Mj. Finlay et al., EFFECT OF TILLAGE BELOW THE SEED ON EMERGENCE OF WHEAT SEEDLINGS IN AHARDSETTING SOIL, Soil & tillage research, 28(3-4), 1994, pp. 213-225
Two field experiments investigated the effect of tilted and untilled s
oil below the seed and the effect of a press wheel on the emergence of
wheat (Triticum aestivum L.) seedlings on a hardsetting soil at Tatur
a, Victoria, Australia. Soil physical properties of the seedbed includ
ing penetrometer resistance, temperature and water content were record
ed. The fate of seeds and seedlings and the length of roots were deter
mined. In the experiments, germination was high (over 90%) and was not
affected by the depth of tillage the press wheel or by temporary wate
rlogging, but several physical conditions of the soil restricted emerg
ence. In the first experiment, the rate and final emergence (at Day 10
) was increased by tillage below the wed (e.g. at 46-90 mm depth) in s
pite of the penetrometer resistance of soil at 0-20 mm depth being 50%
greater than that in the treatment untilled below the seed. The roots
of the seedlings in the treatments untilled below the seed were tempo
rarily waterlogged (at Days 0-1) and grew in soil that was drier (at D
ays 3-9) and harder than in treatments tilled below the seed. In the s
econd experiment, the press wheel increased the rate of emergence by d
ecreasing the sowing depth by 10 mm. Tillage below the seed increased
the rate of emergence by decreasing the penetrometer resistance of the
soil to less than 2.0 MPa.