• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.1
• /
• pp.16-24
• /
• 1998

To determine the optimum application of fertilizers for the cultivation of Chinese cabbage in plastic film house, twenty soils which contain different salts contents were taken from 4 different area of plastic film house cultivation, Youngdong. Boeun county, Cheongweon county, and Cheongju city. The dry weight and the amount of N. P, and K uptakes of Chinese cabbage in the plot of no fertilization were considered as the factors representing the fertility of the soil. And a difference of dry weight and the amounts of N, P, and K uptakes of plants between the plot of fertilization and no fertilization were considered as the factors representing the total effect of fertilizer and fertilizer N, P, and K effects. respectively. These factors of soil fertility and fertilizer effects were estimated by correlation and regression with soil tests in order to find the critical levels and recommended method for optimum fertilization of Chinese cabbage. Chinese cabbage transplanted in two soils, having the electrical conductivity of 9.3 and 15.2 dS/m, were not able to root due to the salts toxicity. The content of inorganic N, the electrical conductivity, and CEC were founded to have significant correlation with the factors of both the soil fertility and fertilizer effects for the cultivation of Chinese cabbage. To determine the weighting degree for the productivity and the fertilizer effects, the standardized partial regression coefficient was analyzed by regression among the factors of fertility, the fertilizer effects, and the soil tests. The coefficient for inorganic N($NH_4-N$ and $NO_3-N$) was obtained as the absolute value of 756-1871 and this value was extremely higher than those of other soil tests which was 0.07-4.11. These results suggested that the content of inorganic N is the best tests for the estimation of the productivity and the fertilizer effects for the cultivation of Chinese cabbage in plastic film house. The critical level of inorganic N($NH_4-N+NO_3-N$) estimated by Cate-Nelson split method for maximum productivity and zero point of fertilizer effect was 220 mg/kg for all the factors of estimation. These results suggested that no application of fertilizer N. P, and K is required at the critical level of inorganic N of soil. Consequently the optimum application of fertilizer N, P, and K for the cultivation of Chinese cabbage in plastic film house was possible to determine by the critical level of inorganic N of soil. The critical level of electrical conductivity was estimated as 2.8 dS/m by the same method.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.4
• /
• pp.313-319
• /
• 1992

To investigate effects of water stress on apparent photosynthetic, transpiration rates, leaf orientation, yield and its related traits, four soybean varieties were planted on the Wagner pots in a plastic house covered with polyethylene film. As the light intensity and leaf temperature in a day increased, the movement of central leaflet in the second leaf of main stem occurred earlier than that of the lateral leaflet. The apparent photosynthetic rate of the central leaflet was higher than that of the lateral leaflet, but light intercept and leaf temperature of lateral leaflet were higher than those of the central leaflet. The apparent photosynthetic rate had highly positive correlation with the photon flux density, stomatal conductance and temperature, respectively. The photon flux density, stomatal conductance, transpiration and photosynthetic rates in the control were significantly higher than those in the water stress plot. The yield and its related traits in the water stress plot became decreased significantly in comparison with the control.

• Korean journal of applied entomology
• /
• v.36 no.3
• /
• pp.237-242
• /
• 1997

Comparative studies on suppression possibility with three phytoseiid mite species (An.thly,seiu,sw omersleyi Schicha. A. ,fidIrrc~i.Gs arman and T\ulcornerphlorlrotiiu.s oc~c~idetitaliNs esbit) to the two-spotted spider mite (Te~trrrt~yc.Iir~l~l\ulcorner.i\c .(re Kwh) on kidney bean leaves in field and greenhouse were carried out. In the field experiments with the initial prey -predator ratio of 4 : 1. I0 : I and 20: I . A. ,firllrrcis suppressed successfully the prey populations at all three ratios 17 days after the initial infestation. A. wornc,r-;leyi \uppressed the prey population only at the ratio of 4 : 1, while T. oc~c~ideritcr1iw.s as unable to suppress the prey population at all tested ratios. In the greenhouse experiments with the initial prey-predator ratio of 10: 1, A. jil1ltrci.s could suppress the prey population continuously during the infestation period. A. ~~otnc~r,slceoyuil d suppress the prey population for 13 days after the initial infestation, while T. occie1mttrli.s could suppress the prey population for 8 - 23 days after the initial infestation.

