• 한국유기농업학회지
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• 제25권4호
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• 한국작물학회지
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• 제44권2호
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• pp.97-101
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• 1999

No-till direct seeding cultivation of rice has major advantages such as saving of labor and cost by eliminating tillage, preparation of seed bed and trans-planting procedure compared to the conventional transplanting cultivation. A field experiment was conducted to evaluate the effects of straw treatment and nitrogen levels on the rice growth in no-till direct-seeding cultivation. Rice straw, vetch straw, and the mixture of both of the straws were mulched on the surface of soil before seeding while 4 levels of nitrogen fertilizer, 0, 7, 9, and 11 kkg/10a respectively, were applied at 3 split times, 3-weeks after sowing, 5-weeks after sowing and the panicle initiation stage. Mulching of vetch straw significantly reduced seedling establishment of rice which may be attributed to low oxidation-reduction potential of soil by vetch mulching treatment. Vetch straw increased the concentration of soil ammonium leading to an extension of the greenish leaf to panicle initiation stage. Agronomic nitrogen use efficiency (AD $E_{N}$) in heavy-mixed straw mulching plots was lower than other treatments. Grain yield and AU $E_{N}$ in the vetch treatment were less affected by fertilized N levels. Conclusively, it is suggested that heavy straw mulching was not efficient for rice seedling establishment and nitrogen usage.e.

• 한국환경농학회지
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• 제26권3호
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• pp.223-227
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• 2007

토양의 질산태 질소를 이용하여 시설 오이의 적정 질소 시비량을 결정하고자 질산태 질소 함량이 67-343 mg/kg의 범위를 갖는 8곳의 시설재배 토양으로부터 오이를 공시작물로 표준시비구와 무시비구에 대한 생산력 검정시험을 포트 재배로 조사하였다. 오이의 수량은 최소 1,006 g/plant에서 최대 2,369 g/plant로 토양 질소함량 수준에 따라 다양한 생산능력의 차이를 보였다. 토양의 질산태 질소는 Agronomic efficiency(AE)과 N use efficiency(NUE)와는 부의 상관을 보였다. 질소 무비 재배를 위한 시험 전 토양의 질산태 질소 임계기준은 토양의 질산태 질소 함량에 대한 AE 및 NUE의 관계를 Cate-Nelson 일원분류의 분산분석법으로 비교하고 또한 무비구의 수량 및 지상부의 질소 흡수량과의 관계로부터 추정하였을 때 약 260 mg/kg으로 나타났다. 질소 표준 시비가 요구되는 시험 전 토양의 질산태 질소 임계기준은 70 mg/kg으로 추정되었다. 질산태 질소 함량이 70-260 mg/kg 범위의 토양에서는 Y=-1.032X + 269.2(Y: 질소시비량, kg/ha; X: 시험 전 토양의 질산태 질소 함량, mg/kg) 추천식으로 질소시비량을 결정할 수 있다.

• Near Infrared Analysis
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• 제1권2호
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• pp.35-39
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• 2000

The purpose of this research was to find out suitable soil sample preparation and sample holding tools for NIR reflection radiation for estimating soil components. NIR reflectance was scanned at 2nm intervals from 1,100 to 2,500nm with an InfraAlyzer 500(Bran+Luebbe Co.). Coarse(2.0mm) and fine(0.5mm) soil sample and various sample holding tools were used to obtain mean diffuse reflection of the soil for the calibration and validation of the calibration set in estimating moisture, organic matter and total nitrogen of the soils. Multiple linear regression was used to obtain the best correlation of NIR spectroscopy method. Correlation of NIR spectroscopy method. Correlation of NIR spectra for finely and coarsely sized soil did not show much difference. The standard errors of prediction(SE) using different types of sample holding tools for organic matter, total nitrogen and soil moisture were better than 0.765, 0.041 and 0.63% respectively. From the results it can be concluded that NIR spectroscopy with flow type cell could be used as a fast routine testing method in quantitative determination of organic matter, total nitrogen and soil moisture.

