RA 00110.pdf - OAR@ICRISAT

Table 2. Grain yield (kg ha -1 ) of pearl millet as affected by
different interrow and intrarow spacing.
Intrarow
spacing (cm)
30
15
10
Mean
C D 5%
Interrow
Source: Gautam (1970).
Interrow spacings (cm)
75 60
2440 2680
3080 3260
3550 3650
3020 3190
Intrarow
520
45 Mean
2400 2503
3750 3363
3310 3501
3150 3122
Interaction
500
yields 25-50%. Dicotyledenous and monocotyledenous
weeds of several species, including sedges,
infest pearl millet fields. Manually uprooting them
becomes rather difficult because of the soggy nature
of the soil during the rainy season, so chemical weed
control has been recommended (Gautam and Kaushik
1980b). In experiments conducted between
1970 and 1973 at 15 locations in India, triazine compounds
(propazine and atrazine) when applied at the
preemergence stage controlled 71-96% of the weeds,
increasing the yield by almost 30-40% over the
unweeded control. Chemical weed control (Table 3)
was more economic than manual weeding ( A I C M I P
1970-73).
Fertilizer Use
Tandon (1980) estimated the nutrient removal by
different crops grown in rainfed situations, and
reported that at the present productivity level, pearl
millet removes 72 kg of N + P + K ha -1 a -1 , whereas
only 10-11 kg of these nutrients are actually applied.
It is estimated that for the production of 100 kg of
grain, pearl millet requires 3.6 kg of N, 0.8 kg of P,
and 3.4 kg of K. Fertilizers not only increase aboveground
growth, but also below-ground root proliferation.
In this way replenishment of the soil nutrients
encourage more efficient water use.
Nitrogen Fertilizers
Of the three macronutrients, response to N has
almost been universal in all regions of the country
where pearl millet is grown. The optimum rate of N
fertilization in experiments averaged over 5 years
and 30 locations (Gautam et al. 1981) ranged from
92-137 kg ha -1 at a response level of 6.0-10.5 kg grain
kg -1 N applied. The output/input ratio of nitrogenous
fertilizer ranged between 0.8 and 2.7 in different
zones (Table 4).
Because rainfall distribution is not predictable,
nitrogen application of about 100 kg ha -1 is not
advisable because of the high N losses associated
with volatilization, leaching, ordenitrification. Splitting
the N application, half at sowing and the balance
3 weeks later was reported to be beneficial at
several locations in experiments conducted over 3
years (Fig. 2). In further experiments conducted by
Gautam and Kaushik (1984), it was obvious that the
omission of N at sowing is not advisable, because the
later application did not compensate for the omission
at the initial stage of crop growth (Table 5).
Legumes as Preceding Crops
Legumes are reported to fix 45-217 kg ha -1 N in their
root nodules (LaRue and Patterson 1981), which is
Table 3. Effect of weed control treatments on grain yield of pearl millet.
Treatments
Unweeded control
Hand weeding (3 times)
Propazine 0.5 kg a.i. ha -1
Propazine 0.5 kg a.i. ha -1 + Hand weeding (1 time)
Atrazine 0.5 kg a.i. ha -1
Atrazine 0.5 kg a.i. ha -1 + Hand weeding (1 time)
Grain yield
(kg ha -1 )
1870
2670
2410
2530
2310
2490
Mean dry weight
of weeds
(kg ha -1 )
1610
60
470
500
460
450
Weed control
efficiency
(%)
-
96
71
69
71
72
Source: AICMIP (1970-73).
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