Journal Search Engine

ISSN : 1229-3857(Print)
ISSN : 2288-131X(Online)

Korean Journal of Environment and Ecology Vol.29 No.6 pp.842-849
DOI : https://doi.org/10.13047/KJEE.2015.29.6.842

Effects of Rare-earth Fertilizer on the Shoot Cuttings’ Rooting of Vitex rotundifolia L. and Tamarix chinensis Lour.1

Chong Min Park²*, Kyu Kwan Jang³

교신저자 Corresponding author: Tel: +82-63-270-2639, Fax: +82-63-270-2592 , cmpark@jbnu.ac.kr

Received July 21, 2015 Review October 1, 2015 Accepted November 12, 2015

Abstract

This study investigated the effects of rare-earth fertilizer on the shoot cuttings’ rooting of Vitex rotundifolia L. and Tamarix chinensis Lour. The shoot cutting test was carried in 2008 and the main results are summarized as follows. The rate of rooting and the average roots increased in both number and length when rare-earth fertilizer is treated in V. rotundifolia and T. chinensis in comparison to those of the untreated control plot. In particular, when rare-earth fertilizer is diluted with water 1/2500, the rooting outstandingly increases. This result is almost similar to the effect of the rooting stimulant, IAA. Although there is no differentiation in its rooting rate according to the density, the rooting of T. chinensis shows a 100 percent effect on in the entire treated plot but not in the untreated control plot, so it is usable as a rooting stimulant. As for shoot cuttings’ rooting, depending on the time immersed in diluted solution of rare-earth fertilizer, both V. rotundifolia and T. chinensis showed relatively higher percentages in all treatment plot immersed for 60 minutes than for 10 minutes. In conclusion, considering the results of the rooting percentage and the average number and length of roots of V. rotundifolia and T. chinensis, the shoot cuttings’ rooting appeared higher in percentage when they were immersed in the rooting stimulant for sixty minutes with a lower density than 1/2500. This result shows that rare-earth fertilizer can be utilized as an alterative for IAA rooting stimulants currently available in the market.

Key Words : ROOTING RATE , ROOTING STIMULANT , NUMBER AND LENGTH OF ROOTS

희토광물계비료가순비기나무와위성류의 삽목발근에미치는영향1

박 종민²*, 장 규관³

²Dept. of Forest Environmental Science, Chonbuk National University. 568 Baekjedaero Deokjingu Jeonju-city, 54896, Korea
³Botanical Garden of Wonkwang University. Iksan-si, 54538, Korea
()

초록

본 연구는 순비기나무와 위성류의 삽목증식에 있어서 희토광물계 비료가 발근성적에 미치는 효과를 구명하기 위하여 수행되었다. 삽목시험은 2008년에 수행되었으며, 그 결과를 요약하면 다음과 같다. 순비기나무와 위성류의 발근율, 평균 뿌리 수, 평균 뿌리길이는 희토비료를 처리할 때 무처리 대조구에 비해 증가한 경향을 보였다. 특히, 희토비료 1/2500 희석액의 발근효과가 뚜렷하였다. 이러한 성적은 IAA 발근촉진제에 상응하는 결과이었다. 다만, 위성류의 발근 율은 무처리 대조구를 제외한 모든 처리구에서 100%의 발근율을 보임으로써 희토비료 희석액 농도에 따른 발근율의 차이는 없었으나, 발근촉진 효과는 기대할 수 있었다. 희토 희석액의 침지시간에 따른 삽수의 발근성적은 순비기나무와 위성류의 모든 처리구에서 10분 침지한 처리구보다는 60분 침지한 처리구에서 상대적으로 높은 경향을 보였다. 따라서 순비기나무와 위성류의 발근율, 평균 뿌리수 및 평균 뿌리길이 등을 분석한 결과를 기준으로 희토 처리 수준 및 효과를 판단하면, 발근촉진제 처리농도는 희토 1/2500 이하의 저농도에서 60분 침지할 경우 삽수 발근 향상에 충분한 효과가 있었다. 따라서 시험에 사용한 희토광물계 비료는 시판되고 있는 IAA 발근촉진제 대체품으로서의 이용 가능성을 확인할 수 있었다.

