Problem Solving at Nursery Production Sites Using Biodegradable Pot
Flower Cultivation Course: Kojima Nahiro(Instructor: Maeda Takahide)
1. Introduction
Plastic is an essential material for modern agriculture. However, petroleum, which is the raw
material of plastic, does not decompose easily in nature, creating the problem of a significant
environmental burden at the time of disposal. To solve these problems, Tokai Kasei Co., Ltd. ofMino City, Gifu Prefecture, has developed an environmentally friendly pot made of biodegradable
plastic. Biodegradable plastic is a general term for plastic that is decomposed into water andcarbon dioxide by bacteria in the soil or water. Planting with the pot can be done in flower beds,etc. to improve the efficiency of planting work and increase the added value of seedling products.
For these reasons mentioned above, environmentally friendly biodegradable pots are considered
useful at flower production sites. However, they are not yet widespread due to the difficulty incontrolling the speed of decomposition and high cost. Therefore, we cultivated seedlings inbiodegradable pots at our school and investigated the effect on growth and the durability of thepots during cultivation.
2. Marigold Cultivation Tests Using Biodegradable Pots
(1) Materials and Methods
On June 14, 2021, the marigold 'March Orange' was sown in 288-hole cell trays and germinated ina hotbed tunnel in a mist room; on June 28, 2021, the plants were potted in No. 3 pots. The pots
used for potting up were Pot 1, Pot 2, Pot 3, Pot 4, and regular polypots, which have different
biodegradable components, A total of 10 treatment wards were set up, using conditioned peat moss(Promix BX) and "Hana-gokoro" culture medium. After potting, the plants were kept on a pool bench
in a No. 2 greenhouse (not heated), and the four plants in each treatment ward were photographed
approximately every week to determine the degree of pot deterioration. Classifying the pots withno anomalies as "Degree of Deterioration 0," those with thinning surfaces as "Degree ofDeterioration 1," those with tears as "Degree of Deterioration 2," and those with holes as "Degreeof Deterioration 3," the investigation of the degree of deterioration was conducted until November4, 2011. Temperature and solar radiation (MJ/m2) in greenhouse No. 2 were recorded with aProfinder throughout the growing season. Grass height, number of flowers, and leaf color valuesof 12 plants in each treatment ward were examined on July 27, when more than half of the plants
in all treatment wards flowered, and root length, as well as pH and EC values of the culture medium
were examined on August 2.
(2) Results and Observation
Growth surveys showed no significant differences in grass height, leaf color, root length, and EC
values among the treatment wards. Looking at the progress of pot deterioration in each treatment
Ward (Figures-1 and 2), it can be seen that pot deterioration began on July 27 for pots 2, 3, and 4of biodegradable pots in all of the culture media. Of these treatment wards, the degradation
progressed faster in the treatment wards with biodegradable pots 2 and 3. In addition,
biodegradable pot 1 began to degrade after late September. No degradation of the pots wasobserved in the normal polypots during the study period. Degradation of biodegradable pots occurs
due to hydrolysis, microbial degradation, and UV degradation. Therefore, I summarized the datewhen degradation degree 2 was first observed in each treatment ward, the cumulative temperature,and cumulative amount of solar radiation at that time (Table-1). The cumulative temperature andcumulative amount of solar radiation on the day when Degree of Deterioration 2 pots were firstobserved could be an indicator that the biodegradable pots will begin to deteriorate. Therefore,
going forward, it is necessary to conduct similar tests in marigold production in spring to further
verify the relationship between pot deterioration and cumulative temperature and cumulative
amount of solar radiation.

Degree of Pot Deterioration

Jul. 5, 12, 19, 27, Aug. 13, 30, Sep. 15, 22, Oct. 7, 27, Nov.4 Survey Date
Treatment Ward 1(Biodegradable Pot 1)

Treatment Ward 2(Biodegradable Pot 2)

Treatment Ward 3(Biodegradable Pot 3)

Treatment Ward 4(Biodegradable Pot 4)Treatment Ward 5(Normal Polypot)

Degree of Pot Deterioration

Figure-1: Transition of the Degree of Pot Deterioration in Each Treatment Ward (averagevalue: n=4) (culture medium: adjusted peat moss)

Jul. 5, 12, 19, 27, Aug. 13, 30, Sep. 15, 22, Oct. 7, 27, Nov.4 Survey Date
Treatment Ward 6(Biodegradable Pot 6)

Treatment Ward 7(Biodegradable Pot 7)

Treatment Ward 8(Biodegradable Pot 8)Treatment Ward 9 (Biodegradable Pot 9)Treatment Ward 10(Normal Polypot)

Figure-2: Transition of the Degree of Pot Deterioration in Each Treatment Ward (averagevalue: n=4) (culture medium: Hana-gokoro)
Table-1: Dates When the Degree of Deterioration 2 Was Observed in Each Treatment
Ward, and the Cumulative Temperature and Cumulative Amount of Solar Radiation atThat Time
Treatment Ward

Pot Types

Dates when the PotsofDegreeofDeterioration 2 Were
Observed

Cumulative Temperatureof the Dates When theDeterioration of Pots Were
Observed

Treatment Ward1

Biodegradable Pot 1

Oct. 273008.7℃

Cumulative Amount of
Solar Radiation of theDates
When
theDeterioration of Pots Were
Observed
579.5(MJ/㎡)

Treatment Ward2

Biodegradable Pot 2

Jul. 27

799.5℃

167.0(MJ/㎡)

Treatment Ward3

Biodegradable Pot 3

Aug.131274.7℃

262.9(MJ/㎡)

Treatment Ward4

Biodegradable Pot 4

Sep. 222282.7℃

419.3(MJ/㎡)

Treatment Ward5
Treatment Ward6

Normal Polypot
Biodegradable Pot 1

Oct. 72628.4℃

579.5(MJ/㎡)

Treatment Ward7
Treatment Ward8
Treatment Ward9
Treatment Ward10

Biodegradable Pot2
Biodegradable Pot3
Biodegradable Pot4
Normal Polypot

Aug.13
Aug.13Oct. 7-1274.7℃
1274.7℃
2628.4℃-262.9(MJ/㎡)
262.9(MJ/㎡)
579.5(MJ/㎡)-