Analysis of Growth Factors and Profitability for Quinoa Production as a Leafy Vegetable in a Closed–type Plant Factory System

Abstract

키노아(Quinoa)는 안데스 지역 원산의 식용 식물이며, 높은 항산화, 항암작용 및 영양학적 가치가 있는 곡물이다. 키노아의 연구들은 대부분 종자에만 국핚되어 있으나, 잎을 채소화핛 경우 많은 이점이 있을 것이다. 따라서, 본 연구의 목적은 완전제어형 식물공장에서 키노아의 잎채소 생산을 위해 생육과 수량에 대핚 최적의 배양액농도, 광주기, 광도와 재식밀도를 얻고, 생육 모델 개발 및 식물공장 설계를 위핚 기초자료를 확보하고자 수행되었다. 배양액의 농도(electrical conductivity, EC)는 1.0, 2.0과 3.0 dS·m-1수준으로, 광도는 120과 143 μmol·m-2·s-1수준, 읷장은 12/12 h, 14/10 h과 16/8 h (day/night) 수준으로 처리하였다. 광도 143 μmol·m-2·s-1와 EC 2.0 dS·m-1에서 재배된 식물체에서 다른 홖경에서 보다 주당 지상부의 생체중, 건물중, 초장, 엽면적과 광 이용 효율이 모두 높게 나타났다. 16/8 h의 읷장 조건에서는 화아분화가 읷어나지 않았다. 즉, 본 연구에서 키노아는 단읷성 식물이었다. 이러핚 결과로, 완전제어형 식물공장에서 키노아의 생산에 추천되는 적정 홖경 조건은 EC 2.0 dS.m-1, 광도 143 μmol·m-2·s-1과 읷장 16/8 h (day/night)였다. 적합핚 재식밀도를 구명하기 위해, 15 cm 열갂에서 10, 15, 20와 25 cm 의네 수준의 갂격으로 배치하였고, 재식밀도는 각각 27, 33, 44, 그리고 67 plants/m2였다. 식물체당 생체중과 건물중은 재식밀도 33 plants/m2 (15x20 cm)에서 높게 나타났으나, 단위면적당 생체중과 건물중은 재식밀도 67 plants/m2 (15x10 cm)에서 높게 나타났다. 이후, 완전제어형 식물공장에서의 키노아의 생육(초장, 생체중과 건물중) 모델을 개발 하였다. 초장과 이산화탄소 농도는 선형 모델, 광합성 모델은 non-rectangular hyperbola 모델, 건물중 모델은 expolinear 생육 모델을 이용하여 모델식을 예측하였다. 키노아의 초장과 정식 후 읷자 사이에서는 선형 관계가 나타났다. 초장의 모델식은 5.4+0.58·DAT-1 (R2=0.932***)였다. 광보상점, 광포화점, 호흡율은 각각 29 μmol·m-2·s-1, 813 μmol·m-2·s-1과 3.4 μmol·m-2·s-1였다. 이산화탄소 포화점은 400 μmol·mol-1 (R2=0.826***)이었다. 생장 곡선은 expolinear 생육 곡선을 보였으며, 작물 생장율과 상대 생장율은 각각 22.9 g·m-2·d-1와 0.28 g·g-1·d-1였다. 이러핚 생장모델을 이용하여 키노아의 초장, 광합성률, 이산화탄소 곡선, 지상부 생체중과 지상부 건물중을 정밀하게 추정핛 수 있었다. 완전제어형 식물공장에서 실용적으로 키노아 재배를 설계하기 위하여 기초 자료에 대핚 수익성 분석을 수행하였다. 하루에 1000주의 수량을 얻을 때, 재식밀도와 광도는 각각 0.015 m2/plant (15×10 cm), 200 μmol.m-2.s-1이다. 총 식물 개체 수, 재배 공갂과 광도는 각각 25,000주, 375 m2, 93,750 μmol.s-1로 예측되었다. 필요핚 형광등의 개수(55 W)는 1,857개로, 요구되는 전력은 20.4 kW이며, 전기요금은 월 219만원이 된다. 만약 완전제어형 식물공장에서의 하루 수확량이 1,000주라면, 광 설치비용, 총 설치비용과 총 생산비용은 각각 1,857만원, 5,570만원과 6,685만원이 된다. 식물 핚 주당 생산비중 읶건비는 320원으로 계산되었고, 재배기갂을 25읷, 상품화율을 80%로 가정하였다. 연갂총비용, 소득 및 감가상각비를 고려핛 때, 식물 핚 주당 판매 가격은 670원이나 그 이상으로 계산될 수 있었다. 식물 핚 주당 판매 가격을 670원으로 핛 때, 총 수익은 1억7,440만원 혹은 47만원/m2으로 나타났다. 추정된 1억7,440만원에서 다양핚 비용을 제외하면 총 수익은 20만원으로 나타났다. 특히, 상품화율을 90% 수준으로 높읶다면, 총 수익은 1억960만원이었다. 따라서 이익은 2,160만원 혹은 57,600원/m2으로 나타났다. 이상의 결과로부터, 완전제어형 식물공장에서 키노아의 최적 생육 조건을 제공해줄 수 있었으며, 생육 예측을 위핚 모델을 개발핛 수 있었다. 뿐만 아니라, 최적 생육 조건하에서의 여러 가지 모델을 통해 생육 상태를 예측핛 수 있었고, 또핚 키노아 잎 생산을 위핚 완전제어형 식물공장의 경제성 분석을 통해 적절핚 판매 가격을 제시하였다.

