Weed suppression by green manure in an agroecological system

Abstract

Green manure promotes efficient suppression of weeds, but green manure species can exhibit distinct behaviors, depending on the environmental conditions. This study aimed to evaluate the potential of soil mulching and weed suppression by spring/summer green manure species grown in the spring/summer season, at different growth stages and after management (cut), for 90 days during the cassava crop cycle. The study was carried out in the 2010/2011 season, in a system managed under agroecological principles. The treatments consisted of different green manure species and arrangements: Crotalaria juncea, Cajanus cajan, Canavalia brasiliensis, Canavalia ensiformis, Pennisetum americanum, Crotalaria juncea and Pennisetum americanum intercropped; Mucuna aterrima, Sorghum bicolor, a mixture of all the green manures in study and a control plot under fallow. The experiment was arranged in a randomized block design with four replications. The evaluations of the soil cover either by the green manures or weeds were performed at 45, 90 and 105 days after the emergence of the green manures. The cassava crop was planted under reduced tillage system at 11 days after the cut of the green manures. The percentage of soil covered by weeds and the dry matter produced were evaluated at 30, 60 and 90 days after planting. The results showed that the green manures had a suppressive effect on weeds during their life cycle, as well as during the first months after its management (cut), composing the mulch.

2019

“…The jack bean plants increased the soil cover from 8% at 84 DAE of maize to 61.63% at 144 DAE of maize, verifying that its daily coverage ratio was 0.77. This confirms the potential for a faster growth rate of the jack beans after the initial period of establishment, in agreement to the results obtained by Favero et al (2001), Padovan et al (2011) and Recalde et al (2015). The Brazilian jack-beans and lablab-bean presented a final rate ground cover 30% (Fig.…”

“…1). This greater ground cover speed of black mucuna observed, corroborating the results obtained by Recalde et al (2015) where it completely covered the ground, reducing the weeds cover up to 343%, in comparison with control. The black mucuna adapted well to the consortium with maize, even sown after the corn Table 1.…”

“…However, the cover crops compete with the main crop, on intercropped system, at different scales, depending on the humidity, air, light, and nutrients available. One of the legume cover crops species that has been highlighted on the consortiums, due to its soil cover rate speed, is the black mucuna, which can fully cover the soil after only 60 DAS (Favero, 2001;Recalde et al, 2015). Some authors had suggested the jack beans, in addition to the increase in grain yields effect, cover the soil efficiently (Padovan et al, 2011;.…”

Períodos De Interferência De Plantas Daninhas No Cultivo De Sorgo Granífero, Com E Sem Adubação Nitrogenada De Cobertura

“…Embora o sorgo proporcione boa supressão de plantas daninhas (Recalde et al, 2015;Borges et al, 2014;Khaliq et al, 2011), o que em parte pode ser atribuída ao seu efeito alelopático (Franco et al, 2011), o seu desenvolvimento e a sua produção também estão sujeitos aos efeitos de fatores bióticos como doenças, pragas, nematoides e plantas daninhas (Rodrigues et al, 2010) e aos fatores abióticos como nutrição mineral, clima e disponibilidade de água (Peiter & Carlesso, 1996). Dentre os fatores bióticos a interferência de plantas daninhas responde por uma grande parcela na perda da produtividade de grãos (Cabral et al, 2013), uma vez que as mesmas atuam diretamente na competição por luz, água e nutrientes, além de poderem exercer efeito alelopático (Pitelli, 1985).…”

Alternativas para restauração florestal de pastagens

“…De forma similar ao que ocorre naturalmente no processo sucessional em campo, essas plantas podem auxiliar no controle de gramíneas ao crescerem rapidamente em altura e diâmetro de copa, sombreando as áreas adjacentes; melhorar o microclima local tipicamente estressante para indivíduos introduzidos ou regenerantes; servir como pontos de abrigo e descanso para a fauna e atrair dispersores caso produzam frutos carnosos; e até protegerem os indivíduos arbustivos-arbóreos de interesse na restauração contra geadas severas RORATO et al, 2017). Alguns estudos exploraram o uso de espécies leguminosas que, de forma adicional, desempenham a função de adubação verde atuando também como fixadoras de nitrogênio e melhorando a fertilidade do solo (GUERRA et al, 2007;BELTRAME;RODRIGUES, 2008;TEODORO et al, 2011;TIMOSSI et al, 2011;CASTRO, 2013;ISERNHAGEN et al, 2014;RECALDE et al, 2015). Outros utilizam espécies agrícolas que podem proporcionar algum retorno financeiro durante o processo de restauração, especialmente para pequenos e médios proprietários SILVA et al, 2015;.…”