키워드 : 발근율 , 발근촉진제 , 뿌리 수 및 길이

This article has been cited by 0 article in crossref

Cited-By

Funding:

INTRODUCTION

Rare-earth indicates the existence of 17 elements including 15 elements of lanthanides, yttrium (Y), and scandium (Se) of the periodic table. It exists in water and air of the Earth in tiny quantities(Lee et al., 2009). Humans consume about 2.25㎎ of rare earth every day in daily life; 0.002~0.057% of it is found in general plants; and 0.015~0.025% is in soil. Rare earth has unique chemical characteristics, showing various physiochemical reactions such as reduction, control of nutrition absorption, and catalysis reacting to molecules within cells (Lee et al., 2009). Such physiochemical reaction of rare earth is known to have several effects such as chromophorization, photosynthesis, and enhancement of resistance to disasters by affecting the growth and development of plants(Heo et al., 2003b).

When rare earth was treated in beets, its photosynthetic rate increased greatly, and vitality of Amylase and IAA increased as well(Xie, 1991; Zhang, 1991); it increased rice production by an average of 9.5% per 10a(Man and Lee, 2000) during the duration of rice's growth. In addition, Zhang and others(2000) proved that rare earth has enhancement effects on crop’s resistibility on drought, coldness, and harmful insects because it catalyzes the formation of proline, an indicator that verifies the resistibility against the disastrous environment of plants. Recently developed rare earth fertilizer in Korea is known to have the effect of increasing tolerance for drought, humidity, heat, and cold and strengthening stems which prevents lodging(Zhang, 2001). Consequently, studies on the effects of rare earth trials on crops are actively in progression(Heo et al., 2003a; Heo et al., 2003b; Jin, 2008; Lee et al., 2009).

However, there are very few studies on the effects of rare earth trial using trees as subjects. There is a record of an experiment by Park and others(2013) on the effect of trials of rare earth mineral kingdom fertilizer on salt resistance of Pinus strobus and P. thunbergii. In this study, compared to that of an untreated control plot, the survival rate of Pinus strobus increases the most when treated with 1/2000 diluted solution of rare earth once, as well as that of P. thunbergii which increases the most when treated twice with 1/2000 diluted solution. Furthermore, the survival rate of both species increased in 200mM of highly concentrated NaCl treatment plots compared to the untreated control plots. This result shows the effect of treatment of rare earth fertilizer.

Meanwhile, in the progression of business, the Saemangeum reclamation project district located in Jeollabuk-do should make a tree belt and green zone in stages and according to the practical use of land purpose; thereby, it requires a great number of trees. Landfill soil on the reclamation area is physically and chemically very poor so the salt tolerance of trees needs to be considered first when planting since rooting and growth of trees are unfavorable in this soil. Various planting base composition techniques such as using earth from other land, ground fill-up, drainage, desalination, and soil improvement through organism addition must be used to accomplish the goal(Yu, 1990; Koo and Ahn, 1993).

This study was started in order to study the effects of rare earth fertilizer, known for enhancing resistibility on various disasters through physiobiochemical mechanism, on uprooting as a part of the tree proliferation method.

MATERIALS AND METHODS

1.Testing materials and cultivation condition

This study uses Vitex rotundifolia L and Tamarix chinensis Lour as testing materials which are known to have high salt tolerance, according to preceding studies (Park and Lee, 2004; Park and Kim, 2006; Park et al., 2009; Park and Park, 2001). It uses cutting slips of hardwood of V. rotundifolia collected at a V. rotundifolia. habitat near Jakeundang shore of Gyeokpo-ri, Byeonsan-myeon, Buan-gun, Jeollabuk-do on May 9th, 2008. And as for T. chinensis, it uses a sample collected from Shin-ri, Sanggwan-myeon, Wanju-gun, Jeollabuk-do on October 6th, 2008.

