Fate of allelochemicals in the soil

Abstract

Allelochemicals are compounds released by one plant or plant residues that may have a negative or positive effect on other plant. The importance of allelopathy was extensively explored during the past three decades, with the work concentrating in the extraction and identification of the chemicals, and demonstration of activity in petry dish experiments. These compounds interact in the soil environment similarly as herbicides and are subject to processes of degradation such as microbial degradation, oxidation, and photolysis, and processes of removal or transfer, such as volatilization and adsorption. The objective of this review was to access the fate of allelochemicals in the soil environment to help to find strategies to increase its activity. The activity of allelochemical is limited in time (because of slow release from the donor material) and in space (because of the interaction with the environment). Demonstration of allelopathy should include the fate of the proposed chemical in the soil environment, presenting studies of degradation and removal processes.

Allelopathic Effects of Sunflower Residue on Growth of Rice and Sbsequent Wheat Crop

“…The negative effect of the RI on root and shoot growth as well as grain yield of the two wheat varieties was not as much pronounced as was in case of the two rice varieties. It could be due to degradation of allelochemicals in the soil by physical, chemical, and microbial processes (Katase, 1981;Hess et al, 1992;Vidal and Bauman, 1992). However, in treatments where RI+NPK was applied in previous rice crop, the response of the two wheat varieties was different.…”

Allelopathy, an alternative tool to improve cropping systems. A review

“…Drought, irradiation, temperature, nutrient limitation, competitors, disease and damage from insects have been pointed out as factors that can cause an increased release of allelochemicals from allelopathic plants (Fig. 2) (Cseke and Kaufman, 2006;Einhellig, 1996;Vidal and Bauman, 1997).…”

“…Processes such as those mentioned above are responsible for the addition of allelochemicals to the system, for which the amount added depends on donor plant biomass and density, and phenologic stage as well as the concentration and solubility of specific allelochemicals (Seigler, 1996;Weidenhamer, 1996). On the other hand, leaching, physiochemical processes, microbial breakdown and uptake by plants are factors that can reduce the soil concentration of allelochemicals (Inderjit, 2001;Inderjit et al, 2001;Vidal and Bauman, 1997) (Fig. 3).…”

Efeitos do manejo mecânico e químico da aveia-preta no milho em sucessão e no controle do capim-papuã

“…Jacobi & Fleck (1998), ao avaliarem o efeito alelopático de resíduos culturais de genótipos de aveia sobre soja e capim-papuã, em laboratório, constataram potencial alelopático em diversos genótipos de aveia. No entanto, para que ocorra ação alelopática é necessário que as fitotoxinas sejam produzidas e liberadas em quantidades suficientes para atingir a concentração letal (Vidal & Bauman, 1997). A concentração de aleloquímicos no solo depende do tipo e da taxa de decomposição do resíduo cultural e de outros fatores como atividade microbiana, temperatura do solo e precipitação pluvial (Roman & Velloso, 1993).…”