Effects of irrigation and P fertilization on root growth and yield of wet-seeded and transplanted rice

摘要

Two field experiments were conducted at the wet land farm of TNAU, Coimbatore during 1993 and 1994 to study the effect of different sources and levels of P with two irrigation regimes on both wet-seeded and transplanted rice systems. Higher yield could be obtained in wet-seeded rice compared to transplanted rice under the present set of environment. Irrigation applied at frequent intervals resulted in higher grain yield of wet-seeded and transplanted rice during first and second year, respectively, over delayed irrigation. In wet-seeded rice, application of 50 kg P_2O_5 ha~(-1) resulted in significantly higher grain yield over 137.5 kg P_2O_5 ha~(-1), while it was not so for transplanted rice. In wet-seeded rice, root dry weight reached its peak at 90 days after sowing and then decreased sharply and reached minimum at the time of harvest, while in the transplanted rice system, root dry weight reached its peak at harvest stage only. In both the systems, the highest root cation exchange capacity (CEC) could be observed during the early growth stages of the crop and as the growth advanced, the CEC of roots decreased considerably.