Current Issue 2019. Vol.38, Iss.3

Orginal Articles

• Relation of Organic Matter Content and Nitrogen Mineralization of Soils Collected from Pepper Cultivated Land

  Yejin Lee, Seulbi Lee, Yangmin Kim, Yosung Song, Deogbae Lee / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 119-123

  https://doi.org/10.5338/KJEA.2019.38.3.26

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Estimation of soil nitrogen supply is essential to manage nitrogen fertilization in arable land. In Korea, nitrogen fertilization is recommended based on the soil organic matter content because it is difficult to assess nitrogen (N) mineralization of upland soils directly. In this study, the relationship between soil organic matter (SOM) content and N mineralization was investigated to explore the limitation of using SOM in predicting soil N mineralization.

  METHODS AND RESULTS:

  Soil samples from the 0 to 10 cm depth were collected from 18 individual pepper cultivated fields in Tae-an and Chung-yang provinces before fertilization. N mineralization in the soils was quantified using incubation for 70 days at 30℃. The mineralizable soil N (MSN) was positively correlated with SOM, and the relation equation between MSN and SOM was‘MSN(kg 10a^-1) = 0.2933*SOM(g kg^-1) + 0.0897 (r²=0.6224, p<0.001)’. However, the differences of N mineralization among the soils with the similar concentrations of soil organic matter were about 3 to 4.6 times, suggesting that the other soil factors such as total N concentration or EC should affect N mineralization.

  CONCLUSION:

  We concluded that SOM alone could not reflect the capacity of soil to supply N that is used for recommendation of N fertilization rate. Therefore, other soil properties should be considered to improve N fertilization management in arable land for sustainable agriculture.

• Effects of Soil Improvement and Growth of Watermelon on Plastic Film House by Soil Treatment of Miscanthus sinensis

  Byung-Koo Ahn, Do-Young Ko, Hyo-Jin Kim, Tae-Bok Kim, Hyong-Gwon Chon, Yong-Gu Kang / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 124-132

  https://doi.org/10.5338/KJEA.2019.38.3.27

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Silver grass (Miscanthus sinensis) No. 1 was developed for production of bio-ethanol, and for the purpose the silver grass growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, the other application potentials except for using as the bio-energy resources should be considered because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for improvement of soil quality in the plastic film house.

  METHODS AND RESULTS:

  The silver grass was applied at 5, 10, 15 and 20 Mg/ha and tilled before the watermelon was planted in the plastic film-house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been cultivated for 3 years(2017~2019). Soil aggregation, soil chemistry, and the growth characteristics were investigated, when the watermelon was harvested every year. Soil aggregation levels at the 2nd and 3rd year of watermelon harvest were similar from the plot applied with the silver grass at 5 Mg/ha and the control plot, and increased in the silver grass treated plots with more than 10 Mg/ha. However, there was no statistically significant difference between the plots. The nitrogen mineralization of silver grass in the control plot tended to be similar to the 5 Mg/ha plot, but the silver grass treated plots with over 10 Mg/ha showed low nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass of the silver grass, but pH was in inverse with the applied mass. Soil organic matter content, available phosphate, and exchangeable cations increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha was treated.

  CONCLUSION:

  The use of the silver grass at 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.

• Relationship Assessment on Amount of Irrigation Water & Productivity of Rice by Production Function

  Seung-Oh Hur, Soonkun Choi, Sojin Yeop, Seong-Chang Hong, Dongho Choi / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 133-138

  https://doi.org/10.5338/KJEA.2019.38.3.23

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Production function gives the equation that shows the relationship between the quantities of productive factors used and the amount of product obtained, and can answer a variety of questions. This study was carried out to evaluate the relationship between irrigation water used for rice production and rice productivity by the production function which shows the mathematical relation between input and output.

  METHODS AND RESULTS:

  The statistical data on rice production and on the amount of irrigation water were used for the production function analysis. The analysis period was separated for 1966-1981 and 1982-2011, based on goal’s change on agriculture from 'increasing food' to 'complex farming'. The relation between irrigation and yield considering production function is a short-term production function both before and after 1982. These results can be expressed by the sigmoid relation. When comparing the graphs of the two analyzed periods, there are differences in quantity between the maximum point and the minimum point during the same analysis period, which can be called an ‘Irrigation Effect’ by the difference of irrigation, and ‘Technical Effect’ by the difference by inputs like as fertilizers etc.

