Biomass from Allelopathic Agroforestry and Invasive Plant Species as Soil Amendments for Weed Control—A Review

Abstract

Effective weed management faces increasing legislative restrictions for the use of herbicides due to their toxicity and environmental persistence. In addition, the linear increase in resistant weeds threatens to render authorized herbicides useless. In a post-herbicide era, under the IWM strategy, allelopathy can play a relevant role since many plants can produce a variety of allelochemicals with different structures and modes of action, capable of inhibiting the germination and growth of different weed species. Inspired by green manuring with cover crops, the use of allelopathic biomass from weeds, invasive species, residues of forestry plantations, and other abundant wild plants has some advantages over green manures grown in situ or other alternatives such as applying plant extracts or essential oils. Beyond the ecosystem services provided by green manures, the potential use of allelopathic biomass offers extra opportunities for the science and practice of holistically integrated weed management because (i) the investment of resources and time for producing cover crops would be alleviated, and (ii), new use of agroforestry residues and a sink for harmful weed biomass is provided. In this review, we compile the current knowledge of those allelopathic species whose biomass, used as soil amendment, effectively controlled weeds. In addition, the complex allelopathic processes underlying the effectiveness of cover crops and allelopathic biomass used as green manures for weed control are revisited.

Climate Change Challenges in Temperate and Sub-Tropical Fruit Tree Cultivation

“…actinidiae (Psa) have caused significant economic losses, and several climatic models have been tested to evaluate the risk of global expansion in kiwifruit-growing areas [75]. Apart from pests and diseases, invasive plant species have also arisen as a problem for the agricultural sector [76][77][78][79]. One of the most pronounced is the tree of heaven (Ailanthus altissima (Mill.)…”

“…One of the most pronounced is the tree of heaven (Ailanthus altissima (Mill.) Swingle) [76] (Figure 5), an invasive tree species with rapid growth, tolerant to many abiotic stress factors, and with a high degree of allelopathy due to the production and into-the-soil exudation of the toxic compound ailanthone [78] (Figure 6).…”

Application of Allelopathy in Sustainable Agriculture

“…Plant-based weed management approaches are considered crucial in the new IWM [4,12], including allelopathic cover crops, the less explored biomass from allelopathic agroforestry, and invasive species used as soil amendments for weed control [13], which is introduced in the present SI as a strategy for a circular economy. From a holistic point of view, plant-based weed management complies in different ways with the do no signifi-cant harm (DNSH) principle, by providing different benefits and services to the agroecosystems.…”