Estimation and Spatial Analysis of Agriculture Plastic Waste Case Study: Karangdowo Subdistrict, Klaten Regency, Central Java Indonesia

Plastic waste is well known as generated from domestic activities; however, agricultural activities, including fertilizing, spraying pesticides, and soil covering, have the potential to generate plastic waste. Many studies indicated that agricultural plastic waste (APW) can cause pollution of agricultural land, impacting soil health, biodiversity, and productivity. Therefore, this study aims to estimate the loading rate of APW and its potential for recycling. The data was collected from farmers in Karangdowo district, Klaten City, Central Java province, Indonesia, based on clustering and random samples. Data on land area, crop type, planting frequency, pesticide and fertilizer application was determined to estimate APW loading rate. Mapping of the estimation of the loading rate of APW and plastic-type in each village was processed using QGIS software. The results show four types of plastic with a total estimation per year: plastic sacks (949.6 kg/year), plastic bottles (182.9 kg/year), plastic bags (697.0 kg/year), and mulch (12913.6 kg/year). There were three types of plastics: High Density polyethylene (HDPE), Low Density Polyethylene (LDPE), and polypropylene (PP). Although the horticulture area was less than 10% of total agricultural area in each village, it generated the highest LDPE from the use of mulch. Ringinputih village has the highest estimation of recycle potential HDPE, LDPE, and PP compared with the other villages due to having the most significant horticultural area and variation of crops.


Introduction
Plastic waste has become a problem in various countries, including Indonesia.According to the Indonesia National Plastic Action Partnership (NPAP) (2020) [1], the average production of plastic waste in Indonesia reaches 6.8 million tons per year, and 70% needs to be managed effectively [1].About 47% of plastic waste is burned, 14% is disposed of in landfills but needs to be appropriately managed, and the remaining 9% is leaked into waterways and the sea.Poor plastic waste management pollutes the environment and harms ecosystems, fisheries, and tourism.Burning plastic waste in the open risks air pollution caused by hazardous substances [2].Apart from household waste, another source of plastic waste is from agricultural activities.As an agricultural country, Indonesia has a high potential to produce plastic waste from the agricultural sector.Changes in traditional agricultural patterns to modern agriculture have led to an increase in the use of plastic.To increase production and protect crops, plastics are widely used in various agricultural activities such as: fertilizing, spraying pests, and covering the soil.Poor management of agricultural plastic waste (APW) can cause pollution of agricultural land so that it has an impact on soil health, biodiversity, and productivity [3].Plastic particles in soil can be sourced from plastic fragments from soil mulching, pots, irrigation and drainage pipes, crop covering, packing, and containers [4].
Plastics in the soil can be a source of microplastics for other parts of the environment.Microplastics on the soil surface can be transported through run-off and erosion and enter water bodies [5].In addition, microplastics can migrate from the soil surface to deeper soil layers [6] [7].Several studies have shown that microplastics in soil can affect soil physio-chemical characteristics (density, structure, and waterholding capacity).In addition, microplastics also influence the physio-chemical properties of plants, such as root growth and nutrient uptake [8].Moreover, the presence of microplastics in the soil can reduce the diversity, rate, and movement of soil biota, reduce the amount of biomass of soil fauna, and increase microbial biomass and activity [9].To minimize the impact of APW on the environment for example by recycling and reusing.However, the more APW is scattered in the environment (leaved on the ground, improperly disposed or burned), the potential for reuse and recycling will be decrease, and the potential for harm to the environment will increase [10].Therefore, it is necessary to carry out the integrated APW management.APW research and its recycling potential is still rare in Indonesia.Thus, this study aims to determine the loading rate of plastic waste generate from agricultural activities and its potential for recycling.

Studi Location
The research was conducted in Karangdowo subdistrict, Klaten Regency, Central Java, Indonesia.Geographically, Karangdowo subdistrict is located at 110⁰43'19' to 110⁰45'59 east longitude and at 7⁰40'35' to 7⁰45'07' south latitude and altitude is 500 -1000 meters above sea level (Figure 1).The area of Karangdowo subdistrict is 2,923 Ha which includes 19 villages, 2,045 Ha or around 70% of the area is agricultural area.The number of families in Karangdowo subdistrict is 15,063, with a total population of 45,176 people [11].

