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Agriculture and Food Sciences Research 
Vol. 5, No. 2, 68-72, 2018 

ISSN(E) 2411-6653/ ISSN(P) 2518-0193 
DOI: 10.20448/journal.512.2018.52.68.72 

     

 
 
 
Forecasting Waste Agricultural Plastics Generation in the Republic of Korea and 
its Policy Implications 

 
Youngjae Chang1     

Geumsoo Kim2
     

 

 
( Corresponding Author) 

 
1Professor, Division of Management Science, Inje University, South Korea 
2Professor, Department of Global Commerce, Hoseo University, South Korea 

 

 
Abstract 

The generation of waste plastics mulch is predicted to decline after 2019 and then stabilize at 
around 200,000 tons per year. This is within the current gross treatment capacity of private and 
public facilities. However, the Korean Waste Agricultural Plastics (WAP) management system is 
vulnerable to market uncertainty, which might lead to uncontrollable accumulation of untreated 
waste plastics as experienced in 2005. Shifting from the KECO (Korea Environment Corporation)-
led system to a more flexible market-oriented system is recommended. 

 
Keywords: Waste agricultural plastics, Recycling, Waste management. 

 
Citation | Youngjae Chang; Geumsoo Kim (2018). Forecasting 
Waste Agricultural Plastics Generation in the Republic of Korea 
and its Policy Implications. Agriculture and Food Sciences Research, 
5(2): 68-72. 
History:  
Received: 7 June 2018 
Revised: 13 August 2018 
Accepted: 18 September 2018 
Published: 15 October 2018 
Licensed: This work is licensed under a Creative Commons 

Attribution 3.0 License  
Publisher: Asian Online Journal Publishing Group 
 

Contribution/Acknowledgement: Both authors contributed to the 
conception and design of the study. 
Funding: This study received no specific financial support. 
Competing Interests: The authors declare that they have no conflict of 
interests. 
Transparency: The authors confirm that the manuscript is an honest, 
accurate, and transparent account of the study was reported; that no vital 
features of the study have been omitted; and that any discrepancies from the 
study as planned have been explained. 
Ethical: This study follows all ethical practices during writing.   

 

 

Contents 
1. Introduction ...................................................................................................................................................................................... 69 
2. Korean WAP Management System .............................................................................................................................................. 69 
3. Forecasting Wap Generation ........................................................................................................................................................ 70 
4. Conclusion ......................................................................................................................................................................................... 71 
References .............................................................................................................................................................................................. 72 
 

 
 
 
 
 
 

 

 

 

 

 

 

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Agriculture and Food Sciences Research, 2018, 5(2): 68-72 

69 
 

 

1. Introduction 
Modern farming takes advantage of  a wide range of  plastics and large amounts of  WAP are inevitably 

generated. Vinyl-house horticulture and insulated rice seedbed preparation are practiced nationwide and, in 2015, 
approximately 320,000 tons of  WAP was generated. This figure has remained almost the same over the last decade. 
The collection rate has stagnated at just under 60%. Therefore, collection and proper treatment of  WAP, including 
recycling, is a serious social concern in Korea. 

In Korea, WAP are classified as municipal solid waste, the final treatment of  which is the responsibility of  the 
basic administrative districts (i.e., eup, myon, dong)1. Therefore, in principle, these districts have to collect and 
recycle or conduct final disposal (landfilling and incineration) of  WAP. However, farmers do not have sufficient 
incentives to take waste plastics to private collectors or public collection points voluntarily and the basic 
administrative districts do not have the resources to deal with the waste fully. Waste vinyl-house plastic coverings 
are relatively clean and thus well-collected and almost recycled through market. However, the most prevalent type 
of  waste plastics, mulching Low Density Polyethylene(LDPE) and High Density Polyethylene(HDPE), which 
accounted for 76% of  the total 322,964 tons of  waste generated in 2015, would create a serious problem if  left 
intact in fields. Uncollected and improperly treated waste plastics are detrimental to the environment and also 
undermine agricultural land productivity.  

