Cover crops (CCs) are a promising and sustainable agronomic practice to ameliorate soil health and crop performances. However, the complex of relationships between CCs, the soil, and the plant nutritional status has been little investigated. In this article, for the first time, we critically review, under a holistic approach, the reciprocal relationships between CCs and the soil physical and hydraulic properties, microbial, and faunal communities, soil nutrient availability, and plant nutritional status in temperate climates. For each of these topics, we report the current state of understanding, the influence of CC management options and suggested strategies, thus including both fundamental and applied aspects. In addition, we provide a detailed focus on the history of CCs and a list of the main temperate CCs. Cover cropping is a helpful practice in improving the physical, chemical, and biological soil properties, optimizing nutrient use efficiency and reducing the dependency of crops on external supplies of nutrients. The interactions between CCs and the nutritional status of soil and plants are complex and dynamic. Their understanding could be useful to set up an appropriate and site-specific management of fertilization. Management options play a key role in developing an effective and context-specific cover cropping.

In the face of yield losses caused by weeds, especially in low-input agricultural systems, and environmental pollution due to the excessive use of synthetic herbicides, sustainable weed management has become mandatory. To address these issues, allelopathy, i.e., the biochemical phenomenon of chemical interactions between plants through the release of secondary metabolites into the environment, is gaining popularity. Although many important crops are known for their allelopathic potential, farmers are still reluctant to use such knowledge practically. It is therefore important to assist advisors and farmers in assessing whether allelopathy can be effectively implemented into an eco-friendly weed management strategy. Here, we aim to give a comprehensive and updated review on the herbicidal potential of allelopathy. The major findings are the following: (1) Crops from different botanical families show allelopathic properties and can be cultivated alone or in combination with other non-allelopathic crops. (2) Many allelopathic tools can be adopted (crop rotation, intercropping, cover cropping as living or dead mulches, green manuring, use of allelochemical-based bioherbicides). (3) These methods are highly flexible and feature increased efficiency when combined into an integrated weed management strategy. (4) Recent advances in the chemistry of allelopathy are facilitating the use of allelochemicals for bioherbicide production. (5) Several biotechnologies, such as stress induction and genetic engineering techniques, can enhance the allelopathic potential of crops or introduce allelopathic traits de novo. This review shows how important the role of allelopathy for sustainable weed management is and, at the same time, indicates the need for field experiments, mainly under an integrated approach. Finally, we recommend the combination of transgenic allelopathy with the aforementioned allelopathic tools to increase the weed-suppressive efficacy of allelopathy.

Current awareness about the environmental impact of intensive agriculture, mainly pesticides and herbicides, has driven the research community and the government institutions to program and develop new eco-friendly agronomic practices for pest control. In this scenario, integrated pest management and integrated weed management (IWM) have become mandatory. Weeds are commonly recognized as the most important biotic factor affecting crop production, especially in organic farming and low-input agriculture. In herbaceous field crops, comprising a wide diversity of plant species playing a significant economic importance, a compendium of the specific IWM systems is missing, that, on the contrary, have been developed for single species. The main goal of this review is to fill such gap by discussing the general principles and basic aspects of IWM to develop the most appropriate strategy for herbaceous field crops. In particular, a 4-step approach is proposed: (i) prevention, based on the management of the soil seedbank and the improvement of the crop competitiveness against weeds, (ii) weed mapping, aiming at knowing the biological and ecological characteristics of weeds present in the field, (iii) the decision-making process on the basis of the critical period of weed control and weed thresholds and iv) direct control (mechanical, physical, biological and chemical). Moreover, the last paragraph discusses and suggests possible integrations of allelopathic mechanisms in IWM systems.