• 한국토양비료학회지
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• 제37권2호
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• pp.83-90
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• 2004

토양의 EC와 관개수중 질산태 질소 함량이 상추의 생육에 미치는 영향을 구명하고자 본 시험을 수행하였다. 가로, 세로, 높이가 각각 42, 54.5, 22 cm인 사각포트에 토양 EC가 비교적 낮은 토양과 높은 토양 40 kg을 충진 시켰으며, 각각의 토양에 무비료구, 토양검정시비량의 질소 50% 감비구, 토양검정시비구를 두고 질산태 질소 함량이 각각 6.6 및 $21.0mg\;L^{-1}$인 두 가지 지하수를 관개수로 이용하여 상추를 재배하였다. EC가 낮은 토양에서 질소 함량이 낮은 지하수를 관개한 경우, 무비구, 토양검정시비량의 질소 50% 감비구 및 토양검정시비구의 상추 생산량은 각각 6,733, 11,933 및 $12,733kg\;ha^{-1}$이었고, 질소함량이 높은 지하수를 관개한 경우 무비구, 토양검정시비량의 질소 50% 감비구 및 토양검정시비구의 상추 생산량은 각각 9,733, 13,400 및 $12,800kg\;ha^{-1}$이었다. EC가 높은 토양에서 질소함량이 낮은 지하수를 관개한 경우 무비구, 토양검정시비량의 질소 50% 감비구 및 토양검정시비구의 상추 생산량은 각각 12,400, 12,867 및 $10,400kg\;ha^{-1}$이었고, 질소함량이 높은 지하수를 관개한 경우 무비구, 토양검정시비량의 질소 50% 및 토양검정시비구의 상추 생산량은 각각 13,600, 14,067, $10,733kg\;ha^{-1}$이었다. 비료에 의한 질소 흡수는 토양검정시비구보다 토양검정시비량의 질소 50% 감비구에서 더 높았다. EC가 낮은 토양에서는 관개수중의 질소가 상추에 의해 흡수 이용되었으나, EC가 높은 토양에서는 관개수에 의한 질소 공급은 없는 것으로 나타났다. 이와 같은 결과를 보면 엽채류에 대한 시비량은 토양 양분 및 관개 지하수중의 질소함량을 고려하여 결정되어야 할 것으로 사료된다.

• 한국토양비료학회지
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• 제27권3호
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• pp.232-237
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• 1994

발작물 재배시(栽培時) 토양(土壤)에 시용(施用)한 질소(窒素)(요소(尿素))가 토양수분조건(土壤水分條件)을 달리하였을 때, 작물재배시기별(作物栽培時期別)로 어떻게 이동(移動)하는가를 공명(空明)하기 위하여 사양토에서 Ladino clover를 재배(栽培)하면서 microplot(지름 20cm, 길이 85cm) 시험(試驗)을 수행(遂行)하였다. 질소비료(窒素肥料)로 요소(尿素)를 토양에 시용(施用)했을 때 대부분의 요소(尿素)가 단시일내에 가수분해되어 시험시작(試驗始作) 1개월(個月) 후(後)에는 시용(施用)한 요소(尿素)의 95%가 $NH_4$-N로 되었으나 $NO_3$-N로 형태변환(形態變煥)되는 데는 비교적 오랜 시일이 걸렸다. 토양중 $NO_3$-N는 시험시작(試驗始作) 2개월(個月) 후(後)에 $NH_4$-N보다 많아졌고, 2.5개월(個月) 후(後)에는 $NH_4$-N보다 2배 이상 많아졌다. 토양중에 $NH_4$-N가 많았던 시험초기(試驗初期)에는 무기태질소(無機態窒素)의 하향이동(下向移動) 속도(速度)가 느렸으나, $NH_3$-N가 $NH_4$-N보다 현저하게 많아진 2.5개월(個月) 이후에는 하향이동(下向移動)이 매우 빠르게 일어났다. 시험시작(試驗始作) 3.5개월(個月) 후(後)에는 대부분의 $NO_3$-N가 50~80cm 깊이의 토층(土層)에 분포하였다. 토양수분조건(土壤水分條件)이 좋을수록 무기태질소(無機態窒素)의 하향이동(下向移動)이 활발하게 일어났으며 식물체(植物體)에 의한 흡수량(吸收量)도 많아 microplot내 토층에 남아있는 양이 적어졌다. 최종수확기(最終收穫期)에 나지구(裸地區)에서는 시용질소(施用窒素)의 92%인 3.66g의 질소가 microplot 외부(外部)로 하향이동(下向移動)되었다. 무관개구에서는 시용질소(施用窒素)의 57%가 식물체에 의해 흡수(吸收)되었고 37%가 토양중에 남아있었다. 관수점(灌水點) 0.2 bar 처리구(處理區)에서는 식물체에 의한 질소흡수량(窒素吸收量)이 4.03g으로서 시비량(施肥量)보다 많았으며, microplot 외부(外部)로 하향이동(下向移動)도 많이 일어나 근류균에 의한 공중질소(空中窒素) 고정량(固定量)도 많은 것으로 생각된다.

