Ruth O. Escasinas1* and Oscar B. Zamora2
Rice yield fluctuates because of environmental influences on morphological and physiological processes, as well as inadequate human intervention, to stabilize crop productivity. A field experiment was conducted in two cropping seasons at the experimental area of the Department of Agronomy, Visayas State University, Baybay, Leyte to evaluate the morphological and physiological performance of lowland rice grown at different water, spacing and nutrient management. Different sources of fertilizers were designated as the mainplot and plant spacing as the subplot nested within two water regimes, ie, continuous flooding and no flooding.
Lowland rice s under no flooding were shorter than those under plant continuous flooding. No flooding gave higher root pulling resistance, crop growth rate, net assimilation rate, leaf area index and harvest index and consequently produced higher grain yield of PSB Rc18. No flooding and continuous flooding water management resulted in the formation of aerenchyma cells in roots of rice plants which had statistically similar cell number and measurement. Wider spacing of 40cmx40cm gave the highest RPR. Water, spacing and nutrient management did not influence the phyllochron and total number of leaves on the main culm of PSB Rc18. However, PSB Rc18 at early growth stages tended to have longer phyllochron because of transplanting shock.
No flooding, application of composted goat manure and closer spacing of 20cmx20cm is the best treatment combination that g ve similar yield to rice plants a applied with inorganic fertilizer at the rate of 90-30-30kg ha-1 N, P2O5, K2O.
Keywords: crop growth rate, harvest index, leaf area index, net assimilation rate, phyllochron, aerenchyma cells