  CONCLUSION:

  The results could be useful as information for assessing the relationship between agricultural water and the productivity of rice and predicting rice productivity by irrigation water in Korea.

• Effect of Agricultural Land Use on Abundance, Community Structure and Biodiversity of Epigeic Arthropods

  Jin U Eo, Myung-Hyun Kim, Hyung kyu Nam, Young Ju Song / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 139-144

  https://doi.org/10.5338/KJEA.2019.38.3.17

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Epigeic arthropods participate in ecological functions as predators, decomposers and herbivores. The purpose of this study was to investigate the responses of some dominant arthropods in rice fields to different forms of agricultural land management.

  METHODS AND RESULTS:

  The abundance of microarthropods was compared between rice fields and uplands in the non-growing season. Collembola, Oribatida and Mesostigmata were more abundant in the upland fields than in the paddy fields. The community composition and diversity of epigeic arthropods were compared between fallow and rice fields. The total abundance and species richness of spiders and ground beetles were not significantly different in the two types of agricultural fields. The abundance of Arctosa kwangreungensis was greater in fallow fields than in cultivated fields. The community structure of arthropods was compared between paddy fields with and without barley. The cropping system altered the community composition of spiders but not their biodiversity. Barley cultivation increased the abundance of ground beetles but decreased that of spiders. We suggest that this contrast was partly due to the availability of plants that provided shelter and food for ground beetles.

  CONCLUSION:

  These results show that soil use intensity and cropping system alter the community composition of epigeic spiders and ground beetles. This could result in ecosystem-level alterations with respect to the control of pests and weeds. Our results also suggest that biodiversity of ground-dwelling arthropods may not increase during short fallow periods.

• Influence of Crop Load on Bitter pit incidence and Fruit Quality of 'Gamhong'/M.9 Adult Apple Trees

  Hun-Joong Kweon, Moo-Yong Park, Yang-Yik Song, Dong-Yong Lee, Dong-Hoon Sagong / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 145-153

  https://doi.org/10.5338/KJEA.2019.38.3.22

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  The 'Gamhong' cultivar, middle season apple with big fruit size and high soluble solid content, has been bred in Korea. However, it was hard to cultivate the cultivar in Korea by serious bitter pit. The relationships between shoot growth, fruit size, and bitter pit may be affected by crop load. This study was conducted for 2 years (7~8 years after planting) to investigate vegetative growth, fruit quality, bitter pit incidence, return bloom, and gross income for optimum crop load of 'Gamhong'/M.9 adult apple tree.

  METHODS AND RESULTS:

  The crop load was assigned to 4 different object ranges as follow: 45~64, 65~84, 85~104, and 105~124 fruits per tree. The vegetative growth, average fruit weight, percentage of fruits heavier than 375 g, soluble solid content, and return bloom increased significantly at the crop load range of 45~64 fruits. However, the lowest total gross income per tree may have been caused by the highest bitter pit incidence and the lowest yield per tree in any other crop load range. The total gross income and yield per tree increased significantly at the crop load range of 105~124 fruits and return bloom dropped to 40%, and hence it was possible to occur biennial bearing. It was 85~104 fruits that biennial bearing did not occur and total gross income was as high as the crop load range of 105~124 fruits. Also, the yield of high grade fruits per tree, with fruit weight of 400~499 g and none bitter pit on fruit surface, was highest at the crop load range of 85~104 fruits, compared to other crop load range.

  CONCLUSION:

  In considering fruit size, bitter pit incidence, return bloom, and gross income, the optimum crop load range of 'Gamhong'/M.9 adult apple tree in high density orchard was 85~104 fruits per tree.

• Effect of Occurrence of Scion Root on the Growth and Root Nutrient Contents of ‘Shiranuhi’ Mandarin Hybrid grown in Plastic Film House

  Seok-Beom Kang, Young-Eel Moon, Gyeong-Rok Yankg, Jae-Ho Joa, Seong-Gap Han, Hae-Jin Lee, Woo-Jung Park / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 154-158

  https://doi.org/10.5338/KJEA.2019.38.3.24

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  ‘Shiranuhi’ mandarin is a major cultivar among all late ripening type of citrus, and is widely cultivated in Korea. However, many farmers have reported scion root problems in their orchard resulting in reduced flowering and fruiting. It is necessary that the physiology of scion-rooted ‘Shiranuhi’ mandarin trees is further understood.

