Potencial alelopático de extratos aquosos foliares de aveia sobre azevém e amendoim-bravo Effect of extracts from the above-ground part of oat genotypes on ryegrass and wild poinsettia

O trabalho teve por objetivo avaliar o efeito alelopático de extratos aquosos de cinco cultivares de aveia branca (Avena sativa L.) e quatro de aveia preta (Avena strigosa Schreb), nas concentrações de 0, 25%, 50% e 100%, sobre a germinação e o desenvolvimento das plântulas de azevém (Lolium multiflorum Lam.) e amendoim-bravo (Euphorbia heterophylla L.). O delineamento utilizado foi o inteiramente casualizado distribuído em um trifatorial (genótipos de aveia x plantas infestantes x concentrações do extrato). Utilizaram-se placas de Petri contendo 25 sementes de plantas infestantes que foram umedecidas com extrato da parte aérea dos genótipos de aveia. As variáveis observadas foram: percentual de germinação, comprimento de radícula e de hipocótilo, avaliados aos 14 dias após a instalação do experimento. Os extratos aquosos das cultivares de aveia branca e preta inibiram o potencial alelopático sobre a germinação e o desenvolvimento das plantas daninhas testadas, e os genótipos de aveia branca 'IPR 126', 'UTF Iguaçu' e 'Fundacep FAPA 43' e de aveia preta 'UPFA 21 Moreninha' e 'UTG 9715' foram mais efetivos na inibição da germinação e no desenvolvimento do azevém e amendoim-bravo.<br>The objective of this study was to evaluate the allelopathic effect of aqueous extracts from five common oat (Avena sativa L.) and four black oat (Avena strigosa Schreb) cultivars, at concentrations of 0, 25, 50, and 100%, on the germination and development of ryegrass (Lolium multiflorum Lam.) and wild poinsettia (Euphorbia heterophylla L.) plantlets. A completely randomized design was adopted, distributed as a triple factorial arrangement (oat genotypes × weeds × concentrations). The experiment consisted of Petri dishes containing 25 weed seeds moistened with extract from the above-ground part of the oat genotypes. The following variables were observed: germination percentage, radicle length, and hypocotyl length, evaluated at 14 days after the experiment was installed. The aqueous extracts from common oat and black oat cultivars showed allelopathic potential on the germination and development of the weeds tested. Common oat genotypes 'IPR 126', 'UTF Iguaçu', and 'Fundacep FAPA 43', and black oat genotypes 'UPFA 21 Moreninha' and 'UTG 9715' were the most effective to inhibit ryegrass and wild poinsettia germination and development

Incorporating Beliefs and Experiences into Choice Experiment Analysis: Implications for Policy Recommendations

We show that respondents\u27 beliefs about future outcomes and prior recreational experiences affect policy recommendations from choice experiments. For New England residents, we find that willingness to pay for a new national park in Maine differs based on respondents\u27 stated beliefs about the status quo long-term land use. We also find that respondents who do (do not) hunt or snowmobile would pay significantly more (less) for a park allowing these activities. Land managers may find a two-park solution (one allowing the activities and one prohibiting them) would be best; this insight would be missed when neglecting to model conflicting recreational preferences