• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.3
• /
• pp.253-259
• /
• 2010

This experiment was conducted to evaluate water use efficiency of barley, wheat, and millet as a substitution crop for rice of fallow paddy field. Dry weight (DW), evapotranspiration, and transpiration of crop grown on the lysimeters controlled with 5 levels of groundwater table (GWT), 0, 25, 50, 75, and 100 cm were evaluated for optimum GWT and water use efficiency. All the lysimeters randomized with four replication arrangements were filled up sandy loam and were adjusted to the constant bulk density treated with twice water infiltration from bottom side to upper side of lysimeter. DW of barley, wheat, and millet in the plot of 0cm GWT that is saturated soil showed 34.9%, 44.7%, and 37.1% of that in the plot of 100 cm GWT, respectively showing a serious obstacle in crop growth. Evapotranspiration ratios calculated by evapotranspiration volume (mL) per DW were 166~605 mL for barley, 136~481 mL for wheat, and 81~418 mL for millet showing the order of barley > wheat > millet. Evapotranspiration ratio was increased with decrease of groundwater table that is the condition of moisture saturation. Estimation of GWT for maximum DW of wheat was 76 cm, and those of barley and millet were 100 cm below. The volumetric moisture content of lysimeter soil with cropping was markedly decreased as increase of crop growth because moisture supplying capability by capillary rise of water was less than amount of moisture required by crop.

• Journal of Biosystems Engineering
• /
• v.3 no.2
• /
• pp.114-125
• /
• 1978

The use of petroleum fuels in grain drying causes problems of high cost and management. To solve these problems, it is required to study on soLar energy as an alternative to petroleum fuels for grain drying. The purposes of this study were to find out the optimum received area and air flow rate of a flat-plate solar air collector for grain drying and to assess its effects on grain drying with a small grain bin. The results of this study are summarized as follows ; 1. The calculated optimum tilt angles of the collector in the summer and autumn drying seasons were 20 and 50 degress, respectively, in suwon area. 2. The outlet temperature of the collector was $36^\circ C$ on the daily average with the maximum of $36^\circ C$ at 12:00 o clock. Solar radiation on the collector surface was 1.04 ly( 1 langley = 1 cal/$cm^2$) per minute on the daily average and 1.30 ly per minute on the maximum at 11:00am. The thermal efficiency of the collector was 62.4 percent on the daily average, and the air flow-rate per unit receiving are was 1.03 $m^3$/min/$m^2$.4. The calculated optimum receiving area and the air flow-rate per unit cubic volume for paddy in autumn drying season was 2 $m^2$ and 2$m^3$/min , respectively. 5. not significantly difference in the collector efficiency was appeared between the rotating and fixed type of solar collector. 6. For drying of wheat with 0.6 meter of the depth in the bin, approximately 9 hours were required to reduce the moisture content from 21.6% to 13% with air follow rate of 5 $m^3$/min an initial moisture per cubic meter of wheat and with air temperature of $52^\circ C$. 7. In the drying test of rough rice with a turning operation in a grain bin approximately 21 hours were required to reduced the moisture from 21% to 14.5% with airflow rate of 2 $m^3$/min per cubic meter of rice and the air temperature of $43.5^\circ C$. 8. Over-drying at the bottom and less -drying at the top of the grain mass was resulted from the high -temperature of drying air which was obtained from the flat-plate solar collector in this test. An appropriate operation should be prepared for the uniform moisture of the grain in the bin.

• Journal of Korean Society for Geospatial Information Science
• /
• v.12 no.4 s.31
• /
• pp.3-12
• /
• 2004

It is necessary to manage water resources in rural areas in order to achieve proper development of new water resources, sustainable usage and reasonable distribution. This paper aims to analyze multi-temporal Landsat-7 ETM+data for soil moisture that is essential for crops in Ahnsung area. The ETM data was also fused with KOMPSAT-1 images in order to be used as backdrop watershed maps at first. Multi-temporal Images showed also the characteristics of soil moisture distribution. Images taken in April showed that rice paddy had as low reflectance as artificial features. Compared with April scenes, those taken in Hay and June showed wetness index increased in the rice paddies. The mountainous areas have almost constant moisture index, so the difference between the dates was very low while reservoirs and livers had dramatic changes. We can calculate total potential areas of distribution of moisture content within the basin and estimate the areas being sensitive to drought. Finally we can point out the sites of small rice paddies lack of water and visualize their distribution within the same basin. It can be said that multi-temporal Landsat-7 ETM+ and KOMPSAT data can be used to show broad drought with quick and simple analysis. Drought sensitiveness maps may enable the decision makers on rural water to evaluate the risk of drought and to measure mitigation, accompanied with proper data on the hydrological and climatic drought.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.6
• /
• pp.409-416
• /
• 2013

