• Korean Journal of Soil Science and Fertilizer
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• v.42 no.4
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• pp.257-265
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• 2009

The long-term effects of soil management history on microbial communities are still poorly understood. Our objectives were to determine the impact of long-term application of soil amendments on microbial communities in rice paddy fields. The treatments selected were control where crops were grown without any nutrient application (CON); nitrogen-phosphorus-potassium (NPK); NPK plus compost (CNPK); NPK plus lime (LNPK); and NPK plus silicate (WNPK). The long-term addition of organic and inorganic amendments significantly changed soil chemical properties. The amount of organic carbon increased in the treatments with fertilizer and amendments over that in the soil without inputs. However, we could not observe the differences of bacterial population among the treatments, but the number of aerobic bacteria increased by the addition of amendments. Isolates from the rice paddy soils before irrigation were Dactylosporangium, Ewingella, Geobacillus, Kocuria, Kurthia, Kytococcus, Lechevalieria, Micrococcus, Micromonospora, Paenibacillus, Pedobacter, Pseudomonas, Pseudoxanthomonas, Rhodococcus, Rothia, Sphingopyxis, Stenotrophomonas, and Variovorax. Dominant genera were Arthrobacter, Kocuria, Kurthia, and Bacillus in the long-term field. Microbial biomass was the highest in the compost treatment (CNPK), and was the lowest in the CON. Dehydrogenase activity in soils treated with rice compost straw was the highest and the activity showed an increasing trend according to treatment as follows: CON < WNPK < NPK = LNPK < CNPK. These results demonstrate that soil management practice, such as optimal application of fertilizer and amendment, that result in accumulations of organic carbon may increase microbial biomass and dehydrogenase activity in long-term rice paddy soils.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.82-85
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• 2009

This study was performed to investigate if elevated $CO_2$ affects the residue pattern of $^{14}C$ in the soil environment after $^{14}C$-carbaryl treatment $^{14}C$-carbaryl was applied on the rice plant-grown greenhouse soil exposed to atmospheric and elevated $CO_2$ conditions. $^{14}C$-radioactivity was measured in the rhizospheric soil and rice straw samples six months after $^{14}C$-carbaryl application. Significantly high radioactivity was observed in the soil exposed to atmospheric $CO_2$ as compared to that in the soil exposed to elevated C(h. Background level of radioactivity was observed in rice plant samples. These observations suggest the possibility that elevated $CO_2$ may affect residual radioactivity of $^{14}C$-carbaryl in the soil rather than that in the plant.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.231-240
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• 1987

With a purpose to obtain basic informaton for improving poorly drained soil, a pot experiment was conducted about the effect of percolation rate on growth and yield of rice under application of wollastonite and rice straw as soil conditioner. The sandy and clayey soils were selected to compare difference in effectiveness of poor drainage. The results were summarized as follows: 1. Increasing or percolation rate increased rice yield in both sandy and clayey soils, but the effectiveness on yield increase was greater in clayey soil than in sandy. 2. Various materials of soil solution produced from the process of soil reduction were high at the early growing stage, but they were gradually decreased at the later growing stage. 3. With increasing percolation rate, the contents of N, $P_2O_5$ and $K_2O$ in rice plant were decreased, but that of $SiO_2$ was increased. 4. The number of roots at harvest was greater with increased extension as infiltration rate was increased.

• Applied Biological Chemistry
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• v.6
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• pp.45-50
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• 1965

To confirm the increase effect of $MNH_4$ which has been compounded as a result of two years' potted rice experiments, we have established simple experiment areas in the paddy field of Kyung-Puk, Kyung-Nam and Chon-Puk Provinces and have done the completely randomized design experiments with the following results. 1. Comparison of the gross weight of the harvested rice (Straw included) : The $MNH_4$ 1-area has produced 10-28% more harvest than that of control-area. 2. Comparison of the weight of the Unpolished Rice: The $MNH_4$ 1-area has shown 10-23% increase compared with the control-area. 3. In the comparison of the nutrients of the rice from the $MNH_4-area$ with those of the rice from the control area, $MNH_4-area$ showed increase of $N_2$, $P_{2}O_5$ and $SiO_2$ but a slight decrease of $K_2O$.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.35-40
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• 1997

This study was conducted to investigate methane emission under different rice cultural practices in paddy soil (Jeonbug Series, occurring on fluvio-alluvial plain). The rates of application of fresh rice straw were 5,000kg/ha in combination with 110 and 160kg N/ha as chemical fertilizer. The methane emission among the rice cultural practices was in the order of transplanting cultivation, direct seeding on flooded surface and direct seeding on dry paddy field. The average methane flux was $10.27mg/m^2/h$ in direct, seeding on dry paddy field and $24.1mg/m^2/h$ in transplanting cultivation. The diurnal variation of methane emission at heading stage was high from 9 a.m. till 7 p.m. and the methane emission rate was highly correlated with air temperature fluctuation and soil Eh. The seasonal change of methane flux was high from ear formation stage to heading stage.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.14-20
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• 1985

This study was carried out to evaluate the effects of whole layer placement of total of N.P.K. application with clay mineral such as Bentonits and Zeolite on the growth and the yield of rice in different sandy soils. The results obtained were as follows ; The yield was increased by whole layer placement of total amount of N.P.K. application with clay minerals in both soils examined compared with the treatment of N.P.K. only. In fine sandy loam soil, it was increased significantly at 5% level at N.P.K. + Zeolite 1.0 M/T and in fine sandy soil, at 5 % and 1 % at N.P.K. + Bentonits 0.5 M/T and N.P.K. + Bentonite 1.0 M/T, respectively. The nitrogen and silica content of rice straw at heading stage were increased and were tended to increase in phosphate and exchangeable cations such as potassium. calcium and magnesium by whole layer placement of total amount of N.P.K. application with clay mineral. The chemical properties of both soils were changed slightly after the harvest of rice by the whole layer placement of total amount of N.P.K. application with clay mineral ; pH, C.E.C., exchangeable base and available silica content were increased.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.2
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• pp.149-154
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• 1971

