• 한국작물학회지
• /
• 제51권2호
• /
• pp.179-185
• /
• 2006

The Ministry of Agriculture and Forestry announced in 2001 that the overall amount of paddy land set aside for rice will be cut down by 12% by 2005, decreasing from 1.08 million to 953,000 hectares. When evaluating the value of paddy rice systems, the multi-function of paddy systems in the monsoon climate is vital importance. The main functions of paddy rice systems are to conserve biodiversity and maintain sustainability. Some crucial environmental benefits of the paddy rice systems include: flood prevention, recharge of water resources, water purification, soil erosion and landslide prevention, soil purification, landscape preservation and air purification. The paddy rice systems in Korea, which are more diverse than upland crop systems, are known to be composed of 14 orders, 36 families and 134 species. The sustain ability of paddy rice production systems can never be overestimated. Rice is part of the culture and even the heart of spiritual life in the area under the monsoon climate. Therefore paddy rice systems should be preserved with the highest priority being the enhancement of the systems' multi-function. As an outlook to future research, the need of joint and interdisciplinary research projects between economists and natural scientists at inland as well as international levels were emphasized in establishing the development of counter-measure logic through actual proofed analysis.

• 한국토양비료학회지
• /
• 제49권1호
• /
• pp.7-11
• /
• 2016

Winter crops have been recognized as an alternative to soil management for fertility and crop productivity in paddy soil. Recently, rape has been produced at winter season and there is little research results on reduction of N fertilizer by adding rape residues for rice cultivation. In this study, we investigated the productivity and quality of rice by applying with 0, 27, 63, $90kg\;ha^{-1}$ of N fertilizer after input of rape residues into soil for two years. The highest yield of rice was average $4.68Mg\;ha^{-1}$ at the treatment applied with the $90kg\;N\;ha^{-1}$ with rape residue. It was reduced to N rate from 31.6 to $43.2kg\;N\;ha^{-1}$ in comparison to $4.53Mg\;ha^{-1}$ of maximum yield in treatment added $90kg\;N\;ha^{-1}$ with rape. Amylose content in rice was similar among treatments with/without rape residue, but protein content was lower in treatment with rape residue than in those without rape residue. In conclusion, input of rape residue in rice cultivation could be alternative to reduction of N fertilization and improvement of quality by adjusting rice productivity in paddy soil under cropping system.

• 한국토양비료학회지
• /
• 제50권3호
• /
• pp.150-161
• /
• 2017

This study was conducted with the data of monitoring on soil chemical properties of rice paddy soils in Gyeongbuk Province. The selected soil chemical properties were analyzed every 4 year from 1999 to 2015. The soil pH measured in 2015 was higher than pH 6.0, which was 0.3-0.4 pH unit higher than data until 2007 survey year. The mean content of organic matter was greater than $24g\;kg^{-1}$ since 2003, but 35% of soil samples remained below the recommended level ($20-30g\;kg^{-1}$) in 2015. The mean concentration of available phosphate was maintained at $40mg\;kg^{-1}$ higher than the upper recommendation level ($80-120mg\;kg^{-1}$), and more than 40% of paddy soils tested were found to have less than the recommendation level during the survey period. The exchangeable K concentration ranged from 0.25 to $0.39cmol_c\;kg^{-1}$. Exchangeable Ca showed an average at the optimum range ($5.0-6.0cmol_c\;kg^{-1}$) during the monitoring period. Exchangeable Mg decreased linearly ($0.02cmol_c\;kg^{-1}\;year^{-1}$) from $1.55cmol_c\;kg^{-1}$ as of 1999 to below the lower level of the recommendation range ($1.5-2.0cmol_c\;kg^{-1}$). The amount of available $SiO_2$ was increased significantly from 2011 to over the recommendation level (${\geq}157mg\;kg^{-1}$). It was revealed that the soil chemical properties of rice paddy fields was influenced by topology, soil texture, type and region as result of principal component analysis or cluster analysis. Therefore, an assessment on chemical properties of rice paddy soils should be performed to consider various soil physical conditions and agronomic practices such as fertilization, cropping system, and so on. Because of the high variability of nutrient levels across Gyeongbuk Province, nutrient management based on soil fertility test is required by respective farm land unit.

