Nutrient requirements of white clover based pastures on a krasnozem basalt at Maleny, south-eastern Queensland

Abstract

Nutrient deficiencies of old kikuyu (Pennisetum clandestinum Hochst.) and paspalum (Paspalum dilatatum Poir.) pastures on a krasnozem on basalt at Maleny, Queensland, were investigated. On the establishment of white clover (Trifolium repens L.), significant responses to phosphorus, potassium, molybdenum, and lime were recorded ; where clover did not establish well, as in the kikuyu sward, the overriding deficiency appeared to be nitrogen. Maximum response to phosphorus, as NaH2PO4, was achieved at a rate equivalent to 10 cwt superphosphate an acre. However, soil equilibrium potentialSP values and pot results with Ca(H2PO4), suggested a maximum near 20 cwt an acre might have been expected. An initial molybdenum application of 1 oz an acre was adequate : the main effect of lime was to release molybdenum in this acid soil (pH 4.6 in M/100 CaCl2). Aluminium and manganese were not toxic ; nevertheless, lime increased the yield and nitrogen content of clover grown in pots, possibly due to preferential nodule formation by the introduced rather than the 'native' rhizobia at the higher soil pH.