PRODUCTIVITY AND PHYSIOLOGICAL QUALITY OF IRRIGATED RICE SEEDS UNDER SALT STRESS AND CARBONIZED RICE HUSK ASHES FERTILIZATION.

The yield potential of rice in Brazil can be severely impaired by salinity, which affects about 2 % of the country's rice cultivation lands. Conditions of high salinity may be caused by inappropriate irrigation practices and soil flooding by sea water in coastal regions. Therefore, the objective of this study was to evaluate the effect of carbonized rice husk ashes applied to the soil on the yield and physiological seed quality of rice grown under salt stress. The experimental design was randomized blocks with five levels of factor A (0.0, 500, 1000, 1500 and 2000 kg ha-1 of rice husk ash) and three of factor B (0.0, 4.0, and 8.0 mM of NaCl) applied to the soil, with four replications. The response variables were the number of panicles per plant, number of seeds per plant, seed weight per plant, number of sterile glumes per plant and 1000 seed weight. The physiological quality of seeds was assessed through the germination test, first germination count, cold test, accelerated aging, seedling shoot and root lengths and field emergence. The salinity caused a negative effect on the agronomic traits and physiological quality of rice seeds. Weight and physiological quality of rice seeds were positively affected by increasing doses of carbonized rice husk ashes, even in the presence of salt concentrations in the soil. [ABSTRACT FROM AUTHOR]