جستجوی مقالات مرتبط با کلیدواژه « icp » در نشریات گروه « آب و خاک »

Because the range between boron (B) deficiency and toxicity thresholds in soils for many plants is very short, accurate evaluation of available soil B status by soil testing is necessary for proper use of B fertilizer. This study was conducted to compare ICARDA and Soil Science Society of America (SSSA) procedures as the most commonly used methods to determine available soil B. A total of 20 surface soils with different physical and chemical properties were selected and their available B concentration was measured by ICP method and the colorimetric procedures proposed by ICARDA and SSSA. The effect of activated carbon application and the presence of suspended colloids on B concentration was also investigated. Mean available B concentration in the soils for ICARDA and SSSA methods by ICP were 2.59 and 2.86 mg/kg, whereas those by azomethine-H were 2.43 and 2.69 mg/kg, respectively. The relationship between B measured by ICP and azomethine-H for SSSA indicated a higher correlation ( ) and a better fit to 1:1 line than ICARDA ( ). Mean B concentrations were 2.86 mg/kg using hot 0.02 M  and 2.84 mg/kg using hot water. The use of activated carbon decreased B in extracts significantly. The mean of available B extracted from the soils using hot water with carbon was 2.59 mg/kg, whereas it was 2.84 mg/kg without carbon. Use of 0.2, 0.4 and 0.6 g carbon per 40 ml of B solutions with different initial concentrations yielded the mean B recovery of 104.9, 100.4 and 97.6%, respectively. Because of suspended colloids, B concentrations in extracts filtered through Whatman 40 filter-paper were higher than those filtered through Whatman 42. Without the use of carbon, predicted error in B determination due to color in extract ranged from 0 to 0.88 mg kg-1. Generally, the SSSA method measured available soil B more accurate than ICARDA and it is therefore recommended to use.