Phosphorus loss from fertilization is a significant source of pollution to freshwater lakes worldwide. Production of flowers, vegetables, staple food and vineyard in regions surrounding Dianchi, Erhai, Fuxian and Xing...Phosphorus loss from fertilization is a significant source of pollution to freshwater lakes worldwide. Production of flowers, vegetables, staple food and vineyard in regions surrounding Dianchi, Erhai, Fuxian and Xingyun lakes in Yunnan Province is large-scale. Previous studies have shown that annual fertilizer application rates (AFARs) were excessive in these regions. Significant amount of arable land near lakes has been used to build recreational parks with plants that receive less fertilization to reduce P loading. To answer whether rAFARs were associated with specific crops, AFARs of specific land uses were investigated through interviews. To estimate P loading, NaHCO3-P and NaOH-P concentrations were measured in 753 soil samples of selected layers (0 - 5, 5 - 20, 20 - 40 cm) in regions surrounding these lakes. Soil texture, pH, and cation exchange capacity (CEC) were analyzed to characterize soils. P loading was high ranging from 999 to 2094 mg P/kg as measured by NaOH-P, and levels of NaHCO3-P from 18.6 to 92.2 mg P/kg. AFARs to flower (4745 kg/ha), and vegetable (2967 kg/ha) were higher than those applied to staple food (945 kg/ha), and plants in recreation parks (200 kg/ha). The highest NaHCO3-P and NaOH-P concentrations in selected layers were associated with production of flowers, vegetables, and grapes. Although all layers of soils that were used for recreation parks in regions near Dianchi lake contained lower NaHCO3-P, NaOH-P was almost as high as with soils cultivated with flowers probably reflecting historical additions or differences in soil type. Here we show for the first time in local regions that the production of flowers, grapes and vegetables was a critical source contributing to the buildup of both readily available (NaHCO3-P) and reversibly available P (NaOH-P). Build-up of recreational parks with plants that receive less fertilization would be a long-term remediation to reduce P loading of soils in regions near Dianchi lake.展开更多
Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its...Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its effectiveness needs to be verified. An integrated reclamation technology with Yellow River sediment was evaluated using a comparison of actual crop production soil profile analysis in Jining City, China. The results indicated that reconstructed soil profile of the reclaimed farmland was less effective in retaining water and in supporting plant growth than that of the unaltered farmland. Some measures are proposed, such as reducing the drainage velocity to allow sedimentation and retention of the clay and silt, changing the techniques of filling the Yellow River sediment and increasing the organic matter content in the soil layers to improve the capacity to retain water in the reclaimed farmland.展开更多
Low pH is a major limiting factor for the production of black pepper (Piper nigrum L.) in Hainan province. Black pepper gardens often exhibit a decrease in soil pH (to 5.5 - 5.0) on orchards with a multi-year producti...Low pH is a major limiting factor for the production of black pepper (Piper nigrum L.) in Hainan province. Black pepper gardens often exhibit a decrease in soil pH (to 5.5 - 5.0) on orchards with a multi-year production history. An exploratory hydroponic experiment was conducted to examine the effects of increasingly acid nutrient solution pH (7.0, 5.5, 4.0, and 3.5) on seedling growth, tissue nutrient concentrations and root morphological traits. The results indicated that low pH may directly inhibit root development and function, limit K, Ca and Mg absorption and reduce seedling growth. At pH 5.5, black pepper attained maximum growth, while the minimum growth occurred at pH 3.5. It can be concluded that low pH reduces plant growth and is associated with low root nutrient concentrations of Ca and Mg, which may explain the decline of the yield in the seven pepper gardens of the Institute.展开更多
