• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.2
• /
• pp.144-150
• /
• 2014

Yams (Dioscorea spp), which are edible or medicinal tuber crops, are a important crop in South Korea. Yams require a high level of soil fertility. The various cultural practices such as fertilizing and plowing were tested for marketable tuber production in Chinese yam (Dioscorea opposita). Tuber yield was also affected by organic matters in soil. Application higher level of organic matters result in increased each tuber weight and tuber yield per unit area. The nutrient absorption quantity of the plant such as nitrogen, phosphoric acid, calcium and potassium was increased from 100~120 days after planting, which time to begin tuber enlargement. The tuber yield was increased when the fertilization increased in quantity. Total yield and marketable ratio were the highest in 31~32 kg/10a of nitrogen fertilizer. From above result, income become larger with increase of marketable yield and quality improvement at 63% (27 kg/10a) level of conventional N fertilization (43 kg/10a). The tuber yield was not significantly different between with in various application level of potash fertilizer. Tuber size and weight decreased accordingly to decreased fertilizing level, so the rates of small tubers increased greatly at cultivation without chemical fertilizer. In considering the accumulation rates of allantoin in Chinese yam tubers, the apt harvest season was after October. The allantoin quantity of it was not influenced with nitrogen fertilizing. Moreover it was advantageous with decrease of chemical fertilizer and appropriate fertilizing in soil environment protection. Commercial tuber's number and yield were increased in trenching before planting with trencher compared with rotavating with tractor.

• Journal of Bio-Environment Control
• /
• v.25 no.2
• /
• pp.106-110
• /
• 2016

In this study, a planting density-growth-harvest (PGH) chart was developed to easily read the growth and harvest factors such as crop growth rate, relative growth rate, shoot fresh weight, shoot dry weight, harvesting time, marketable rate, and marketable yield of common ice plant (Mesembryanthemum crystallinum L.). The plants were grown in a nutrient film technique (NFT) system in a closed-type plant factory using fluorescent lamps with three-band radiation under a light intensity of $140{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 12 h. Growth and yield were analyzed under four planting densities ($15{\times}10cm$, $15{\times}15cm$, $15{\times}20cm$, and $15{\times}25cm$). Shoot fresh and dry weights per plant increased at a higher planting density until reached an upper limit and yield per area was also same tendency. Crop growth rate, relative growth rate and lost time were described using quadratic equation. A linear relationship between shoot dry weight and fresh weights was observed. PGH chart was constructed based on the growth data and making equations. For instance, with within row spacing (= 20 cm) and fresh weight per plant at harvest (= 100 g), we can estimate all the growth and harvest factors of common ice plant. The planting density, crop growth rate, relative growth rate, lost time, shoot dry weight per plant, harvesting time, and yield were $33plants/m^2$, $20g{\cdot}m^{-2}{\cdot}d^{-1}$, $0.27g{\cdot}g^{-1}{\cdot}d^{-1}$, 22 days, 2.5 g/plant, 26 days after transplanting, and $3.2kg{\cdot}m^{-2}$, respectively. With this chart, we could easily obtain the growth factors such as planting density, crop growth rate, relative growth rate, lost time and the harvest factors such as shoot fresh and dry weights, harvesting time, marketable rate, and marketable yield with at least two parameters, for instance, planting distance and one of harvest factors of plant. PGH charts will be useful tools to estimate the growth and yield of crops and to practical design of a closed-type plant production system.

• Journal of Bio-Environment Control
• /
• v.31 no.4
• /
• pp.393-400
• /
• 2022

Postharvest quality of sweet pepper fruits was mainly defined as external appearance, i.e., shape, fruit weight and surface color. These quality traits tend to involve esthetic appeal, it disregards gustatory properties and nutritional value. However, comparative studies according to the marketability of sweet pepper fruits are insufficient. This study was carried out to compare the physicochemical components, antioxidant activity and carotenoid contents of marketable and unmarketable sweet pepper fruits (Capsicum annuum L.). Physicochemical components (proximate composition, minerals and total phenolic contents) and antioxidant activities using various methods were investigated. The proximate composition values (%) of marketable and unmarketable fruits were: moisture (90.28 and 90.29), ash (0.74 and 0.26), crude protein (0.67 and 0.72), crude lipid (0.38 and 0.32). There were no significant differences in antioxidant activity, while total phenolic content was higher in marketable fruit. Carotenoids contents were 29.3 ± 2.6 and 31.9 ± 2.9 ㎍·g^-1 in marketable and unmarketable fruits respectively, and identified β-carotene, violaxanthin, neoxanthin, and zeaxanthin. Lutein and capsaicin were not detected. In this study, potential value of unmarketable sweet pepper fruit could be identified to be applied as a food ingredient and functional food material.