• 한국토양비료학회지
• /
• 제16권2호
• /
• pp.162-167
• /
• 1983

논토양(土壤) 성분(成分)의 용탈(溶脱)에 미치는 유기물(有機物)의 영향(影響)을 구명(究明)하기 위하여 퇴비(堆肥)와 볏짚을 시용(施用)하여 Pot 시험(施驗)으로 투수조건하(透水條件下)에서 수도(水稻)를 재배(栽培)하면서 용탈(溶脱) 성분(成分)을 분석검토(分析檢討)한 결과(結果)는 다음과 같다. pH는 볏짚시용구(施用区)보다 퇴비시용구(堆肥施用区)가 약간 높았다. 철과 망간의 용탈량(溶脱量)은 볏짚시용구(施用区)가 퇴비(堆肥) 시용구(施用区)보다 많고 수도재배(水稻栽培)에 의(依)해서도 증가(増加)되었다. 석회(石灰)과 고토(苦土)는 경시적(經時的)으로 용탈(溶脱)이 증가(増加)되었고 퇴비시용구(堆肥施用区)가 볏짚시용구(施用区)보다 용탈량(溶脱量)이 많았다. 가리(加里)와 암모니움은 경시적(經時的)으로 용탈량(溶脱量)이 감소(減少)하고 퇴비시용구(堆肥施用区)가 볏짚시용구(施用区)보다 용탈(溶脱)이 많이 되었다. 인산(燐酸)은 재배(栽倍)와 더불어 용탈량(溶脱量)이 증가(増加)되고 볏짚시용구(施用区)의 용탈량(溶脱量)이 많았다. 규산(珪酸)은 재배(栽倍)와 더불어 용탈(溶脱)이 감소(減少)되고 볏짚시용구(施用区)의 용탈량(溶脱量)이 더 많았다.

• 한국농공학회지
• /
• 제43권6호
• /
• pp.154-162
• /
• 2001

This study was performed to examine the rice growth and nutrient change in paddy soil with reclaimed sewage irrigation. Total nitrogen and total phosphorus in the experimental system were analyzed before and after rice culture. The experiment lasted three consecutive years, and this paper presents results of the last year. Additional supply of nutrients to the rice culture by reclaimed sewage irrigation was significant and it increased the yield. Nutrient uptake by rice plant increased with more nutrient supplied, however. there was limit in plant uptake. Nutrient accumulation occurred in the soil and it was more apparent for the phosphorus where most of the remaining quantity was accumulated while substantial amount of nitrogen was lost during the growing season. This study suggested that additional nutrient supply by reclaimed sewage irrigation might be a supplemental benefit to the rice culture, and it can help the fertilization management. However, long term effects of continual reclaimed sewage irrigation should be assessed carefully including nutrient mass balance in the paddy rice culture system.

• 한국자원식물학회지
• /
• 제35권5호
• /
• pp.686-695
• /
• 2022

벼 대체 밭작물(검정콩, 들깨, 참깨)과 연계한 밀 이모작 작부체계를 적용한 논에서 조경밀 생산성과 밀가루의 품질 특성을 살펴보았다. 전작으로 검정콩, 참깨, 들깨를 재배하였던 포장은 벼를 재배한 논보다 토양의 pH는 높고, 전기전도도는 낮았다. 그리고, 유효인산(Av. P₂O₅), Ca²⁺과 Mg²⁺ 함량은 벼를 재배하였던 토양에서보다 높았다. 밀의 생육 특성 중 간장, 수장, 수수, 수당립수는 검정콩 전작 토양에서 전반적으로 양호하였다. 하지만, 밀의 수량은 벼 전작 토양에서보다 대체작물인 검정콩이나 참깨, 들깨의 전작 토양에서 모두100 kg/10a 이상 증가하였다. 더군다나, 단백질 함량과 SDS-침전가가 검정콩, 참깨, 들깨 전작에서 모두 벼 전작에서보다 높았으며, 아밀로스 함량은 벼 전작에서보다 검정콩, 들깨 전작에서 다소 낮았다. 이러한 결과들은 논토양에서 전작으로 참깨나 콩, 들깨 등의 벼 대체 작물들의 재배는 토양의 물리화학적 특성을 개선하고 제빵공정에 좀 더 유리한 고품질의 밀을 생산하는데 이바지할 수 있음을 보여준다.

• Journal of Biosystems Engineering
• /
• 제27권2호
• /
• pp.133-142
• /
• 2002

This is a fundamental study to develop a sensor to detect weeds in paddy field using machine vision adopted spectralphotometric technique in order to use the sensor to spread herbicide selectively. A set of spectral reflectance data was collected from dry and wet soil and leaves of rice and 6 kinds of weed to select desirable wavelengths to classify soil, rice and weeds. Stepwise variable selection method of discriminant analysis was applied to the data set and wavelengths of 680 and 802 m were selected to distinguish plants (including rice and weeds) from dry and wet soil, respectively. And wavelengths of 580 and 680 nm were selected to classify rice and weeds by the same method. Validity of the wavelengths to distinguish the plants from soil was tested by cross-validation test with built discriminant function to prove that all of soil and plants were classified correctly without any failure. Validity of the wavelengths for classification of rice and weeds was tested by the same method and the test resulted that 98% of rice and 83% of weeds were classified correctly. Feasibility of CCD color camera to detect weeds in paddy field was tested with the spectral reflectance data by the same statistical method as above. Central wavelengths of RGB frame of color camera were tried as tile effective wavelengths to distingush plants from soil and weeds from plants. The trial resulted that 100% and 94% of plants in dry soil and wet soil, respectively, were classified correctly by the central wavelength or R frame only, and 95% of rice and 85% of weeds were classified correctly by the central wavelengths of RGB frames. As a result, it was concluded that CCD color camera has good potential to be used to detect weeds in paddy field.