• Research in Plant Disease
• /
• v.14 no.2
• /
• pp.85-89
• /
• 2008

Clubroot of Chinese cabbage, caused by Plasmodiophora brassicae, is one of the most serious plant diseases in the world. The objectives of this study were to investigate the effect of the irrigation times on the development of club root after planting and to evaluate the effect of clubroot disease on yield of chinese cabbage in pot and field. The clubroot disease gradually increased with increasing irrigation frequency after planting. The growth characters and yield of chinese cabbage by irrigation times varied according to soil moisture and clubroot disease severity. Based on marketable yield and control value, an ideal irrigation point was at the soil matric potential of 0.06 MPa. These results suggest that the suppression on clubroot disease development could be achieved by initially reduced irrigation times after planting. Future studies on irrigation times using fungicide treatment and resistant cultivar under natural field conditions are required to improve the control effect of clubroot.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.6 no.1
• /
• pp.60-64
• /
• 1986

To determine the effects of soil moisture on diurnal changes of photosynthesis, transpiration and stomatal resistance, sorghum and soghum-sudangrass hybrid were grown at large concrete pots maintained at 100, 80, 60 and 40% of field moisture capacity. Photosynthesis were measured from a.m. 6 to p.m. 6 on a fine day. 1. Photosynthesis and transpiration reacted similarly to water stress and environmental factors, and they reached at their maximum points from noon to 2 p.m. and decreased sharply after 4 p.m. 2. Photosynthesis and transpiration of sorghum were higher at 60% field moisture capacity than those of the other field moisture capacities. In sorghum-sudangrass hybrid, photosynthesis was in the order of 60>80>40>100% and transpiration was in the order of 60>80>100>40%. 3. Stomatal resistance did not show clear diurnal change and was the lowest at 60% among four field moisture capacities.

• Korean Journal of Weed Science
• /
• v.14 no.2
• /
• pp.101-106
• /
• 1994

Factors affecting phytotoxicity of dithiopyr in rice such as transplanting depth, seedling age, soil texure were examined and mechanism of phytotoxicity in rice was also determined by absorption study of $^{14}C$-dithiopyr in rice seedlings under above conditions. Rice injury was occurred in shallow transplanting depth, young rice seedlings and sandy soil conditions. Higher amount of dithiopyr was absorbed in rice at shallow transplanting depth and sandy soil conditions which may related to phytotoxicity of dithiopyr.

• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.2
• /
• pp.81-87
• /
• 1979

In order to observe the lasting effect of NK-compound mineral fertilizer and organic compound fertilizer including Myweon organic liquid fertilizer, a pot experiment was conducted with rice (Oriza Sativa) variety: Nong Back. These fertilizers were applied as basal and the same amount of urea form of nitrogen was top dressed about a month after transplanting, July seventh, 1977. Results obtained are as follows; 1. The lasting effect of various fertilizers were laid in following decreasing order; Myweon liquid < Organic compound fertilizer (Myweon coop. made) > NK-compound fertilizer (Chosun coop. made) Single fertilizer. It was considered that organic matter served as microbial feed and lead a temporary fixation of available plant nutrients in the soil, and the reduced surface area of the compound fertilizers slowed down the availability of the fertilizers. 2. The fertilizer showing greater lasting effect produced more panicles per hill and less grains per panicle than the fertilizers showing less lasting effect, and brought low maturity, which resulted in low paddy yield the paddy producing efficiency of nitrogen absorbed by straw was also low in the former fertilizers. Such advanced effect of the former fertilizer was considered to be related with the variety of early maturity and unseasonable topdressing of fertilizer which made at the maximum tillering stage. 3. For the production of Japonica type paddy with heavy fertilization which may required to depress the early growth a little and promote the late growth, it might be necessary to develop slow releasing fertilizers such as single fertilizer formulated to a large grains or compound fertilizer containing organic matter. 4. If the nitrogen content of paddy, Nong Back, far excess 0.64 or 0.65% and reaches 0.68% or above, the yield of the variety seemed to be decreased remarkbly through the low maturity rate and thousand grain weight.

