• Journal of The Korean Society of Grassland and Forage Science
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• 제22권2호
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• pp.131-136
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• 2002

A field experiment was carried out to compare the nitrate nitrogen concentration, sugar content and animal intake of low $sorghum{\times}sudangrass$ hybrids (Sorghum bicolor (L.) Moench) grown under application of animal manure in 1995. The application amount of animal manure were 40MT in cattle manure, and 30MT/ha in swine and poultry manure. The four NLCF's recommended hybrids used in this study were Pioneer 988, TE-Haygrazer and NC+ 855 (heading type), and Jumbo(headless type). The nitrate nitrogen concentration of forage was 365mg/kg at 50~60cm of plant height, 501mg at 100~120cm, and 502mg at 200~220cm, regardless of animal manure type and cultivar. The nitrate nitrogen concentration of NC+ 855 and P 988 was 519 and 526mg, respectively, and were higher than that(317mg) of Jumbo(P<0.05). The nitrate nioogen concentration of stems was 376mg, and significantly higher than that(135mg) of leaves(P<0.05) regardless of cultivar, and lower parts of stems and leaves were higher than those of upper parts of plants. The sugar contents of four $sorghum{\times}sudangrass$ hybrids were ranged between 3.1 and $3.7^{\circ}$ in cattle manure, 2.9 and $3.3^{\circ}$ in swine manure, and 2.8 and $4.9^{\circ}$ in poultry manure. The sugar content of NC+ 855 was the highest as $3.9^{\circ}$, p 988 was second as $3.4^{\circ}$, and then TE-Haygrazer and Jumbo were lower as $3.2^{\circ}$ and $2.9^{\circ}$, respectively. Animal intake of sorghum ${\times}$ sudangrass hybrids P 988 and NC+ 855 were slightly higher than those of Jumbo and TE-Haygrazer grown under application of cattle manure. Also the average intake of P 988 was a little higher than that of Jumbo. However, there were no significant differences of forage intake among few recommended $sorghum{\times}sudangrass$ hybrids.

• Journal of The Korean Society of Grassland and Forage Science
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• 제6권3호
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• pp.145-150
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• 1986

The experiments were conducted to study the influence of growth location and cutting microelements macro-and on managements in temperate grasses in Korea and West Germany from 1975 to 1979. The field trials were designed as split plot with three grass species of Dactylis glomerata L., Lolium perenne L. and Festuca pratensis Huds under three cutting regimes at grazing stage, silage stage and hay stage. The results obtained are summarized as follows: 1. Concentrations of macro-and microelements in temperate grasses showed a different response to growth location and growing season. P concentration in the plants was decreased under hot stress in summer, whereas Mg and Na tended to be increased. The seasonal changes in K and Zn were not significant. 2. Morphological growth stage was to be found as an important factors influenced to mineral components. P and K contents in temperate grasses tended to be decreased as morphological development especially under high temperature in Suweon and Cheju. Ca and Mg were less affected by morphological stage and cutting managements. 3. Mean value of Ca/P ratio in the plants were 1.58, 1.33 and 1.21 for meadow fescue, perennial ryegrass and orchardgrass, respectively. Ca/P ratio in grasses tended to be increased as morphological development. 4. Zn deficiency in the plants occured in all grass species and experimental sites. Mean Zn concentration of the plant were 34.2%, 31.2% and 37.8% for Suweon, Cheju and Taekwalyong, respectivelly. Na deficiency occured in orchardgrass and meadow fescue, especially in taekwalyong. Cool temperature resulted in a decrease of Na absorption and accumulation.

• Journal of The Korean Society of Grassland and Forage Science
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• 제27권2호
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• pp.101-108
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• 2007

