Exploring the use of residues from the invasive Acacia sp. for weed control

Abstract

A sustainable practice for weed control and crop protection is the incorporation of green manures with phytotoxic potential. It is gaining attention as a way to reduce the use of synthetic herbicides in agriculture and so pot experiments and field trials were conducted to explore the possible use of residues of Acacia species to alleviate weed emergence. We assessed, under greenhouse conditions, the herbicidal effect of phytotoxic manures from Acacia dealbata and Acacia longifolia applied to soil at different doses (1.5 and 3% w/w) on maize growth, some accompanying weeds, and the physiological profile of soil microbes. Applied at a higher dose, A. dealbata residues reduced the emergence of dicotyledons in the short-term (P < 0.05) and, after 30 days, there was a decrease in total weed emergence (P < 0.005) and a mild effect on weed composition, while total weed biomass remained unaffected. Regardless of the inclusion of Acacia residues, the physiological profile of the soil bacterial community did not show significant alterations. Additionally, we tested A. dealbata residues as a mulch or a green manure at the field scale. Although the effects of manures were site-dependent and affected monocot and dicot weeds differentially, dicots were more sensitive. The herbicide potential of acacia residues was only evident for dicots at sites with low-weed density in the seed bank. Nevertheless, due to the absence of phytotoxic effects on maize and minor modifications in the functional profile of bacterial communities, residues of acacia could be used as a complementary tool used together with other practices to reduce the reliance on synthetic herbicides in maize-based cropping systems.

On the bioherbicide potential of Ulex europaeus and Cytisus scoparius: Profiles of volatile organic compounds and their phytotoxic effects

“…The equivalent biomass quantity on a dry mass basis, composed of only flowers or flowering green branches, was able to produce similar phytotoxic effects, thus pointing out the potential of both species to produce and emit bioactive VOCs from the total aerial biomass. These results extend the interest of both shrub species as sources of natural products with bioherbicide potential, or to be used as bioherbicide green manures, as has been proposed for other allelopathic biomass-rich invasive species [ 36 , 37 ].…”

“…However, they continue to be a largely untapped source of active compounds for potential use in agricultural fields. Interestingly, very recent approaches have proposed the use of allelopathic biomass from forest residues or invasive tree species as bioherbicide green manures [ 36 , 37 ]. Allelopathic biomass incorporated into the soil can release genuine ‘cocktails’ of allelochemicals that could control the germination and growth of different weed species.…”

The Phytotoxic Potential of the Flowering Foliage of Gorse (Ulex europaeus) and Scotch Broom (Cytisus scoparius), as Pre-Emergent Weed Control in Maize in a Glasshouse Pot Experiment

“…Puig et al [14,15] have shown that the incorporation of Eucalyptus globulus leaves as a soil amendment inhibited the emergence of some common weeds of the maize, and notably reduced weed biomass throughout the whole growing period. Souza-Alonso et al [16], using residues from Acacia dealbata and A. longifolia incorporated into the soil, have observed some negative effects on dicotyledon weeds. These practices sum up the recycling of waste material from the agroecosystem, that is, allelopathic forest residues and invasive species, and their use in eco-friendly practices for plant protection.…”

Influence of Acacia dealbata Link bark extracts on the growth of Allium cepa L. plants under high salinity conditions

“…Plant extracts, mulches, or green manures obtained from allelopathic/phytotoxic plant material could be used as a source of natural herbicides in agriculture . The potential herbicidal effect of green manures and mulches based on A. dealbata waste material has been recently assessed on accompanying weeds in maize crops . Despite not being as inhibitory as suspected, Acacia waste was useful in controling dicotyledonous weeds in modestly weed‐infested soils .…”

“…[29][30][31] The potential herbicidal effect of green manures and mulches based on A. dealbata waste material has been recently assessed on accompanying weeds in maize crops. 32 Despite not being as inhibitory as suspected, Acacia waste was useful in controling dicotyledonous weeds in modestly weed-infested soils. 32 On the other hand, methanol-soluble compounds extracted from A. dealbata bark improved the growth of Lactuca sativa under no-stress conditions, 28 suggesting a potential biostimulating effect.…”