locations. The well drained silty loam soils with relatively high organic matter on which

these plantings were established may explain the good growth and nut yield in these

plantations in the absence of added fertilizer.

Inter-cropping may be a good option in macadamia cultivation to bring early cash flows to

farmers. In the clonal trial in Son La, macadamia trees are intercropped with coffee and

both species were planted at the same time. At age 8 years, macadamia trees are starting to

shade out the coffee and will subsequently decrease coffee yields. In our view,

interplanting of macadamia and coffee with planting at the same time may not be a good

combination because both species have wide crowns and long rotations, about 10-15 years

for coffee and 20-30 years for macadamia. Once the coffee crop is shaded out by

macadamia, coffee yields will decrease. As an alternative, in the Central highlands, farmers

planted macadamia in existing coffee plantations 3-5 years before the end of coffee

rotation by removing several rows of coffee and planting the macadamia trees in the spaces

created. After 3-5 years when the macadamias start shading coffee, farmers then remove

the remaining coffee trees (Nguyen Dinh Hai, 2010).

19

Newly planted macadamia in a 12 year low productivity coffee plantation in Dak Lak

Growing of annual crop such as ground nut, maize, casava or upland rice underneath

macadamia for the first 3 - 4 years before canopy closure to provide immediate income to

farmers should be considered as an option for the Northwest.

Macadamia plantation on the terrace in Ba Vi, Ha Noi

Macadamia planted on the terrace at Ba Vi, Ha Noi

All plantations investigated were located on flat land while most landscapes in northwest

are characterized by steeply sloping mountainous topography. There were no macadamia

plantings on steep slopes that we could evaluate. It is anticipated that many problems may

Figure 8. Macadamia planted on the terrace in Ba Vi

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occur when planting macadamia on steep slope, for example planting and maintenance

difficulties, soil erosion, difficulties in nut collection and transport. A pilot plantation of

macadamia on a steep hillside at Ba Vi, by making terraces along the contour and planting

trees on the terraces with planted ground cover to stabilize the soil, is recommended to

provide a reference site for for future planting in the Northwest region. Advantages of

planting trees on the terrace are (i) ease of operation from planting, maintenance and nut

collection; (ii) reduced soil erosion. Further, annual crops can be planted between terraces

and on the terraces in the first 3 years underneath the macadamia plantation. However,

costruction of the terraces would require major investment and this need to be accounted in

development of macadamia in the Northwest.

Growth and nut yield of home garden macadamia in our survey were reasonable and it can

be an alternative for small scale development of macadamia in the Northwest as it is easy

to manage from planting, maintaining and nut collection and less intensive labor and fewer

resources are required. Home garden planting may help to improve communities’

knowledge on this species before mass planting at large scale. Although home garden

planted macadamia may not bring high commercial value to farmers, it can be an

additional food source for the family because of its high value of nutrient content.

Another issue that needs to be taken into account when developing macadamia in the

Northwest is the attack of rodents such as rats, squirrels. It was reported that rats and

squirrels were a big challenge in Ba Vi as they eat mature nuts on the trees or on the

ground.

A final but very important issue for macadamia development in the northwest is

propagation. Vegetative propagation of high quality planting materials is important for

improving nut yields, as shown in the clonal trial at Mai Son where unselected seedlings

yielded very poorly at age 7 and 8 years. Grafting and cutting propagation techniques are

now available at the Institute of Forest Tree Improvement and Biotechnology, Vietnam

Academy of Forest Science. The techniques are simple so that local nurseries with

Macadamia in a home garden in Muong Lay, Dien Bien

21

relatively good infrastructure are able to manage them. Grafted trees with good root

systems are ideal for planting but expensive, while cuttings may be a reasonable choice.

CONCLUSIONS AND RECOMMENDATIONS

Macadamia showed good adaptability and reasonable nut yields in clonal trials, household

plantations and home garden planting at elevation 300 – 700 m a.s.l in the Northwest of

Vietnam. Clones did not differ in growth traits but there were significant different in nut

yield among clones and controls in a clonal trial in Mai Son district, Son La province, with

unselected seedling controls yielding poorly. Clones OC, 246 and 816 had highest and

year-wise stable nut yields and are recommended for planting in flat land at elevations up

to 700 m a.s.l. with deep and fertile silty loam soils in the Northwest.

In summary, some recommendations for sustainable development of Macadamia in the

Northwest are highlighted:

- Mixed plantings of better performing clones OC, 246 and 816 to ensure maximum

cross-pollination between trees in macadamia farms to provide high and stable nut

yields

- Further testing of clonal adaptability and yield in different areas, especially in

higher elevation (above 700 m) to provide better understanding of the adaptability

and yield of clones in different areas in the Northwest

- Inter-cropping in the first year can be a reasonable choice in macadamia cultivation

to ensure maximum returns to the grower. However, selection of inter-cropped

species and inter-cropping method needs to be further studied.

- On the steep slope sites, pilot plantations using known terracing techniques may

need to be established as demonstration for local people to understand the

importance of terracing techniques on steeply sloping sites in preventing soil

erosion and maintaining sustainable nut yield

- We suggest fertilizer/manure rate application trials to determine appropriate

schedules to maintain growth and nut yield in different major soil types in the

potential areas in the Northwest. The critical issue to be investigated in these trials

is whether fertilizer applications are needed to maintain nut yields from age seven

years onwards, once trees start yielding crops. It appears that heavy fertilizer

application is not required for good early growth in the plantations surveyed to

date.

22

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