In Thailand, the site-specific nutrient management technology, known as “Tailor-made Fertilizer Technology (TFT)”, for rice, maize and sugarcane in the Northeastern region was developed between 1997-2007, using the ...In Thailand, the site-specific nutrient management technology, known as “Tailor-made Fertilizer Technology (TFT)”, for rice, maize and sugarcane in the Northeastern region was developed between 1997-2007, using the concepts of precision agriculture together with an approach of building capacity of small farmers. TFT, also called Smart-farming, comprises four components, namely 1) soil series identification, 2) N-P-K testing by soil test kit, 3) fertilizer recommendations using decision-aids and a simplified version of a complex model and 4) farmer empowerment. The benefit of TFT at the rice field of the Huay Kamin chairman farmer group was one example, the technology has been disseminated to the 80 members with a total planting area of about 320 ha. The results revealed chemical fertilizer reduction of 69%, and rice yield increased some 10% - 20% with the improved fertilizer application method. The farmers were encouraged to establish “Soil Clinics” in their communities. In a Soil Clinic, designated and trained farmer leaders analyze soil samples for member farmers and provide TFT recommendations while providing access to fertilizer materials available for sale at competitive prices. At present, there are about 70 soil clinics in 20 provinces with the support of many government and private sectors.展开更多
Objective:To evaluate the synergistic effect ofα-mangostin with tetracycline,erythromycin,and clindamycin against bacteria involved in acne production.Methods:A broth microdilution method was used to determine the mi...Objective:To evaluate the synergistic effect ofα-mangostin with tetracycline,erythromycin,and clindamycin against bacteria involved in acne production.Methods:A broth microdilution method was used to determine the minimum inhibitory concentration(MIC)ofα-mangostin and a range of antibiotics.Synergistic effects on antibacterial activity were determined based on their own MIC,and then using a checkerboard method and a time-kill assay at 37°C for24 h.Results:α-Mangostin exhibited antibacterial activity against Propionibacterium acnes,Staphylococcus aureus,S.epidermidis and S.pyogenes with MIC values of 0.78,3.13,0.78,and 6.25μg/m L,respectively.The results of the checkerboard assay showed thatα-mangostin produced synergistic effects with tetracycline,erythromycin,and clindamycin against all tested bacteria,with a fractional inhibitory concentration index(FICI)between 0.09 and 0.32.Moreover,time-kill curve data indicated thatα-mangostin increased the antibacterial activity of tetracycline,erythromycin,and clindamycin.Conclusion:These findings suggested thatα-mangostin may be used to enhance the antibacterial activity of some antibiotics against bacteria involved in acne production.展开更多
During a 2005 visit with National Agricultural and Forestry Institute (NAFRI) Director, Dr. Kouang Doungsila issued a challenge to these authors to determine if it was true that crops could not be grown in the extensi...During a 2005 visit with National Agricultural and Forestry Institute (NAFRI) Director, Dr. Kouang Doungsila issued a challenge to these authors to determine if it was true that crops could not be grown in the extensive uplands of Xiengkhouang Province, Laos PDR. In response, a two-phase series of experiments was proposed and implemented. The Phase I experiment was to bring soil from the Xiengkhouang province uplands to a NAFRI greenhouse near Vientiane to assess possible nutrient requirements using a nutrient omission experiment. Simultaneously, soils were collected and analyzed from seven recognized agricultural regions of Laos. The initial Vientiane greenhouse experiment indicated that maize did grow, but there were multiple issues of extreme soil acidity and clear deficiencies of phosphorus and other nutrients. Phase II of the study included field studies on the site of soil selected for the greenhouse study. Field experiments were carried out for two years at the site with yields of maize exceeding 5500 kg⋅ha−1 in the first year and exceeding 6250 kg⋅ha−1 in a subsequent year. Intense symptoms of nutrient zinc (Zn) deficiency were observed, however. In 2008 another experiment was designed and carried out that included a Zn variable. The results from that experiment confirmed that maize yields nearing 6000 kg⋅ha−1 were indeed possible. Substantial amounts of lime were needed to correct the strong soil acidity, and a series of other nutrients including N, P, K, and Zn were also required. Ongoing issues are where to obtain the extensive amounts of limestone needed as well as an evaluation of the residual effect of the limestone The finely ground, very reactive burnt lime residual effect was, as expected, short-lived. The results clearly demonstrated that, indeed, it was possible for maize to be produced in the extensive uplands of Xiengkhouang province, in answer to Director Khouang’s challenging question.展开更多