Figure 1 Karangdowo subdistrict and study location
According to Environment Health Risk Assessment (EHRA) study in 2017 and working group (Pokja) of Klaten Regency, Karangdowo subdistrict is categorized as an area at risk of solid waste.There are two aspects that caused this condition, namely technical aspects, and non-technical aspects.The main cause of the technical aspect is the nearest landfill is already overloaded and 58,2 % of solid waste was not processed.On the other hand, the non-technical aspect, the community participation on solid waste management was low.Most of the people do open dumping and waste burning.One source of solid waste is plastic waste originating from agricultural activities.Most of the Karangdowo subdistrict area is agricultural, dominated by rice, corn, and soybeans.The planting and harvest area of rice, corn, and soybeans of Klaten Regency and the composition of agriculture area can be shown in Table 1 and  Rice, corn, and soybean plantation activities generate plastic waste from fertilization and pesticide spraying.For example, plastic waste is produced in sacks of fertilizer containers, pesticide bottles, and mulch for land cover.

Methodology
Data on farmer population, agricultural land area, crop types and population of each village were obtained from secondary data from the Karangdowo Subdistrict Statistics Agency.At the same time, the village boundaries are based on the administrative map of the Karangdowo subdistrict.Plastic consumption in agricultural activities is done by distributing questionnaires with direct interview techniques with farmers.There were 30 respondents from all farmer populations distributed across all villages as representatives of Karangdowo subdistrict.The data collected included the following data: crop type, land status (owned/leased), land location, planting period, crop type, farm size, harvest frequency, irrigation needs, type and quantity of fertilizers and pesticides, and plastic mulch use.
Respondents were assumed to be homogeneous and considered representative of each village.
Data analysis was conducted by categorizing the types of plastic, namely sacks, bags, bottles and jerry cans, and mulch packaging.The total plastic usage each year has calculated the type of plastic with the planting frequency (Equation 1).Then the amount of waste generation per year was done by summing up the total weight of each type of plastic used during the year.Loading rate of total plastic (each type) was total plastic per year divided with plantation area (Equation 2).Loading rate estimation each village was determined by multiply averaging plastic loading rate (each plastic type) from all the sampling area with plantation area each village.

Respondent Information
Respondents were obtained from ten villages with many farmers and large agricultural land in the district.The distribution of the number of respondents, land area and irrigation status for each village can be seen in (Table 3 and Figure 2) Based on Table 3 and Figure 2, most respondents were male (73.3%), while 26.7% were female.Land ownership status is privately owned or leased land with 50% each.Most of the land has access to irrigation, and only 13.3% still need access to irrigation.Most farmers only grow rice (40%), vegetables (23%), and secondary crops (10%) such as corn, sweet potato, and beans; the rest are a combination of two or three types of crops (Figure 3).While the types of vegetables often planted are chilli (73%), the rest (27%) are tomatoes, turnips, cauliflower, cucumber, and eggplant.Based on interviews, farmers with access to irrigation tend to plant the same type of crop (monoculture), such as rice, continuously (at least 2-3 times a year).However, some respondents have varied cropping patterns (polyculture) by combining paddy with secondary crops such as corn and sweet potato.
Several factors influence cropping patterns in Indonesia, including water availability, land conditions and altitude, presence of pests and diseases, ease of obtaining seeds and marketing of agricultural products [12].Irrigation accessibility encourages farmers to plant rice throughout the year, but it harms the development of pests and disease plants.The recommended pattern is to maintain rice planting twice a year but includes secondary crops in the third growing season [12].

