• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.751-759
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• 2016

It is known that the poor soil fertility of newly reclaimed saline soils is due to the lack of organic matter and available mineral nutrients for crop production. The effect of green manuring with Sesbania aculeata in combination with five rates of urea-N treatments (N0. N25, N50, N75, N100) on the productivity of a subsequent whole-crop barley and the fertility of the reclaimed saline soil in Saemangeum was evaluated in the field during 2013-2014 growing season. Sesbania was grown during summer season (June to October). The amount of Sesbania incorporated was $16.2Mg\;ha^{-1}$. Sesbania contributed to $393kg\;N\;ha^{-1}$ to the soils when ploughed down and incorporated before whole-crop barley cultivated. The performances of whole-crop barley following sesbania incorporation were significantly affected by a combination of Sesbania manuring and different N rates. The N fertilizer equivalence without N fertilizer following Sesbania was 42.6% ($63.9kg\;N\;ha^{-1}$), compared with N100 ($150kg\;N\;ha^{-1}$) in fallow soils. The whole-crop barley yield responded to N fertilizer rates in both sesbania-amended and fallow soil. The yield response to nitrogen rates in fallow soil was linear (Y=0.0586X+3.3011, $R^2=0.9534$), whereas that in sesbania-amended soils was quadratic (Y= -0.001X2+0.1322X+5.7143, $R^2=0.9576$). The yield of whole-crop barley in sesbania-amended with increasing N rates was increased up to SN75 (115 kgN) $10.3Mg\;ha^{-1}$. Apparent N recovery (ANR) of whole-crop barely showed decreased with sesbania plus increasing rates of N fertilizer. Despite higher yield with sesbania manuring plus increasing N rates, the contributions of N from Sesbania with increasing N rates to whole-crop barley were decreased, whereas those from fertilizer increment due to excessively mineralized Nitrogen. Considering yield, ANR, N contribution from Sesbania and nitrogen fertilizer, the optimum N rate was N50 rate following sesbania incorporation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.314-314
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• 2017

Anthropogenic activities have increased the concentrations of greenhouse gases, such as $CO_2$, $CH_4$, $N_2O$, HFCs, $SF_6$, and PFCs, in the atmosphere. Among others, $N_2O$ is well known as an important greenhouse gas accounting for 7.9% of the total greenhouse effect and the effect of its emission is 310 times greater than that of $CO_2$. Agricultural $N_2O$ emissions are now thought to contribute to about 60% of the global anthropogenic $N_2O$ emission, which have been increased primarily due to fertilizer N consumption and manure management. Therefore, the reduction of $N_2O$ emissions in agriculture is being required. This study was conducted to determine the variation of $N_2O$ emissions by no-tillage (NT) and conventional tillage (CT) practices in the cultivation of soybean from the sandy loam soils under the different kinds of fertilizer treatments June through September 2016 in Cheong-ju, Republic of Korea. An experimental plot, located in the temperate climate zone, was composed of two main plots that were NT and CT, and were divided into four plots, respectively, in accordance with types of fertilizers (chemical fertilizer, liquid pig manure, hairy vetch and non-fertilizer). Among all the treatments, $N_2O$ emission was the highest in August and the lowest in June. When $N_2O$ emissions were evaluated during the growing season (June to September) in all fertilizer treatments, NT with hairy vetch treatment emitted the highest $N_2O$ emission in August, whereas, $N_2O$ emissions was the lowest in NT with non-fertilizer treatment in June, respectively (p = 0.05). Based on the cumulative amount of $N_2O$ emissions during the growing season of soybean, NT had lower $N_2O$ emission than CT by 0.01 - 0.02 kg $N_2O$, although NT had higher $N_2O$ emission than CT by 0.03 kg $N_2O$ in only the chemical fertilizer treatments. As a result, it seems that the applications of liquid pig manure and hairy vetch rather than chemical fertilizer could decrease the $N_2O$ emission in NT, compared to CT.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.8-14
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• 2013