Millet and sorghum are major dryland cereal crops, however their growth and productivity is limited by soil water stress with varying intensity. The major objective of this study was to evaluate water stress of millet and sorghum yield under drainage classes of poorly drained soil and to test the effect of the installed pipe drainage in poorly drained paddy soil to minimize crop stress. The research was carried out in poorly drained paddy fields located at alluvial slopping area resulting in non-uniform water content distribution by the inflow of ground water from the upper part of the field. Stress Day Index (SDI) was determined from a stress day factor (SD) and a crop susceptibility factor (CS). SD is a degree of measurement by calculating the daily sum of excess water in the profile above 30cm soil depth ($SEW_{30}$). CS depends on a given excess water on crop stage. The results showed that sum of excess water day ($SWD_{30}$) used to represent the moisture stress index was lower on somewhat poorly drained soil compared with poorly drained soil on 117 days. CS values for sorghum were 57% on $3^{rd}$ leaf stage, 44% on $5^{th}$ leaf stage, 37% on panicle initiation, 23% on boot stage, and 16% on soft dough stage. For proso millet CS values were 84% on $3^{rd}$ leaf stage, 70% on $5^{th}$ leaf Stage, 65% on panicle initiation, 53% on boot stage, and 28% on soft dough stage. And for foxtail millet the values were 73% on $3^{rd}$ leaf stage, 61% on $5^{th}$ leaf stage, 50% on panicle initiation, 29% on boot stage, and 15% on soft dough stage. SDI of sorghum and millet was more susceptible to excess soil water during panicle initation stage more poorly drained soil than somewhat poorly drained soil. Grain yield was reduced especially in proso millet and Foxtail millet compared to Sorghum.

• Applied Biological Chemistry
• /
• v.34 no.3
• /
• pp.258-261
• /
• 1991

In order to establish the optimum drying temperature of the heated air blast-grain circulation dryer, a 2 ton scale of paddy was used in this experiment. The temperatures of heated air used were 45, 50, 55, 60, 65 and $70^{\circ}C$. Moisture content of the paddy was reduced to 15% from 24% by drying. The higher air temperature, the shorter drying time and the less fuel consumed. The portion of cracked kernels was found to be low as $3{\sim}10%\;at\;40{\sim}55^{\circ}C$, but was very high to $28{\sim}30%\;at\;60{\sim}70^{\circ}C$. The germination percent was very high as 98 and 93% at 40 and $45^{\circ}C$, but it was decreased to 86 and 30% at 50 and $70^{\circ}C$, respectively. The recovery yield of milled rice from paddy was decreased by 1.76, 2.63 and 7.52% at 60, 65 and $70^{\circ}C$, respectively, compared with 75.86% as drying at $40^{\circ}C$. The higher heated air temperature, the less head rice of milled rice was recovered, and the decreased ratio was increased $60^{\circ}C$. The higher heated air temperature, the less alkali disintergation value and gel consistency of milled rice and the more water up take, expanded vlume, total solid in residual liquid and intensity of starch iodine blue value of residual liquid, and those tendency was found clear from $60^{\circ}C$ temperature of heated air.

• Journal of Biosystems Engineering
• /
• v.6 no.2
• /
• pp.58-64
• /
• 1982

The fresh threshed paddy-mat dryings on the various environments were analyzed on their drying characteristics and rice quality resulted. The moisture content of paddy was mainly determined by the accumulated solar energy received, and which was expressed as a simple equation. The drying characteristics revealed to follow a constant rate drying type, and as the depth increased the more typical constant-rate drying pattern was observed. The relationship between the drying rate and bed depth was established with a simple exponential equation. The raking operation during the drying period showed a favorable effect both on the drying rate and the reduction of crack formation. Drying environments such as straw mat, concrete, ground, polyethylene film did not affect significantly the drying rate and rice quality. Considering the drying rate and quality, the optimum bed depth of mat paddy drying was around 6 cm.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.205-205
• /
• 2017