Agriculture Plastic Waste Estimation
In general, agricultural activities that produce plastic waste are fertilization activities and pesticides application in paddy, secondary crops, and vegetables, while mulch is only for vegetable crops.This condition is also similar to the research in China [13].Crop fertilization is carried out 2-3 times during the planting period, namely pre-planting and during planting.According to this study, fertilizers widely used are NPK Phonska brand (52%) and urea (22%).NPK Ponska fertilizer contains N (Nitrogen) (15%), P2O5 (Phosphate) 10%, K (Potassium) 12% and S (Sulfur) 10% [14].Urea fertilizer has a higher nitrogen content than NPK Phonska, around 45-55% [15].Urea is one of the fertilizers subsidized by the government.This fertilizer is usually packed in plastic sacks for 50kg of fertilizer with pink colour.
Another activity that becomes one of the sources of plastic waste is the use of pesticides.Based on respondent data, at least farmers spray pesticides 1-2 times during planting.The classes of pesticides that are widely used are insecticides (50%), fungicides (40%), herbicides (10%) and rodenticides (10%).
Based on the questionnaire results, Ringinputih and Karang Dowo village farmers often use pesticides.
The dominant pesticide active ingredients used were carbofuran and propinep.Carbofuran is mainly applied for paddy and secondary crops.This pesticide has highly toxic properties and acetylcholinesterase enzyme inhibitor [16].It acutely impacts fresh and marine fish and chronically affects the reproductive process.In some countries, this pesticide has been banned because it seriously impacts the environment, especially the aquatic environment [17].Meanwhile, propinep has acute effects on mammals through inhalation and dermal allergy, and no teratogenic effects were found.This active ingredient is used in paddy, secondary crops and vegetables, especially chilli plants [18].Farmers also use pesticides with organic active ingredients to be relatively environmentally friendly.Pesticide packaging mostly in plastic bottles or plastic bags with different volumes and sizes.
Plastic mulch is only used on horticultural crops such as chillies, tomatoes, mustard greens, cauliflower, cucumber, long beans, green beans, and eggplant.In contrast, paddy, and secondary crops such as corn and sweet potatoes do not use plastic mulch.The amount and size of plastic mulch used depends on the farm's area and the plants' moisture conditions.There are various sizes in 1 roll of plastic mulch, namely 235 m x120 cm, 400 m x 80 cm, 520 m x 120 cm, and 850 m x 80 cm, depending on the planting distance.Summary of land area, composition, and weight of plastic waste total per year can be show in Table 4 and Figure 4 below.4, the average weight of mulch plastic is dominant compared to plastic sacks, plastic bags, and plastic bottles in the horticulture area although the land area for horticulture is mostly less than 10 % of the total land area in each village (Figure 4).In addition, Karangputih village, the average weight of waste per hectare for plastic sacks, plastic bags and plastic bottles for horticultural crops are higher than secondary crops and paddy field area.The average weight per hectare of land per year of plastic sacks, plastic bags, and plastic bottles is similar between villages.However, it varies significantly for plastic mulch, which is influenced by the crop area, crop type and planting distance.The average value between villages was used to estimate the potential total amount of plastic waste based on the land area of each crop for each village.The estimation of plastic waste per village can be seen in Figure 5.

Environmental impact and the potential of recycle of APW
In many regions, APW is disposed of using one of four disposal methods, each method has its own adverse environmental impact.These methods are on-site burial, on-site burning, illegal dumping and disposal in municipal landfills [20].The observation data show that most of the APW in the Karangdowo subdistrict was burned altogether with rice husk or dumped in the agriculture area and irrigation channels (Figure 6), and only a few were reused (plastic sacks).Burning APW in open environment will release numerous harmful substances to the environment compartment (air, water, soil) [20].Illegal dumping and on-site burial can cause severe pollution.The agricultural films could reduce the availability of soil nutrient conversion and hinder soil microbial activity.Furthermore, it caused the soil to harden due to

Plastic sack
Plastic bag the disruption of soil structure formation and permeability.Thus, the soil capacity for water absorption and water retention gradually decreased.In addition, illegal dumping cause ecological environmental damage.Mulch residues cause water pollution and impact the quality of irrigation and drainage.Plastic fragments can threaten fish's survival due to gastrointestinal dysfunction and physical deterioration [21].
When APW remain in the soil, some additive materials of plastic will leach, transmit and penetrate to the soil and the groundwater.These materials may enter to grain, vegetables and animal bodies which directly affecting the people's health who consume it.When APW are burned, some pollutant would be release to the atmosphere such as dioxin and other Persistent Organic Pollutants (POPs).POPs can enter to human body through inhalation dan food chain which could cause cancer [21].Furthermore, APW of plastic pesticide container should be manage as hazardous solid waste.According to the Ministry of Environmental and Forestry Regulation No.6 2021, solid waste that has toxic characteristics with acute toxicity level (LD50) less than 5000mg/Kg is categorized as hazardous waste [22].The toxicity of pesticides found in this study ranged from slightly toxic (>5000mg/Kg) to toxic (<5000mg/Kg).Based on Indonesian Government Regulation No.27 2020, we should reduce hazardous waste using environmentally friendly pesticides and reuse all or part of hazardous waste (e.g.pesticide containers).If hazardous waste handling individually is too challenging, it should be done collectively and handed over to a specific waste management facility established by the government [23].Almost all APW can be recycled and enter the recycling chain as long as it is relatively clean and dry.These plastic materials must be decontaminated prior to incorporation into a material recycling procedure [24].However, the management of APW is left to farmers so that when APW stockpiling, farmers will burn it on farm [20].There are several types of polymers used in agricultural waste such as high-density polyethylene (HDPE), low-density PE (LDPE), polypropylene (PP), polyester, polyvinyl chloride, poly-styrene, PE Terephthalate, nylon and biopolymer.Plastic also contain heavy metal, stabilizers, and dyes which can restrict the categories of products that can be manufactured from recycled materials [25].According to this study, there are three groups of polymers were identified, namely: HDPE (plastic bottle), LDPE (plastic bag and mulch), and PP (plastic sack).HDPE is a petroleum-based thermoplastic polymer and one of the most versatile plastic materials used in various applications, such as plastic bottles, cutting boards, and pipes.If not recycled, HDPE will cause environmental problems such as difficulty in decomposing; in the environment, the weight will become lighter so that it easily ends up in other environments such as forests, rivers, and oceans, and the recycling value will decrease if it is in dirty conditions [10].On the other hand, LDPE (mulching films), if not appropriately applied, maintained, and removed from fields, will remind in the soil in large quantities.Damage and incorrect retrieval during application will contribute to film fragmentation.Furthermore, soil contamination and plant residue of the plastic make logistics and recycling processes difficult and uneconomic [10].
PP is a downstream petrochemical product formed from the "olefin monomer" propylene [26] identified in 1954 [27].It has exceptional characteristics like dimensional stability, high heat distortion temperature, and fire resistance [28].PP also has the advantages of combining natural and artificial fibers and producing a new product [29].Since PP is naturally thermoplastic, many industries find it very beneficial because it can be heated, cooled, and reheated without significantly degrading its original composition [30].In addition, PP can be mixed with biodegradable polymers such as thermoplastic starch (TPS) and polylactic acid (PLA).However, these biodegradable polymers were detected as PP impurities during a recycled process that could impact the mechanical and thermal properties of recycled PP [31].Advanced techniques were required to eliminate the impurities of recycled PP.Moreover, these techniques would affect the environment.Therefore, it is easier to recycle pure PP than blended PP [31].
The loading rate of HDPE, LDPE, and PP for each village was estimated by the average type of plastic produced per hectare per year multiplied by the land area (Figure 8).Ringinputih village has the highest potential of generating HDPE, LDPE and PP.Compared with HDPE and PP, LDPE potential was found in four villages, namely Ringinputih, Tumpukan, Soka, and Kupang village, due to the large horticulture area.This study showed that although Karangdowo sub-district has the potential to recycle APW, the management of APW needs to be carried out properly.Various efforts need to be made, such as involving farmers to collect, separate, and transport APW to the plastic recycling centre.

