RA 00015.pdf - OAR@ICRISAT

Table 49. Sorghum and pearl millet/pigeonpea intercrop grain yields as affected by different treatments
on an Alfisol at ICRISAT Center, 1976-1977.
Intercropping
Treatment P applied Sorghum Pigeonpea Pearl millet
(kg/ha) (kg/ha) (kg/ha) (kg/ha)
1 a 0P 680 620 340
2 20 P as Phosphate Rock 930 660 320
3 40P 850 790 400
4 80P 770 710 480
5 160P 1270 580 220
6 80 P Phosphate Rock + Sulphur in 1100 690 350
Pellets
7 80 P " + 3 0 tons/ha 1600 740 490
F Y M mixed
8 80P " +5P(SP) 1160 700 480
banded
9 5 P as Super Phosphate (SP) banded 1280 760 430
10 10P 1790 750 420
11 20P 2040 610 580
12 30 Tons/ha F Y M 1710 850 540
L.S.D. (0.05) 660 - -
a Available N, P, and K prior to fertilization:
0- to 15-cm depth, 80, 2.8, and 126 ppm, respectively
15- to 30-cm depth, 94, 3.6, and 108 ppm, respectively
ability, soil samplings were taken in each of the
four replicates of the "Steps in Improved Technology"
experiment. Four treatment combinations
involving local vs. improved fertilization
and management, plus a fallow plot, were sampled.
Soil samples were taken at 0 to 15,15 to 30,
30 to 60, and 60 to 90 cm at monthly intervals
from an area of 9 x 12 m in size in each treatment.
Each sample consisted of a composite of 10
subsamples taken at random. The samples were
immediately treated with toluene, dried at 60° C,
and thoroughly mixed. A 5-g sample was then
extracted with CuSO 4 and the nitrate nitrogen
Concentration determined on a 5-ml aliquot of
extracting solution by the phenol disulphonic
acid method.
This investigation was started in July 1976 and
will be continued for several years in an attempt
to establish a trend in seasonal status of nitrate
and available nitrogen in these soils. Early
samplings indicate large variability in nitrate
concentration with depth and time. Thus, large
numbers of replications and repeated samplings
will be necessary to establish reliable trends. The
present data will be combined and summarized
with next year's data and reported at that time.
Boron Toxicity on Ratooned Pigeonpea
Severe necrosis of the leaf margins in ratooned
pigeonpeas was observed in March 1977. The
symptom was the most severe on the oldest leaves
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