• Horticultural Science & Technology
• /
• v.30 no.6
• /
• pp.650-656
• /
• 2012

The aims of the experiment, conducted over three years in the Central Europe field conditions, were (1) to investigate the effect of growing period (plantings in the middle and at the end of August: $1^{st}$ and $2^{nd}$ term, respectively) on yield and chemical composition of the non-heading Chinese cabbage (Brassica rapa var. chinensis) cultivars 'Taisai', 'Pak Choy White', and 'Green Fortune', and (2) to develop regression models to evaluate the changes in crop yields as a function of weather conditions. A highest marketable yield was obtained from 'Taisai' (65.71 and 77.20 $t{\cdot}ha^{-1}$), especially in the $2^{nd}$ term of production. Low yield, observed for 'Pak Choy White' was due to its premature bolting. Almost 39% ($1^{st}$ term) and 70% ($2^{nd}$ term) of plants of this cultivar formed inflorescence shoots before harvest. The highest dry matter level was observed in the leaf petioles of 'Taisai', while 'Green Fortune' was the most abundant of carotenoids and L-ascorbic acid. The content of soluble sugars was the lowest for 'Pak Choy White'. In a phase of harvest maturity, more of the analyzed constituents were gathered by plants from earlier plantings, and differences were as follows: 4.7% (dry matter), 26.3% (carotenoids) and 22.1% (L-ascorbic acid), in comparison to $2^{nd}$ term of production. Significant increase of soluble sugars level was observed for plants from later harvest. The regression model for marketable yield of Chinese cabbage cultivar 'Taisai' as a function of maximum air temperature can predict the yield with accuracy 68%. The models for yield or bolting of 'Pak Choy White', based on extreme air temperatures and sunshine duration, were more precise (98%). It should be pointed out that Taisai could be recommended for later growing period in Central Europe conditions with regard to maximum yield potential. 'Green Fortune' was notable for its uniform yielding. To obtained plants of higher nutritional value, earlier time of cultivation should be suggested. Described models can be successfully applied for an approximate simulation of Chinese cabbage yielding.

• Korean journal of applied entomology
• /
• v.48 no.2
• /
• pp.229-236
• /
• 2009

Cage experiments by artificial infestations with different initial densities of Frankliniella occidentalis were conducted to analyze damages and develop control thresholds of F. occidentalis on greenhouse eggplant in 2005 and on greenhouse sweet pepper in 2007. In the eggplant experiment, the infestations of F. occidentalis resulted in direct damage on fruit surface and non-marketable fruits which had several thin or thick lines or bleaching patches on the surface. F. occidentalis adults were frequently found on the flowers of eggplants, while nymphs were mainly observed on leaves. The fruit yield of eggplants was not significantly different among experimental plots with different initial density of F. occidentalis. Relationship between % non-marketable fruits among harvested fruits of eggplant and sticky trap catches of F. occidentalis (no. thrips/trap/week) at two weeks before the harvest showed a positive correlation. Using the estimated relationship, the control threshold of F. occidentalis on greenhouse eggplant was estimated at 10 adults per week at two weeks before the harvest when 5% of non-marketable fruit was applied for the gain threshold. In the experiment of sweet pepper, the direct damage by F. occidentalis was observed on the fruit surface and calyx, and the marketable grade of the damaged fruits decreased. The significant yield loss of marketable fruits was found in plots with high initial introduced-densities. There was a high relationship between thrips density and percentage of damaged fruits. Assuming 5% yield loss (non-marketable fruit) for the gain threshold, the control threshold of F. occidentalis on greenhouse sweet pepper was 4.8 adults per trap and 0.9 individuals per flower at two weeks before harvest.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.35 no.2
• /
• pp.117-121
• /
• 1990

A sweet corn hybrid, Golden Cross Bantam 70, was grown at 5 plant populations (5,000, 6,000, 7,000, 8,000, and 9,000 plants/10a) under the transparent P .E. film mulch to find the best yield evaluation method. Plant population did not affect early plant growth, culm length, ear height, and silking date. However, number of tillers at harvest decreased but leaf area index increased with increased plant population. Marketable ears were divided into two classes; the first grade of which husked ear weight over l50g (unhusked ear weight 230g) and the second grade of which husked ear weight between 100 and 150g (unhusked ear weight between 180 and 230g) according to the whole sale market price. Average length, thickness, and weight of marketable ears over 100g of husked ears decreased with increased plant population. The proportion of ears over 150g decreased with increased plant population. However, total number and weight of marketable ears and gross income per 10a calculated considering weight and number of ears increased with plant population. There were highly positive correlations between gross income and ear number or ear weight per unit area. At high plant populations the number of marketable ears was overestimated but ear weight underestimated compared with gross income. Dry matter yield of stover increased with increased plant population and ranged 755-944kg/10a with 20.7-24.5% dry matter content. Rice black-streaked dwarf virus infection rate was 10.6-14.9%, but it was not related to plant population.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.477-484
• /
• 2020

