• 대한인간공학회지
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• 제35권5호
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• pp.383-389
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• 2016

Objective: In this paper, work time for the representative fruit crops are collected and analyzed using time-diary method, and the collected data were compared with the directly observed work time using GPS device. Background: There is no consistent conclusion which measurement method for work time is accurate. Most of the research results were collected from the environment other than rural area. Therefore, there is need to review reliability of the measurement methods for the agricultural work which are carried out for a long duration. Method: Top five crops (apple, pear, grape, sweet persimmon, and peach) were selected according to the number of farms and cultivation areas. We let fruit growers fill a work diary during one cropping period. A difference between the work-time that was recorded by the farmers and the direct observed worktime using GPS device were analyzed. Results: Average direct work time for the five fruit crops found to be 7.1% of the total work time. Conclusions and Applications: Reliability was secured by recording the daily work diary at each work stage while aware that direct observation is carried on. Data which are being collected by government institutions are obtained by the memories of the respondents. Therefore, it is needed to try the method adopted by this study in order to collect more accurate data.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.332-332
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• 2017

Rice ratooning is the cultural practices to produce easily second rice from the stubble left behind after the main-crop harvest. The main advantage of rice ratooning is that in areas where rice is the main crop, double crop of rice can be grown for additional returns. Three early ripened rice cultivars were tested for estimation their milled rice quality and starch characteristics from main and ratoon rice. The main crop was harvested at mass maturity, after which the tillers were mowed to stubbles of about 10 cm tall. And then it left without any further input until the ratooned plant was ready for harvest. Highly significant variations were detected in the milled rice quality between main and ratoon rice. Protein and amylose contents of ratoon rice were more increased than those of main rice. The Toyo value (gloss) of cooked rice of ratoon crop was measured also higher than that of main crop. It resulted from higher air temperature during grain ripening compared with that of ratoon crop. The mean temperature during ripened period of ratoon rice was favorable for optimal maturation for early ripened rice cultivars. Normalized chromatograms of branch chain length distribution of amylopectin are demonstrated a distinct difference between main and ratoon rice flour. Ratoon rice had higher amount of short chains than that of main crop rice starches. Microscopic examination of rice flours with scanning electron microscopy shows starch granule shapes affected by the cropping types, main and ratoon rice. It showed significant differences among rice starch granule shapes and in granule size between main and ratoon rice. Starch of ratoon rice had more neat and smaller granules than that of main rice.

• 상하수도학회지
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• 제30권1호
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• pp.19-31
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• 2016

The Saemangeum watershed is required to manage water pollution effectively but the effect of liquid manure (LM) on soil and water quality in the basin is not clearly identified as yet. This study aims at assessing the effect on soil of a rice field and water quality of water bodies near the rice field during rice-crop time period to find out the effect of LM, the effect of rainfall, and the effect of rice-crop environment on soil and water quality by analyzing data of nitrogen components. As a result of the LM distribution, $NO_3-N$ was much higher than other N components in the entire soil layers and it was accelerated by rainfall right after the LM distribution. Compared to chemical fertilizer (CF), LM was slightly affected but still influenced on the surface water quality. During weak rainfall, low nitrogen concentration in topsoil was resulted as NH3-N decreased and Org-N and $NO_3-N$ increased. $NO_3-N$ concentration in the water of irrigation canals increased with time. During intensive rainfall, $NO_3-N$ and Org-N of the soil were measured highly in the submerged condition, while the water quality of the rice field was lower due to flooding into the irrigation canal as well as the growth of the rice plants. Also, total nitrogen was increased more than 7 times and it showed serious water quality deterioration due to LM and excessive fertilizer distribution, and rainfall during all rice-crop processes. The effect of LM on water quality should be studied consistently to provide critical data while considering weather condition, cropping conditions, soil characteristics, and so on.