The object of this experiment was to investigate the effect of mixture which consist of different seeding rates and species on dry matter yield and quality in Daejon area. The field trials were conducted from 2003 to 2005 at Chungnam National University in order to evaluate the dry matter yield and quality of different mixture. The experimental design includes three mixture types: Conventional mixtures, CM{orchardgrass(Potomac) 50% + tall fescue (Fawn)20% + Kentucky bluegrass(Kenblue) 20% + white clover(Regal) 10%}, red clover + mixtures, RM{orchardgrass(Potomac) 40% + tall fescue(Fawn) 20% + Kentucky bluegrass(Kenblue) 10% + red clover(Kenland) 30%) and Turf type grass + mixtures, TM {orchardgrass (Potomac) 50% + turf type grass (tall fescue, Millennium 20% + Kentucky bluegrass, Midnight 10% + perennial ryegrass, Palmer III 10%) + white clover(Regal) 10%}. The average DM yield for 2 years of red clover+mixture(11,656kg/ha) was higher than those of the other mixtures(p<0.05). The content of crude protein and dry manu digestibility were higher in red clover+mixture than in other mixtures(p<0.05). but, the content of fibrous compounds like as NDF, ADF, cellulose and lignin were lower in red clover+mixture than in other mixtures(p<0.05). The crude protein dry matter(CPDM) yield was higher in red clover + mixture(2,832kg/ha) than in conventional mixture(2,372kg/ha) and turf type + mixture(2,266kg/ha)(p<0.05). The digestible dry matter (DDM) yield was higher in red clover + mixture(8,881 kg/ha) than in conventional mixture(8,255kg/ha) and turf type + mixture(7,314kg/ha)(p<0.05). In botanical composition at last cutting time in 2005, conventional mixture were maintained orchardgrass 45%, tall fescue 22%, Kentucky bluegrass 5% and white clover 24%. Red clover + mixture were maintained orchardgrass 40%, tall fescue 22%, Kentucky bluegrass 4% and red clover 31%. turf type + mixture were orchardgrass 37%, tall fescue 23%, Kentucky bluegrass 6%, perennial ryegrass 8% and white clover 24%, respectively. As summary, DM yields and quality of mixture species and seeding rates were observed significant difference. The results of this experiment indicated that red clover + mixture was more effective in enhancing the DM yield and forage quality in Daejon area.

• Journal of The Korean Society of Grassland and Forage Science
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• 제33권2호
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• pp.105-110
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• 2013

This study was carried out to investigate the effect of nitrogen (N) fertilization on the forage growth, production and quality of native reed (Phragmites communis) grasses. Field experiments were conducted in Cheonan and in Ansan, 2012. Treatments were control (no N fertilization), 50 kg/ha and 100 kg/ha in Cheonan plots (fertilization on April $30^{th}$, and harvest on June $21^{st}$). Treatments in Ansan plots were control (no N fertilization) and 60 kg/ha (fertilization on May first, and harvest on August first). Forage growth and leaf colors were improved in N fertilized plots. However, the drymatter (DM) percentage was slightly decreased with N fertilization. Forage yields, in terms of DM, crude protein (CP) and digestible DM (DDM), were significantly increased with N fertilization in both sites. In Cheonan, DM, CP and DDM yields per ha were 4,026 kg, 235 kg and 1,850 kg, respectively, in the control plot, and were 4,658 kg, 306 kg and 2,388 kg, respectively, in the N 50 kg plot, and 5,622 kg, 446 kg and 3,143 kg, respectively, in the N 100 kg plot. In Ansan, DM, CP and DDM yields per ha were 2,802 kg, 177 kg and 1,288 kg, respectively, in the control plot, and were 3,876 kg, 294 kg and 1,853 kg, respectively, in the N 60 kg plot. Forage quality in terms of CP content, in vitro DM digestibility (IVDMD) and relative feed value (RFV) were also increased with N fertilization in both sites. In Cheonan, the CP content, IVDMD and RFV were 5.85%, 45.96% and 64.5 (grade 5), respectively, in the control plot, 6.58%, 51.27% and 72.3 (grade 5), respectively, in the N 50 kg plot, and 7.94%, 55.91% and 72.7 (grade 5), respectively, in the N 100 kg plot. In Ansan, the CP content, IVDMD and RFV were 6.30%, 45.98% and 70.2 (grade 5), respectively, in the control plot, and 7.59%, 47.80% and 78.3 (grade 4), respectively, in the N 60 kg plot. In conclusion, N fertilization of 60~100 kg/ha was desirable for greater forage production, with a higher quality of native Phragmites communis achievable. This should only be applied if the fertilization area is not located at a riverside/streamside or in riparian land where there is a high risk of water pollution by fertilization.

