• Journal of Biosystems Engineering
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• v.5 no.2
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• pp.26-39
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• 1980

A study was investigated to find out the mechanical optimum conditions of power tiller-plow system on both paddy field and upland. Mathematical model was developed for the theoretical analysis of this system and the experimentation on the field was carried out with two different sizes of 5PS and 8PS power tiller equipped with rubber tire. 1) The relationship between the plowing depth and draft resistance of the power tiller-plow system was a quadratic function. 2) The minimum point of the specific draft resistance of the 5 PS plow was found at the smaller plowing depth than that of 8 PS plow, therefore we can find that the curved surface of 5PS plow bottom should be improved for the effective plowing operation. 3) As the improvement of the mechanical balance by the desirable change of the curved surface of plow bottom, the relative position of hitch point and dimension of plow beam would be realized, the 5 PS power tiller could be used to plow deeply (about 16-17cm). 4) The virtual acting point of the total draft resistance on the plow bottom approached to the land side as the plowing depth increased. 5) The resultant of vertical reaction force $R_2$ on the landside was increased with the plowing depth, while the vertical reaction force $R_1$ on the wheel was decreased as the slope angle of the body of power tiller increased. 6) For the effective plowing operations ; a) The slope angle of the body should be as small as possible. b) The diameter of the wheel should be as small possible. c) The horizontal and vertical distances $l_2, h_1$ between the wheel axis and plow bottom should be as large as possible. 7) To use the 5PS power tiller as the major unit of agricultural machinery, the curved surface of the 5 PS plower bottom and the mechanism of attachment between the power tiller and the plow should be changed as the indications of this study, and in addition to these, the new operation method of the field work should be developed.

• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.15-27
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• 1981

In order to investigate on the field performance of 3.5PS power tiller and to obtain the optimum using conditions of it, this experiment has been carried on the plowing operation, the rotary harrowing operation and the ridging operation that compared 3.5PS power tiller(KC-450) with the existing 5PS(DT-40) and 8PS(DT-85) power tiller. It has been performed at Suck Jung-Dong, Ansung Country, from March to October in 1980. The results of this field test were obtained as follows; 1. The plowing performance of KC-450 tiller was found to be 125min/10a that was lower than that of DT-85 tiller by 26min/10a in the effective plowing speed 0.9m/sec. 2. The field efficiency of KC-450 tiller was the highest among the power tillers as to be 82 persent that was higher than that of DT-85 tiller by 5 persent in the effective plowing speed 1m/sec. 3. The rotary harrowing performances of DT-40 tiller and DT-85 tiller were higher than that of KC-450 tiller in the rotary harrowing operation of the same speed, and the field efficiency of KC-450 tiller and DT-40 tiller were higher than that of DT-85 tiller in the rotary harrowing operation. 4. The ridging Performance of testing power tillers were nearly equality in the ridging operation of the same speed, and the field efficiency of testing tillers were higher KC-450 tiller than DT-40 tiller, DT-40 tiller than DT-85 tiller. 5. The work performance of power tiller increased with increase in the size of field area. Work performance and field efficiency of KC-450 tiller were higher than other tillers below 8a in field size 6. DT -85 tiller was more useful in deep plowing depth. But below 8a in field size KC-450 tiller was more easily operated and its field efficiency was higher 7. KC-450 tiller should be more useful to operate in the small size field or in the small scale farming and for the cultivation of vegetables, gardening plants, medicinal herb and tobacco plants, or for the cultivation in vinyl house.

• Korean Journal of Plant Resources
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• v.15 no.1
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• pp.72-76
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• 2002

This study was carried out to determine an effective mechanical harvester for rhizomes of Rehmannia glutinosa Libosch. Labor-saving efficiency showed 69∼76% by using tillage operations with power tiller, digger attached to power tiller, and digger attached to tractor compared with manual harvest. Loss percentage of rhizomes by mechanical harvesters was 3.1∼ 9.3% higher, and fresh rhizome yield was 2∼6％ lower than that by manual harvest, respectively. Although it showed higher loss percentage of rhizomes and lower fresh rhizome yield compared with manual harvest, mechanical harvest using digger attached to power tiller or digger attached to tractor was effective in labor-saving for rhizomes of Rehmannia glutinosa Libosch.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.22-29
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• 2001

