Growth and Accumulation of Nutrients by Weeds, in Maize and Legumes Intercrops

Abstract

The presence of weeds on fields is a concern for farmers, due to competition with the commercial crops, reducing yields. The intercropping of maize with legumes provides weed control; after senescence, the nutrients accumulated by plants are released, recycling nutrients. The study of plant species and their diversity is called phytosociology. This study aimed at evaluating the accumulation of dry phytomass by maize intercropped with legumes and weeds species, and at evaluating nutrient cycling and the phytosociology of weeds. The experiment consisted of maize intercropped with legumes cover crops: jack-beans, Brazilian jack-beans, velvet bean, lablab-beans, and pigeon pea, and the control treatment (maize without intercrop), all without chemical or mechanical weed control. Maize was sown in the plots, and legumes were sown 64 days after maize. Maize was harvested 120 days after sowing (DAS), and legumes at 144 DAS. Weeds were sampled at 84 and 144 DAS. It was possible to evaluate the accumulation of dry phytomass, the nutrient content of the intercrop components, and the phytosociology of weeds. The phytomass accumulation by maize was not affected by the intercrop with legumes. The intercrop with velvet bean accumulated higher dry phytomass and suppressed weeds. Jack beans accumulated dry mass, but did not suppress weeds. The intercropping system changed the diversity of weeds. Panicum maximum, Commelina nudiflora, Commelina benghalensis, Leonotis nepetaefolia and Melampodium divaricatum stood out by presenting higher values of phytosociological index and nutrient recycling.

Supressão de plantas espontâneas e produção de milho-verde consorciado com adubos verdes

“…Uma alternativa viável a este cenário pode ser o consorcio do milho-verde com adubos verdes que suprime as plantas espontâneas (NOLLA et al, 2018) pelo efeito de sombreamento e estresse de competição criado pelo dossel de um maior número de plantas cultivadas em uma unidade de área (NAHER et al 2019). Além disso, pode manter a fertilidade do solo pela fixação biológica do nitrogênio atmosférico (CHIEZA et al 2017;KUTAMAHUFA et al, 2022).…”

“…Em consórcio de milho e Crotalaria juncea, Chieza et al (2017) observaram fornecimento de nitrogênio à produção de grãos e benefícios ao sistema. Nolla et al (2018) verificaram supressão de plantas espontâneas de 34,5 a 60% pelos adubos verdes, Lablab purpureus, Canavalia brasiliensis e Mucuna aterrima consorciados com milho.…”

“…Aos 15 DAE verificou-se 12 espécies m-2 e aos 30 DAE, 9 espécies m-2. Os tratamentos com maiores quantidades de espécies foram milho com vegetação espontânea (MVE), C. spectabilis (MCS) e D.lablab (MDL) (Figura 1).A maior riqueza de espécies nos consórcios do milho-verde com C. spectabilis e D. lablab provavelmente decorreu do lento crescimento desses adubos verdes, pois o fechamento da copa do milho exerce controle cultural, restringindo a germinação de novas plantas espontâneas por meio do sombreamento(HELVIG et al, 2020).Kutamahufa et al (2023) observaram em milho consorciado com leguminosas que a cobertura do solo foi mais rápida e completa pela combinação de seus dosséis que reduziram a emergência e crescimento de plantas espontâneas mais eficazmente que em monocultivo.A elevada riqueza de espécies na testemunha mostrou que a ausência dos adubos verdes favoreceu o desenvolvimento das plantas espontâneas Nolla et al (2018). também evidenciaram na ausência das leguminosas aumentos da diversidade de plantas espontâneas.…”

Cover crops in pear (Pyrus communis) orchards: effects on soil nematode assemblage

“…The highest plant species richness and available P content in non-saline soil were associated with nematode assemblages´ trophic structure. Floristic diversity has a potential role in soil P input due to a differential accumulation of P in each plant (23), which contributes to an increasing this nutrient of limited mobility in the soil profile. In the present study, P was probably released by the decomposition of plant residues from vegetation that was mown over the summer.…”