Evaluation of the Bray 1, lactate, Truog and Colwell soil tests as predictors of triticale grain production on soil fertilized with superphosphate and rock phosphate

• Published in: Technical report - Western Australian Department of Agriculture Division of Plant Industries (Australia) no. 34
• Main Authors: Bolland, M.D.A. (Western Australian Dept. of Agriculture, Perth. Plant Nutrition Branch), Gilkes, R.J. (Western Australian Dept. of Agriculture, Perth. Div. of Plant Industries)
• Format: Publication
• Language: English
• Published: South Perth, W.A. (Australia) Western Australian Department of Agriculture 1991
• Subjects: ANALISIS DEL SUELO; ANALYSE DE SOL; AUSTRALIA OCCIDENTAL; AUSTRALIE OCCIDENTALE; FERTILIDAD DEL SUELO; FERTILITE DU SOL; FOSFATO MINERAL; FOSFATOS; PHOSPHATE; PHOSPHATE NATUREL; PROPIEDADES FISICO-QUIMICAS SUELO; PROPRIETE PHYSICOCHIMIQUE DU SOL; SUPERFOSFATO; SUPERPHOSPHATE; TRITICALE (GRAMINEAE)

In a field experiment in Western Australia, six levels of three different phosphorus (P) fertilizers (triple superphosphate, TSP; Queensland (Duchess) rock phosphate, QRP; North Carolina rock phosphate, NCRP) were applied once only at the start of the experiment in 1984. Grain yield of triticale (x triticosecale) was measured from 1984 to 1988. In February-March after 1984, soil samples were collected to measure soil extractable P (soil test values) using four reagents (Bray 1, lactate, Truog and Colwell). The soil test values were related to the grain yields produced later on in each year from 1985 to 1988. All four soil test reagents were equally predictive of yield, except that for rock phosphate the Truog soil test predicted higher levels of P to produce the same yield than the other soil test reagents. It is concluded that soil testing for P provides crude predictions of plant yield.