This study was conducted to investigate the effects of slow-releasing fertilizer and sowing date on waxy corn propagated through double cropping without tillage. "Mibaek 2" was sown for first cropping on March 25^th, April 5^th, and April 15^th, and for second cropping on July 5^th, July 15^th, and July 25^th in 2018-2019. In order to save labor, slow-releasing fertilizer was utilized only one time before sowing. The accumulated temperature from sowing to silking was about 590-700℃. It took 65-77 days when "Mibaek 2" was sown in early April, but the one sown in early July took 42-52 days. In the first cropping, the culm length and ear length caused by the sowing date had no statistical significance, but the kernel set length was the highest at 123 cm in the sowing district on April 5^th. The weight of marketable ears was the highest at 100%, in addition to soil testing-based recommended fertilization. Meanwhile, in the second cropping, culm length, ear length, and yield were less compared to the first cropping. The culm length, kernel set length, ear length, and seed set length decreased as sowing date was delayed. The number and yield of marketable ears were the highest at 100%, in addition to soil testing-based recommended fertilization like in the first cropping. It has been found that securing yield by July 15^th to finish the second seeding of the crop in the central part of Korea is advantageous. These results of this study will be helpful to farmers for the double cropping of waxy corn cultivation and management.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.1
• /
• pp.52-56
• /
• 1991

In 1986, at Cheju and Seoguipo, a sweet com hybrid, Golden Cross Bantam 70, was grown at 5 phosphate rates (0, 8, 16, 24 and 32 kg/l0a) to determine effects of phosphate rate on growth and yield of sweet com and to recommend the optimum phosphate rate for sweet com production in volcanic ash soils of Cheju province. Days to silking were shortened 1 to 2 days by phosphate application of more than l6kg/10a. Culm length, ear height and fresh stover yield/l0a did not differ between two locations, but linearly increased as phosphate rate was increased from 0 to 32kg/10a. Average length and weight of marketable ears were greater at Cheju than at Seoguipo and linearly increased as phosphate rate increased. The number of marketable ears per plant and per l0a did not differ between two locations, but quadratically increased as phosphate rate increased. The economic optimum phosphate rate estimated on the basis of the quadratic model, ranged 25.6 to 27.4kg/10a at various fertilizer-to-ear price ratios.

• Journal of Bio-Environment Control
• /
• v.9 no.3
• /
• pp.151-155
• /
• 2000

In order to investigate the optimum irrigation point by soil water tension in oriental melon grown in plastic greenhouse during low temperature season, irrigation points from 10 days before fruiting to 10 days before harvesting were examined with 10, 20, 30 and 50 kPa, respectively. Total amount of water applied was 92.5mm at 10kPa but not irrigated at 50kPa due to the unreach of irrigation point. Fruit weight increased with increased soil water content; it was 456g at 10kPa but 324g at 50kPa. While marketable yield of fruit was lowest at 10 kPa due to increased fermented fruit. Sugar content in fruit was highest at 30 or 50 kPa but lowest at 10kPa. As a result, for higher sugar content and marketable yield, the recommended irrigation point is 30kPa of soil water tension.

• Journal of Bio-Environment Control
• /
• v.2 no.1
• /
• pp.37-45
• /
• 1993

The purpose of this research was to develop ideal substrates for the production of good quality tomatoes in bag culture system and also to improve media with low or no environmental pollution by blending and mixing artificial substrate including peatmoss, perlite, vermiculite, granular rockwool, polyphenol resin foam, bark, and smoked rice hull. The highly efficient media proved by experiments were vermiculite, smoked rice hull, polyphenol resin foam, granular rockwool, and perlite, which showed good results in the early growth as well as the marketable yield of tomato in the bag culture. Tomato plants grown in the media mixed with peatmoss, vermiculite and granular rockwool at the ratio of 3 : 1 : 1(by volume) showed the highest marketable yield, and the next at the ratio of 2 : 1 : 1. The perlite-granular rockwool mixtures at the ratio of 2 : 3 and 1 : 4, and the peatmoss vermiculite mixtures at the ratio of 2 : 3 and 3 : 2, seemed to be promising media for bag culture.