An excess soil water condition is one of the major problems for the field crops growing in paddy fields because of their poor drainage and less availability for oxygen uptake which leads to adversely affect the photosynthesis. Therefore, the current study was undertaken with aim to investigate the effects groundwater level on the photosynthetic response of soy bean (Urum), red bean (Arari), sesame (Geonbaek), perilla (Dayu) after the transplanting to the lysimeter to investigate the plant-water relation and their effect on photosynthesis. The chlorophyll content of the crops according to the humid conditions of the soy bean, sesame and the perilla was found to be 5%, 6.89 % and 13.7% higher than that of the groundwater treated at 40cm, respectively. On the other hand, the chlorophyll content of adzuki bean decreased 6.6% from the groundwater level of 40cm, and the sorghum decreased by 5.7%. As a result of investigating the Fv / Fm value of groundwater, the adzuki bean at 20cm above groundwater was lower than that of groundwater by 40cm immediately before flowering. The Fv / Fm value of soy bean and sesame at 40cm above groundwater were lowered by flowering under groundwater 20 cm and Fv / Fm value of sorghum is increased at 40 cm treatment immediately before flowering while the Fv / Fm values of the perilla had no significant difference in comparison to those at 20 cm and 40 cm of groundwater. In the case of chlorophyll fluorescence reaction, it is known that the when the absolute value is closer to 0.82, the stress is considered less. As a result of comparing the numerical values of the crops, it was found that the sorghum was the most stressed followed by adzuki bean and sesame, while the soy beans and perilla was found on the average, as they received less stress.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.2
• /
• pp.203-209
• /
• 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as $0.2{\sim}0.4$ ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

• Korean Journal of Food Science and Technology
• /
• v.33 no.4
• /
• pp.427-436
• /
• 2001

The effects of storage form (paddy and milled rice) and storage period (1, 2, and 3 years) of rice at low temperature $(4^{\circ}C)$ on physicochemical properties of milled and cooked rice and sensory characteristics of cooked rice were investigated. The proximate compositions except moisture content of rice decreased as the storage period increased. Water binding capacity, solubility and swelling power of rice flour decreased with the extended storage period. In the amylogram, the initial pasting temperature, paste viscosity and breakdown of paddy rice flour slurry decreased after 2 years of storage. Moisture content of cooked rice increased while the amount of water evaporated during cooking decreased. These trends were obvious with the longer storage period. Lightness and yellowness of cooked rice were greatly changed after 3 years of storage, regardless of storage form. Texture profile analysis of cooked rice by Texture Analyzer revealed that hardness, fracturability, gumminess were gradually increased while adhesiveness decreased as the storage period of rice increased. A trained panel found that color intensity, intactness of grains, rancid flavor, rice bran flavor, wet cardboard flavor, hardness and chewiness of cooked rice increased with the longer storage period. However, glossiness, transparency, plumpness, puffed corn flavor, dairy flavor, boiled egg white flavor, sweet taste, adhesiveness to lips, smoothness and inner moisture decreased with the extended storage period up to 3 years. Instrumental hardness was highly correlated with sensory hardness.

• Journal of Biosystems Engineering
• /
• v.43 no.2
• /
• pp.148-159
• /
• 2018

Purpose: Unmanned air vehicle (UAV) remote sensing was applied to test various vegetation indices and make prediction models of protein content of rice for monitoring grain quality and proper management practice. Methods: Image acquisition was carried out by using NIR (Green, Red, NIR), RGB and RE (Blue, Green, Red-edge) camera mounted on UAV. Sampling was done synchronously at the geo-referenced points and GPS locations were recorded. Paddy samples were air-dried to 15% moisture content, and then dehulled and milled to 92% milling yield and measured the protein content by near-infrared spectroscopy. Results: Artificial neural network showed the better performance with $R^2$ (coefficient of determination) of 0.740, NSE (Nash-Sutcliffe model efficiency coefficient) of 0.733 and RMSE (root mean square error) of 0.187% considering all 54 samples than the models developed by PR (polynomial regression), SLR (simple linear regression), and PLSR (partial least square regression). PLSR calibration models showed almost similar result with PR as 0.663 ($R^2$) and 0.169% (RMSE) for cloud-free samples and 0.491 ($R^2$) and 0.217% (RMSE) for cloud-shadowed samples. However, the validation models performed poorly. This study revealed that there is a highly significant correlation between NDVI (normalized difference vegetation index) and protein content in rice. For the cloud-free samples, the SLR models showed $R^2=0.553$ and RMSE = 0.210%, and for cloud-shadowed samples showed 0.479 as $R^2$ and 0.225% as RMSE respectively. Conclusion: There is a significant correlation between spectral bands and grain protein content. Artificial neural networks have the strong advantages to fit the nonlinear problem when a sigmoid activation function is used in the hidden layer. Quantitatively, the neural network model obtained a higher precision result with a mean absolute relative error (MARE) of 2.18% and root mean square error (RMSE) of 0.187%.