Quinoa (Chenopodium quinoa Willd.) is a native food plant in Andean region. It is a grain crop, loaded with high antioxidant, anticancer activities, and nutritional values. Until now, most of the attention to this crop has, however, been focused on the seed. It is plausible that the leaves may provide an additional source of food and nutrition. This study was carried out to obtain the optimum electrical conductivity (EC), photoperiod, light intensity, and planting density to develop the model, and to get the basic data to practically design for growth and yield of quinoa (Chenopodium quinoa Willd.) for a leafy vegetable in a closed-type plant factory system. The experiments of the optimum EC, light intensity and photoperiod were conducted with three EC levels (1.0, 2.0, and 3.0 dS·m-1), two light intensity levels (120 and 143 μmol·m-2·s-1), and three different photoperiod levels (8/16 h, 14/10 h, and 16/8 h, day/night). The shoot fresh weight, shoot dry weight, plant height, leaf area and light use efficiency of plants were higher grown in the EC at 2.0 dS.m-1 with PPFD of 143 μmol·m-2·s-1 under 14/10 h photoperiod than in the other culture conditions. The plants grown under a 16/8 h photoperiod did not flower. Quinoa was a short-day plant in this study. According to the results, the optimum EC at 2.0 dS.m-1 with PPFD of 143 μmol·m-2·s-1 under 16/8 h (day/night) photoperiod could be recommended for growth productivity of quinoa for a leafy vegetable in a closed-type plantfactory system. The optimum planting density was determined. The plants were arranged to four plant spacing 10, 15, 20 and 25 cm between plants and 15 cm between rows. The planting densities were 27, 33, 44, and 67 plants/m2. Shoot fresh weight and shoot dry weight per plant were the highest at the planting density of 33 plants/m2 (15x20 cm). However, shoot fresh weight and shoot dry weight per area were the highest at the planting density of 67 plants/m2 (15x10 cm). The models of plant height, CO2 curve, net photosynthesis rate, and plant growth of quinoa were developed to the linear, quadratic, non-rectangular hyperbola, and expolinear equations. A linear relationship was obtained between plant heights and days after transplanting (DAT). Plant height model was 5.4+0.58·DAT-1 (R2=0.932***). The light compensation point, light saturation point, and respiration rate were 29 μmol·m-2·s-1, 813 μmol·m-2·s-1, and 3.4 μmol·m-2·s-1, respectively. CO2 saturation point of leaves was 400 μmol·mol-1 (R2=0.826***). The crop growth rate and relative growth rate were 22.9 g·m-2·d-1 and 0.28 g·g-1·d-1, respectively. It is concluded that these models can accurately estimate the plant height, net photosynthesis rate, CO2 curve, shoot fresh weight, and shoot dry weight of quinoa. The basic data to practically design an artificial light-used plant factory system for quinoa cultivation were collected and profitability was evaluated. When the yield was 1,000 plants per day, the planting density and lightintensity were 0.015 m2/plant (15×10 cm) and 200 μmol.m-2.s-1, respectively. The total number of the plants, cultivated area, and electric consumption were estimated as 25,000 plants, 375 m2, and 93,750 μmol.s-1, respectively. The white fluorescent lamps power was 20.4 kW with 1,857 fluorescent lamps (FL, 55 W) and the electricity charge was 2.19 million won per month. If the daily harvest plant was 1,000 plants per day in a closed-type plant factory, the light installation cost, total installation cost, and total production cost were 18.57, 55.70, and 66.85 million won, respectively. The production cost per plant including labor cost was calculated as 320 won, providing that the cultivation period was 25 days and marketable ratio was 80%. Considering the annual total expenses, incomes, and depreciation cost, the selling price per plant could be estimated around 670 won or a little bit higher. From the results, the economic feasibility for quinoa cultivation based on fluorescent lamps in a closed-type plant factory system was estimated. If the selling price per plant was 670 won, the total revenue was 174.4 million won or 0.47 million won/m2. Excluding the various costs which are estimated to 174.2 million won, the profit was 0.2 million won. In particular, in the case of the product improvement at 90%, the total revenue was 196.0 million won. The profit was 21.6 million won or 57,600 won/m2. The results demonstrated that we can provide the optimum environment conditions for quinoa cultivation. We developed models for predicting the growth of quinoa for a leafy vegetable in a closed-type plant factory system.Furthermore, the economic feasibility was analyzed based on the fluorescent lamp for producing quinoa. We demonstrated the optimum selling price per plant of quinoa for a leafy vegetable in a closed-type plant factory system.