• Journal of The Korean Society of Grassland and Forage Science
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• 제40권1호
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• pp.29-36
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• 2020

This study was conducted to suggest the new grassland grade system on evaluating the grassland status. The grassland status has been evaluated based on the forage yield (good, fair and poor) by municipal authorities. The grassland grades by current system were 19 good, 11 fair and 11 poor among the 41 grassland farms from 6 provinces. This evaluation result differed greatly from the result of actual measurement of forage yields which showed all poor. The big difference was resulted from failing the reflection of the various characteristics, such as different seasonal growth and harvest frequency. Furthermore, the lack of consistent examining date and method added the inaccuracy of current grassland grade system. The new grassland grade system based on the grassland vegetation ratio (grass, weed and bare soil) was initially designed into 6-grade system (1st; 100~80%, 2nd; 79~60%, 3rd; 59~40%, 4th; 39~20%; 5th; 19~1% and 6th; 0% on the basis of grasses proportion), but later was changed into 4-grade system (1st, 2nd, 3rd, and 4th grades are 70% or more, 50% or more, 50% or less, and 0% of forage proportion, respectively) after reflecting the opinion of grassland farms and municipal authorities. Re-evaluation on the grassland status using the 4-grade system resulted in the total 80% consisted of 2nd, 3rd and 4th grade which means most grasslands needs the partial reseeding or the rehabilitation of entire grassland. Pictures and schematic diagrams depicting the 4-grade system were presented to improve the objectivity of evaluation. The optimal time for assessing grassland status is fall when plant height 20~30 cm. Conclusively, the 4-grade system is an efficient method for all non-professionals including grassland farms or municipal authorities in assessing the grassland status. To apply this system to the field, the institutional arrangements such as amendment of grassland act should take place in advance.

• Economic and Environmental Geology
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• 제48권6호
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• pp.431-449
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• 2015

The study area is located in the western part of the Precambrian stock type of Sancheong anorthosite complex, the Jirisan province of the Yeongnam massif, in the southern part of the Korean Peninsula. We perform a detailed field geological investigation on the Sancheong anorthosite complex, and report the characteristics of lithofacies, occurrences, foliations, and research formation process and its mechanism of the Sancheong anorthosite complex. The Sancheong anorthosite complex is classified into massive and foliation types of Sancheong anorthosite (SA), Fe-Ti ore body (FTO), and mafic granulite (MG). Foliations are developed in the Sancheong anorthosite complex except the massif type of SA. The foliation type of SA, FTO, MG foliations are magmatic foliations which were formed in a not fully congealed state of SA from a result of the flow of FTO and MG melts and the kinematic interaction of SA blocks, and were continuously produced in the comagmatic differentiation. The Sancheong anorthosite complex is formed as the following sequence: the massive type of SA (a primary fractional crystallization of parental magmas under high pressure)${\rightarrow}$ the foliation type of SA [a secondary fractional crystallization of the plagioclase-rich crystal mushes (anorthositic magmas) primarily differentiated from parental magmas under low pressure]${\rightarrow}$the FTO (an injection by filter pressing of the residual mafic magmas in the last differentiation stage of anorthositic magmas into the not fully congealed SA)${\rightarrow}$the MG (a solidification of the finally residual mafic magmas). It indicates that the massive and foliation types of SA, the FTO, and the MG were not formed from the intrusion and differentiation of magmas which were different from each other in genesis and age but from the multiple fractionation and polybaric crystallization of the coeval and cogenetic magma.

• Economic and Environmental Geology
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• 제50권6호
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• pp.537-544
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• 2017

Stable carbon isotope ratio of carbon dioxide (${\delta}^{13}C_{CO2}$) is used as an important indicator in the researches for global climate change and carbon capture and sequestration technology. The ${\delta}^{13}C$ value has been usually analyzed with Isotope Ratio Mass Spectrometer (IRMS). Recently, the use of Laser Absorption Spectrometry (LAS) is increasing because of the cost efficiency and field applicability. The purpose of this study was to suggest practical procedures to prepare laboratory reference gases for ${\delta}^{13}C_{CO2}$ analysis using LAS. $CO_2$ gas was adjusted to have the concentrations within the analytical range. Then, the concentration of $CO_2$ was assessed in a lab approved by the Korea Laboratory Accreditation Scheme and the ${\delta}^{13}C_{CO2}$ value was measured by IRMS. When the instrument ran over 12 hours, the ${\delta}^{13}C$ values were drifted up to ${\pm}10$‰ if the concentration of $CO_2$ was shifted up to 1.0% of relative standard deviation. Therefore, periodical investigation of analytical suitability and correction should be conducted. Because ${\delta}^{13}C_{CO2}$ showed the dependency on $CO_2$ concentration, we suggested the equation for calibrating the concentration effect. After calibration, ${\delta}^{13}C_{CO2}$ was well matched with the result of IRMS within ${\pm}0.52$‰.

