RA 00048.pdf - OAR@ICRISAT

Session 6
Production Technology
L R. House*
Discussant—2
An important use of sorghum is as an intercrop.
There are numerous combinations: sorghum in
maize in Central America, sorghum in cowpeas in
Brazil, sorghum in millet in West Africa, and
sorghum in pigeonpea in India, serve as examples.
Beside space relationships there is concern
about modification of the plants themselves,
usually in terms of plant height and maturity. This
is a debated issue; an example will help. There is
a situation in India where there is interest in the
dry sowing of sorghum and pigeonpea before the
monsoon rains. It is valuable if the sorghum crop
can be harvested in mid September as the
pigeonpeas begin to expand; however this is a
period of expected rainfall resulting in the weathering
of the sorghum grain. It may be possible to
use a later-maturing type with erect leaves and/or
long internodes between uppermost leaves to
reduce competition with the pigeonpeas.
There is concern both for the poor farmer of
limited means and in producing adequate food to
meet demands. The concept of a two-pronged
thrust directed at a rapid increase in production in
areas of less moisture stress while contributing to
improved production capability of the poor farmer
in climatically harsher areas was mentioned and is
of interest at ICRISAT. In addition, the concern for
increased production in already highly developed
agricultural situations was recognized and is
important to our concern about availability of
adequate quantities of food.
I have been impressed by the precision of
sowing gained with some tractor-mounted planters
and the resultant effect on stand. This heavy
equipment moves the soil rather than being
moved by the soil; so, for example, seeds can be
placed at a desired depth, seed, fertilizer, soil
insecticides, and herbicides can be placed pre-
* Principal Plant Breeder and Leader, Sorghum Program,
ICRISAT.
cisely and uniformly, and uniform interrow spacing
permits easy cultivation. It would seem that
some concepts from this kind of tractor-drawn
equipment could be adopted to simple animaldrawn
tools. The addition of simple guage wheels
to control depth of sowing, rolling disc planter
shoes to slice rather than drag through the soil,
some form of press wheels to firm soil around the
seed; guide discs to reduce side slip, and a
marker to better judge interrow distance may be
adopted to existing farmer equipment. The value
of animal-drawn tool carriers is recognized and
their effective use demonstrated. A closer look at
the possibility of improving yet simpler equipment
is questioned.
Weed control is undertaken in many areas by
hand pulling or the use of a simple hand tool. An
improvement in methods of weed control would
permit more timely weeding at lower costs.
Weeds can be a major constraint to production
and their control deserves more attention, particularly
in the developing countries.
The concept of minimum tillage has evolved in
developed countries. A problem has been slower
warming of the soil following the cold winter,
there being as much as 5°C difference between
fully tilled and minimum tilled fields. This may be
of interest in tropical areas where soils are
frequently very hot at the time of sowing. This is
an aspect of the general problem of stand
establishment, the concern for which has been
mentioned.
The idea of using sorghum to conserve water
for irrigation in areas where the water table is not
being adequately recharged is interesting. The
concept of protective irrigation in India developed
years ago. The concept of sorghum as a water
efficient plant could be important in a range of
situations where water availability is limited.
Effective policies to help ensure water use in this
way are important to this consideration.
The importance of biological nitrogen, and
International Crops Research Institute for the Semi-Arid Tropics. 1982. Sorghum in the Eighties: Proceedings
Symposium on Sorghum, 2-7 Nov 81, Patancheru. A.P., India. Patancheru. A.P. India: ICRISAT.
of the International
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