殺草劑巴拉刈在數種土壤中的吸附與脫附之研究

陳鴻基(H. J. Chen) ； 李國欽(G. C. Li)

《中華民國雜草學會會刊》 12卷1期 (1991/02) Pp. 1-13

https://doi.org/10.6274/WSSROC-1991-012(1)-001

摘要

利用不同物化特性之12種土壤研究巴拉刈在土壤中之吸附情形發現巴拉刈與土壤親和力常數因土壤有機質含量增加而減少，與土壤之pH及游離氧化鐵與粘粒含量也有關，但不如有機質含量之影響為顯著。計算12種土壤對巴拉刈的最大吸附量發現若以每公頃每年施用十次每次二公斤，則吸附能力最大之土壤需要1260年而吸附能力最小者也需要315年。將各種土壤對巴拉刈之最大吸附量與土壤中各種單一因子作一比較發現，在某些土系中巴拉刈之最大吸附量隨CEC之增加而增加，在另外土系中則與CEC無正相關關係，同時發現最大吸附量與土壤之pH有明顯的正相關關係。PH值高且CEC也高之土壤最大吸附量也最高。有機質含量與巴拉刈在土壤中之最大吸附量無相關關係。土壤中游離氧化鐵含量對巴拉刈在土壤中之最大吸附量受pH之影響甚大。此等結果顯示任何單一因子都無法解釋各種土壤之間最大吸附量差異之原因。利用逐步迴歸分析發現最大吸附量與pH關係最好，其次是CEC及pH之複合影響，最後是粘粒含量、CEC、pH之間的複相關關係。研究脫附量與土壤性質間之相關關係發現相同性質土壤吸附量愈大者其脫附率（D%）愈高，不同土壤其脫附率因吸附量之增加而增大之範圍不同，脫附率增大範圍較大者其CEC均較低，脫附率之增大也與土壤之pH值及游離氧化鐵有關，與有機質之含量無顯著之關係。利用多重迴歸關係測試12種試驗土壤的吸附與脫附量之關係發現脫附量之對數值與吸附量之間有明顯的相關存在。這些公式可用於藉分析脫附量來計算土壤中吸附巴拉刈之多少，並推算污染之情形。以飽和氯化銨淋洗吸附有巴拉刈的土壤發現極大部份吸附之巴拉刈能用飽和氯化銨以離子交換形式將它交換出來，在12種土壤中無法交換出來的量，也因土壤之不同而不同，其中含高嶺石較多者較易被交換出來，而含蛭石或有機質較多者則不易被交換出來，由於吸附在土壤中之巴拉刈會被銨離子交換出來，故在施用巴拉刈後隨之施用氮肥，尤其是液態氮或尿素，再經雨淋洗，可能就很容易造成巴拉刈之脫附。

關鍵字

巴拉刈 ； 吸附 ； 脫附 ； Langmuir方程式

並列摘要

By studying the adsorption of paraquat on 12 solis of different physical and chemical characteristics, it was found that the affinities between paraquat and soil were increasing with the decrease of soil organic matter contents. The effect of soil pH, and free iron oxide, and clay contents on the affinity constants were also found but not as significant as soil organic matter contents. Calculating the maximum adsorption of paraquat on 12 soils revealed that in order to saturate the soil with paraquat if paraquat was applied into the soils ten times per year and 2 Kg per hectare each time, it takes about 1260 years for the soil with the highest adsorption capacity and takes about 315 years for the soil with the lowest adsorption capacity among the 12 soils tested. By comparing the maximum adsorptions found in the soils with the soil pHs, CEC, and the levels of soil organic matter and free iron oxide, it was found that there was no single factor could be used to explain the differences of maximum adsorptions of paraquat among 12 soils tested. By treating the data with stepwise regression, it was found that maximum adsorption of paraquat on the soils were multiply correlated with clay contents, pH, and CEC. The interaction between clay, pH, and CEC seems to be the major factor to determine the maximum adsorption of paraquat in the soils. Study on the desorption of paraquat from the soils showed that the desorption rate (D%) was positively correlated with the amount of paraquat adsorbed in the soils with similar characteristics. Theincrease of desorption rates with the increase of the ranges of adsorption were different among the soils tested. The higher desorption rates were found in the soils with lower CEC. The pH and the free iron oxide contents also affected the desorption rates. The effect of soil organic matter contents on the desorption rates was not significant. By treating the correlation between adsorption and desorption found that the logarithm of desorption have a very good linear correlation with the amount of paraquat adsorbed on 12 soils. The data of desorption could be used to calculate amount of paraquat adsorbed with these formula and predicted the pollution level. A considerable desorption rate was found when leached the adsorbed paraquat from the soil with water saturated by ammonium chloride, especially from the soil with considerable higher kaolinite content, these results might reveal that the pollution of water by paraquat might be found in the Taiwan environment when ammonium fertilizer is applied in the field.

並列關鍵字

Paraquat ； adsorption ； desorption ； Langmuir equation