KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and relea...KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.展开更多
Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic s...Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.展开更多
Effects of tannic acid on active aluminum species distribution in different pH tea soils in Yunnan and Jiangxi tea gardens were studied by field observation and laboratory analysis.There were 4 species of active alumi...Effects of tannic acid on active aluminum species distribution in different pH tea soils in Yunnan and Jiangxi tea gardens were studied by field observation and laboratory analysis.There were 4 species of active aluminum in the tea soil,i.e.,exchangeable aluminum Al3 +,unimer hydroxyl aluminum Al(OH)2 +Al(OH)+2,acid-soluble aluminum Al(OH)03and humic-acid aluminum Al-HA.Experimental results showed that tannic acid at levels 0 ~0.4 mmol/kg and 0 ~ 2.0 mmol/kg,with the rising of soil pH value,the content of exchangeable aluminum decreased significantly,hydroxyl aluminum,acid-soluble aluminum and humic-acid aluminum were increased gently.When the concentration of tannic acid increased to above 2.0 mmol/kg,the inhibition of higher concentration of tannic acid on content of active aluminum was strengthened with the rising of soil pH value and variation law of 20 ~ 40 cm soil layer was similar to 0 ~ 20cm soil layer.Generally speaking,the content of active aluminum in upper layer of soil were more than subsoil and total content of active aluminum in Yunnan tea soils were higher than Jiangxi tea soils.The correlation analysis showed that the soil pH were positively correlated with hydroxyl aluminum,humic-acid aluminum,pHBC(r = 0.796,0.960,0.852;p < 0.01,0.01,0.01) in 0 ~ 20cm soil layer.pHBC were significant negative correlated with exchangeable aluminum(r =- 904,p < 0.01),hydroxyl aluminum(r =- 645,p < 0.05),and with humic-acid aluminum have a positive correlation,correlation coefficient was0.795(P < 0.05).Meanwhile,the tannic acid addition concentration were 0 ~ 0.4 mmol/kg soils pH were increased significantly,while samples attains a peak pH value afterwards decrease continuously,the relationship between the pH and the concentration of tannic acids accords with the equation:Y pH=- 0.04C DN+3.82(R2= 0.95,P < 0.01).When the concentration of tannic acid up to about 8.0 ~ 12.0 mmol/kg,soil pH keep unchanged.Therefore,we can clearly draw that effects of tannic acid on active aluminum content of the inflection point is not the same in different region of tea garden soil.Low concentration tannic acid can improve the soil content of various forms of aluminum,but with the increase in the amount of tannic acid,the various forms of aluminum content are inhibited.With the soil pH increased,high concentrations tannic acid on the inhibition of the release of active aluminum increased.pH and tannic acid on the total amount of active aluminum garden soil was mutual weakening effect relationship.展开更多
文摘KCl, CaCl2, NH4Cl, NaCl, K2SO4 and KF solutions were used for studying the effects of canons and anions on the dissolution of aluminum and the distribution of aluminum forms respectively. Power of exchanging and releasing aluminum of four kinds of canons was in the decreasing order Ca2+ >K+ >NH+4 >Na+.The dissolution of aluminum increased with the canon concentration. The adsorption affinity of various soils for aluminum was different. The aluminum in the soil with a stronger adsorption affinity was difficult to be exchanged and released by canons. The Al-F complexes were main species of inorganic aluminum at a low concentration of canons, while Al3+ became major species of inorganic aluminum at a high concentration of canons. The results on the effect of anions indicated that the concentrations of total aluminum, three kinds of inorganic aluminum (Al3+, Al-F and Al-OH complexes) and organic aluminum complexes (Al-OM)when SO2-4 was added into soil suspension were lower than those when Cl- was added. The dissolution of aluminum from soils and the distribution of aluminum forms in solution were edicted by the adsorption of Fon the soil. For soils with strong affinty for F- , the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-; but for soils with weak affinity for F- , the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl-. The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.
文摘Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.
文摘Effects of tannic acid on active aluminum species distribution in different pH tea soils in Yunnan and Jiangxi tea gardens were studied by field observation and laboratory analysis.There were 4 species of active aluminum in the tea soil,i.e.,exchangeable aluminum Al3 +,unimer hydroxyl aluminum Al(OH)2 +Al(OH)+2,acid-soluble aluminum Al(OH)03and humic-acid aluminum Al-HA.Experimental results showed that tannic acid at levels 0 ~0.4 mmol/kg and 0 ~ 2.0 mmol/kg,with the rising of soil pH value,the content of exchangeable aluminum decreased significantly,hydroxyl aluminum,acid-soluble aluminum and humic-acid aluminum were increased gently.When the concentration of tannic acid increased to above 2.0 mmol/kg,the inhibition of higher concentration of tannic acid on content of active aluminum was strengthened with the rising of soil pH value and variation law of 20 ~ 40 cm soil layer was similar to 0 ~ 20cm soil layer.Generally speaking,the content of active aluminum in upper layer of soil were more than subsoil and total content of active aluminum in Yunnan tea soils were higher than Jiangxi tea soils.The correlation analysis showed that the soil pH were positively correlated with hydroxyl aluminum,humic-acid aluminum,pHBC(r = 0.796,0.960,0.852;p < 0.01,0.01,0.01) in 0 ~ 20cm soil layer.pHBC were significant negative correlated with exchangeable aluminum(r =- 904,p < 0.01),hydroxyl aluminum(r =- 645,p < 0.05),and with humic-acid aluminum have a positive correlation,correlation coefficient was0.795(P < 0.05).Meanwhile,the tannic acid addition concentration were 0 ~ 0.4 mmol/kg soils pH were increased significantly,while samples attains a peak pH value afterwards decrease continuously,the relationship between the pH and the concentration of tannic acids accords with the equation:Y pH=- 0.04C DN+3.82(R2= 0.95,P < 0.01).When the concentration of tannic acid up to about 8.0 ~ 12.0 mmol/kg,soil pH keep unchanged.Therefore,we can clearly draw that effects of tannic acid on active aluminum content of the inflection point is not the same in different region of tea garden soil.Low concentration tannic acid can improve the soil content of various forms of aluminum,but with the increase in the amount of tannic acid,the various forms of aluminum content are inhibited.With the soil pH increased,high concentrations tannic acid on the inhibition of the release of active aluminum increased.pH and tannic acid on the total amount of active aluminum garden soil was mutual weakening effect relationship.
