• 한국환경농학회지
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• 제36권3호
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• pp.141-146
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• 2017

BACKGROUND: Phosphorus(P) is a vital factor for rice but excess input of phosphorus fertilizer can cause environmental risk and waste of fertilizer resources. We studied to assess the change of available phosphate, P balance, critical concentration of available phosphate under a rice single system. METHODS AND RESULTS: The changes of available phosphate of paddy soil were examined from long-term fertilization experiment which was started in 1954 at the National Academy of Agricultural Science. The treatments were no phosphate fertilization(No fert., and N), phosphate fertilization(NPK, NPKC, and NPKCLS). The available phosphorus concentrations in treatments without phosphate fertilizer (No fert. and N) were decreased continuously. But, after 47 years, available phosphate content in phosphate fertilizer treatment (NPK, NPKC, and NPKCLS) reached at the highest ($245{\sim}331mg\;kg^{-1}$), showing a tendency to decrease afterward. The mean annual P field balance in these treatments (NPK, NPKC, and NPKCLS) had positive values that varied from 16.6 to $17.5kg\;ha^{-1}year^{-1}$, and ratio of residual P were increased. These showed that phosphate fertilizer in soil were converted into the form of residual phosphorus which was not easily extracted by available phosphate extractant. Also, It was estimated that the critical value of available phosphate for rice cultivation was $120mg\;kg^{-1}$ using Cate-Nelson equation. CONCLUSION: We concluded that no more phosphate fertilizer should be applied in rice single system if soil available phosphate is higher than the critical P value.

• 한국토양비료학회지
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• 제46권3호
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• pp.153-162
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• 2013

Most test methods for plant available soil phosphate are based on the extraction with a chemical solution. The objective of this study is to evaluate available phosphate of various tests at different soil phosphate levels. Two experiments were conducted as follows: i) Extracting capacities of soil phosphate tests - Mehlich III, Mehlich II, Bray I, Olsen, Kelowna, and Modified Lancaster(Mod. Lancaster) - were compared with that of Lancaster test for the soils collected from 32 paddy and 27 upland fields with various soil chemical properties. ii) Field trials on comparing to phosphate uptake by plant were accomplished by cultivating rice and corn plants in the pots filled with the soils. Available phosphate of Lancaster test was significantly correlated with those of Mehlich III, Mehlich II, Bray I, Olsen, Kelowna, and Mod. Lancaster. In upland soils, available phosphates of all the tests were curvilinearly regressed with phosphate uptake by corn. The determination coefficients ($R^2$) of the regression equation between available phosphate in soils and phosphate uptake by plants were ranged from 0.861 (Mehlich III) to 0.741 (Olsen). In paddy soils, the available phosphate measured by Mehlich III and Lancaster was significantly correlated with phosphate uptake by rice. In conclusion, Lancaster and Mehlich III tests could be used for predicting available phosphate in upland and paddy soils.

• 한국토양비료학회지
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• 제50권3호
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• pp.195-202
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• 2017

The volcanic ash soils from the Jeju province have low available phosphate because of the high phosphate fixing power of the soils. Phosphorus fertilizerwas dressed after cultivating green manure crops and before cultivating potatoes in order to investigate potato yields, the available phosphate contents, and phosphorus balance in the soils. Green manure crops cultivated in this study were hairy vetch alone and hairy vetch and rye. During potato cultivation, four treatments were conducted in the experiments; NF (non fertilizer), P fertilizer ($N-P-K=0-25-0kg\;10a^{-1}$), NK fertilizer ($N-P-K=18-0-19kg\;10a^{-1}$), and NPK fertilizer ($N-P-K=18-25-19kg\;10a^{-1}$). There were no differences in the yields of potato stem and tuber from the cultivation plots of different green manure crops. However, in the plots with single-sown hairy vetch and mixed-sown hairy vetch and rye, the yields of potato stem and tuber were higher in the P fertilizer plot than in NF plot. The yield of tuber among the treatments with mixed-sown hairy vetch and rye was the highest in the NPK fertilizer plot. The available phosphate content in soils initially increased with time in all plots, but began to decrease gradually after Oct. 18. The available phosphate contents were high in the plots for phosphate fertilization, and the difference in available phosphate content between non-phosphorus fertilizer plots and phosphorus fertilizer plots increased with time. In the single-sown hairy vetch and mixed-sown hairy vetch and rye plot, the phosphorus balances in NF plot and NK fertilizer plot were very low, while those in the P fertilizer plot and NPK fertilizer plot were high. In conclusion, available phosphate contents in soil and the potato yields were increased by phosphorus fertilization when potatoes planted after cultivating hairy vetch and rye together, compared to hairy vetch alone.