This study proceeded at the nursery green house of the Experiment Forest of the College of Agriculture & Life Sciences of Chonbuk National University. In the case of V. rotundifolia, its cuttings were conducted on May 10th of 2008; those of T. chinensis on Octorber 7th of 2008. For the cutting bed, artificial soil (Vermiculite: Perlite = 1:1, ratio of volume) was made and put into plastic square pots. The cutting bed was managed by watering regularly with sprinklers, by maintaining humidity at 80 or a higher percentage, and by using a blackout curtain to block sunlight by 75%.

2.Rare-earth and IAA treatment

Rare-earth was diluted according to each and different concentrations of ‘Hito-Dajoa' fluid provided by Dongsung N.C.T. Co., Ltd.; the concentration of IAA rooting stimulant, which shows excellent rooting percentage in a study of cutting test of V. rotundifolia and T. chinensis (Park and Lee, 2004; Park and Park, 2001), was used. The treatment of rare-earth fertilizer and IAA is as the following:

1)Rare-earth treatment

There are four levels in treatment concentration: 1/1,000, 1/1,500, 1/2,000, and 1/2,500. The immersion time of cutting slips in diluted solution of rare-earth fertilizer is distinguished by two levels: 10 minutes and 60 minutes. The treatment method is as follows; the bases of cutting slips were immersed in the diluted water combining the concentration of diluted water and immersion time and planted in cutting beds.

2)IAA treatment

The concentration of IAA was 100ppm, and the immersion time was 24 hours. The treatment method entailed planting in a cutting bed after immersing bases of cutting slips in IAA solution for 24 hours.

3)Plot design

Testing bed was designed by triple time in each treatment and cutting slips were managed at an amount of 200 units in each testing bed.

3.Research categories and methods

In order to analyze the effect on rooting of rare-earth fertilizer according to the concentration of rare-earth diluted solution and the time of immersion, this study measured and analyzed the test result 60 days after cutting. Figure 1 shows status of test plot arrangement and rooting score of Vitex rotundifolia cutting slips at 60 days after cutting. Measurement categories are the survival rate and withering rate, rooting rate and number of rooting, measurement of root length(the longest, the shortest, and the average length of roots), result of untreated ones and IAA, and comparison analysis. Statistical analysis of variance was conducted using PROC GLM procedure in the SAS statistical package (SAS Institute, 2010).

4.Statistical analysis

An analysis of variance (ANOVA) test was performed to determine whether there were significant differences in rate of rooting, number of roots and length of roots means because of the treatment concentration and immersion time of cutting slips in diluted solution of rare-earth fertilizer. A significance level of 0.05 was used for both the ANOVA procedure(SAS, 2003).

RESULTS AND DISCUSSION

1.Rooting score of Vitex rotundifolia

With the hardwood of V. rotundifolia, various concentrations of rare-earth fertilizer diluted water and different immersion times of cutting slip bases were applied to be planted in spring, and 60 days later the rate of rooting, average number of roots and their length were measured; the results are as follows in Table 1.

1)Rate of rooting

The rate of rooting according to the concentration of diluted solution of rare-earth fertilizer showed 62% in untreated control plots, 69% in 1/1000 of diluted solution of rare-earth, 70% in 1/1500 diluted solution, 74% in 1/2000 diluted solution, and 85% in 1/2500 diluted solution. The rate of rooting in IAA 100ppm treated plots was 82%. In the rate of rooting, the significant difference within treatments was showed at 95% probability. In other words, rates of rooting of all treated plots including rare-earth fertilizer and IAA all increased compared to untreated control plots. In particular, treated plots immersed in 1/2500 diluted solution of rare-earth fertilizer for 10 and 60 minutes showed a 22~24% greater effect of rooting catalysis compared to the untreated control plots. It is an effect exceeding rate of rooting of the IAA rooting stimulant.

The rate of rooting according to the time of immersion of diluted solution of rare-earth fertilizer showed an average of 73.5% when immersed for 10 minutes and an average of 75.5% when immersed for 60 minutes; it generally showed a higher rate of rooting in 60 minutes immersion.