• 한국작물학회지
• /
• 제44권2호
• /
• pp.102-105
• /
• 1999

Mineralization of organic N is an important factor in determining the appropriate rate of organic matter application to paddy fields. A kinetic analysis was conducted for nitrogen mineralization of rice, barley, Chinese milk Ovetch (Astragalus sinicus L.; MV) and narrow leaf vetch straw in paddy soil. Nitrogen immobilization occurred rapidly and its rate increased in straw with high C/N ratio. The amount of nitrogen mineralization was rapid in the first year of rice-vetch cropping system. The rate constant (K) depended on the C/N ratio of organic matter. Mineralization of straw increased at high temperature. The amount of available N increment resulted in fast mineralization of straw, especially in rice and barley straw. Chinese milk vetch had the greatest mineralization rate at all temperatures and fertilization levels followed by narrow-leaf vetch. However, rice and barley straws with high C/N ratio immobilized the soil N at the initial incubation duration. Chinese milk vetch or narrow leaf vetch was not effectively mineralized in mixed treatments with rice or barley straw. The mineralization rate of organic matter was mostly affected by the C/N ratio of straw and temperature of incubation. Organic matter with low C/N ratio should be recommended to avoid the immobilization of soil N and the increasing mineralization rate of straw.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.340-340
• /
• 2017

Rice straw is very important to maintain fertility in agricultural soil with several aspects such as carbon and nitrogen cycles in Korea. Recently, concerning about climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. Rice straw is most representative source of organic material produced in agricultural sectors. In order to evaluate changes of soil carbon treated by rice straw during cultivating rice in paddy field, we carried out to treat rice straw with 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ at $50{\times}50{\times}20cm$ blocks made of wood board, and analyze contents of fulvic acid and humic acid form, and total carbon periodically. The experiment was conducted in 2013-2016, and sampled with interval in a month. The organic material was applied to treatment blocks in 2 weeks ago in rice transplanting of each year. Total carbon in beginning time is low as $7.9g\;kg^{-1}$. The contents of total carbon with treatments of rice straw after experiment are recorded as 8.7, 11.2, 9.5, 10.5, and $10.9g\;kg^{-1}$ applied by 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$, respectively. When trend lines were calculated on changes of soil carbon in periods of experiments, The trend equations of soil carbon changes with treatments of 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ were Y=0.0015X+8.479, Y=0.073X+8.2577, Y=0.0503X+8.4477, Y=0.0822X+8.2103, and Y=0.082X+8.5736. These trends suggested several results. When rice straw was applied in cultivating paddy fields, most carbon in rice straw would be decomposed regardless the amount of rice straw in soil. We calculated sequestration rate of applied rice straw as about 0.1% per year during rice cultivation in paddy fields. It means that if farmer want to increase 1% soil organic matter by using application of rice straw returned after cultivation, famer should apply rice straw continuously for ten years. The change of soil carbon as fulvic acid, humic acid, and humane is showed that only content of carbon as mumine is increased significantly while fulvic acid and humic acid were changed in range of 10 to 30% among total carbon in soil. In conclusion, to sequestrate soil carbon with rice straw, it is important for rice straw to apply continuously every year. The amount of rice straw applied is not much effected to increase soil organic matter.

• 한국토양비료학회지
• /
• 제46권6호
• /
• pp.487-493
• /
• 2013

The effects of long-term fertilization on soil biological properties and microbial community structure in the plough layer in a rice paddy soil in southern Korea were investigated in relation to the continuous application of chemical fertilizers (NPK), straw based compost (Compost), combination these two (NPK + Compost) for last 40 years. No fertilization plot (Control) was installed for comparison. Though fertilization significantly improved rice productivity over control, the long-term fertilization of NPK and compost combination was more effective on increasing rice productivity and soil nutrient status than single application of compost or chemical fertilizer. All fertilization treatments had shown significant improvement in soil microbial properties, however, continuous compost fertilization markedly increased soil enzyme and microbial activities as compared to sole chemical fertilization. Results of microbial community structure, evaluated by EL-FAME (ester-linked fatty acid methyl esters) method, revealed big difference among Control, NPK, and Compost. However, both Compost and Compost+NPK treatments belonged to the same cluster after statistical analysis. The combined application of chemical fertilizer and organic amendments could be more rational strategy to improve soil nutrient status and promote soil microbial communities than the single chemical fertilizer or compost application.