Soil water status, maize growth and yield under traditional farming practices at Bvumbwe -Malawi.
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Date
1996
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
An experiment was conducted at Bvumbwe Research Station in Malawi with the
objective of characterizing the soil water status and maize (Zea mays) growth and yield
under traditional tillage practices. Four tillage practices namely Open Ridge (OR),
Residual Ridge (RR), Basin Ridge (BR) and Tie Ridge (TR) systems were used as treatments. Instantaneous soil water content was determined in situ by using tensiometers (Model
2900F1) set in the field within 0 - 45 cm depth on rows, interrows, and 2/3 distance
from interrows. Weekly gravimetric determinations of soil water at 0 - 45 cm depth
were used to assess the profile soil water distribution characteristics at different maize
development stages. Infiltration measurements soon after cultivation and after
harvesting were determined by the double ring method. Runoff collection tanks were
installed at the edge of each plot to collect runoff discharges from respective plots.
Plant performance was assessed on a complete randomised block design (CRBD).
Treatment BR maintained the highest profile soil water content on rows, interrows and
2/3 distance from interrows during the greater part of the season, RR had the lowest
whereas TR and OR had an intermediate profile soil water content. Row soil water
readings were normally lower than interrows with a mean differrence of about 4.5 mm
in OR and RR, 6.3 mm in BR and 5.4 mm in TR. The differential patterns of recharge
and drying within the profile created spatial variations in soil water content at different
depths. There was significant correlation between spatial variations and the mean soil
water content. Subsurface recharge from interrows to rows, narrowed the spatial
variations in soil water content in BR by about 0.0021 and a minimal rate of0.00065 in
RR.
Temporal variances in soil water content ranged from 0.0086 in BR and TR to 0.0053
in RR with intermediate temporal variance for OR treatment. The soil water behaviour
showed a temporal dependence on spatial variations and a spatial dependence on
temporal variations. Higher soil water content in BR was attributed to basin storage
which promoted in situ water retention allowing longer periods for infiltration process
■ to take place leading to the low runoff coefficient of 10% in BR, 18% in TR, 29% in
OR and 47% in RR.
Maize performance was significantly related to the soil water content with the highest
growth rate in BR treatment of 2.11 cm/day, TR 1.93 cm/day in TR, 1.84 cm/day in
OR and 1.39 cm/day in RR at 59 DAP. Tasselling rate, leaf area Index, dry matter yield
responded positively to the soil water variations in the treatments.
Description
Dissertation
Keywords
Soil status, Maize growth, Maize yield, Malawi