In a spring cutting test of hardwood of V. rotundifolia, Park and Park(2001) reported a 42.2% rate of rooting in untreated control plots, 76.7% in Rootone powder attached ones, 52.2% in Sucrose 2% control ones, 66.7% in NAA 50ppm ones, 75.6% in NAA 50ppm+Sucrose 2% control ones, 78.9% in NAA 100ppm ones, 82.2% in NAA 100ppm+Sucrose 2% ones, 81.1% in NAA 200ppm ones, 85.6% in NAA 200ppm+Sucrose 2% ones, and 82.2% in NAA 400ppm control ones and NAA 400ppm+Sucrose 2% ones, all of which recorded a minimum of 42.2% and a maximum of 85.6% of rate of rooting.

The enhancement effect of cuttings’ rooting effect of diluted solution of rare-earth fertilizer can be evaluated similarly to the rooting effect of Rootone powder and NAA which Park and Park(2001) used.

2)Number of roots

The average number of roots according to the concentration of diluted solution of rare-earth fertilizer is 5.19 in untreated control plots, 7.38 in rare-earth 1/1000, 7.83 in 1/1500, 8.25 in 1/2000, and 8.37 in 1/2500. In the IAA 100ppm treated plots, the largest average number of roots, 8.97 was recorded. In the average number of roots, the significant difference within treatments was showed at 95% probability. Being different from the rate of rooting, IAA 100ppm control plots recorded the largest number of roots, but all rare-earth fertilizer treated plots showed a large increase in the number of roots compared to standard plots. Especially, the number of roots in rare-earth 1/2500 diluted solution showed a high effect equivalent to the IAA stimulant.

The number of roots according to the immersion time in the diluted solution of rare-earth fertilizer was 7.51 for 10 minutes on average, and 8.40 for 60 minutes, which means that immersed plots for 60 minutes had more roots than those of 10 minutes.

Park and Park(2001) conducted spring cutting of V. rotundifolia hardwood, and reported that the average number of roots of each cutting slip was 2.0 in untreated standard plots, 3.7 in Rootone powder attached treated plots, 2.3 in Sucrose 2% ones, 2.6 in NAA 50ppm ones, 2.7 in NAA 50ppm+Sucrose 2% ones, 3.7 in NAA 100ppm ones, 5.4 in NAA 100ppm+Sucrose 2% ones, 4.6 in NAA 200ppm ones, 6.0 in NAA 200ppm+ Sucrose 2% ones, 5.7 in NAA 400ppm ones, and 4.0 in NAA 400ppm+Sucrose 2% ones.

In this study, the number of roots was 5.19 even in untreated control plots, which is slightly more than the average roots of the study conducted by Park and Park(2001), and this is due to the difference of test environments. However, the result that all the diluted solution of rare-earth fertilizer had 7~9 roots was far more than the number of roots achieved by Park and Park. Cutting slips with more roots are significant, because they can be an important factor that gives a good influence on the root-taking and growth of seedlings.

3)Length of roots

The average root length according to the concentration of diluted solution of rare-earth fertilizer is 2.10cm in untreated standard plots, 2.63cm in rare-earth 1/1000, 2.92 cm in 1/1500, 3.29cm in 1/2000, and 3.36cm in 1/2500. In IAA 100ppm treated plots, the average length was 4.09cm. In the average root length, the significant difference within treatments was showed at 95% probability. Like the number of roots, IAA treated plots showed the highest results in the length. Furthermore, compared to standard plots, all rare-earth fertilizer treated plots indicated increased length of roots. Especially, the length of root in rare-earth 1/2500 showed a high effect equivalent to that of IAA treated plots.

The length of roots by immersion time in diluted solution of rare-earth fertilizer is 2.78cm on average for 10 minutes, and 3.31cm for 60 minutes, meaning that the length of roots tends to increase in general in the case of 60 minute immersed plots.

