RESPONSE OF WHEAT, TRITICALE, BARLEY, AND CANOLA TO LIME ON 4 SOIL TYPES IN NORTH-EASTERN VICTORIA

Lime requirement curves based on relative yield and pH data for 4 soil types were derived to estimate the amount of lime required to reach m aximum yield for wheat, triticale, barley, and canola. Simple equation s expressing lime requirement as a function of soil pH accounted for > 90% of the variation in applied lime on 3 soil types (red brown earth, red podsolic, podsolised red earth). When aluminium and manganese (0. 01 mol CaCl2/L extracted) were included in these equations, either ind ividually or together, they did not improve the relationship significa ntly for these 3 sites; however, manganese significantly improved the predictability of lime for solodic soil. A comparison of this model wi th a laboratory-based model showed good cor-relation for 3 soils (red brown earth, red podsolic, podsolised red earth), but the laboratory m ethod underestimated the field lime requirement of solodic soil.