  METHODS AND RESULTS:

  This experiment was conducted to understand the growth response and physiology of scion-rooted ‘Shiranuhi’ mandarin hybrids. In our study, ‘Shiranuhi’ mandarin trees were divided into two groups: trees without scion roots (control) and trees with scion roots. The experiment was conducted in Seogwipo of Jeju, with ten replicates for each group. Growth of trees with scion roots was more vigorous and the trees were taller than the controls. Tree height and trunk diameter of scion-rooted trees were significantly higher than those of control trees. Exposed length of rootstocks of scion-rooted trees was significantly lower (by about 2 cm) than that of control trees (8.6 cm). In terms of root nutrition, carbon contents of scion-rooted trees was significantly lower than that of control trees, but nitrogen and potassium concentrations in scion roots were significantly higher than those in control roots.

  CONCLUSION:

  Based on the results, we infer that growth of scion-rooted trees was very vigorous and the content of nitrogen in these roots was higher than that in the control tree roots. Thus, the carbon/nitrogen ratio of scion roots was significantly lower than that of the control roots.

• Assessment & Estimation of Water Footprint on Soybean and Chinese Cabbage by APEX Model

  Seung-Oh Hur, Soonkun Choi, Seong-Chang Hong / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 159-165

  https://doi.org/10.5338/KJEA.2019.38.3.25

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  The water footprint (WF) is an indicator of freshwater use that appears not only at direct water use of a consumer or producer, but also at the indirect water use. As an indicator of ‘water use’, the water footprint includes the green, blue, and grey WF, and differs from the classical measure of ‘water withdrawal’ because of green and grey WF. This study was conducted to assess and estimate the water footprint of the soybean and Chinese cabbage.

  METHODS AND RESULTS:

  APEX model with weather data, soil and water quality data from NAS (National Institute of Agricultural Sciences), and farming data from RDA (Rural Development Administration) was operated for analyzing the WF of the crops. As the result of comparing the yield estimated from APEX with the yield extracted from statistic data of each county, the coefficients of determination were 0.83 for soybean and 0.97 for Chinese cabbage and p-value was statistically significant. The WFs of the soybean and Chinese cabbage at production procedure were 1,985 L/Kg and 58 L/Kg, respectively. This difference may have originated from the cultivation duration. The WF ratios of soybean were 91.1% for green WF and 8.9% for grey WF, but the WF ratios of Chinese cabbage were 41.5% for green WF and 58.5% for grey WF.

  CONCLUSION:

  These results mean that the efficiency of water use for soybean is better than that for Chinese cabbage. The results could also be useful as an information to assess environmental impact of water use and agricultural farming on soybean and Chinese cabbage.

• Fruit Quality of Rabbiteye Blueberry as Affected by Manual Floral Buds Thinning

  Hong Lim Kim, Won-Byoung Chae, Jin-Gook Kim, Mock-hee Lee, Han-Cheol Rhee, Seung-Hui Kim, Yong-Bum Kwack / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 166-172

  https://doi.org/10.5338/KJEA.2019.38.3.29

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Increase in the ratio of small berries in blueberry production decreases the farmers’ profits due to weakening market competitiveness and lowering harvest efficiency. One of the reasons for increased small berries is over fruit-load. For improving productivity and competitiveness of blueberry in Korea, hand-thinning can be applied to increase fruit quality before the developing adequate chemical thinning methods. This study was conducted to investigate the proper timing and methods for floral buds thinning in rabbiteye blueberry.

  METHODS AND RESULTS:

  Eight years old bushes of rabbiteye bluberries ‘Brightwell’ as a primary cultivar and ‘Powderblue’ as a pollinizer were used for this study. Fruit size distribution by leaf-to-fruit ratio was investigated by counting the number of leaves and fruits in canes of 127 ‘Brightwell’ plants whose fruit set varied. Fifty percent of flowers/floral buds were removed in four different floral buds stages such as bud swell, late pink bud, full bloom, and petal fall, and the consumed time for thinning and fruit characteristics were recorded to investigate the effect and proper timing of floral buds thinning. Fruit weight and soluble solids content tended to increase in proportion to leaf-to-fruit ratio and the production of the number of fruits less than 13 mm in diameter decreased when leaf-to-fruit ratio was more than 2.5. Manual floral buds thinning by hands was fastest in full bloom stage and slowest in bud swelling stage. In all cultivars, fruit size was significantly smaller in non-thinning treatment than thinning, and there was, however, no significant difference in total fruit yield. The number of fruits less than 13 mm in diameter increased in both cultivars as floral buds thinning was delayed. Consumed time for picking 90% berries out of total berries per bush was shortest in full bloom stage thinning in ‘Brightwell’ and bud swelling, full bloom thinning in ‘Powderblue’. These were 25 and 20 days faster than no thinning, respectively.