Park and Park(2001) reported that the average length of roots of each unit of hardwood cutting of V. rotundifolia was a minimum of 1.5cm and a maximum of 3.4cm. In this study, the result was a minimum of 2.63cm and a maximum of 3.36cm in rare-earth fertilizer treated plots, which showed no significant difference from the previous study.

Seen above, when the effect of rare-earth fertilizer treatment is judged based on the rate of rooting, and the number and the length of root of V. rotundifolia hardwood cutting slips, it was found that a low concentration of rare-earth 1/2500 with 60 minutes' immersion had enough of an effect to increase rooting. In addition, rare-earth fertilizer turned out to be a competitive alternative to IAA root stimulant currently available on the market.

2.Rooting score of Tamarix chinensis

With the subjects of T. chinensis hardwood, the concentration of diluted solution of rare-earth fertilizer, and the immersion time of cutting slip bases were divided into various types to be planted in autumn, and 60 days later, the rate of rooting, average number of roots and their length were measured; the results are as follows in Table 2.

1)Rate of rooting

The rate of rooting according to the concentration of diluted solution of rare-earth fertilizer showed 95% in untreated standard plots, and 100% in all the treated plots of diluted solution of rare-earth fertilizer and IAA treated plots. There was not the significant difference within treatments in the rate of rooting. In other words, all treated plots except the standard plots had a 100% rate of rooting, which means there is no difference in the rooting rate according to the concentration of rare-earth fertilizer and immersion time, but, compared to untreated plots, the possibility of rooting rate improvement could be expected.

Park and Kim(2006) had already conducted a autumn cutting test using T. chinensis hardwood. In their study, they used vermiculite+perlite as bed soil and planted cutting slips after dipping them in variously combined rooting stimulants IAA and NAA between 50~2300ppm. The result is that while standard plots showed a 40% rooting rate, the rooting rate of rooting stimulant treated plots increased, with a minimum of 60% (NAA 100ppm) and maximum of 100% (IAA 100ppm). In addition, they reported root stimulating effect according to various sorts of rooting stimulants and treatment concentration did not show any consistent tendency.

In this study, all the rare-earth fertilizer treated plots showed a 100% rooting rate which is the same score reported from the previous study of IAA 100ppm. With the result, it is possible to judge that rare-earth fertilizer has almost the same root stimulating effect as IAA and NAA.

2)Number of roots

The average number of roots according to the concentration of diluted solution of rare-earth fertilizer is 2.10 in untreated control plots, 2.65 in rare-earth 1/1000, 3.63 in 1/1500, 3.92 in 1/2000, and 4.04 in 1/2500. The IAA 100ppm treated plots achieved 4.61. In the average number of roots, the significant difference within treatments was showed at 95% probability. Like the case of V. rotundifolia, IAA treated plots recorded the highest result, and all rare-earth fertilizer treated plots showed an increased number of roots compared to standard plots. Especially, the number of roots in rare-earth 1/2500 diluted solution showed a high effect equivalent to IAA stimulant.

The number of roots according to the immersion time in the diluted solution of rare-earth fertilizer was 3.27 for 10 minutes on average, and 3.85 for 60 minutes, which means that plots immersed for 60 minutes achieved an increase in the number of roots in general.

The result of the study of Park and Kim(2006) demonstrated 2.2 roots in the standard plots from autumn cutting with T. chinensis hardwood, and a higher number of roots was found in all of the root stimulant treated plots than standard plots, with a minimum of 2.5 (Rootone powder) and a maximum of 4.3(NAA 800ppm).

3)Length of roots

The average root length according to the concentration of diluted solution of rare-earth fertilizer was 3.13cm in untreated standard plots, 3.28cm in rare-earth 1/1000, 3.63 cm in 1/1500, 3.96cm in 1/2000, and 4.31cm in 1/2500. In IAA 100ppm treated plots, the average length was 4.35cm. In the average root length, the significant difference within treatments was showed at 95% probability. All rare-earth fertilizer treated plots indicated an increased length of roots, and the length of root in rare-earth 1/2500 for 60 minutes showed the highest effect.

