Effect of seedbed conditions, planting rain, and seed vigour on establishment of maize
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Date
1997
Authors
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Publisher
Sokoine University of Agriculture
Abstract
A study was conducted to evaluate the effect of (a) moisture content at cultivation
on the resulting seedbed conditions, (b) seedbed conditions to establishment of low
and high vigour maize seeds, (c) planting rain on the establishment of maize
seedlings, and (d) interaction between seedbed, planting rain and seed vigour on
establishment.
Two mainplots, each with 5 subplots, were laid out.
Water
equivalent to 50 mm rain was applied uniformly al each of the two mainplots on the
same day. A day after application of 50 mm equivalent of water, ploughing was
undertaken sequentially, a subplot every day. for 5 days resulting in 5 seedbed
conditions (SBC) giving treatments SBC 1-5
High and low vigour maize seeds
were planted. Planting rain equivalent to either 40 mm or 15 mm was applied to one
of the two mainplots.
Bulk density ((ph), aggregate size distribution and penetration resistance (PR) were
employed to evaluate the effect of soil moisture content at cultivation on the
resulting SBC, and its effect on the establishment of maize. Results were that, cpb
was significantly (P<0.05) higher than in the virgin land only in the 40 mm planting
rain treatments. Aggregate sizes < 0.6 mm, 2 mm, 4 mm, 6.3 in in, 11 mm, 20 mm
and >20 mm were categorised. Aggregates < 6.3 mm in diameter were 72 and 63%
(in low and high planting rain treatments respectively) in SBC 3 and were higher
than in other SBCs. PR at 4 n】m depth was lowest (< 1 MPa) in SBC 3 in both
mainplots.
Overall emergence was low for low vigour seeds compared to high vigour seeds.
Best emergence was observed in SBC 3 which had lowest PR and high percentage
of aggregates < 6.3 mm diameter in both planting rain treatments.
followed by SBC 4 in 40 mm planting ram treatments.
This was
Poor emergence was
observed in SBC 1 and 5 in I 5 in in planting rain plots and in SBC 1, 2 and 5 in 40
mm planting rain plots. Seedbeds with poor emergence had high PR values (>2
MPa) and high percentage of large aggregates (> 6.3 mm diameter).
Significant (P<0.05) differences in shoot height and in number of leaves per plant
were only observed when vigour categories were compared. The inleraction between
seedbed, planting rain and seed vigour had no significant effect on establishment of
maize.
Conclusions from this study are that: for ploughing to result into a SBC which
favours crop establishment in the study area, it should be undertaken 3 and at most
4 days after high rains (50 mm).
High planting rain (40 mm) resulted in best
emergence in a seedbed ploughed 3-4 days after watering at a gravimetric soil
moisture content of 23 to 20%.
Seeds should be tested for vigour before being
marketed or planted to reduce poor establishment due to low vigour seeds. Further
research should be carried out in other areas to quantify the contribution of the
studied factors on crop establishment so as to provide appropriate intervention
measures.
Description
Dissertation
Keywords
Soil moisture, Seed deterioration, Seed purity, Seed germination, Seedbed condition