In Korean high yielding varieties developed by crosses between indica and japonica rice, the most limiting factor for yield may be attributed to the less number of the tillers in the unit area. The goals of this study is to find out the effect of the temperature factors as well as cultural practices on the development and increase of tillers of Dasanbyeo, the high yielding indica crossed japonica cultivar. The effect of temperature was examined under controlled phytotron condition with 6 levels of temperature, 15, 17, 19, 22, 24 and 26$^{\circ}C$, respectively, For the experiment, the leading japonica variety in Korea, Hwaseongbyeo, was used for the check cultivar for the comparison with Dasanbyeo. The high temperature also accelerated the initiation and termination of tiller development. The cultivar difference in the speed of tiller development was observed, for example, more rapid development of tiller in Dasanbyeo than in Hwaseongbyeo was observed at the high temperature range of 24-26$^{\circ}C$, while the vice versa phenomena was observed at lower temperature range of 17-22$^{\circ}C$. The first secondary tiller of Dasanbyeo was observed on the 16, 17, 23, 27 and 38 days after transplanting (DAT) at 26$^{\circ}C$, 24$^{\circ}C$, 22$^{\circ}C$, 19$^{\circ}C$, and 17$^{\circ}C$, respectively. Those of Hwaseongbyeo was 19-22, and 26 DAT at 19-26$^{\circ}C$ and 17$^{\circ}C$, respectively. The last effective tiller of Dasanbyeo was observed on 27-33 DAT for the primary tiller, 20-41 DAT for the secondary tiller. Those of Hwaseongbyeo were 23-40 DAT for primary tiller, and 24-40 DAT for the secondary tiller, and 24-40 DAT for the secondary tiller.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.412-420
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• 2015

Even though phosphorus (P) is essential element for plant growth and development, it is not enough for crop production in soil. To breed more P deficient tolerance rice, screening and selection in rice population is needed. We tried to develop more simple and rough screening method for breeding of P deficient tolerance rice. In P deficient condition, tiller number was dramatically decreased among yield components in rice. Though this result, we confirmed tiller number could be the best marker in screening of P deficient tolerance rice. 480 rice genetic resources were cultivated in rice bed tray filled with P deficient soil for four weeks and each dry weight was measured. Among them, the 55 kinds of genetic resource were selected then cultivated in paddy field with 3 fertilizer conditions. Plant dry weight and tiller number in ripening stage were shown significant difference according to P condition. Plant dry weight and tiller number in ripening stage was highly correlated especially in P deficient condition. Furthermore, the tiller number in ripening stage and plant dry weight in rough screening were shown high degree correlation. Though these results, we might expect measuring of plant dry weight after cultivation in rice bed tray filled with P deficient soil could be a simple and effective screening method in selection of P deficient tolerance rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.348-348
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• 2017

This experiment was conducted to investigate the aspect of tiller occurrence, growth and yield of sorghum according to planting density and sowing date. The subject of this experiment is to supply basic data to inhibit non-productive tillers uneconomical and cumbersome for mechanical harvesting. Also another subject was to evaluate optimum planting density and sowing date in central district area. Total number of tillers was more in 80cm ridge than 60cm ridge and it was increased as the planting distance was wider from 15cm to 30cm on the each ridge. Ratio of effective tillers was higher in 60cm ridge than 80cm ridge and it was decreased as planting distance was wider from 15cm to 30cm. The lower the planting density, the more increased total number of tillers, whereas effective tillers were decreased as planting density was high. Average of total number of tillers of three varieties was higher in sowing date of 2 May (1st sowing date), whereas ratio of effective tillers was the highest in sowing date of 23 May (2nd sowing date). Hwanggeumchal showed the highest total number of tillers (1.2 tillers), while Moktaksusu had the lowest total number of tillers (0.8 tillers) among three varieties. There were no significant difference between planting density and days to heading and ripening date from seeding. Culm length increased as planting density was high, but ear length, grains per ear and 1000 grain weight were decreased on the other hand. The highest yield of sorghum per 10a was obtained from $60{\times}20cm$ planting density among 6 planting densities.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.446-459
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• 2000

This study was carried out in order to find out an effective machinery utilization strategy by conducting a survey on utilization and maintenance of agricultural machinery. The survey showed that the no. of utilization hours for power tiller in a year was 190.2hrs, 208.6hrs for tractor, 59.1hrs for rice transplanter, 74.0 hrs for combine, 44.6 cultivator and 254.4hrs for 4.4hrs for grain dryer. The period covered the time the machine was until it became unserviceable. The results are as follows: 10.0yrs for power tiller, 7.5yrs for tractor, 7.4yrs for rice transplanter and 5.4yrs for combine. This indicate that the actual period of use for power tiller and rice transplanter was longer than the expected period of duration years so there is a need for adjustment. The factors considered by the farmers for purchasing agricultural machine were: farm size(32%), machine operation (26.0%), performance(l4.0%) and post or after sales service(12.6%), according to the survey. It showed that repair cost rate in a year was classified into major agricultural machine; 4.8% for combine; 3.9% for tractor; 3.5% for rice transplanter; 2.0% for power tiller; 1.6% for grain dryer; and 1.2% for cultivator. The reasons for poor maintenance were insufficient after sales service(25%) and difficulty in buying parts(75%) because of the unavailability of parts in local shops(55%), imported models(30%) and outmoded model(15%).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.294-301
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• 1987

