• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.307-319
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• 1999

The aim of this study is to assess the OSMI (Ocean Scanning Multi-spectral Imager), whose central bands are 443nm, 490nm, 510nm, 555nm, 670nm, and 865nm, for agricultural applications. Radiance measurements, used to determine per cent reflectance of canopies and soils, were acquired with spectro-radiometers (Li-1800;330∼1,100nm, GER-SFOV;350∼2,500nm, and MSR-7000; 300∼2,500nm) in situ for crops and indoors for soils. OSMI equivalent bands and their ratio values were prepared(20nm interval for bands 1∼5; 40nm interval for band 6) by averaging spectral reflectance values to the real OSMI bands and analyzed as to crop growth parameters, leaf area index (LAI), total dry matter, and growth index in crops and physiochemical properties in soils. Spectral variations for each growth stage in rice and for crop discrimination in upland crops were significant statistically. In soils, clay and water content, CEC (Cation Exchange Capacity), free iron oxide, and some cation content were correlated with the OSMI equivalent bands. The result of this study shows OSMI wave bands would be promising for agricultural application in terms of spectral information and resolution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.3
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• pp.15-20
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• 1980

Heritability of heading date, maturing date and culm length were high and the year variation was relatively low. Yield components were considerably low in heritability due to large year variation. Direct effects of number of spikes/$m^2$ and 1, 000 grain weight to yield were high. For improved selection efficiency, at least three years continuous evaluation of experiments would be desired.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.08a
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• pp.57-74
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, the two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if prescribed N for site-specific fertilizer management at panicle initiation stage (VRT) could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, ,33 kg N/ha at PIS) method. The trial field was subdivided into two parts and each part was subjected to UN and VRT treatment. Each part was schematically divided in $10\times10m$ grids for growth and yield measurement or VRT treatment. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for this calculation were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with average of 57kg/ha that was higher than 33kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%\;and\;7.1\%$ in VRT from $14.6\%\;and\;13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. Although N use efficiency of VRT compared to UN was not quantified due to lack of no N control treatment, the procedure used in this paper for VRT estimation was believed to be reliable and promising method for managing within-field spatial variability of yield and protein content. The method should be received further study before it could be practically used for site-specific crop management in large-scale rice field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.4
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• pp.108-114
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• 1980

A deterministic conceptual erosion model which simulates detachment, entrainment, transport and deposition of eroded soil particles by rainfall impact and flowing water is presented. Both upland and channel phases of sediment yield are incorporated into the erosion model. The algorithms for the soil erosion and sedimentation processes including land and crop management effects are taken from the literature and then solved using a digital computer. The erosion model is used in conjunction with the modified Kentucky Watershed Model which simulates the hydrologic characteristics from watershed data. The two models are linked together by using the appropriate computer code. Calibrations for both the watershed and erosion model parameters are made by comparing the simulated results with actual field measurements in the Four Mile Creek watershed near Traer, Iowa using 1976 and 1977 water year data. Two water years, 1970 and 1978 are used as test years for model verification. There is good agreement between the mean daily simulated and recorded streamflow and between the simulated and recorded suspended sediment load except few partial differences. The following conclusions were drawn from the results after testing the watershed and erosion model. 1. The watershed and erosion model is a deterministic lumped parameter model, and is capable of simulating the daily mean streamflow and suspended sediment load within a 20 percent error, when the correct watershed and erosion parameters are supplied. 2. It is found that soil erosion is sensitive to errors in simulation of occurrence and intensity of precipitation and of overland flow. Therefore, representative precipitation data and a watershed model which provides an accurate simulation of soil moisture and resulting overland flow are essential for the accurate simulation of soil erosion and subsequent sediment transport prediction. 3. Erroneous prediction of snowmelt in terms of time and magnitute in conjunction with The frozen ground could be the reason for the poor simulation of streamflow as well as sediment yield in the snowmelt period. More elaborate and accurate snowmelt submodels will greatly improve accuracy. 4. Poor simulation results can be attributed to deficiencies in erosion model and to errors in the observed data such as the recorded daily streamflow and the sediment concentration. 5. Crop management and tillage operations are two major factors that have a great effect on soil erosion simulation. The erosion model attempts to evaluate the impact of crop management and tillage effects on sediment production. These effects on sediment yield appear to be somewhat equivalent to the effect of overland flow. 6. Application and testing of the watershed and erosion model on watersheds in a variety of regions with different soils and meteorological characteristics may be recommended to verify its general applicability and to detact the deficiencies of the model. Futhermore, by further modification and expansion with additional data, the watershed and erosion model developed through this study can be used as a planning tool for watershed management and for solving agricultural non-point pollution problems.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.268-275
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• 2005