To elucidate the effects of calcium carbonate applied under upland and flooded conditions on the changes of soil pH, an incubation study of a soil was carried out. The experiment was conducted under the conditions with and without ground rice straw application. The results of the experiment are summarized as follows: 1. The incubation under the upland moisture condition after the application of calcium carbonate raised soil pH as high as calcium hydroxide did, whereas incubation with calos treatment under the flooded condition showed a low pH. 2. Reduction of a soil brought about by the application of ground rice straw has a significant effect on the rise of soil pH. The high pH of a soil thus brought about or raised by the use of lime is gradually reduced as the accumulation of bicarbonate ions and carbon dioxide increases in the soil solution. It may, however, be possible to keep the high pH of a flooded soil by practicing intermittent drainage or cultivation which reduces the content of bicarbonate and $CO_2$ pressure in soil solution. 3. Carbonate and bicarbonate salts which may be produced in flooded and reduced soil increases the buffering capacity of the soil.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.151-156
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• 2006

This study was conducted to investigate effects of granular silicate fertilizer(GSF) on growth, nutrient uptake and quality rice during cultivation. Then the chemical properties of paddy soil used for the cultivation test were pH 5.9, O.M. $13.7g\;kg^{-1}$, avail. $P_2O_5$ $48.9mg\;kg^{-1}$, and avail. $SiO_2$ $79.8mg\;kg^{-1}$. The amounts of GSF treated in the paddy soil were 0, 76, 185, 229, 413 and $489kg\;10a^{-1}$ for control, S-100(control amounts of soil available $SiO_2$), S-130, S-160, S-190 and for S-210 treatments, respectively. At results of rice growth leaf length and tiller number were more remarkable results at treatments of GSF than control. The leaf length of rice at S-100 treatment was the highest as 99.4 cm and the tiller number was the highest as 18.9 ear number at S-130 treatment. At the results of rice yield parameters, the grain and straw yield of rice were showed that all of the GSF applicated treatments were more predominant level than at the control, especially their levels were the highest values as 841.5 and $815.2kg\;10a^{-1}$ at the S-160 treatment, respectively. Also at the results of quality parameters on rice grain, a perfect kernel in the GSF applicated treatments was more increased than at control, but a broken kernel rate was inversely decreased. In results of these aspects, the chemical properties of white rice and the taste of rice by the Toyo MA-90A(Toyo rice quality taster) instrument, amylose content was the lowest value as 18.7%(generally about 20%) at S-160 treatment. Also, Mg/K ratio and rice taste value were the highest level as 0.58 and 69.1 at the S-190 and S-160 treatments respectively. The harvest yields of rice at S-160 and S-190 treatments from these growth factors were more produced about 8-13% than control. Therefore, the GSF application for rice cultivation from these results should be expected to obtain the positive effects as enhancement of rice harvest yield and improvement of quality on the cooked rice taste. Amount of GSF application could be recommended as around $200mg\;kg^{-1}$ for optimal and economical rice cultivation.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.55-67
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• 2006

A survey of 31 organic farmers were conducted to investigate the actual conditions of organic matter application. The amounts of organic matter application in the fields were higher in order of fruit, vegetable and rice farm. The average was 50 ton/ha in vegetable farms. In the green vegetable farms saw dust and animal manure were mainly utilized to make compost. Rice straw, wood chip, and forest bushes were also used for composting. In the fruit vegetable farms materials relatively lower in nitrogen content such as rice straw and cattle manure were used in vegetative period and materials higher in nitrogen content such as oil cake and wild grass were used in reproductive phase. Nutrient balance investigated in the farm in Icheon region who produce lettuce, angelica, and kale continuously in one cropping year indicated surplus in three major nutrients. Nitrogen and phosphorous were in excess by 29 and 10 kg respectively in the organic rice farm in yang-pyoung region. While soil chemical properties in the organic farms are within the adequate range in open field, it is much higher than the limits in the greenhouse soils. Overall application of organic matter is in an oversupply state. This results suggested that the organic matter management should be based on the soil conditions for sustainable cultivation. Chemical composition of organic matters and soil test reports should be considered prior to the application of organic matter.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.35-42
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• 1985

This study was carried out to investigate the effect of environmental factors affecting emergence and control of Sagittaria pygmaea Miquel in greenhouse. Emergence of S. pygmaea delayed as the amount of rice straw increased. When the tuber was sowned at 5 to 7㎝ soil depth the emergence of S. pygmaea delayed more in the hard condition of soil than that of the soft condition the large size tuber of S. pygmaea showed less control rate than the small size one at the rate of 2 to 3㎏ prod/10a of butachlor-naproanilide mixtures. The tubers of S. pygmaea seeded at the deeper soil depth decreased weeding efficicy of this mixture. Butachlor-naproanilide mikture showed higher weeding effects at the high temperature and at 2 to 4cm depths of water management than those of the low temperature and at 0cm and 6cm water depths. Weed control rate increased as the rate of butachlor-naproanilide mixture increased. The rate of 4㎏ (prod.)/10a showed good weed effect regardless of application times till 7.5 leaf stage of S. pygmaea. Tuber production of S. pygmea increased as the application time of mixture delayed.