In the present work, the exchangeable acidity of a red soilcolloid and a latosol colloid at different pH during reacting withfour neutral salts was measured. The results show that theexchangeable acidity increased wit...In the present work, the exchangeable acidity of a red soilcolloid and a latosol colloid at different pH during reacting withfour neutral salts was measured. The results show that theexchangeable acidity increased with increasing amounts of the neutralsalts added, and the relation between them was almost linear. Whenthe amount of the neutral salt added was lower than a certain value,the slop of the line was high, and the slop turned low when theamount exceeded that value, so there was a turning point in eachline. The addition amounts of the neutral salts for the turningpoints were affected by the cation species of the neutral salts, butpH had less effect on them. After the turning points occurred, theexchangeable acidity of the red soil colloid still graduallyincreased with the addition amounts of the neutral salts, but that ofthe latosol colloid did not increase any more.展开更多
The sensitivity of a large number of variable charge soils to acid rain was evaluated through examiningpH-H_2SO_4 input curves. Two derivative parameters, the consumption of hydrogen ions by the soil and theacidtolera...The sensitivity of a large number of variable charge soils to acid rain was evaluated through examiningpH-H_2SO_4 input curves. Two derivative parameters, the consumption of hydrogen ions by the soil and theacidtolerant limit as defined as the quantity of sulfuric acid required to bring the soil to PH 3.5 in a 0.00lmolLi￣(-1) Ca(NO_3)_2 solution, were used. The sensitivity of variable charge soils was higher than that of constantcharge soils, due to the predominance of kaolinite in clay mineralogical composition. Among these soils thesensitivity was generally of the order lateritic red soil >red soil >latosol. For a given type of soil within thesame region the sensitivity was affected by parent material, due to differences in clay minerals and texture.The sensitivity of surface soil may be lower or higher than that of subsoil, depending on whether organicmatter or texture plays the dominant role in determining the buffering capacity. Paddy soils consnmedmore acid within lower range of acid input when compared with upland soils, due to the presence of moreexchangeable bases, but consumed less acid within higher acid input range, caused by the decrease in claycontent.展开更多
基金Project (Nos. 49971046 and 49831005) supported by the National Natural Science Foundation of China.
文摘In the present work, the exchangeable acidity of a red soilcolloid and a latosol colloid at different pH during reacting withfour neutral salts was measured. The results show that theexchangeable acidity increased with increasing amounts of the neutralsalts added, and the relation between them was almost linear. Whenthe amount of the neutral salt added was lower than a certain value,the slop of the line was high, and the slop turned low when theamount exceeded that value, so there was a turning point in eachline. The addition amounts of the neutral salts for the turningpoints were affected by the cation species of the neutral salts, butpH had less effect on them. After the turning points occurred, theexchangeable acidity of the red soil colloid still graduallyincreased with the addition amounts of the neutral salts, but that ofthe latosol colloid did not increase any more.
文摘The sensitivity of a large number of variable charge soils to acid rain was evaluated through examiningpH-H_2SO_4 input curves. Two derivative parameters, the consumption of hydrogen ions by the soil and theacidtolerant limit as defined as the quantity of sulfuric acid required to bring the soil to PH 3.5 in a 0.00lmolLi￣(-1) Ca(NO_3)_2 solution, were used. The sensitivity of variable charge soils was higher than that of constantcharge soils, due to the predominance of kaolinite in clay mineralogical composition. Among these soils thesensitivity was generally of the order lateritic red soil >red soil >latosol. For a given type of soil within thesame region the sensitivity was affected by parent material, due to differences in clay minerals and texture.The sensitivity of surface soil may be lower or higher than that of subsoil, depending on whether organicmatter or texture plays the dominant role in determining the buffering capacity. Paddy soils consnmedmore acid within lower range of acid input when compared with upland soils, due to the presence of moreexchangeable bases, but consumed less acid within higher acid input range, caused by the decrease in claycontent.
