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appears adequate, therefore no response to fertilizer potassium application was
obtained. However, the increased productivity of winter chickpea would also
mean increased removal of potassium from the soil, particularly because little
crop residues are returned to the soil in the cropping system in the region. For this
reason, there would be a need to ensure some kind of a monitoring system for soil
fertility status so that it may not become a major constraint to increased
productivity.
Need for a periodic application of micronutrients might also arise in future,
although at present there are no indications of the need for their application. In
fact, winter chickpeas -em to have an advantage over the spring chickpeas in so
far as iron nutrition is concerned. Several genotypes of chickpea on calcareous
soils show a conspicuous deficiency of iron when planted in spring. This deficiency
is induced because of the increased bicarbonate content in the soil in early
spring. The winter-planted crop isable to accumulate adequate amount of iron in
the plant by the time this stage is reached so that no deficiency is observed.
Weed Management
The winter-planted crop is likely to face a more serious weed problem than the
spring crop as most of the weeds that could compete with the spring crop are
killed by the preparatory tillage. In the winter-planted crop, the winter weeds
emerge with the crop and thus offer serious competition to the crop. In a weed
control study with the winter- planted crop, yield was reduced by about 42%
when no weeding was done as compared with the hand weeded check. However,
timely hand weeding or mechanical weed control may become difricuit because
of the winter rains. Therefore alternate weed management practices would be
needed.
Development of an early crop canopy by the use of narrower row-spacing and
higher seed rate can improve the competitive ability of the crop over the weeds.
Also, use of preemergence herbicides such as Tribunil at 4 kg product/ha has
given some control of annual weeds. The need for identifying more efficient
selective herbicides is obvious. Realizing this, an International Weed Control
Trial was started during the 1980-81 cropping season. This trial is being conducted
in different parts of the region by the national program scientists. It includes
three preemergence herbicides (clilorbromuron, methabenzthiazuron and terbutryne)
at three rates of application, two hand weeding treatments and a weedy
check. Data on weed count, at the onset of flowering of winter-planted chickpea,
in one such trial at Tel Hadya during 1980-81 scason revealed that chlorbromuron
at 2 kg a.i./ha and methabenzthiazuron at 3.5 kg a.i./ha gave good
control of weeds. The weed .ount was 5.9 and 3.4 weedplants/m 2 under the two
herbicide treatments, respectively, as against 25.2 weedplants/m 2 under the
weedy check.