RA 00015.pdf - OAR@ICRISAT

Table 48. Effect of row spacing and nitrogen application on sorghum upon grain yields of sole and
intercropped sorghum and pigeonpea on a Vertisol* at ICRISAT Center, 1976-1977.
Crop
Zero N on sorghum
60 N on sorghum
Row
spacing Yield LER Yield LER
Sole sorghum
Sole sorghum
Sole pigeonpea
Sole pigeonpea
(cm) (kg/ha) (kg/ha)
45
90
45
90
1530
1760
1540
1400
-
3520
3320
1370
1370
-
Intercropping (alternate
rows 45 cm)
Sorghum 1660 1.01 2980 .87
Pigeonpea 1050 0.71
920 .67
Total Land Equivalent Ratio (LER)
L.S.D. (0.05) sorghum-1060; pigeonpea-310.
a Available, N, P. and K prior to fertilization:
0-to 15-cm depth, 78, 6.0, and 356 ppm, respectively
15-to 30-cm depth, 63, 1.1, and 237 ppm, respectively
1.72
1.54
This is a 4-year experiment, and some of the
treatments have had only their first annual
application. Some preliminary information was
obtained, however. In the sorghum series, 10 and
20 kg/ha of P as super phosphate and 30 ton/ha of
F Y M (farmyard manure) gave significant yield
increases. In all other treatments there was a
positive trend, but it was not significant. The
pearl millet yield was extremely low due to
extreme drought in September and October and
there was no significant difference in pigeonpea
yields (Table 49).
An experiment was initiated to evaluate the
response of chickpea genotypes to phosphorus
on a Vertisol. Ten promising genotypes from
chickpea breeders were tested at four levels of P
(0, 10, 20, and 40 kg/ha).
Since this was the first crop grown after
clearing the land, the average yield levels were
very low (320 kg/ha). There was a small but
significant response to phosphorus application.
The genotype mean yields were significantly
different, but the interactions between P levels
and genotypes were not significant.
Seasonal Changes in Nutrient Status
A better understanding of seasonal changes in
nutrient status throughout the year under various
soil and crop management systems is vital to
the development of management systems for
crop residues and organic wastes, as well as for
arriving at soil- and water-management practices
which optimize nutrient availability to crops and
minimize losses. There is some evidence of a
buildup of nitrate in the soil profile during the
noncropped season prior to the rainy season
(Krantz, et al. 1944 and Wetselaar, 1961a). In
order to study this phenomenon on a yeararound
basis, a soil sampling program to measure
the seasonal changes in nitrate nitrogen and
"available" N in the upper 90 cm of a Vertisol
and an Alfisol was initiated.
To obtain a statistical measure of the vari-
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