The newly developed fertilizer is the slow-releasing fertilizer which can be used as a basal fertilizer without no additional fertilization at tillering stage. It has 30-4-6% of $N-P_2O_5-K_2O$ and was coated with mixture of LDPE (Low density polyethylene), EVA (Ethylene vinyl acetate), BDP (Bio degraded polymer), TALC and nonionic surfactant for the controlled release up to 50 days after application. Coating materials were designed to be decomposed naturally. This fertilizer can be applied directly to the seedling tray mechanically just before transplanting, resulting in significant labor saving effect. The developed slow-release fertilizer, which can replace both basal fertilization and top dressing at tillering stage by single application directly to seedling tray, showed the highest release at 14~21 days after transplanting. Considering the plant growth at different growth stages and yield, the optimal application rate of developed slow-release fertilizer was 300 g per rice nursery tray and the yield of rice at this application rate was 5.25 MT/ha. Rice quality in terms of head rice grain ratio, amylose content, whiteness, and taste value decreased as fertilization rate increased from 200 g to 500 g per nursery tray. Fertilization rate based on quantity of fertilizer ingredients (N, P, K) was reduced by 49.3% compared to the standard application rate and there was 49.2% reduction in labor input for fertilization.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.369-377
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• 2014

This study was carried out to evaluate the effect of rice husk (RHB) and food waste biochar (FWB) on upland soil with sandy loam texture, in terms of physico-chemical analysis, lettuce seed germination test, and orgainc carbon leaching experiment. RHB and FWB had different physico-chemical properties each other. Carbon to nitrogen ratio (C/N ratio) of RHB was 32, showing two times higher than that of FWB. FWB had high salt and heavy metal content, compared to RHB. This is probably due to different ingredients and production processing between two biochars each other. Results of germination test with Lettuce showed lower germination rate when FWB was applied because of higher salt concentration compared to control and RHB. Organic carbon leaching test using saturated soil column (${\Phi}75{\times}h75mm$) with $10MT\;ha^{-1}$ biochar application rate, showed higher saturated hydraulic conductivity in rice husk biochar treatment column, compared to control and food waste biochar treatment. The highest total organic carbon concentration in column effluent was lower than those in both of rice husk biochar and food waste biochar, whereas the differences was negligible after 9 pore volumes of effluent. Consequently, biochars from byproducts such as rice husk and food waste in sandy loam textured upland soil could enhance a buffer function such as reduction of leaching from soil, but the harmful ingredient to crops such as high salt and heavy metals could limit the agricultural use of biochars.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.175-194
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• 1979

The soil organic matter contents in arable land are generally low in Korea. Thus it is generally agreed that the application of organic materials to soils would be much beneficial. Present paper is a review on the effectiveness of organic mat ter application in uplands and lowlands. 1. The effect of organic matter application in uplands are of more clear and simple to explain as compared to that in lowlands. In uplands, appropriate application of organic matters such as compost and various crops residues improves the physical properties of soils leasing to increased water holding capacity, better aeration, and decrease in soil erosion. 2. In lowland, rice soils under water logged conditions the effect of organic matter application on rice yield is not straight borward and demands more refined knowledges for the interpretation of it. 3. It is found that the application of compost in rice soils is more effective when nitrogen fertilizer application is limited it dicating that nitrogen contained in the organic maerials can become available to rice plant and plays an important role for increased yield of rice under the condition where nitrogen fertilizer supply is limited. 4. Application of organic matter does not always bring about the desirable effects. Very often the organic matter application results in more intensive soil reduction leading to the accumulation of harmful substances which would can cancel out the positive effects of organic matter. This is partiunlarly true in poorly drained soils. 5. Rice straw or compost, when applied rice soils, supply sizeable amounts of available silicate to rice plant resulting in yield increase. 6. Although the effectiveness of organic matter application on rice yield in short term experiments is not consistent due to many reasons, the long term effect of organic matter is significant. 7. The term of the $O.M/SiO_2$ ratio in rice soils can serve as a criterion for the judgement of whether organic matter or silicate fertilizer is needed to be applied in a certain soil.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.4
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• pp.199-217
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• 1975

For the establishment of efficient method of potassium topdressing on rice the optimum time and amount were investigated and discussed on the basis of available data from nutriophysiological studies, soil characteristics and fertilizer trials in fields. The followings were pointed out. 1. According to yield rice plants require more potassium around heading under water culture. 2. Potassium involves in harvest index, filled grain ratio, grain weight and number of spikelets per panicle. 3. Potassium is lost after heading in most fields in spite of highest requirement during this period. 4. The higher $K_2O/N$ ratio in straw at harvest is, the higher the yield. 5. Relatively low efficiency of potassium fertilizer under the field condition may be due to improper application method rather than natural supply from soil and irrigation water. 6. Appropriate topdressing time appears at in effective tillering stage for the prevention of nitrogen excess and at 15 to 20 days after transplanting, ear formation stage and 5 days after heading for the prevention of soil reduction damage. Two times of topdressing for clayey soil and three times for sandy soil seems reasonable in practice together with nitrogen topdressing, 7. The reasonable ratio basal to topdressing of potassium fertlizer seems to be 2/3 and $N/K_2O$ ratio of fertilization for ear formation stage appeared also as 2/3.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.502-509
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• 2013