For this reason, the KECO has established collection and treatment networks and subsidizes farmers and 
treatment firms in cooperation with local governments. In 2010, on average, 100 won per kg of  collected waste 
came from subsidies of  which 14 won was provided by the provincial government, 76 won by the city governments, 
and the remaining 10 won by the central government. However, this subsidization scheme has not been strong or 
flexible enough, resulting in insufficient and stagnated collection rates. As urbanization has advanced, now in farms 
only the old people are left. This trend is making it more expensive to bring waste plastics to collection points, but 
the level of  subsidies has remained almost the same for a long time. On the treatment side, there has sometimes 
been overcapacity and insufficient capacity at other times. This disequilibrium in market may be resolved by price 
adjustment. However, this takes time and there are highly likely to be negative impacts such as a backlog of  
untreated waste plastics. To ease this fluctuation in demand and supply KECO operates treatment companies and 
subsidized private treatment companies. The focus of  this paper is not on the design of  this system but only on the 
provision of  materials to aid discussion by estimating and predicting WAP generation and collection. 

The paper is organized as follows. In the next section, we provide an overview of  the Korean WAP 
management system, including time trends of  WAP generation and collection, WAP-related materials flow, and so 
on. In section 3, we forecast WAP generation and collection for the next 5 years and compare this with the current 
treatment capacity. We then discuss the policy implications of  our empirical results. Finally, Section 4 contains 
some concluding remarks. 
 

2. Korean WAP Management System 
2.1. Legal Position of  WAP in the Korean Waste Management System 

WAP is municipal solid waste and the collection and final treatment of  it is the responsibility of  the basic 
administrative districts in Korea. Therefore, farmers here do not have as strong an incentive for collecting and 
properly treating as farmers in Japan and Taiwan, who are responsible for the proper final treatment and thus 
almost all WAP is collected and treated via proper channels [1, 2].  
 

2.2. Materials Flow in WAP Management and KECO 
As shown Table 1 the total amount of  generated WAP has remained around 320,000 tons per year for the last 

decade. Mulching LDPE is the most prevalent type of  waste (approximately 40%), followed by HDPE (35%) and 
vinyl-house LDPE (20%). 
 

Table-1.  WAP Generation, Collection, and Treatment in Korea 

        Unit: tons 

Year Generation Collection Collection rate (%) Treatment Untreated Inventory 

2009 310,009 189,238 61.04 236,259 72,973 

2010 324,101 176,849 54.57 208,377 41,444 

2011 331,490 181,609 54.79 185,424 37,628 

2012 337,877 178,130 52.72 180,950 34,809 

2013 332,575 189,306 56.92 174,181 49,934 

2014 329,239 188,279 57.19 193,065 45,168 

2015 322,964 186,965 57.89 211,143 21,141 

        Source: KECO internal data 
 

Farmers are advised to bring any generated WAP to community collection points. At this stage local 
governments subsidize farmers to increase their collection rate, combining the subsidies from the KECO (or central 
government) and the provincial government. Designated private collectors then bring the collected WAP to 
KECO-operated storage facilities. (see Figure 1). The collection rate has not exceeded 60% for the last decade. 
What has contributed the most to the low collection rate was House LDPE (see Table 2), but this one was almost 
recycled voluntarily through market. A total of  72,000 tons of  mulching LDPE, HDPE, PVC and other waste 
plastics went uncollected, which is a real problem.  
 
 

 

 
1This does not mean that farmers are legally allowed to leave WAP in fields. They are legally prohibited from disposing waste improperly. 



Agriculture and Food Sciences Research, 2018, 5(2): 68-72 

70 
 

 

Table-2.  Collection Rate by Type (2015) 

               Unit: tons per year, % 

 Generation(a) Collection(b) Collection rate((b/a)*100) 

House LDPE 69,414 4,964 7.15 

Mulching LDPE 128,241 88,275 68.84 

HDPE 118,715 92,064 77.55 

PVC and others 6,594 4,914 74.52 

Total 322,964 186,965 57.89 

              Source: KECO internal data 

 
KECO has two options for the treatment of  collected WAP: KECO itself  treats or gets it done by private firms. 

As of  2016, KECO operates seven treatment facilities with a treatment capacity of  80,000 tons per year. In 2015, 
just over 100 thousands tons should be left for private firms. Six of  treatment firms have the capacity to process 
6,000-8,000 tons each per year. KECO auctions off  some part of  the remaining WAP to private firms and for the 
other part of  the remaining WAP, KECO subsidizes private firms to treat. The treatment subsidy was introduced 
in 2005 when the volume of  untreated WAP became a serious social concern. The subsidy was at its highest level 
in 2008 but has been declining since then. 