• 한국환경농학회지
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• 제31권4호
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• pp.375-377
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• 2012

BACKGROUND: Hairy ventch (Vicia villosa) is a good green manure for supplying nitrogen in arable soil. Ammonia emission from rice fields can occur, and the degree of this emission can be great. However, quantitative information of ammonia emission from paddy soil using green manure is required to obtain emission factors for rice cropping in Korea. METHODS AND RESULTS: Ammonia emission from flooding soil with different application rate of hairy vetch was measured using the closed chamber method. For this study, hairy vetch was applied at rates of 0 (control), 500 (H500), 1000 (H1000), 2000 (H2000), and 3000 (H3000) kg/ha (fresh matter basis). This experiment was conducted for 54 days under flooding condition. The total NH3 emission throughout the experiment period was 0.32, 0.54, 1.20, 4.20, and 6.20 kg/ha for control, H500, H1000, H2000, and H3000, respectively. The ratio of NH3 emission to applied nitrogen by hairy vetch for each treatment was 0.7, 1.4, 3.2, and 3.2% for H500, H1000, H2000, and H3000, respectively. CONCLUSION(S): A very small amount of ammonia emission was recorded in the present study. Therefore, the use of hairy vetch in paddy field instead of chemical fertilizer can reduce ammonia emissions.

• 한국작물학회지
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• 제61권2호
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• pp.104-112
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• 2016

A double-cropping system with soybean (Glycine max) following the cultivation of potato, garlic, and onion is widely adopted in the southern region of Korea. For this system, marginal dates for planting must be determined for profitable soybean yields, because the decision to plant soybean as a second crop is occasionally delayed by harvest of the first crop and weather conditions. In order to investigate the effect of planting date on soybean yield, three cultivars (early and late maturity) were planted on seven different dates from May 1 to July 30 in both paddy and upland fields across 2012 and 2013. Soybean yields were significantly different among the planting dates and the cultivars; however, the interaction between cultivar and planting date was not significant. Based on linear regression, the maximum yield of soybean was reached with a June 10 planting date, with a sharp decline in yield for crops planted after this date. The results of this study were consistent with those of a previous one that recommends early and mid-June as the optimum planting period. Regardless of soybean ecotype, a reduction in yield of greater than 20% occurred when soybean was planted after mid-July. Frost during soybean growth can reduce yields, and the late maturity cultivars planted on July 30 were damaged by frost before completing maturation and harvest; however, early maturity cultivars were safely harvested. For sufficient time to develop and reach profitable yields, the planting of soybean before mid-July is recommended.

• 농업생명과학연구
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• 제44권2호
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• pp.1-6
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• 2010

강활의 재배체계를 확립하기 위하여 다섯 종류의 토성과 및 3요소 시용량을 표준, 1/2량, 1.5배량을 달리하여 포트시험으로 강활의 생육상황과 수량을 조사하였다. 재배기간 중 월별 평균기온은 평년에 비해 5, 6, 8, 10월만 높았으며 그 외는 같거나 낮았다. 그 결과 토성별 시비량에 있어서는 3요소 시비량이 많을수록 생육이나 수량이 많은 경향을 보였다. 토양 이화학성중 유기물, 인산은 시비량이 많을수록 높았으나 다른 화학성분들은 시비량과 유의성 있는 관계를 보이지 않았다. 강활의 수량은 양토에서 가장 많았으며 식토에서 가장 적었으므로 강활의 노두로 재배하는 북강활의 적정 재배 토성은 양토임이 밝혀졌다.

• 한국토양비료학회지
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• 제48권4호
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• pp.246-254
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• 2015

This study explored the effect of rainfall pattern and soil characteristics on water management in rice paddy fields, using a soil water balance model, BUDGET. In two sites with different soil textural group, coarse loamy soil (Gangseo series) and fine soil (Hwadong series), respectively, we have monitored daily decrease of water depth, percolation rate, and groundwater table. The observed evapotranspiration (ET) was obtained from differences between water depth decrease and percolation rate. The root mean square difference values between observed and BUDGET-estimated ET ranged between 10% and 20% of the average observed ET. This is comparable to the measurement uncertainty, suggesting that the BUDGET model can provide reliable ET estimation for rice fields. In BUDGET model of this study, irrigation requirement was determined as minimum water need for maintaining water-saturated soil surface, assuming 100 mm of bund height and no lateral loss of water. The model results showed different water balance and irrigation requirement with the different soil profile and indicated that minimum percolation rate by plow pan could determine the irrigation requirement of rice paddy field. For the condition of different rainfall distribution, the results presented different irrigation period and amounts, representing the importance of securing water for irrigation against different rainfall pattern.