文摘Phosphorus loss from fertilization is a significant source of pollution to freshwater lakes worldwide. Production of flowers, vegetables, staple food and vineyard in regions surrounding Dianchi, Erhai, Fuxian and Xingyun lakes in Yunnan Province is large-scale. Previous studies have shown that annual fertilizer application rates (AFARs) were excessive in these regions. Significant amount of arable land near lakes has been used to build recreational parks with plants that receive less fertilization to reduce P loading. To answer whether rAFARs were associated with specific crops, AFARs of specific land uses were investigated through interviews. To estimate P loading, NaHCO3-P and NaOH-P concentrations were measured in 753 soil samples of selected layers (0 - 5, 5 - 20, 20 - 40 cm) in regions surrounding these lakes. Soil texture, pH, and cation exchange capacity (CEC) were analyzed to characterize soils. P loading was high ranging from 999 to 2094 mg P/kg as measured by NaOH-P, and levels of NaHCO3-P from 18.6 to 92.2 mg P/kg. AFARs to flower (4745 kg/ha), and vegetable (2967 kg/ha) were higher than those applied to staple food (945 kg/ha), and plants in recreation parks (200 kg/ha). The highest NaHCO3-P and NaOH-P concentrations in selected layers were associated with production of flowers, vegetables, and grapes. Although all layers of soils that were used for recreation parks in regions near Dianchi lake contained lower NaHCO3-P, NaOH-P was almost as high as with soils cultivated with flowers probably reflecting historical additions or differences in soil type. Here we show for the first time in local regions that the production of flowers, grapes and vegetables was a critical source contributing to the buildup of both readily available (NaHCO3-P) and reversibly available P (NaOH-P). Build-up of recreational parks with plants that receive less fertilization would be a long-term remediation to reduce P loading of soils in regions near Dianchi lake.
基金This research was supported by National Key Technology Research and Development Program （2012BAC04B03） during the Twelfth Five-Year Plan Period and National Natural Science Foundation of China （Grant No. 41771542）.
文摘Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its effectiveness needs to be verified. An integrated reclamation technology with Yellow River sediment was evaluated using a comparison of actual crop production soil profile analysis in Jining City, China. The results indicated that reconstructed soil profile of the reclaimed farmland was less effective in retaining water and in supporting plant growth than that of the unaltered farmland. Some measures are proposed, such as reducing the drainage velocity to allow sedimentation and retention of the clay and silt, changing the techniques of filling the Yellow River sediment and increasing the organic matter content in the soil layers to improve the capacity to retain water in the reclaimed farmland.
文摘Low pH is a major limiting factor for the production of black pepper (Piper nigrum L.) in Hainan province. Black pepper gardens often exhibit a decrease in soil pH (to 5.5 - 5.0) on orchards with a multi-year production history. An exploratory hydroponic experiment was conducted to examine the effects of increasingly acid nutrient solution pH (7.0, 5.5, 4.0, and 3.5) on seedling growth, tissue nutrient concentrations and root morphological traits. The results indicated that low pH may directly inhibit root development and function, limit K, Ca and Mg absorption and reduce seedling growth. At pH 5.5, black pepper attained maximum growth, while the minimum growth occurred at pH 3.5. It can be concluded that low pH reduces plant growth and is associated with low root nutrient concentrations of Ca and Mg, which may explain the decline of the yield in the seven pepper gardens of the Institute.