• The Korean Journal of Mycology
• /
• v.41 no.4
• /
• pp.248-254
• /
• 2013

A Gram-negative bacterium was isolated from mushroom media that markedly reduces the level of extracellular toxins (i.e., tolaasins) produced by Pseudomonas tolaasii, the most destructive pathogen of cultivated mushrooms. The HC1 strain was selected as detoxifying tolaasin by bioassay on potato and it was identified Pseudomonas sp. by the cultural, morphological and physiological characteristics, and analysis of the 16S rRNA. The isolated bacterium is saprophytic but not parasitic nor pathogenic to cultivation mushroom. The isolated bacterium for P. tolaasii cell, was sufficient for detoxification in vitro. Inoculation of the isolated bacterium prevents the development of bacterial disease in Pleurotus ostreatus, Flammunia velutipes and Agaricus bisporus. Control efficacy of brown blotch of strain HC1 treatment was 69, 68 and 55% on Agaricus bisporus, Flammulina velutipes and Pleurotus ostreatus, respectively. The suppressive bacterium may be useful in future for the development of biocontrol system and the construction of genetically modified edible fungi resistant to the disease caused by P. tolaasii.

• The Korean Journal of Mycology
• /
• v.42 no.3
• /
• pp.219-224
• /
• 2014

A gram-negative bacterium was isolated from spent substrate of Agaricus bisporus and showed marked antagonistic activity against Pseudomonas tolaasii. The bacterium was identified as Pseudomonas azotoformans by based on the cultural, biochemical and physiological characteristics, and 16S rRNA gene sequence. The isolated bacterium was saprophytic but not parasitic nor pathogenic to cultivation mushroom. The isolated bacterium for P. tolaasii cell was not sufficient for inhibition in vitro. Control efficacy of Pseudomonas azotoformans HC5 to brown blotch of P. tolaasii was 73, 78, and 71% on A. bisporus, Flammulina velutipes, and Pleurotus ostreatus, respectively. In the future, the suppressive bacterium may be useful for development of a biocontrol system.

• Journal of Life Science
• /
• v.14 no.4
• /
• pp.689-695
• /
• 2004

This study was investigate the occurrence of bottom rot caused by Rhizoctonia solani at the crisphead lettuce fields in Uiryeong-gun, Gyeongsangnam-do from November to December in 2003. Incidence of bottom rot on crisphead lettuce was up to 5.3% at the six plastic houses. A total of 30 isolates of R. solani were obtained from diseased leaves of plants and were tested by artificial inoculation to the host. Among them, PY-1 isolate was selected showing highly virulent on the whole plant and was identified as R. solani AG1 (IB) based on the anastomosis test, morphological and cultural characteristics. Symptoms of bottom rot by PY-1 isolate produced small dark brown, depressed and elliptical spots on the lower part of leaves in the early stage as same as at the fields, were enlarged onto the upper part of leaves later, and the infected plant wilted and ultimately died in the end. For the pathogenicity test, triturated mycelia-inoculum (A$_{550}$=1.0) of PY-1 isolate was selected the most effective inoculum showing disease incidence of 51.1% for the mycelial inoculation at pot assay. Otherwise, WSRP media-inoculum (wheat brane ： sawdust ： rice brane ： PDB media=30 g ： 10 g ： 10 g ： 100 ml, w/w/w/v) of PY-1 isolate was effectual inoculum showing disease incidence of 61.6% for soil inoculation at the plastic house. Also, in selection of density and amount of inoculum, most suitable density of triturated mycelia-inoculum and amount of WSRP media- inoculum were determined as $A_{550}$=1.0 and 40 ml, respectively. This is the first report on the pathogenicity test using by WSRP media-inoculum of R. solani PY-1 isolate for the bottom rot of crisphead lettuce.