 

 
Figure-1. Flow diagram of  WAP generation, collection, and treatment 

                                 Source: KECO internal data 

 

3. Forecasting Wap Generation 
3.1. Methodology 

Forecasting is a two-state process. First, we attempt to identify the determinants of  WAP generation (MPE) 
through a regression analysis. Specifically, WAP generation is regressed on potential determinants such as paddy 
size (paddy), field size (field) and vinyl-house farming (House) as follows 

: 

MPE = β0 + β1paddy + β2field + β3House + ε                                                   (1) 
 

Based on this estimation, we then forecast the future MPE. To do this, we need to estimate the future values of  
explanatory variables: we regress each of  the explanatory variables on the respective previous values and time. We 
use the estimated value of  one coefficient as its future value if  it is statistically significant. If  there is no statistical 
significance, we will average the previous 5 years' values to use as future values for each variable over 5 years. 
 

3.2. Data 
We use panel data covering nine regions across 12 years (2004 through 2015)2. As our dependent variable, we 

use only waste mulching plastics generation, which accounts for approximately 80% of  the total, because the 
remainder, vinyl house coverings, is almost recycled voluntarily through the market. Table 3 provides summary 
statistics for our data. 
 

Table-3. Summary Statistics 

  MPE Paddy Field House 

 Mean 26,289.56 106,379.23 4,439.76 80,904.06 

 Stand. dev. 12,146.60 61,947.29 4,729.77 27,252.56 

 Min. 1,319.00 18.00 0.00 52,100.00 

 Max. 59,634.00 219,337.00 18,287.00 152,095.00 

Note: MPE, paddy, field, and House stands for mulching plastics generation, size of  paddy field, size of  dry field, and size of  
vinyl house, respectively. MPE is measured in tons and the other variables are measured in hactares. 
Source: KECO internal data and the Korea Statistical Information Service(kosis.kr). 

 

 
 

 
2 As of  2018, there are 16 so-called wide autonomous administrative units in Korea. However, due to the availability of  data, we have merged these units into 
nine regions. For example, Seoul and its surrounding Kyunggi Province were merged into an area referred to as the Captial area. 



Agriculture and Food Sciences Research, 2018, 5(2): 68-72 

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3.3. Empirical Results 
We first checked the poolability of  the time-series and cross-sectional data. Based on an F-statistic (0.42652) 

we could reject the null hypothesis that the coefficients are not stable at the 5% level. We then checked for 
autocorrelation in error terms using the Breusch-Godfrey/ Wooldridge test, which has detected the presence of  
autocorrelation. We have added the lag term for dependent variable to set our final regression model as follows: 

 

MPE = β0 + β1paddy + β2field + β3House + β4lag(MPE) + ε                                       (2) 
 

We have found no autocorrelation in error terms after testing this new model using the Breusch-Godfrey/ 
Wooldridge test (chi-square statistic=2.1548). In addition, the Honda Test showed no individual effect (standard 
normal statistic=0.024989), but a time effect (standard normal statistic=4.6167). Finally by using the Hausman test 
we selected a random effects model (chi-square statistic=5.6698) [3, 4]. 
  Table 4 presents the results of  regression analysis. House (size of  vinyl house farming) and lag(MPE) are 
significant at the 5% and 1% level, respectively. The effect of  lag(MPE) is statistically significant and is strong. 
Almost 67 percent of  WAP generated in the last year is again generated any of  this year in inertia. Notice that the 
effect of  field (size of  dry field) is almost the same as that of  House (size of  vinyl house farming), but it is not 
statistically significant. 

 
Table-4. Results of  Regression Analysis 

  Coefficient Standard error t-value P-value 

Intercept 574.9600 1901.1000 0.3024 0.7630 

Paddy 0.0189 0.0116 1.6276 0.1070 

Field 0.0893 0.1403 0.6361 0.5263 

House 0.0737 0.0302 2.4409 0.0165 * 

Lag(MPE) 0.6715 0.0749 8.9676 0.0000*** 

                     Note: *,**,and *** represent the 10%, 5%, and 1% significance level, respectively. 

 
We now turn to predicting the future values of  explanatory variables. We then insert them into Equation (2) to 

obtain the future values of  MPE. Table 5 shows a summary of  the future values of  explanatory variables obtained 
using the aforementioned method. 
 

