Upland Rice and Allelopathy

Abstract

Upland rice (Oryza sativa L.) is mainly grown in Asia, Africa and Latin America. Yield potential of upland rice is quite low and invariably this crop is subjected to many environmental stresses. Further, when upland rice is grown in monoculture for more than two to three years on the same land, allelopathy or autotoxicity is frequently reported. Allelopathy involves complex plant and plant chemical interactions. The level of phytotoxicity of allelochemicals is influenced by abiotic and biotic soil factors. Adopting suitable management strategies in crop rotation can reduce or eliminate allelochemicals phytotoxicity. Rice yields can be improved by growing rice in rotation with other crop species. Allelochemicals of rice can be used for control of weeds in this crop as well as other crops that are grown in rotation with rice. This review highlights that present knowledge of allelopathy in upland rice is inadequate and fragmentary, and therefore, more controlled Vol. 34, Nos. 9 & 10, pp. 1311-1329, 2003 This article is a U.S. government work, and is not subject to copyright in the United States. COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSISand field studies are needed to understand and to reduce the detrimental effects of allelopathy in the upland rice production.

Grain yield and termite damage in rice by compaction on the furrow and seed treatment

“…This lower grain yield in the third experiment, in comparison with the second one, is in alignment with the results obtained by several other authors, who do not recommend the continuous cultivation of upland rice in the same area due to the sharp fall in productivity (Fageria & Baligar, 2003;Nie et al, 2009;Godoy et al, 2013). This decline in grain yield has been attributed to allelopathic effects (Fageria & Baligar, 2003), which are any direct or indirect harmful effects of a plant on another one through the production of chemical compounds released into the environment.…”

Allelopathy as a mechanism for the invasion of Typha angustifolia

“…Allelopathy research on wetland ecosystems may be less common than in terrestrial ecosystems because of an assumption that allelochemicals would be diluted and less effective in an aqueous environment (Ervin and Wetzel 2003). However, allelopathy has been extensively documented in agriculturally managed wetlands demonstrating that allelochemicals can reach phytotoxic levels in an aqueous environment (Fageria and Baligar 2003;Olofsdotter et al 2002). For example, Oryza sativa L. (rice) has been found to be allelopathic, and breeding efforts are underway to produce O. sativa varieties with enhanced allelopathic effects against common agricultural weeds (Olofsdotter et al 2002).…”

Correlação entre produtividade do arroz no sistema semeadura direta e atributos do solo

“…Quando o arroz de terras altas é cultivado por dois ou mais anos na mesma área, ocorre queda acentuada da sua produtividade em relação ao primeiro cultivo (2.266 kg ha -1 ), o que tem sido atribuído a efeitos alelopáticos (Fageria & Baligar, 2003).…”

“…Ao longo do tempo essas alterações podem representar a perda da qualidade do solo. Além disto, é possível que o acúmulo de exsudatos liberados pelas plantas de arroz com os cultivos sucessivos também altere a comunidade microbiana (Fageria & Baligar, 2003). Outra provável causa de perturbação da microbiota é a redução da porosidade de aeração com o aumento da microporosidade em detrimento da macroporosidade uma vez que a correlação entre qCO 2 e a microporosidade foi significativa e positiva (r = 0,52; p < 0,01).…”