Abstract
A pot study was conducted during the year 1987-88 on rice and wheat to evaluate the effect of different sources of P (nitrophos, single super phosphate, diammonium phosphate and triple super phosphate) in soils having ESP of 10, 14, 27 and 41. Phosphorus for rice and wheat was applied 30 and 50 mg kg-i soil along with a basal dose of N, K @ 45, 23 and 75, 25 mg kg-i soil, respectively. The P sources improved the productive tillers, grain and straw yields of rice and wheat, single super phosphate remained superior. The increasing sodicity levels decreased the number of tillers, grain and straw yields and P uptake. Phosphorus uptake was increased by applying P fertilizer in sodic soil, being maximum for SSP followed by TSP, OAF, NP and the control.
INTRODUCTION response of wheat and rice to P carriers was investigated under sodic soil conditions.
According to estimates about 5.53 rnha of arable land in Pakistan are affected by salinity and sodicity (Muhammad, 1983). In saline/sodic environments, the availability and uptake of P becomes a problem (Chhabra 0 al., 1981). It has been noted that grain yield of rice was increased by applica-tion of P in saline-sodic soils (laid et al., 1979). The yields of rice and wheat were not affected by P application in individual year in uncultivated sodic soil, but over a period of 6 years the yield of fertilized plots was more than the corresponding controls (Chhabra, 1985), Smith and Spcnchc (1974) in pot trials noticed that single super phosphate increased the grain yield of wheat in 2/3 among the 71 trials. Ahmad (1.988), compared different P sources in a pot study, observed better P uptake, grain and straw yield of wheat with application of single su-per phosphate. In (lie present study, growth
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MATERIALS AND METHODS
A pot experiment was conducted on rice and wheat during the year 1987-88 at the Soil Salinity Research Institute Camp at Faisalabad to evaluate the effect of different sources of phosphorus (nitrophos, single super phosphate, diammonium phosphate and triple super phosphate) under four ESP levels (10, 14, 27 and 41). A normal loam textured (Ec, 1.9 EIS m1, pHs 7.9, Oslon P 7 ppm, ESP 10) was collected from the field. The sodicity levels were developed by the addition of NaHCOA. Ten kg of this soil were added in each pot. The treatments were: Control, nitrophos (N/P), single super phosphate (SSP), dianamonium phosphate (DAP) and triple super phosphate (TSP). Phosphorus for rice and wheat was applied 6!) 30 and 50 mg kg-I soil along with a basal dose of N, K @1 45, 23 and 75, 25 nig kg -1 soil, respectively as ammonium
