Smart mini-tuber potato seed cultivation -

Smart mini-tuber potato seed cultivation

The aeroponic plant root environment has a significant role in producing high-quality seed tuber potatoes. This study showed the method used to maintain the aeroponics root chamber temperature conditions. An air conditioning system was adopted to supply air with the optimal temperature range for mini-tuber potato seed cultivation. The vapor compression refrigeration type was applied in the air conditioning system. The root chamber temperature is controlled and monitored using an Arduino Uno board system. The root chamber temperature treatment operated in the 10 ◦C – 20 ◦C range. This temperature range improved the potato seed tuber yield. The field experiment reveals that the stolon number produced by potato seeds cultivated in the root chamber with conditioned temperature was up to 77% greater than the number of potato seeds cultivated in the root chamber with the unconditioned temperature.

During plant growth with the aeroponics technique, a nutrient-rich water solution is sprayed in form of a mist onto the hanging plant root using sprinkler irrigation. Water and nutrients are absorbed by the plant roots and the growing parameters, such as temperature, humidity, pH, and nutrient solution electrical conductivity, maintained and controlled as a result of the plant growth conditioning environment.

System Design

The aeroponics system developed in this research is a closed environment type. The potato plants are separated from the plant roots by the plant growth structure covered above the root chamber. A nutrient-rich water solution is sprayed into the plant roots with high steam in the root chamber using a fogging system. The nutrients are supplied from a reservoir that has a closed water flow cycle with the root chamber. With the closed water flow cycle, the remaining water micro-droplets from the spray can flow back to the nutrient reservoir.

The root chamber air temperature is maintained by an air conditioning system. The conditioned air temperature circulates in a closed off-cycle to maintain the potato plant roots optimally absorbing the nutrient for healthy growth. The conditioned air temperature of the root chamber is provided by a refrigeration system. The refrigeration system is controlled by the automation and monitoring system through root chamber air temperature acquisition system using temperature sensors. The root chamber air temperature maintenance and control is the main focus of this research to achieve an essential potato plant growth environment.

The Root Chamber Air Circulation and Conditioning

The air flows from the refrigeration system through an air duct to the root chamber. The air distributed inside the root chamber thus flows returning to the refrigeration system through a return air duct. The air continuously circulates to maintain the root chamber temperature. The air is conditioned by the refrigeration system according to a set temperature. Conditioned air supplied to the root chamber cycles continuously, going on to distribute air.

Air Conditioning System

The refrigeration system was designed considering it can maintain the root chamber temperature in the at 10 °C‒20 °C range.  From the air conditioning design perspective, the root chamber and potato roots are defined as the cooling load. Therefore, the cooling load is derived into wall gain, product and wall infiltration loads. The wall gain load comes from all root chamber walls, the infiltration load comes from the root chamber roof (potato plant support structure) and the product load comes from the potato plant roots. The root chamber wall is designed using three material layers that consist of Styrofoam, plywood and plastic.

The Control and Monitoring System

The root chamber temperature is maintained by the air conditioning system and controlling by automation system. The automation system is based on a microcontroller. The refrigeration system is operated using an operating driver controlled by a microcontroller based on the comparison between the set temperature and the root chamber temperature.

System Testing

Testing was performed to verify the developed system’s functionality and performance before the system is used for the experiment of mini-tuber potato seed cultivation. In this test, the supply air temperature was set at 17 ◦C and the temperature differential was set at ±4 ◦C. When the main power system is turned on, the refrigeration and air conditioning system were examined firstly to make sure it can provide conditioned supply air. The compressor pressure indicators (LP and HP) and sight glass can be used to verify that the refrigerant is flowing according to the vapor compression refrigeration cycle. The temperature indicator shows that the supply air temperature can be maintained according to the temperature setting point at 17 ◦C. The system voltage and current consumption was at normal level as shown on the voltage and current indicator. This result also verified that the control system worked according to the design. The temperature sensors were placed inside of the root chamber in three different locations at 3 m, 7.5 m, and 12 m from the supply air inlet. The testing also verified that the temperature data was recorded continuously in real-time by the data logger in the microSD memory. The testing results show the air conditioning system can maintain the root chamber temperature distribution ranging from 12 ◦C to 20 ◦C. That temperature range is needed for mini-tuber potato seed cultivation.

Experimental Procedure

Three root chambers were prepared for seed potato cultivation. The root chamber placed in the semi greenhouse without environmental condition control (temperature, humidity). There are two root chambers with unconditional temperature (root chamber_1 and root chamber_3) and one root chamber with conditional temperature (root chambar_2). The root chamber_2 temperature will be maintained at 15 ◦C with the temperature differential at 5 ◦C, while the temperature in the other root chamber is only monitored and recorded by the data logger. The healthy potato seed from seed sown put on the growing structure of Aeroponics root chamber with spacing among other plants is 25 cm and composed of four rows of the potato plant. The potato seed roots are suspended below the root chamber growing structure. In order to minimize the ambient temperature infiltration into the root chamber, the growing structure was wrapped with the silver color plastic. The nutrient solution is sprayed onto the plant roots by the fogging system every 10 min for 30 s. The mini-tuber potato seeds are harvested in three month.

Conclusions

The aeroponics root chamber temperature conditioning method was applied in a mini-tuber potato seed cultivation field experiment. Potato seed tuber yield was improved. The root chamber temperature conditioning produced a significant effect on mini-tuber potato seed cultivation using aeroponics. The field experiment results revealed the optimal root chamber temperature treatment increased mini-tuber potato seed tuber yield (up to 77%) compared with mini-tuber potato seed cultivation in the unconditioned root chamber. The root chamber maintained potato roots in the 10 ◦C–20 ◦C temperature range.

Reference:

Kuncoro, C.B.D., Sutandi, T., Adristi, C. and Kuan, Y.D., 2021. Aeroponics root chamber temperature conditioning design for smart mini-tuber potato seed cultivation. Sustainability, 13(9), p.5140.