000			02243nam a2200169Ia 4500
008			220216s9999 xx 000 0 und d
100			_aAbraham Joshua
245		0	_aOrganic carbon estimations in soils: Analytical protocols and their implicatios
260			_bRubber Science _c2013
300			_a45-54
520			_aSeveral protocols for the estimation of soil organic carbon (SOC) are in practise by different laboratories. Quantitative to semi quantitativemethods are followed for different objectives. Dry combustion protocols are quatitative in nature and are utilized to standardise other protocols. walkley-Black (WB) protocol for organic carbon is widely followed in many laboratories because it is rapid and affordable.However, it is semi- quantitative in nature and do not completely recover the organic carbon in soils. Also considerable sample to sample variations in the recovery of carbon are reported. Through the application of external heat in WB protocols (modified-WB) more recovery, though not complete, of SOC is reported. If WB or modified- WB protocols are followed, standardization with an accurate method is necessary and correction factors need to be generated to account for the non recovered portion of organic carbon in soil. The soils of different rubber growing regions were analysed by WB, modified- WB and dry combustion(DC) methods and the values were compared. It is found that, sample to sample, the recovery percentage of SOC widely varied when WB or modified- WB protocols was followed compared to the values generated by DC protocol. On an averege 71 percent recovery of SOC by WB method and 92 percent recovery by modified-WB method were observed. Correction factors of 1.3850 for WB and 1.1299 for modified-WB were derived to account the non recovered portion of soil organic carbon. After applying the derived correction factor, the values obtained by WB and modified-WB method were not significantly differing from the values generated bt DC method, suggesting that the correction factors hold good when a group of samples are considered.
650			_aDry combustion method
650			_aSoil Organic carbon
650			_aSoil organic matter
650			_aWalkley- Black method
942			_cJS
999			_c64462 _d64462