The length of roots by immersion time in a diluted solution of rare-earth fertilizer was 3.52cm on average for 10 minutes, and 4.07cm for 60 minutes, meaning that the length of roots increased in general in the case of 60 minute immersed plots.

Park and Kim(2006) conducted an autumn cutting using T. chinensis hardwood and reported that standard plots had 5.8cm and recorded its maximum length of 9.7cm (NAA 50ppm). They reported that root stimulant treatment was effective in root length increase but there was no consistent tendency. In this study, the length of root showed relatively poor results in comparison to the previous study.

Seen above, when the effect of rare-earth fertilizer treatment is judged from the rate of rooting, and the number and the length of root of T. chinensis hardwood cutting slips, it was found that concentration of rare-earth fertilizer demonstrated enough effect to increase rooting of cutting slips in 1/1000~1/2500 treated plots without a large difference. The higher the concentration of rare-earth fertilizer and the longer the immersion time, the more and the longer the average number and length increased slightly. Thus, rare-earth fertilizer proved to be an alternative product in substitution of NAA and IAA root stimulant currently available on the market.

Figure

Figure 1..

Status of test plot arrangement and rooting score of Vitex rotundifolia cutting slips

Table

Table 1..

Final rooting score of Vitex rotundifolia*

*Within each measurement variable, means sharing a common letter do not differ significantly at a ∞=0.05 according to Duncan’s Test.

Rare-earth treatment	Immersion time	Rate of rooting (%)	Number of roots (No.)	Length of roots (cm)
Control	-	62c	5.2±3.4c	2.1±1.3c
1/1000	10 minutes	66bc	6.8±3.9b	2.6±1.5bc
	60 minutes	72b	8.0±1.7ab	2.9±0.7b
1/1500	10 minutes	68bc	7.6±1.4ab	2.8±1.1b
	60 minutes	72b	8.1±2.0a	3.1±1.2b
1/2000	10 minutes	74ab	7.9±1.8ab	3.1±0.8b
	60 minutes	74ab	8.6±1.5a	3.5±1.6ab
1/2500	10 minutes	84a	7.8±3.1ab	3.0±0.8b
	60 minutes	86a	8.9±2.6a	3.7±1.4ab
IAA(100ppm)	24 hours	82a	9.0±2.3a	4.1±2.1a

Table 2..

Final rooting score of Tamarix chinensis*

*Within each measurement variable, means sharing a common letter do not differ significantly at a ∞=0.05 according to Duncan’s Test.

Rare-earth treatment	Immersion time	Rate of rooting (%)	Number of roots (No.)	Length of roots (cm)
Control	-	95	2.1±0.4c	3.1±1.5bc
1/1000	10 minutes	100	2.4±1.4bc	3.2±1.6bc
	60 minutes	100	2.9±1.1b	3.4±0.7bc
1/1500	10 minutes	100	3.4±1.5b	3.5±1.2b
	60 minutes	100	3.9±0.7ab	3.8±0.8ab
1/2000	10 minutes	100	3.6±1.8ab	3.8±1.3ab
	60 minutes	100	4.2±2.0a	4.1±2.3ab
1/2500	10 minutes	100	3.8±2.1ab	3.7±2.0b
	60 minutes	100	4.3±1.7a	4.9±1.1a
IAA	24 hours	100	4.6±1.3a	4.4±1.5ab