• 한국농공학회논문집
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• 제63권4호
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• pp.13-21
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• 2021

The feasibility of HWS for agricultural use was analyzed through a crop cultivation test to utilize the hydroponic waste solution (HWS) generated from the nutriculture greenhouse. The fertilizing effect of HWS was assessed on the basis of the inorganic nitrogen (N) mostly existed in HWSs, and nitrogen (urea) fertilizer. Lettuce was selected as the target crop influenced by the soil treatment and also for the crop cultivation test. Thus, the change in growth characteristics of lettuce and that in chemical characteristics of the soil were investigated. In terms of the growth of lettuce, the C control group with 70% nitrogen (urea) fertilizer and 30% HWS and the D control group with 50% nitrogen (urea) fertilizer and 50% HWS were more effective than the practice control group (B) with 100% nitrogen (urea) fertilizer. The results of this study confirmed the combined applicability of the chemical fertilizer and HWS for crop cultivation. Because NO₃-N present in HWS has a high possibility of leaching into the soil, its applicability as a fertilizer has been considered to be relatively low in Korea. However, if an appropriate mixing ratio of urea fertilizer and HWS could be applied, the problems associated with leaching of nitrate nitrogen could be reduced with beneficial effects on crop cultivation. Thus, future studies are required on the treatment effect of HWS with repeated cultivation, impact assessment on the surrounding environment, and appropriate fertilization methods using nitrogen (urea) fertilizer and HWS. These studies would facilitate the sustainable recycling of HWS.

• 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.

• 한국토양비료학회지
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• 제7권3호
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• pp.147-154
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• 1974

질소(窒素)의 정조생산효율을 높이는 방법(方法)을 찾고자 정조수량(精租收量)(Y) 질소효율(E) 및 질소흡수량(窒素吸收量)(N)간(間)의 상호관계(相互關係)를 우리나라와 일본자료(日本資料)에 의(依)하여 찾아보았다. E와 N간(間)의 관계는 수개(數個) 계층(階層)으로 구분(區分)할 수 있었으며 각계층내(各階層內)에서 Y=EN=(b-aN)N 관계(關係)가 성립(成立)되었으며 여기서 b는 E의 이론적최대치(理論的最大値)였고 a는 이론적(理論的) 최대수량(最大收量)에서의 E/N치(値)였다. 수도고수량(水稻高收量) 연구(硏究)에 있어 현재(現在)의 기술(技術)은 효율 56.8에 이르렀으며 이때 질소흡수량(窒素吸收量)은 15.5kg이었다. 장래(將來)의 목표(目標)는 질소(窒素) 흡수량(吸收量) 17kg에서 효율 63에 이르는 것으로 나타났다. 일본독농가(日本篤農家)에서는 이 수준(水準)에 이미 도달(倒達)했을 가능성이 있다. 질소효율(窒素效率)의 증가(增加)없이는 고수량(高收量)을 달성(達成)할 수 있는 질소흡수(窒素吸收)가 증가(增加)되지 않는 것으로 보였다. 토양질소(土壤窒素)의 효율(效率)과 흡수량(吸收量)의 증대(增大)가 전체질소(全體窒素)의 효율증대에 필수요건(必須要件)으로 나타났다.

• Applied Biological Chemistry
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• 제41권8호
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• pp.583-586
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• 1998

Porous ceramic cups are used for monitoring ion concentration in soil solutions in various time course and depth. A soil solution sampler was constructed in laboratory by inserting pliable perfluoroalkoxy(PFA) tubings into porous cup through holes in PVC rod segment which plugged top opening of the porous cup. The system was installed in drip irrigated soil in a vertical position, and nitrogen movement below the drip basin was monitored. To collect soil solution, vacuum in the cup was applied with a hand vacuum pump. The samples obtained were sufficient enough to run quantitative analyses for a number of chemicals. Nitrogen transformation and movement could be well defined, and the system seemed to be relevant to the other soil solution samplers in monitoring chemical movement in soil. Although this system has general deficiencies found in the other samplers using ceramic cup, it could be easily constructed at a low cost. Since the tubing was pliable, the cups could be installed in horizontal position, and this allows installations of the cups at more precise depth increments and also more precise samplings of soil solution at each depth.