Conclusion
The study shows that the highest total estimation based on plastic type was plastic sacks (949.6 kg/year), followed by plastic bottles (182.9 kg/year), plastic bags (697.0 kg/year), and mulch (12913.6 kg/year).There were three types of plastics: High Density polyethylene (HDPE), Low Density Polyethylene (LDPE), and polypropylene (PP).The highest LDPE was generated from mulch from the horticulture area, which is less than 10% of the total agricultural area.Compared with the other villages, Ringinputih village has the highest estimation of recycle potential HDPE, LDPE, and PP due to having the most significant horticultural area and variation of crops.

Figure 3
Figure 3 Combination of plant type (n=30)

Figure 4
Figure 4 Percentage of plastic waste base on the agricultural type

Figure 5
Figure 5 Estimation of APW each village in Karangdowo sub-district Based on the figure above, Ringinputih village has the highest loading rate among other villages for all four types of APW (sack, bag, bottle and mulch).While other villages vary depending on the type of plastic.The highest loading rate among plastic type is mulch (>900 kg/year).Ringinputih, Soka, Tumpukan, and Kupang villages have high mulch loading rates due to the large area of horticultural land compared to the other villages.Mulch is widely used in horticulture because it has many benefits such as control soil temperature and moisture, reduce pesticide use, prevent erosion in heavy rain, improve water consumption efficiency, earlier harvests and increase crop yields [10][19].

Figure 8
Figure 8 Estimation of HDPE, LDPE and PE from each village in Karangdowo sub-district

Table 1 .
Type of Plantation in Karangdowo District

Table 2 .
Composition of Agriculture area of villages in Karangdowo District

Table 3 .
Distribution of respondent (n=30), land type and area, and irrigation status Figure 2Land ownership status, respondent gender, and irrigation status from respondent (n=30)

Table 4 .
Summary of composition and weight of plastic waste each village per year P : Paddy; SC: Secondary Crops; H: Horticulture Figures 7 show the percentage of HDPE, LDPE, and PP for each village and agriculture type based on questionnaire data.Tumpukan villages.While PP has a higher percentage in Karangtalun village and LDPE in Munggung and Soka villages.Karangwungu, Bakungan, Karangdowo, and Ringinputih villages have a composition of HDPE, LDPE, and PP with different percentage.Whereas the other villages only have two variations of polymer.Paddy and secondary crops tend to generate HDPE and PP compared with horticulture which produces 95% of LDPE from mulch and plastic bags.
10 Figure 7 Percentage of HDPE, LDPE, and PP from total APW each village (left) and agriculture type (right)