• 한국연초학회지
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• 제2권1호
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• pp.68-77
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• 1980

土壤中 有效燐酸 含量이 相異한 圃地(350, 140, 35ppm)에 燐酸質 肥料를 0, 5, 10, 15, 20, 30kg/10a로 各各 處理하였을 때 담배의 生育과 品質에 미치는 효과를 調査하였다. 담배의 生育은 生育後期에 下位地(35ppm)만 燐酸質 肥料 增施 效果가 認定되었으며 乾物重은 담배 生育과 同一한 傾向이었다. 담배의 成熟과 葉中 化學成分은 燐酸質 肥料에 影響을 받지 않았다. 乾葉의 品質은 土壤中 有效燐酸 含量에 關係없이 비슷하였으며 收量은 下位地에서만 燐酸質 肥料의 增施效果가 認定되어 10kg/10a 施肥면 충분한 生産量을 期待할 수 있는 것으로 나타났다.

• 한국연초학회지
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• 제13권2호
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• pp.71-79
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• 1991

The experiment was conducted to investigate accumulation o( phosphate in tobacco production area. The results are as follows: 1) The content of available P in burley production area was about 200ppm higher than that in flue-cured tobacco production area, the available P content of 20% tobacco fields surveyed was above 1000ppm P. 2) Tobacco fields having 200ppm of available P which were grouped as medium category for phosphate recommendation were more than 90% out of tobacco fields surveyed. 3) Total phosphate content was above 4000ppm in 42.5% burley tobacco fields before transplanting, and 2000~3000ppm in about 40% flue-cured tobacco fields. 4) Phosphate fractions in soil increased in order of Al-P > Fe-P > Ca-p, and their content was about 50% of total phosphate in tobacco fields surveyed. 5) pH value in most of tobacco fields surveyed ranged from 4.5 to 5.0 and, field soils with pH value below 5.5 were 64 %.

• 한국토양비료학회지
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• 제32권3호
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• pp.268-273
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• 1999

토지이용 유형과 유효인산 함량이 다양한 56개 토양을 대상으로 범용 분광광도계를 사용한 Lancaster법과 분석과정 및 측정과정을 간편화시킨 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 측정한 유효인산함량에 대하여 정확도 및 정밀도를 비교 분석하였다. 두 방법으로 분석된 인산함량은 고도의 유의성 있는 정의상관 ($r=0.998^{***}$)을 보였으며, 기울기는 0.97로 거의 일치하여 두 방법간의 정확성은 차이가 없었다. 또한, 두 방법으로 측정된 인산함량 분석결과의 표준편차, CV, 상대정밀도(RS)는 거의 차이가 없으므로 정밀도에서도 차이가 없었다. 따라서, 분석과정 및 기기조작의 편리성 및 신속성을 고려한다면 Soiltek$^{(R)}$ KA-1에서 제시하는 방법으로 유효인산 함량을 측정하는 것도 유용한 방법이라고 생각된다.

