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RELATIONSHIP OF
PLANT AVAILABLE SULPHUR WITH SOIL CHARACTERISTICS, RAINFALL AND YIELD
LEVELS OF OILSEED CROPS IN POTHWAR PAKISTAN
RIZWAN KHALID1,
KHALID SAIFULLAH KHAN1*, ZAHID AKRAM2, RAHMATULLAH QURESHI3
AND MUHAMMAD GULFRAZ4
Abstract: A
study was carried out in order to assess the status of plant available S
in the 15 rain-fed arable soils of Pothwar, Pakistan and to evaluate its
relationships with soil characteristics, rainfall distribution and yield
levels of oilseed crops in the region.
The contents of
plant available S
(0.01 M
CaCl2 extractable SO4-2-S)
in the soils varied from 5.7 to 21.7 µg g-1 soil (mean 11.7
µg g-1 soil) and corresponded to 7.0 to 13.8% of the total S
in the soils. The adsorbed S contents ranged from 1.9 to 7.8 µg g-1
soil (mean 4.8µg g-1 soil) forming 2.0 to 7.3% of the total S
in the soils. The organic S contents ranged from 68.4 to 140.4 µg g-1
soil (mean 97.0 µg g-1 soil) accounting for 81.5 to 89.3% of
the total S in the soils. The 0.01 M CaCl2 extractable SO4-2-S
was highly significant positive correlated with total S and organic S in
the soils. Significant positive relationships also existed between 0.01
M CaCl2 extractable SO4-2-S and the
clay, ECe, organic C, total N, and extractable P contents in
the soils. Significant negative relationships of 0.01 M CaCl2
extractable SO4-2-S were observed with the CaCO3
and pHs of the soils. Among the climatic factors, 0.01 M CaCl2
extractable SO4-2-S showed significant positive
correlation with the mean annual temperature, while the significant
negative relationships with rainfall from July to August, total annual
rainfall and the rainfall from September to June. A strong positive
relationship existed between 0.01 M CaCl2 extractable SO4-2-S
contents and the average yield level of oilseed crops (r = 0.80**).
Among different crops, groundnut yield had highly significant
correlation (r = 0.90**) with the CaCl2
extractable SO4-2-S followed by the sunflower (r =
0.70**), while the rapeseed/ mustard yield had the lowest (r
= 0.59*).
1Department
of Soil Science and Soil & Water Conservation, 2Department of
Plant Breeding & Genetics, 3Department
of Botany, and 4Department of Biochemistry, Pir Mehr Ali Shah
Arid Agriculture University Rawalpindi, Pakistan
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