Early predictions of crop yields call provide information to producers to take advantages of opportunities into market places, to assess national food security, and to provide early food shortage warning. The objectives of this study were to identify the most useful parameters for estimating yields and to compare two model selection methods for finding the 'best' model developed by multiple linear regression. This research was conducted in two 65ha corn/soybean rotation fields located in east central South Dakota. Data used to develop models were small temporal variability information (STVI: elevation, apparent electrical conductivity $(EC_a)$, slope), large temporal variability information (LTVI : inorganic N, Olsen P, soil moisture), and remote sensing information (green, red, and NIR bands and normalized difference vegetation index (NDVI), green normalized difference vegetation index (GDVI)). Second order Akaike's Information Criterion (AICc) and Stepwise multiple regression were used to develop the best-fitting equations in each system (information groups). The models with $\Delta_i\leq2$ were selected and 22 and 37 models were selected at Moody and Brookings, respectively. Based on the results, the most useful variables to estimate corn yield were different in each field. Elevation and $EC_a$ were consistently the most useful variables in both fields and most of the systems. Model selection was different in each field. Different number of variables were selected in different fields. These results might be contributed to different landscapes and management histories of the study fields. The most common variables selected by AICc and Stepwise were different. In validation, Stepwise was slightly better than AICc at Moody and at Brookings AICc was slightly better than Stepwise. Results suggest that the Alec approach can be used to identify the most useful information and select the 'best' yield models for production fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.256-261
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• 2005

The experiment was conducted at the Ban­gabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur to study the response of chickpea (Cicer arietinum L) to dual inoculation of Rhizobium and arbuscular mycorrhiza, poultry litter, nitrogen, and phosphorus on spore population and colonization, nodulation, growth, yield attributes, and yield. The performance of Rhizobium inoculant alone was superior to control in all the parameters of the crop studied. Among the treatments dual inoculation of Rhizobium and arbuscular mycorrhiza in presence of poultry litter performed best in recording number and dry weight of nodules, dry weight of shoots and roots, number of pods/plant, number of seeds/pod, and seed yields of chickpea. The highest seed yield of 3.96g/plant was obtained by inoculating chickpea plants with dual inoculation of Rhizobium and arbuscular mycorrhiza in association with poultry litter. Treatments receiving dual inoculation of Rhizobium and arbuscular mycorrhiza in presence of nitrogen and phosphorus, Rhizobium inoculant in presence of nitrogen and phosphorus, and that of arbuscular mycorrhiza in presence of nitrogen and phosphorus were similar as that of treatment receiving dual inoculation of Rhizobium and arbuscular mycorrhiza in presence of poultry litter. From the view point of nodulation, growth, yield attributes, and yields of chickpea, dual inoculation of Rhizobium inoculant and arbuscular mycorrhiza along with poultry litter was considered to be the balanced combination of nutrients for achieving the maximum output from cultivation of chickpea in Shallow Red Brown Terrace Soil of Bangladesh.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.571-582
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• 1994

Three livestock/crop demonstration-cum-training farms have been established on plots of half, one and two acres, typical of the "Kandyan Forest Garden System" Vegetables, bananas, pepper, coffee, coconut and fruit trees are widely spaced, for intercropping with grass, and have been surrounded with live fences that also provide fodder for livestock to increase the family income. Each unit is operated by a selected employee and his family under a monthly incentive scheme based upon the gross margin. On these farms the technical parameters in dairying are better than elsewhere in the Mid-Country. Economic performance over 1985-1992 showed that dairying contributed most to the total gross margin of the half, one and two acre units, i.e. 31, 63 and 69%, respectively. Next came crops (29%, 37% and 19%), poultry (22%, 0% and 9%), and goats (18%, 0% and 3%). In the three farms the cash income per Sri Lankan Rupee spent was 1.5, 4.6 and 2.1, respectively. The overall ratio was 3.2 for dairying, 1.1 for poultry, 4.5 for goats and 9.9 for crops. Actual family labour in the three farms was 548, 548 and 639 days, compared to the 270, 330 and 440 days anticipated in the initial feasibility study. The average incentive payments, which were 20% (half acre), 61% (one acre) and 133% (two acres) of the parastatal salary of the employee, were only insufficient for the extra labour applied in the half acre unit. Dairying and goats proved to be attractive cash earners with a domestic fuel were important benefits. Poultry did little to improve farm income.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.37-47
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• 2017