• 한국토양비료학회지
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• 제49권3호
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• pp.265-270
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• 2016

Accumulated Phosphate can be released by ligand exchange reaction of organic acids. The objective of this study was to evaluate effects of the organic acids on the availability of phosphate and the growth of crop in phosphate and salts accumulated soil. Soil samples were collected from farmer's plastic film house. Available phosphate and electrical conductivity of soil were $3,005mg\;kg^{-1}$ and $16.63mg\;kg^{-1}$ which were 6 and 8 times higher than the optimum range of soil for crop growth, respectively. Corns were cultivated in pots for 2 months. Treatments were no treatment (control), phosphate fertilizer (P), citric acid (CA) 1, 5, 10 mM, and oxalic acid (OA) 1, 5, 10 mM. Water soluble phosphorus, available phosphate, corn growth and uptake were determined after cultivation. Results showed that organic acids increased water soluble phosphorus and available phosphate. For the level of 10 mM, the order of effectiveness of organic acids for water soluble P was citric acid (44%) > oxalic acid (32%). Height and dry weight of corns were increased significantly by the treatment of citric acid 1 and 5 mM. Also, corn absorbed more phosphorus, nitrogen, potassium, calcium and magnesium in the treatment of citric acid 1 mM than these of other treatments. Even though phosphate availability of soil was enhanced by addition of citric acid 10 mM, the growth of corns decreased because high concentration of citric acid caused salt damage by increasement of electrical conductivity. Thus, the citric acid of 1 mM has the potential to improve the availability of phosphate and the healthy growth of corns.

• 농업과학연구
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• 제49권3호
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• pp.463-481
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• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.

• 한국토양비료학회지
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• 제46권5호
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• pp.308-312
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• 2013

The monitoring of chemical dynamic changes in controlled horticultural lands is very important for agricultural sustainability. Field monitoring was performed to evaluate the soil chemical properties of 200 controlled horticultural soil samples in Gyeongnam province every 4 years from 2000 to 2012. Soil chemical properties such as pH, amount of organic matter, available phosphate, nitrate nitrogen, and exchangeable potassium, calcium, magnesium, and sodium were analyzed. The amount of exchangeable calcium and soil pH were significantly higher in 2012 than in 2000. In 2012, the frequency distribution for values of pH, organic matter, available phosphate, and exchangeable potassium, calcium, and magnesium that were within the optimum range was 16.0%, 22.5%, 11.5%, 3.5%, 2.5%, and 5.0%, respectively. Especially, available phosphate and exchangeable calcium were excess level with portions of 76.0% and 96.5%, respectively. These results indicated that a balanced management of soil chemical properties can reduce the amount of fertilizer applied for sustainable agriculture in controlled horticultural lands.

• 한국토양비료학회지
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• 제36권6호
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• pp.384-390
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• 2003

논토양의 환경기준 인산지표 예측기술개발을 위하여 논토양 35점을 $25{\pm}1^{\circ}C$ 에서 1, 2, 4주간 담수 항온한 결과 담수 항온 전 풍건 토양의 $0.01M\;CaCl_2$ 가용인산 함량과 유효인산 함량 및 인산흡수능의 관계는 습토로 분석할 경우 상관계수의 크기는 유효인산/인산흡수량>유효인산>유효인산/인산흡수계수>인산흡수량>총인산>인산흡수계수 순이었고, 항온기간별 상관계수 크기는 습토로 분석할 경우 항온이 길어질수록 상관계수는 점점 낮아 졌으나, 건토로 분석할 경우는 이와 반대 경향이었다. 토양의 유효인산 함량과 인산흡수량을 활용하여 $0.01M\;CaCl_2$ 가용인산 농도를 추정할 수 있는 관계식 $0.01M\;CaCl_2-P=0.0828$ (유효인산/인산흡수량) + 0.0374을 얻었으며, 이러한 관계식은 토양의 인산 함량과 인산흡수 특성을 고려하여 작물재배에 필요한 적정 유효인산 함량의 추정과 토양 인산의 유실 가능성 등을 예측하는데 활용될 수 있을 것이다.