  CONCLUSION:

  Although the effect of floral buds thinning varied depending on the cultivars, our results confirmed that floral buds thinning was effective for the early intensive harvesting and the increase of the large fruit ratio and the harvesting productivity. Also, in order to increase thinning efficiency, it is recommended to remove the flower buds before the full bloom stage.

• Monitoring of Pesticide Residues Concerned in Stream Water

  Yee-Jin Oh, Hye-Young Kwon, Jin-Ho Ro, Dan-Bi Kim, Byeong-Chul Moon, Min-Seok Oh, Hyun-Ho Noh, Sang-Won Park, Geun-Hyoung Choi, Song-Hee Ryu, Byung-Seok Kim, Kyeong-Seok Oh, Chi-Hwan Lim, Hyo-Sub Lee, In-Seong Hwang / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 173-184

  https://doi.org/10.5338/KJEA.2019.38.3.21

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  This study was carried out to investigate pesticide residues from fifty streams in Korea. Water samples were collected at two times. Thee first sampling was performed from april to may, which was the season for start of pesticide application and the second sampling event was from august to september, which was a period for spraying pesticides multiple times.

  METHODS AND RESULTS:

  The 136 pesticide residues were analyzed by LC-MS/MS and GC/ECD. As a result, eleven of the pesticide residues were detected at the first sampling. Twenty eight of the pesticide residues were detected at the second sampling. Seven pesticides were frequently detected from more than 10 water samples. Ecological risk assessment (ERA) was carried out by using residual and toxicological data. Four scenarios were applied for the ERA. Scenario 1 and 2 were performed using LC50 values and mean and maximum concentrations. Scenarios 3 and 4 were conducted by NOEC values and mean and maximum concentrations.

  CONCLUSION:

  Frequently detected pesticide residues tended to coincide with the period of preventing pathogen and pest at paddy rice. As a result of ERA, five pesticides (butachlor, carbendazim, carbofuran, chlorantranilprole, and oxadiazon) were assessed to be risks at scenario 4. However, only oxadiazon was assessed to be a risk at scenario 3 for the first sampling. Oxadiazon was not assessed to be a risk at the second sampling. It seems to be temporary phenomenon at the first sampling, because usage of herbicides such as oxadiazon increased from April to march for preventing weeds at paddy fields. However, this study suggested that five pesticides which were assessed to be risks need to be monitored continuously for the residues.

• Effects of Disease Resistant Genetically Modified Rice on Soil Microbial Community Structure According to Growth Stage

  Soo-In Sohn, Young-Ju Oh, Jae-Hyung Ahn, Hyeon-jung Kang, Woo-Suk Cho, Yoonsung Cho, Bum Kyu Lee / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 185-196

  https://doi.org/10.5338/KJEA.2019.38.3.18

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  This study investigated the effects of rice genetically modified to be resistant against rice blast and rice bacterial blight on the soil microbial community. A comparative analysis of the effects of rice genetically modified rice choline kinase (OsCK1) gene for disease resistance (GM rice) and the Nakdong parental cultivar (non‐GM rice) on the soil microbial community at each stage was conducted using rhizosphere soil of the OsCK1 and Nakdong rice.

  METHODS AND RESULTS:

  The soil chemistry at each growth stage and the bacterial and fungal population densities were analyzed. Soil DNA was extracted from the samples, and the microbial community structures of the two soils were analyzed by pyrosequencing. No significant differences were observed in the soil chemistry and microbial population density between the two soils. The taxonomic analysis showed that Chloroflexi, Proteobacteria, Firmicutes, Actinobacteria, and Acidobacteria were present in all soils as the major phyla. Although the source tracking analysis per phylogenetic rank revealed that there were differences in the bacteria between the GM and non‐GM soil as well as among the cultivation stages, the GM and non‐GM soil were grouped according to the growth stages in the UPGMA dendrogram analysis.

  CONCLUSION:

  The difference in bacterial distributions between Nakdong and OsCK1 rice soils at each phylogenetic level detected in microbial community analysis by pyrosequencing may be due to the genetic modification done on GM rice or due to heterogeneity of the soil environment. In order to clarify this, it is necessary to analyze changes in root exudates along with the expression of transgene. A more detailed study involving additional multilateral soil analyses is required.