Reference

Bates LS , Waldren RP , Teare ID (1973) Rapid determination of free proline for water stress studies , Plant Soil, Vol.39 ; pp.205-207
Beadle CL Hall DO , Scurlock JMO , Balhάr-Nordenkampf HR , Leegood RC , Long SP (1993) Growth analysis , Photosynthesis and production in a changing environment, a filed and laboratory manual, Chapman & Hall, ; pp.36-46
Chun PK (2008) Effects of Rare-earth on the germination and growth of whole crop barley , A master’s thesis at graduate school of agricultural development, Chonbuk National University, ; pp.3-9(in Korean with English abstract)
Heo SN , Lee SW , Park HS , Kim SO , Park CS , Ryou JW (2003a) Effects of Rare-earth and nitrogen application on the growth and nitrate content of Chinese Cabbage , Bulletin of Agricultural College Chonbuk National University, Vol.34 ; pp.136-142(in Korean with English abstract)
Heo SN , Lee SW , Park HS , Cho KH , Park WY , Chung JK (2003b) Effects of Rare-earth on the growth, nitrate accumulation and insecticide remained in Spinach and Lettuce , Bulletin of Agricultural College Chonbuk National University, Vol.34 ; pp.143-149(in Korean with English abstract)
Koo BH , Ahn KY (1993) A study on the factors to cause defect of landscape plants in the reclaimed area of the southern and western seaside in Korea , Seoul Nat'l. Univ. J. Agric. Sci, Vol.18 (2) ; pp.83-93(in Korean with English abstract)
Lee JK , Yun SY , Jeong MW , Kim JK , Park HS , Im YC , Kim WH , Lee SH , Ji HJ (2009) Influence of Rare-earth on the productivity and values of forage of Crimson Clover and Hairy Vetch , Journal of The Korean Society of Grassland and Forage Science, Vol.29 (1) ; pp.19-24
Man G , Lee DW (2000) Influence of Rare-earth test on the enhancement of produce production and pesticide residue drop. International symposium on “Agricultural use of new material, Rare-earth mineral” , Institute of Agricultural Science & Technology Chonbuk National University, ; pp.11-21
Park CM , Kim YK (2006) A study on propagation and growth characteristics of Tamarix chinensis for development of plant using in coast environmental forests , Journal of the Korean Institute of Landscape Architecture, Vol.34 (3) ; pp.79-90(in Korean with English abstract)
Park CM , Lee SK (2003) A study on the growth characteristics of Vitex rotundifolia seedlings for extension of rehabilitation plant-Mainly on the tolerance to the salt concentration of soil , Journal of Korea Society Forest Engineering Technique, Vol.2 (3) ; pp.237-246(in Korean with English abstract)
Park CM , Park CS , Park WJ (2013) Effect of Rare-earth fertilizer on the salinity tolerance of Pinus strobus and P. thunbergii , Journal of Agriculture & Life Sciences, Vol.44 (2) ; pp.1-9(in Korean with English abstract)
Park CM , Park ES (2001) Growing characteristics and propagation of Vitex rotundifolia for development of rehabilitation plant in seaboard area , Korean Journal of Environment and Ecology, Vol.15 (1) ; pp.57-68(in Korean with English abstract)
Park JM , Park CM , Ezaki T (2009) Ecological study on the Vitex rotundifolia communities in Korea , Journal of the Japanese Society of Coastal Forest, Vol.8 (1) ; pp.17-23(in Korean with English abstract)
SAS (2003) SAS 9.1 TS Level 1M2 , SAS Institute, Inc,
Xie HG (1991) Research advancement on application of Rare-earth in agriculture , China Science Bulletin, Vol.36 (8) ; pp.561-565(in Chinese with English abstract)
Yu EY (1990) Survival rates of landscape trees at a Korea industrial seaside reclamation site-Industrial area in Inchun , A master’s thesis at graduate school of environmental science, Han Yang University, ; pp.37-47(in Korean with English abstract)
Zhang YS (1991) Effect of Rare-earth on the activity of some enzyme in sugar beet leaf and its relation to the growth , J. South Effects of Rare-earth Fertilizer on the Shoot Cuttings' Rooting of West Agric. Unive, Vol.13 (4) ; pp.-416(in Chinese with English abstract)
Zhang YS (2001) Study and application of Rare-earth for produce production. International symposium on “Agricultural use of new material, Rare-earth mineral” , Institute of Agricultural Science & Technology Chonbuk National University, ; pp.5-8(in Chinese with English abstract)
Zhang HJ , Bao YM , Zhang YS (2000) Application of Rare-earth in agriculture, animal husbandry and cultivating industry , Applied Rare-earth and Life Cooperation of Baodou-city, ; pp.35-80(in Chinese)