Direct and Residual Effect of Rock Phosphate on Growth and Yield of Rice in an Acidic Soil Issak M.1,*, Sutradhar G.N.C.2, Rahman M. M.3, Firdousi J.4, Hossain A.T.M.5, Sultana A.4 1Department of Soil Science, SAU, Dhaka, Bangladesh. 2Dept. of Soil Science, SAU, Dhaka, Bangladesh. 3Soil Science Division, BARI, Joydevpur, Gazipur, Bangladesh. 4SAU, Dhaka, Bangladesh. 5PRC, BARI, Joydevpur, Gazipur, Bangladesh *Email: mdissaksau07@yahoo.com
Abstract A field study was conducted in acidic shallow red brown terrace soils of Sher-e-Bangla Agricultural University, Dhaka situated at 90.50° ‘East longitude and 24.09° North latitude at 8.2 msl under the T. aman - it - T. aman cropping system during 2004–2005 to study the direct and residual effects of rock phosphate (PR) as compared to Triple Superphosphate (TSP) on the growth and yield of Transplanted aman (T. aman) rice (BRRI Dhan 39) as main crop, Boro rice (BRRI Dhan 29) as residual crop -1 and T. aman rice (BRRI Dhan 30) as residual crop-2. Experiments were laid out in a Randomized Complete Block Design (RCBD) with five treatments including TSP, two rates of PR, a combination of two sources and a control in four replications. The dry matter production of T. aman rice (BRRI Dhan 39) as main crop and Boro rice as residual crop-1 did not differ significantly, whereas residual crop-2 showed significant difference at maximum tillering (MT) stage as well as panicle initiation (PI) stage. At MT and PI stages, overall maximum dry matter production was found in treatment T5. A significant grain and straw yield difference was found in all the treatments of different cropping seasons where main crop produced maximum grain (4.00 t ha−1) and straw (6.64 t ha−1) yield in treatment T5 (17.5 kg P from PR and 17.5 kg P from TSP). In case of first residual crop, significant yield difference was found over the control (T1) and the highest grain yield (6.8 t ha−1) and straw yield (7.47 t ha−1) were obtained in the treatment T5 where a judicious mixture of PR(17.5 kg P ha−1) and TSP (TSP 17.5 kg P ha−1) was used. In case of residual crop-2, the treatment T3 and T5 had a significant residual effect regarding grain yield of T. aman (BRRI Dhan 39) as main crop but application of full does of P as PR and 210 kg P applied in the main crop had no significant effects on yield of rice. The residual crop-2 under the treatment T5, produced the maximum grain (4.5 t ha−1) and straw (4.8 t ha−1) yield. Top Keywords Rice, phosphorus, rock phosphate, acidic soil. Top |