Nutrient Uptake and Inflow Rate into Rice Roots at Varying Periods of Growth under Different Soil-Water Regimes

Dry matter production, uptake of N, P, K, Fe, Mn and Zn in relation to varying periods of growth of two varieties of rice (Oryza sativa L.) and nutrients inflow rate in roots under different soil-water regimes were studied in a field lysimeter experiment. Shoot dry weight increase was high under flooding (F), continuous drainage rates of 1.8 and 3.8 cm/day (D₁ and D₂) and flooding followed by drainage for 2 and 4 days (FD₁ and FD₂) treatments. Under recycling treatment (R) growth was very low at the beginning then it was suddenly enhanced. Root dry weight increase was continuous under all soil-water regimes. Maximum absorption of nutrients was with submergence treatments (D₁, D₂, F and R) as compared to FD₁, FD₂ and unsaturated conditions (1/3 bar and 0–5 bar). The inflow rate of nutrients was the maximum under unsaturated treatments and was higher with drainage treatments than under F and R.