In this study, we analyzed the variability of irrigation water amounts based on the combination of various crops and soil textures using the Irrigation Water Management Model (IWMM). IWMM evaluates the degree of agricultural drought using the Soil Moisture Deficit Index (SMDI). When crops are damaged by the water scarcity under the drought condition indicating that the SMDI values are in negative (SMDI<0), IWMM irrigates appropriate water amounts that can shift the negative SMDI values to "0" to crop fields. To test the IWMM model, we selected the Bandong-ri (BDR) and Jucheon (JC) sites in Gangwon-do and Jeollabuk-do provinces. We derived the soil hydraulic properties using the near-surface data assimilation scheme form the Time Domain Reflectrometry (TDR)-based soil moisture measurements. The daily root zone soil moisture dynamics (R: 0.792/0.588 and RMSE: 0.013/0.018 for BDR/JC) estimated by the derived soil parameters were matched well with the TDR-based measurements for validation. During the long-term (2001~2015) period, IWMM irrigated the minimum water amounts to crop fields, while there were no irrigation events during the rainy days. Also, Sandy Loam (SL) and Silt (Si) soils require more irrigation water amounts than others, while the irrigation water were higher in the order of radish, wheat, soybean, and potato, respectively. Thus, the IWMM model can provide efficient irrigation water amounts to crop fields and be useful for regions at where limited water resources are available.

• Journal of Ginseng Research
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• v.28 no.4
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• pp.165-172
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• 2004

Ginseng is traditionally cultivated worldwide in cold continental climates. It is now also being cultivated in maritime environments such as New Zealandis. This paper reports a number of growth and quality parameters for plants grown under those conditions over two growing seasons and the intervening winter dormant period. While shoot biomass peaked mid-summer, in contrast, root biomass peaked late autumn/early winter. Starch, sucrose, fructose, glucose and inositol were detected in the roots. Starch concentrations were highest in early autumn (mean 470 mg $g^{-1}$ dry weight) and lowest in mid spring (218 mg $g^{-1}$ dry weight). Sucrose concentrations were low during early summer until late autumn but increased rapidly with the onset of winter and peaked during mid spring (168 mg $g^{-1}$ dry weight). Fructose and glucose concentrations were similar and peaked in late spring (5.3 and 6.2 mg $g^{-1}$ dry weight). Inositol concentrations peaked in mid summer (1.7 mg $g^{-1}$ dry weight). Starch/sugar ratios were high during summer and autumn and low during winter and spring. Ginsenoside concentrations and profiles showed that the six major ginsenosides, Rgl, Re, Rb1, Rc, Rb2 and Rd, were present, but Rf was absent. Concentrations did not vary with sampling date. The most abundant ginsenosides were Re (15.9 to 17.5 mg $g^{-1}$ dry weight) and Rb1 (10.7 to 18.1 mg $g^{-1}$ dry weight). Combined, they accounted for < $75{\%}$ of total ginsenoside concentrations. Limited taste tests indicated that highest root quality occurred during late autumn, after the shoots had senesced. However, quality could not be related to plant chemistry.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.353-358
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• 2012

This study was conducted to enhance the propagation of Acanthopanax divaricatus and Acanthopanax koreanum through different cutting practices. For propagation by cuttings, scions were taken on September 1. This already has hard skin and showed much higher values in terms of root length, root number, rooting ratio and root weight than those taken on June 30 and August 1. Regardless of cutting date, 50% shading resulted to the highest root length, root number, root ratio and root weight. Meanwhile, 95% shading significantly reduced these parameters compared with no shading. These results suggest that over-shading may inhibit root growth. Two growth regulators, IBA (concentration of 1,000, 2,000, 3,000 ppm) and Rootone-F (0.4%) were also tested of its effect to the cuttings. Rootone-F was found to be more effective than IBA. Cutting treated with Rootone-F had slightly higher root length and root number. A. koreanum which grows well in hot climatic condition showed better rooting ability than A. divaricatus.