1Agriculture and Agri-Food Canada, Box 760, Indian Head, SK, S0G 2K0.
2Manitoba Zero Tillage Research Association, Box 1000A, RR#3, Brandon, MB R7A 5Y3.
3Agriculture and Agri-Food Canada, Research Centre, 107 Science Place, Saskatoon, Saskatchewan, S7N 0X2.
4Agriculture and Agri-Food Canada, Box 1000A, RR#3, Brandon, MB R7A 5Y3.
The adoption of zero tillage practices require the development of innovative ways of working with surface residues and tall stubble. One such method is the use of wide row spacings. The objective of this study was to study the effects of row spacing, seeding rates and seed-placed P on plant populations, seedling development, dry matter production at antithesis, grain yield and root diseases in barley, durum and spring wheat. Three row spacings (10, 20 and 30 cm), three seeding rates (67, 134 and 201 kg ha-1for wheat and durum and 43, 86 and 129 kg ha-1for barley) and three rates of seed-placed P (0, 18 and 36 kg ha-1of P2O5 ). Mono-ammonium phosphate (12-51-00) was used. The study was conducted on an Indian Head heavy clay soil and a Newdale clay loam. Plant densities were not reduced by seed-placed P, but as row spacing increased, there was a reduction in plant numbers. Seedling development, as measured by Haun stage, was hastened with the addition fertilizer of fertilizer P in barley and spring wheat but not durum while an increase in seeding rates delayed seedling development. Changes in row spacing did not affect seedling development. Dry matter production at antithesis was increased with seed-placed P and increased seeding rates but decreased with increased row spacing. Grain yields were improved with seed-placed P and with increased seeding rates with no differences among row spacing. Root diseases were not changed by row spacing and seeding rate but tended to be lower with the addition of seed-placed P. Based on the results, it would appear that high rather than low seeding rates should be used at all times because of observed improvements in P response with the higher seeding rates. Further studies of row spacing, seeding rate and fertilizer P placement should be undertaken to increase phosphorus fertilizer use efficiency.