• Simulative Study of Effects of LM Microorganism on Environment: Analyses of Metabolomes and Soil Microbial Communities

  Ji-Hoon Lee, Min-Gyu Ki / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 197-204

  https://doi.org/10.5338/KJEA.2019.38.3.19

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Living modified microorganisms (LMMs) have been focused in two very different aspects of positive and negative effects on ecology and human health. As a model experiment, wild type and a foreign origin gene-harboring modified E. coli strains were subjected to comparison of their metabolomes and potential effects on soil microbiota in the laboratory sets. This study assumes the unintentional release of LMMs and tries to suggest potential effects on the soil microbiota even at minimal settings.

  METHODS AND RESULTS:

  Metabolomes from the wild type and LM E. coli were analyzed by NMR and the profiles were compared. In the laboratory soil experiments, the two types of E. coli were added to the soils and monitored for the bacterial community compositions. Those metabolomic profiles did not show significant differences. The microbial community structures from the time series soil DNAs for both the sets using wild type and LMO also did not indicate significant changes, but minor by the addition of foreign organisms regardless of wild or LMO.

  CONCLUSION:

  Even if the recombinant microorganism (LMO) is released into the soil environment, the survival of microorganisms in the environment would be one of the major factors for the transfers of foreign genes to other organisms and diffusion into the soil environment.

• A Survey on the Residual Pesticides on Agricultural Products on the Markets in Incheon from 2016 to 2018

  Jeong-Eun Park, Mi-Yeon Lee, Sun-Hoi Kim, Sung-Min Song, Byung-Kyu Park, Soon-Jae Seo, Jae-Yong Song, Myong-Je Hur / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 205-212

  https://doi.org/10.5338/KJEA.2019.38.3.20

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  This survey conducted on agricultural products in Incheon for the past three years from 2016 to 2018 to detect residual pesticides and to monitor the use of pesticides.

  METHODS AND RESULTS:

  Residual pesticides were analyzed for a total of 5,937 agricultural products in Samsan wholesale market, traditional market and large retailers in Incheon. Samples were analyzed by multi class pesticide method using GC-MS/MS, LC-MS/MS, GC-ECD/NPD, and UHPLC. In 59 cases (1.0%) residual pesticides were detected improperly and these cases exceeded maximum residue limits (MRLs).

  CONCLUSION:

  The ratios of violative agricultural products were similar each year at approximately 1.0% per year, but the residual pesticide detection rates with the limit included in the samples were shown to be gradually decreasing to 17.9%, 12.6%, and 11.2% annually. The frequency of violative residual pesticides was high in order of Diazinon, Chlorpyrifos, Iprodione, etc. Residual pesticide monitoring might be needed in the future continuously, as violations in agricultural products distributed in Incheon are shown at a similar level every year.

• Status and Changes in Chemical Properties of Upland Soil from 2001 to 2017 in Korea

  Yi-Hyun Kim, Myung-suk Kong, Eun-Jin Lee, Tae-Goo Lee, Goo-Bok Jung / Korean Journal of Environmental Agriculture / 2019 / v.38, no.3, 213-218

  https://doi.org/10.5338/KJEA.2019.38.3.28

  Abstract Full-Text PDF

  Abstract

  

  BACKGROUND:

  Monitoring of the dynamic changes of chemical properties in agricultural land is very important for agricultural sustainability. Chemical properties of agricultural soils in Korea have been investigated at four-year interval in the order of paddy, plastic film house, upland, and orchard soils since 1999.

  METHODS AND RESULTS:

  Total 8,160 topsoil samples were taken from the upland in 2001, 2005, 2009, 2013, and 2017, respectively. Soil chemical properties such as pH, electrical conductivity (EC), organic matter (OM), available phosphate (Avail. P₂O₅), and exchangeable (Exch.) cations (K, Ca, and Mg) were analyzed. Soil pH and Exch. Ca contents have increased since 2001. Average concentration of Avail. P₂O₅ increased from 547 mg kg^-1 in 2001 to 657 mg kg^-1 in 2017. Average concentration of Exch. Ca in 2017 was higher than the upper limit of its optimal range for upland cultivation. Excess and deficiency of chemical properties of upland soils comply with soil analysis and fertilizer prescription.

  CONCLUSION:

  We concluded that excessive nutrient in upland needed to be properly managed with soil test.