This experiment was carried out to investigate the occurrence of tiller and its proportion to grain yield under 5 different plant densities. Plant density 5 x 5cm was more favorable for increasing the number of spikes per unit area, where leads to improve grain yield. Effective tillers showed only main stem, M$_1$-axil and M$_2$-axil, indication more effective tillers in M$_1$ rather than main stem. Every tillers held at least 6 leaves to bear spikes, indicating that main stem has 12 -13 leaves. Leaves attached on main stem M$\sub$0/ and M$_1$ were very important as main source of photosynthesis, especially under more compart plant densities while leaves of M$_1$ occupied 66.8% in a plant. The proportion of grain yield of each tiller to total grain yield per plant was high in main stem under conpact plant density, in M$_1$ stems under less compact plant density, and in M$_2$ -stems under wide plant density, indicating same result on multiple regression analysis.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.3
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• pp.151-158
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• 2002

In Korean high yielding varieties developed by crosses between indica and japonica rice, the most limiting factor for yield increase may be attributed to the less number of tillers per unit area. The goal of this study is to find out the effect of the environmental factors as well as cultivation practice on the development and increase of tillers of Dasanbyeo, the high yielding indica / japonica hybrid cultivar. The effect of temperature was examined with 3 different light intensity, 220,600, and 1220 $\mu$㏖/s/$m^2$, respectively. For all the experiments, the leading japonica variety in Korea, Hwaseongbyeo, was used fur the check cultivar for the comparison with Dasanbyeo. The increase of the tillers was more prominent in Dasanbyeo than in Hwaseongbyeo at 220 $\mu$㏖/s/$m^2$ of light intensity, while the similar increase of tiller no. was found at 600 $\mu$㏖/s/$m^2$ of light intensity treatment. However, Hwaseongbyeo showed more rapid increase of tiller at 1220 $\mu$㏖/s/$m^2$ of light intensity. The mean number of the primary tiller ranged 5 to 7 in Dasanbyeo, and 2 to 7 in Hwaseongbyeo, showing greater variation in the latter case. However, the secondary tiller number ranged from 2 to 13 for the former, and 2 to 12 for the latter. The earliest initiation of tiller node of Dasanbyeo and Hwaseongbyeo was observed on 6 and 4 days after transplanting(DAT), respectively, at 600 $\mu$㏖/s/$m^2$ of light intensity, while 10, and 7 DAT, respectively, at 1,220 $\mu$㏖/s/$m^2$. No cultivar difference was observed at 600 $\mu$㏖/s/$m^2$ with the 18 DAT. The ratio of effective tiller was lower in Dasanbyeo, ranging from 47 to 55% than in Hwaseongbyeo, ranging from 72 to 100%.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.53-58
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• 2009

The propose of this study was to find out optimum conditions for no-tillage rice-winter cover crops cropping system. A field research was conducted to evaluate productivity and quality of rice cultivars (Dongjinbyeo and Junambybyeo) in rice-winter cover cropping systems at Doo-ryangmyeon., Sacheon, Gyeongsangnam-do, Korea from January 2005 to October 2006. The experimental soil was Juggog series (fine silty, mesic family of Fluvaquentic Eutrndepts). The rice cultivars were experimented under some different high residue farming systems, i.e. no-tillage no treatment (NTNT), no-tillage amended with rice straw (NTRS), no-tillage amended with rye (NTR), no-tillage amended with Chinese milkvetch (NTCMV), tillage no treatment (TNT), and conventional cropping system (Control). The miss-planted rate was 8.8% in 2005 and range of 10.8% to 13.3% in 2006 at NTR, and the other treatments were carried out at miss-planted rate ranging from 1.2% to 5.0%. Tiller numbers of Junambyeo, and Dongjinbyeo in both of years were the highest in Control, and decreased nearly in NTCMV, NTR, NTRS, NTNT, and TNT in that order. The lowest grain yield was observed in TNT both cultivars due to the lower tiller numbers per area, and spikelet numbers per panicle. Also, no-tillage treatments were lower grain yield than control. On the other hand, 1,000-grain weight was lowest in control due to higher tiller numbers per area, and spikelet numbers per panicle. Ripened grain ratio was a similar aspect in all treatments. The palatability score of milled rice was lowest in control while protein content of milled rice was highest in control. The NTCMV was considered an effective sustainable farming practice for rice yield and quality.