To estimate greenhouse gas (GHG) emission, we established inventory of conventional rice cultivation from farmers in Gunsan and Iksan, Jeonbuk province in 2011~2012. This study was to calculate carbon footprint and to analyse the major factor of GHGs. We carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we tried to suggest agricultural methods to reduce GHGs that farmers of this case study can apply. Carbon footprint of rice production unit of 1 kg was 2.21 kg $CO_2.-eq.kg^{-1}$. Although amount of $CO_2$ emissions is largest among GHGs, methane had the highest contribution of carbon footprint on rice production system after methane was converted to carbon dioxide equivalent ($CO_2$-eq.) multiplied by the global warming potential (GWP). Source of $CO_2$ in the cultivation of rice farming is incomplete combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ emitted during rice cultivation and major factor of $CH_4$ emission is flooded paddy field in anaerobic condition. Most of the $N_2O$ emitted from rice cultivation process and major sources of $N_2O$ emission is application of fertilizer such as compound fertilizer, urea, orgainc fertilizer, etc. As a result of sensitivity analysis due to the variation in energy consumption, diesel had the highest sensitivity among the energies inputs. If diesel consumption is reduced by 10%, it could be estimated that $CO_2$ potential reduction is about 2.5%. When application rate of compound fertilizer reduces by 10%, the potential reduction is calculated to be approximately 1% for $CO_2$ and approximately 1.8% for $N_2O$. When drainage duration is decreased until 10 days, methane emissions is reduced by approximately 4.5%. That is to say drainage days, tillage, and reducing diesel consumption were the main sources having the largest effect of GHG reduction due to changing amount of inputs. Accordingly, proposed methods to decrease GHG emissions were no-tillage, midsummer drainage, etc.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.465-470
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• 2011

Liquid fertilizer and composted cattle manure were applied to an agricultural land. This study was conducted to find the pathway of the nutrients transport. Nitrogen concentration was decreased by the repeatable precipitation in surface runoff, but the nitrate concentration in ground water was gradually increased by biological metabolism, especially with pig liquid fertilizer. Phosphorus was mostly adsorbed into the soil, and its reduction was affected by the soil drain by surface runoff in the summer. Averaged adsorption capacity of the phosphorus via Jar-test was determined as 21.5 mg P/kg of soil.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.21-27
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• 2013

The present study explored the way to desalinate seawater for agricultural irrigation using forward osmosis (FO) process using liquid fertilizer as draw solution. FO experiments were performed in a cross flow mode using flat sheet FO membrane. The effect of membrane orientation, flow rate, and draw solution concentration on the performance of forward osmosis was investigated by measuring water flux of forward osmosis membrane. The water flux when the draw solution was placed against the membrane active layer was lower than the water flux when the feed solution was placed against the membrane active layer. This results indicated that the decrease of effective osmotic pressure by dilutive internal concentration polarization was less than that by concentrative internal concentration polarization. Increasing flow rate from 66.7 to 133.1 $cm^3$/min resulted in increase of the water flux when the membrane active layer orient to draw solution and feed solution, respectively. The reduction of resistance to water flow increased water flux at higher flow rate. The water flux of FO membrane increased with increasing draw solution concentration from 10000 to 30000 mg/L. The water flux for $KH_2PO_4$ draw solution was similar to that for commercial fertilizer. Optimization of FO process would contribute to economically desalinate brackish water for agricultural use.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.169-176
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• 2013

This survey was conducted to investigate the present conditions of operational management in the 45 animal manure public resource center (APRC) in Korea. The regional distribution, processing capacity per year, capacity of liquid fertilizer storage tank, solid-liquid separation, utilization of facilities, odor reduction facility, on-site odor strength, complained in the community, liquid fertilizer sprayed area, use the Agrix, land application recipe, composting degree, quality management and general grading were surveyed and evaluated. General grading was divided with 5 stages (very good, good, fair, lack and bad). The number of evaluated "very good" animal manure public resource center was 7, and "good" was 5 and more than "fair" was 27. However, the number of evaluated negatively including "lack" and "bad" was occupied as 40% of the 45 animal manure public resource center.