Table-5. Future Values of  Explanatory Variables 

 Year Paddy Field House 

2016 998,953.6 273,912.4 989,065.2 

2017 992,768.4 274,119.1 973,989.8 

2018 985,095.7 274,911.6 984,324.6 

2019 940,259.2 258,131.9 992,162.6 

2020 914,167.4 234,499.8 968,638.2 

             
  The 95% confidence interval for the predicted values of  MPE is summarized in Table 6. 
 

Table-6. 95% Confidence Interval for the Prediction of  MPE 

 Year  Lower Bound  Point Estimate  Upper Bound 

2016       221,466.6        247,363.4        273,260.2  

2017       224,616.4        247,827.1        271,037.8  

2018       226,404.7        248,955.6        271,506.6  

2019       190,964.2        232,544.9        274,125.6  

2020       174,274.4        209,293.8        244,313.2  

 
As shown in Table 6, the generation of  MPE is predicted to decline after 2019. It is also predicted to stabilize 

at around 200,000 tons per year after that. Although there is a little increase in the MPE collection rate, for 
example 80%, there would be no repeat of  the huge accumulation of  WAP that occurred on 2005 because the 
present treatment capacity (approximately, private 50 thousand and public 80 thousand annually) would suffice. 
However, due to the uncertainty in the recycled products market (for example, China’s recent suspension of  
recycled vinyl imports and fluctuations in petroleum markets) private WAP recycling firms may go bankrupt, 
causing a supply shortage for treatment services, which occurred in 2005. 
 

4. Conclusion 
The amount of  WAP collected by KECO is predicted to stabilize at around 160,000 tons per year. Given the 

current treatment capacity, this would not lead to issues if  the amount of  untreated WAP significantly increased, 
as it did in 2005. However, this KECO-led system is vulnerable to various market uncertainties regarding recycled 
products and petroleum markets. 

Unlike Korea, Japan and Taiwan define WAP as industrial waste. Therefore, farmers in these countries are 
responsible for the proper treatment of  WAP. In both countries the central government does not play such active a 
role as it does in Korea. Collection and treatment occur in response to market mechanisms [5-7]. In light of  the 
situation in these countries, Korea also needs to strengthen the legal responsibility of  producers and consumers 
(farmers) of  agricultural plastics to ensure proper WAP management. Specifically, we can consider the alternatives 
that by putting agricultural plastics into EPR(Extended Producer’s Responsibility) items, producers are made 



Agriculture and Food Sciences Research, 2018, 5(2): 68-72 

72 
 

 

responsible for collecting and treating WAP or that by reclassifying WAP into industrial waste farmers are made 
responsible for proper treatment [8].  

We do not exclude the role of  governments in WAP management. Governments may adopt the role of  
facilitating the smooth operation of  markets. Taiwanese government compensates farmers for sorting and bringing 
waste plastic containers to treatment firms, but not for general WAP. Japanese government also compensates 
farmers for bringing waste plastics to collection points. In addition, it also operates a minimum level of  public 
treatment facilities as a buffer for market uncertainty [6, 7]. 
 

References 
[1] E. Hosoda, Waste policies and related legislation in Japan. Ch.1 In The economics of waste management in East Asia- Ed. by M. Yamamoto 

and E. Hosoda. NY, USA: Routledge, 2016. 
[2] S. C. Lee, An introduction to Taiwan's waste management and recycling policy. Ch.6 In the economics of waste management in East Asia- ed. 

by M. Yamamoto and E. Hosoda. NY, USA: Routledge, 2016. 
[3] B. H. Baltagi, Econometric analysis of panel data, 2nd ed. UK: John Wiley & Sons, 2001. 
[4] W. H. Greene, Econometric analysis. NY, USA: MacMillan, 1990. 
[5] H. Takeya, "Collection, disposal and exchange of waste agricultural plastics in Japan, the Republic of Korea and China," Tech 

Monitor, pp. 50-55, 2009. 
[6] NIER(National Institute of Environmental Research), "Japanese resource circulation institutions and status of 3R reference book. 

NIER, ROK, 2015.(in Korean)," 2015. 
[7] TEPA (Taiwanese Environmental Protection Administration), Retrieved: www.epa.gov.tw, 2017. 
[8] R. Porter, The economics of waste. Washington DC, USA: Resources for the Future, 2002. 
 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  

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