EXTRACTANTS AND CRITICAL LIMITS OF AVAILABLE SOIL SULPHUR FOR MUSTARD (BRASSICA CAMPESTRIS VAR. TORIA)
2014
PANDEY, R.N. | GIRISH, B.H.
Pot experiments were conducted for two years using four levels of sulphur (0, 10, 20 and 30 mg S kg-1 soil) in twenty five soils representing five major soil orders (Entisols, Inceptisols, Alfisols, Mollisols and Vertisols) of India to assess the suitability of fourteen extractants for establishing critical limit of available soil sulphur for mustard (Brassica campestris var. Toria). The soils were extracted with 0.15% CaCl2.2H20, 500 mg P L-1 Ca(H2PO4)2, Wolf, Mehlich-2, Mehlich-3, Mehlich-3 + charcoal, modified calcium chloride (0.15% CaCl2.2H2O + 0.5M CH3COONH4 + 0.5M CH3COOH), 0.25M KCl at 40ºC, 0.25M KCl at 50ºC, 0.25M KCl at 50ºC + charcoal, 0.25M KCl at 60ºC, 0.25M KCl at 60ºC + charcoal, 500 mg P L-1 KH2PO4 and 0.125M KCl + 0. 075%CaCl2.2H2O at 50ºC extractants. The soil sulphur content extracted by using 500 mg P L-1 KH2PO4, 500 mg P L-1 Ca(H2PO4)2. H2O, and 0.25M KCl at 60ºC + charcoal did not correlation significantly with any or most of the biological indices of mustard, which indicated that these extractants are not suitable for predicting soil sulphur availability to mustard. On the basis of the magnitude of correlation coefficients with biological indices of mustard, 0.25M KCl at 40ºC was found to be most suitable extractant followed by multinutrient extractant Mehlich-3 + charcoal and 0.25M KCl at 50ºC + charcoal than other extractants studied with critical limits of 6.9, 8.2 and 13.5 mg S kg-1 soil, respectively. The critical concentration of sulphur in 60 days old mustard plants tissue was found to be 0.51% on dry weight basis.
显示更多 [+] 显示较少 [-]