• Korean Journal of Agricultural and Forest Meteorology
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• 제21권4호
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• pp.327-336
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• 2019

Soybean is one of the most important crops of which the grains contain high protein content and has been consumed in various forms of food. Soybean plants are generally cultivated on the field and their yield and quality are strongly affected by climate change. Recently, the abnormal climate conditions, including heat wave and heavy rainfall, frequently occurs which would increase the risk of the farm management. The real-time assessment techniques for quality and growth of soybean would reduce the losses of the crop in terms of quantity and quality. The objective of this work was to develop a simple model to estimate the growth of soybean plant using a multispectral sensor mounted on a rotor-wing unmanned aerial vehicle(UAV). The soybean growth model was developed by using simple linear regression analysis with three phenotypic data (fresh weight, dry weight, leaf area index) and two types of vegetation indices (VIs). It was found that the accuracy and precision of LAI model using GNDVI (R²= 0.789, RMSE=0.73 ㎡/㎡, RE=34.91%) was greater than those of the model using NDVI (R²= 0.587, RMSE=1.01 ㎡/㎡, RE=48.98%). The accuracy and precision based on the simple ratio indices were better than those based on the normalized vegetation indices, such as RRVI (R²= 0.760, RMSE=0.78 ㎡/㎡, RE=37.26%) and GRVI (R²= 0.828, RMSE=0.66 ㎡/㎡, RE=31.59%). The outcome of this study could aid the production of soybeans with high and uniform quality when a variable rate fertilization system is introduced to cope with the adverse climate conditions.

• Journal of Biosystems Engineering
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• 제3권2호
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• pp.22-33
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• 1978

To maintain the self-sufficiency of food production , it is required to improved the productivity and increase the effective utilization of land in the double cropping areas using improved cultivation technology. The following reasons encourage this cours of action because the overlapping rice harvest and barely seeding seasons complete for labour, the lower price of barley makes it financially less attractive to grow and these two facts together are responsible for a decrease in barley being planted in certain more seasonably marginal double cropping areas. Fro these reasons, it is desirable to carry out tests to improve the current cultivation techniques . In this interest , the following studies were carried out in the experimental field located at Banweol-myeon, Whasung-jkun, Gyeonggi-do from October 1977 to July 1978 in order to establish the mechanical method of barley cultivation using the power tiller. The summarized results are as follows. 1. The work performance in the seeding operation using the rotary barley seeder was 68 minutes per 10 ares which compares favourably with 408 min/10a using the conventional method. This is only one sixth of the time required by th conventional method. The operating costs using the rotary barley seeder was 1, 463 won per 10 areas as against 3, 486 Won per 10 ares for the conventional method, showing a saving of about 50% in comparison with the conventional method. 2. In the manure spreading operation, the work performance was 25 min/10a for the manure spreading machine , compared to 1089 min/10a for the manual operations. This is about one fourth of the time required by the conventional method, The operating costs were 810 Won/10a for the machine and 857 Won/10a for the manual labour. This cost shows little advantage by the machine over the manual labor costs. The conventional method of manure spreading will continue pending decision which will develope and improve the machine.3. Work performance in the rolling operation using the barley rolIer was 30 min/lOa which compares favourably with 135 min/10a using conventional method. This was one fourth of the time required by the conventional method. The operating costs were 514 Won/103. for the machine and 1, 003 Won/lOa for manual labour. In the weed control operation, the work performance and operating costs were 45min/lOa, 1, 399won/10a for the herbcide application using the power sprayer, 1, 149min/10a 8, 541won/lOa for the conventional method respectively. This is 26 times higher efficiency in comparison to the conventional method. 4. In the harvesting operation using the reaper binder and tiller attachment, the work performance was 60min/lOa and represents a cost of 2, 039won/10a. The con\ulcornerventional method took 640min/10a at a cost of 4, 757won/lOa. The reaper binder showns a saving of one tenth over the conventional method. The automatic thresher is already recommended for the current situations, and is now being used. 5. From a comparison of the results of the above trials, the serial cultivation system using the attachment for the power tiller such as the rotary barley seeder is now to be recommended for the current barley cultivation system. It is also recommend from these results that the mechanized technology now available must be used to improve and maintain the increase in barley production. It is seen th1t this is the only course now avaihble to solve the peak seasonal requirements of labour needed for l11rvesting and seeding between rice and barley cultivation.