文摘In Thailand, the site-specific nutrient management technology, known as “Tailor-made Fertilizer Technology (TFT)”, for rice, maize and sugarcane in the Northeastern region was developed between 1997-2007, using the concepts of precision agriculture together with an approach of building capacity of small farmers. TFT, also called Smart-farming, comprises four components, namely 1) soil series identification, 2) N-P-K testing by soil test kit, 3) fertilizer recommendations using decision-aids and a simplified version of a complex model and 4) farmer empowerment. The benefit of TFT at the rice field of the Huay Kamin chairman farmer group was one example, the technology has been disseminated to the 80 members with a total planting area of about 320 ha. The results revealed chemical fertilizer reduction of 69%, and rice yield increased some 10% - 20% with the improved fertilizer application method. The farmers were encouraged to establish “Soil Clinics” in their communities. In a Soil Clinic, designated and trained farmer leaders analyze soil samples for member farmers and provide TFT recommendations while providing access to fertilizer materials available for sale at competitive prices. At present, there are about 70 soil clinics in 20 provinces with the support of many government and private sectors.
基金the National Research Council of Thailand(NRCT)for providing a research grant.
文摘Objective:To evaluate the synergistic effect ofα-mangostin with tetracycline,erythromycin,and clindamycin against bacteria involved in acne production.Methods:A broth microdilution method was used to determine the minimum inhibitory concentration(MIC)ofα-mangostin and a range of antibiotics.Synergistic effects on antibacterial activity were determined based on their own MIC,and then using a checkerboard method and a time-kill assay at 37°C for24 h.Results:α-Mangostin exhibited antibacterial activity against Propionibacterium acnes,Staphylococcus aureus,S.epidermidis and S.pyogenes with MIC values of 0.78,3.13,0.78,and 6.25μg/m L,respectively.The results of the checkerboard assay showed thatα-mangostin produced synergistic effects with tetracycline,erythromycin,and clindamycin against all tested bacteria,with a fractional inhibitory concentration index(FICI)between 0.09 and 0.32.Moreover,time-kill curve data indicated thatα-mangostin increased the antibacterial activity of tetracycline,erythromycin,and clindamycin.Conclusion:These findings suggested thatα-mangostin may be used to enhance the antibacterial activity of some antibiotics against bacteria involved in acne production.
文摘During a 2005 visit with National Agricultural and Forestry Institute (NAFRI) Director, Dr. Kouang Doungsila issued a challenge to these authors to determine if it was true that crops could not be grown in the extensive uplands of Xiengkhouang Province, Laos PDR. In response, a two-phase series of experiments was proposed and implemented. The Phase I experiment was to bring soil from the Xiengkhouang province uplands to a NAFRI greenhouse near Vientiane to assess possible nutrient requirements using a nutrient omission experiment. Simultaneously, soils were collected and analyzed from seven recognized agricultural regions of Laos. The initial Vientiane greenhouse experiment indicated that maize did grow, but there were multiple issues of extreme soil acidity and clear deficiencies of phosphorus and other nutrients. Phase II of the study included field studies on the site of soil selected for the greenhouse study. Field experiments were carried out for two years at the site with yields of maize exceeding 5500 kg⋅ha−1 in the first year and exceeding 6250 kg⋅ha−1 in a subsequent year. Intense symptoms of nutrient zinc (Zn) deficiency were observed, however. In 2008 another experiment was designed and carried out that included a Zn variable. The results from that experiment confirmed that maize yields nearing 6000 kg⋅ha−1 were indeed possible. Substantial amounts of lime were needed to correct the strong soil acidity, and a series of other nutrients including N, P, K, and Zn were also required. Ongoing issues are where to obtain the extensive amounts of limestone needed as well as an evaluation of the residual effect of the limestone The finely ground, very reactive burnt lime residual effect was, as expected, short-lived. The results clearly demonstrated that, indeed, it was possible for maize to be produced in the extensive uplands of Xiengkhouang province, in answer to Director Khouang’s challenging question.
