critical value of soil Olsen P for dry direct seeded rice (Oryza sativa)
in a greenhouse study in northwestern India
Rathore2*, R.K. Gupta1, Y. Singh1 and B.
1Department of Soil
Science, Punjab Agricultural University, Ludhiana-141 004, India
Agriculture, ?Lovely Professional University, Phagwara-144 411, India
Author E-mail: email@example.com
Direct seeded rice,
received : 18.08.2015
received : 04.05.2016
received : 16.09.2016
Accepted : 09.11.2016
Aim: In view of the
looming water crisis and shortage of labour during transplanting, dry-seeded
rice (DSR) is an attractive option for rice cultivation in Asia. Presently
limited information is available on optimum nutrient management in DSR.
Compared to puddled transplanted rice, DSR is likely to encounter less
availability of fertilizer phosphorus. The main objective of the study was to
determine critical value of soil Olsen P for DSR.
greenhouse experiment was conducted to study the effect of three levels of
phosphorus (0, 6.5, 13 mg P kg-1 soil) application on dry matter
accumulation and phosphorus uptake of DSR at maximum tillering (MT), panicle
initiation (PI) and flowering stages (FL) in ten different soils varying in
Olsen P and texture. Bulk soil samples (0-15 cm) were collected from
different locations in Punjab state of India and analyzed for initial physical
and chemical properties (pH, electrical conductivity, cation exchange
capacity, organic C, NaHCO3?extractable P, NH4OAc-extractable
K, DTPA-extractable Zn, Cu, Mn, and Fe and particle size distribution). Soil
samples collected at flowering stage were analyzed for Olsen P. Plant samples
were analyzed for total phosphorus content. Cate and Nelson (1971) method was
used to determine the critical limit of soil Olsen P.
low in Olsen P (<5.3 mg kg-1 soil) showed significant increase
in shoot biomass and phosphorus uptake of DSR with the application of 6.5mg P
kg-1 soil compared to control. Critical values of Olsen P for DSR,
below which the crop would suffer yields determined by Cate-Nelson model, was
9.0 mg kg-1soil. Recovery of phosphorus fertilizer at 6.5 mg P kg-1
in different soils ranged from 23.3-42.8%, with lower values for high Olsen P
soils compared to control.The critical value of Olsen P was low at initial
(MT and PI) growth stages than at flowering stage, suggesting that early crop
growth in DSR is more sensitive to phosphorus deficiency.
of DSR to phosphorus application depends on the availability of phosphorus in
soil. A critical level of Olsen P at 9 mg kg-1 soil can be used
for applying fertilizer phosphorus? to DSR.