• 한국농공학회논문집
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• 제61권2호
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• pp.97-104
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• 2019

The purpose of this study was to establish the estimation method of irrigation water amount for sewage treated water reuse for agricultural purpose. To calculate the irrigation water amount, we adopted Penman-Monteith for potential evapotranspiration estimation and applied crop coefficient and irrigation efficiency factor. We developed the irrigation water amount calculation program using C language in Xcode environment. The target district for calculation is having 259 ha of agricultural land located near the Jinyeong Clear Water Circulation Center in Hanrim-myeon, Gimhae city. The meteorological data of the study area were obtained from Changwon weather station from 1986 to 2017. Calculated average and maximum of annual mean potential evapotranspiration were 2.72 mm/day and 6.22 mm/day, respectively. We used K-S (Kolmogorov-Smirnov) for goodness-of-fit test to find optimal probability distribution of annual mean and maximum evapotranspiration. As a result, the normal distribution was selected for the appropriate distribution. The annual mean and maximum potential evapotranspiration for 10-year return period by applying normal distribution were 2.88 mm/day and 6.76 mm/day, respectively. Assuming that the irrigation efficiency is 80%, the irrigation water requirement was calculated as $36.05m^3/day/ha$ and $84.45m^3/day/ha$, respectively, when annual mean and maximum potential evapotranspiration were applied. The actual irrigation water amount can be calculated by applying the crop coefficient and cropping days for the study area based on the developed irrigation water amount estimation program in this study.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.23-23
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• 2022

Recently, soybean production and market price are unstable, even if demand of soybean is maintained. Diverse conditions such as climate change, a decrease in rural population, and consuming affect food industry. In this situation, food security is soaring as important key-word again, and MAFRA is promoting policies for improving soybean self-sufficiency with the goal of 40% until 2030. The point of policy is to extend a production and stabilize a demand for soybean with supporting large-scale soybean paddy-field complex. According to the background, soybean breeding and production research in NICS are proceeded with three parts. First, production improvement with soybean cultivation land enlargement and high-yield cultivar development. Various growth period soybean cultivars for double cropping, irrigation management technologies in paddy field, and hyper-yield and specific-region adaptable cultivar development. Second, reduction of production expense with mechanized cultivation and digital-based field management technologies. Third, consumer-friendly and high quality soybeans with high protein cultivar for alternative protein usage and high food process-ability for soy milk, tofu, soybean sprouts, and grain usage. Each part need to be combined and advanced to improve soybean industry and soybean self-sufficiency.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 춘계학술대회
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• pp.48-48
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• 2020

Assessment of plant genetic resources is applicable when breeding improved plant caltivars. In Korea, early maturing wheat germplasm is anticipated for wheat-rice double-cropping. In this study, we assessed five agronomical traits including days of heading after sowing(HD), days of maturity after sowing(MD), culm length(CL), ear length(EL), and thousand grain weight(TW) of 500 wheat germplasms collected form 10 different countries (Mexico, the United States, Afghanistan, Ethiopia, India, Japan, China, Turkey, Pakistan and Portugal), and grown in Korea. Besides, the correlation between the agronomical traits was analyzed using XLSTAT softerware version 2019 (Addinsoft, NY, USA). The result showed wide-ranging maturity period. Among the entire population, 2 accessions (K256306/JPN/breeding line and K256328/JPN/breeding line) that matured early were identified. Furthermore, HD showed strong correlation with MD (r=0.684) and CL (r=0.610), and weak correlation with the rest two agronomical traits (EL and TW). Overall, the results of our study provides wide spectrum of prospects, and could be applicable to breed new wheat varieties with early maturity.