• Journal of Biosystems Engineering
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• 제3권2호
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• pp.35-61
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• 1978

To find out the power tiller's travel and tractive characteristics on the general slope land, the tractive p:nver transmitting system was divided into the internal an,~ external power transmission systems. The performance of power tiller's engine which is the initial unit of internal transmission system was tested. In addition, the mathematical model for the tractive force of driving wheel which is the initial unit of external transmission system, was derived by energy and force balance. An analytical solution of performed for tractive forces was determined by use of the model through the digital computer programme. To justify the reliability of the theoretical value, the draft force was measured by the strain gauge system on the general slope land and compared with theoretical values. The results of the analytical and experimental performance of power tiller on the field may be summarized as follows; (1) The mathematical equation of rolIing resistance was derived as $$Rh=\frac {W_z-AC \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\] sin\theta_1}} {tan\phi \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]+\frac{tan\theta_1}{1}$$ and angle of rolling resistance as $$\theta _1 - tan^1\[ \frac {2T(AcrS_0 - T)+\sqrt (T-AcrS_0)^2(2T)^2-4(T^2-W_2^2r^2)\times (T-AcrS_0)^2 W_z^2r^2S_0^2tan^2\phi} {2(T^2-W_z^2r^2)S_0tan\phi}\] $$and the equation of frft force was derived as$$P=(AC+Rtan\phi)\[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]cos\phi_1 \ulcorner \frac {W_z \ulcorner{AC\[ [1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]sin\phi_1 {tan\phi[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\]+ \frac {tan\phi_1} { 1} \ulcorner W_1sin\alpha $$The slip coefficient K in these equations was fitted to approximately 1. 5 on the level lands and 2 on the slope land. (2) The coefficient of rolling resistance Rn was increased with increasing slip percent 5 and did not influenced by the angle of slope land. The angle of rolling resistance Ol was increasing sinkage Z of driving wheel. The value of Ol was found to be within the limits of Ol =2\ulcorner "'16\ulcorner. (3) The vertical weight transfered to power tiller on general slope land can be estim ated by use of th~ derived equation: $$R_pz= \frac {\sum_{i=1}^{4}{W_i}} {l_T} { (l_T-l) cos\alpha cos\beta \ulcorner \bar(h) sin \alpha - W_1 cos\alpha cos\beta$$The vertical transfer weight $R_pz$ was decreased with increasing the angle of slope land. The ratio of weight difference of right and left driving wheel on slop eland,$\lambda= \frac { {W_L_Z} - {W_R_Z}} {W_Z} $, was increased from ,$\lambda$=0 to$\lambda$=0.4 with increasing the angle of side slope land ($\beta = 0^\circ~20^\circ) (4) In case of no draft resistance, the difference between the travelling velocities on the level and the slope land was very small to give 0.5m/sec, in which the travelling velocity on the general slope land was decreased in curvilinear trend as the draft load increased. The decreasing rate of travelling velocity by the increase of side slope angle was less than that by the increase of hill slope angle a, (5) Rate of side slip by the side slope angle was defined as $ S_r=\frac {S_s}{l_s} \times$ 100( %), and the rate of side slip of the low travelling velocity was larger than that of the high travelling velocity. (6) Draft forces of power tiller did not affect by the angular velocity of driving wheel, and maximum draft coefficient occurred at slip percent of S=60% and the maximum draft power efficiency occurred at slip percent of S=30%. The maximum draft coefficient occurred at slip percent of S=60% on the side slope land, and the draft coefficent was nearly constant regardless of the side slope angle on the hill slope land. The maximum draft coefficient occurred at slip perecent of S=65% and it was decreased with increasing hill slope angle $\alpha$. The maximum draft power efficiency occurred at S=30 % on the general slope land. Therefore, it would be reasonable to have the draft operation at slip percent of S=30% on the general slope land. (7) The portions of the power supplied by the engine of the power tiller which were used as the source of draft power were 46.7% on the concrete road, 26.7% on the level land, and 13~20%; on the general slope land ($\alpha = O~ 15^\circ ,\beta = 0 ~ 10^\circ$) , respectively. Therefore, it may be desirable to develope the new mechanism of the external pO'wer transmitting system for the general slope land to improved its performance.l slope land to improved its performance.