A comprehensive study was conducted over a 4-year period (1984–87)
to evaluate the water use,
growth and yield responses of pearl millet (Pennisetum glaucum
(L.) R. Br.) cv. CIVT grown with and
without fertilizer (30 kg P2O5 and 45 kg N ha−1)
at the ICRISAT Sahelian Centre, Sadoré, Niger. Our
study showed significant year and fertilizer effects on the growth and
yield of millet at the study site.
Observed year effects were primarily due to the variations in the amount
and distribution of rainfall
in relation to the potential demand for water. During 1984, 1985 and 1987,
total rainfall was below
the long term average, while in 1986 it was above average. While the onset
of rains (relative to the
average date of onset) was early from 1984 to 1986, in 1987 the sowings
were delayed by as much as
33 days. Of all the four years, the separation between the treatments in
the cumulative evaporation
is most evident for 1984, which was a drought year with below-average rainfall
in all the months from
June to September. Cumulative evaporation patterns in 1985 and 1986 were
similar because of regular
rains and high average rainfall per rainy day from June to October. In
1987, sowings were delayed
until 15 July and only 6·9 mm of rainfall was received per rainy
day in July. Hence cumulative
evaporation was initially low and showed a significant increase only after
two significant rain events
in early August. There was a large response to fertilizer in all the years
as small additions of fertilizer
phosphate increased the soluble phosphate in the soil. Fertilizer application
resulted in a small
increase in water use (7–14%) in all years except 1987. Increased
yield due to the application of
fertilizer was accompanied by an increase in the water-use efficiency (WUE)
in all the four years with
the largest increase in 1985. The beneficial effect of fertilizers could
be attributed to the rapid early
growth of leaves which can contribute to reduction of soil evaporative
losses and increased WUE.
Over the four seasons, average increase in the WUE due to the addition
of fertilizer was 84%.
Deep Root Water Uptake Ability and Water Use Efficiency of Pearl Millet in Comparison to Other Millet Species
