Adubação orgânica e estresse hídrico na produtividade e qualidade fisiológica de sementes de arroz vermelho cultivadas em Neossolo Flúvico

Abstract

It known the beneficial effect of organic fertilization on crop productivity, constituting a practice that can help to improve the quality of seeds and minimize the harmful effects caused by water deficiency, which is common in semi-arid regions. This study aimed to evaluate the influence of organic fertilization with manure and water stress, the physiological performance of the varieties of red rice (Oryza sativa L.) Cáqui, Maranhão e MNA 902. The seeds were produced in protected cultivation in pots containing eight pounds of soil, 0-20cm layer, collected in the Piancó Valley region. We tested four doses of cattle manure (0, 4, 8 and 12 t ha-1) in the presence and absence of water stress (60 and 80% of the pot capacity respectively) in a randomized block design in a factorial 3 x 4 x 2 (varieties, manure and water stress), with four blocks. postharvest, the seeds were sent to the Laboratory of Organic Matter DSER / CCA / UFPB to determine productivity. With four months of storage were determined moisture content, weight of 1000 seeds and physiological conditions by germination, first count, IVG, a field emergence, seedling dry weight, electrical conductivity and potassium leaching. experimental design in randomized blocks for emergency test the field and completely randomized for the other tests. The variables that were significant by F test were studied by regression analysis. Red rice seeds showed a germination percentage ranging 98-100%, these results, above the minimum average required for marketing of rice seeds in the main producing states. Drought stress decreased the weight of 1000 seeds and seedling dry weight and therefore increased electrical conductivity and potassium leaching seeds of the variety MNA 902, resulting in loss of physiological quality. The highest yield of red rice seeds can be obtained with manure doses higher than 12 t ha-1. The presence of manure improved the physiological quality of seeds of the variety Cáqui and therefore it is recommended to use this input to improve the production and seed quality.