The agronomic value of annual plant diversity in crop-weed systems

Abstract

. The agronomic value of annual plant diversity in crop-weed systems. Can. J. Plant Sci. 86: 865-874. Enhanced crop or cultivar diversity within annual cropping systems could provide important ecological and agronomic benefits. The agronomic effects of annual plant diversity from mixtures of crop species and barley (Hordeum vulgare L.) cultivar types were compared using richness levels of 1, 2, 5 or 10 randomly selected taxa in a greenhouse experiment. Increasing crop richness increased overall crop dry matter production, production stability (i.e., decreased CV for dry matter production) and weed suppression. These agronomic variables tended to level off after a richness of five to six crop species, suggesting that further increases in crop diversity are redundant. Increasing barley cultivar richness increased crop production in one of two experimental runs, but no effects were observed for weed suppression. Increased light interception related to greater plant canopy height variation in diverse mixtures of species could have contributed to increased productivity in the crop richness experiment. The results of this study suggest that the ecological functions of diversity provide productivity, yield stability and weed suppression benefits for mixtures of crop species, and even perhaps for mixtures of cultivars within a given crop species. ) en comparant leur degré de diversité (1, 2, 5 ou 10 taxons sélectionnés au hasard). Une meilleure diversité accroît la production globale de matière sèche par la culture, stabilise la production (à savoir, diminue le coefficient de variation de la production de matière sèche) et supprime les mauvaises herbes. Ces variables agronomiques ont tendance à atteindre un plateau lorsqu'on arrive à cinq ou six espèces, signe qu'il serait redondant d'augmenter la diversité davantage. La multiplication des cultivars d'orge a relevé la production végétale lors d'un essai sur deux, mais les auteurs n'ont rien noté au niveau de la suppression des mauvaises herbes. La hauteur plus variable du feuillage dans les mélanges d'espèces entraîne une plus forte interception de la lumière, ce qui pourrait expliquer la productivité supérieure observée lors de l'expérience. Les résultats de l'étude laissent croire que, sur le plan écologique, la diversité est bénéfique à la productivité, à la stabilité du rendement et à la lutte contre les adventices dans les mélanges d'espèces cultivées voire de cultivars d'une même espèce.

Advancing Intercropping Research and Practices in Industrialized Agricultural Landscapes

“…While crop diversity affects ecosystem function in agricultural landscapes, the degree of crop diversity necessary for maintaining select ecosystem services remains undetermined [88]. Theoretically, an optimum point exists when ecosystem services are maximized and management complexity is minimized (Figure 9).…”

“…The management complexity is compounded when intercropping is integrated within a crop rotation, a more common practice for crop diversification in industrialized agricultural landscapes. While crop diversity affects ecosystem function in agricultural landscapes, the degree of crop diversity necessary for maintaining select ecosystem services remains undetermined [88]. Theoretically, an optimum point exists when ecosystem services are maximized and management complexity is minimized (Figure 9).…”

Sown Diversity Effects on Yield and Resistance to Weed Invasion: Clues to Improve Mixture Design Under Climatic Change in the Mediterranean

“…Increasing the diversity of agroecosystems may be a tool to respond to these challenges (Brooker et al, 2015;Haughey et al, 2018). Diverse grassland systems have resulted in enhanced yield (Finn et al, 2013;Hooper et al, 2005;Tilman et al, 2002Tilman et al, , 2014, lower fertilizer (Nyfeler et al, 2009;Suter et al, 2021;Weisser et al, 2017) and agrochemical needs linked to reduced incidence of weeds, pests and diseases (Connolly et al, 2018;Van Ruijven et al, 2003), and reduced environmental impact, including reduced nitrogen (N) losses through leaching (Hauggaard-Nielsen et al, 2003;Szumigalski and Van Acker, 2006) and emissions (Cummins et al, 2021;Pappa et al, 2011;Ribas et al, 2015). Diversity may also be an important adaptation strategy against climatic risks in an uncertain future, through enhanced resistance and resilience (Altieri et al, 2015;Isbell et al, 2015;Lüscher et al, 2022;Volaire et al, 2014), after extreme climatic events (Grant et al, 2014;Haughey et al, 2018;Sunil et al, 2020) or under sub-optimal environmental growing conditions (Porqueddu et al, 2016;Psyllos et al, 2022).…”

Can rice genetic diversity reduce Echinochloa crus‐galli infestation?

“…, 2007). Thus, interest in alternative methods to control E. crus‐galli increased recently (Itoh, 2005; Szumigalski & Van Acker, 2006; de Vida et al. , 2006; Han et al.…”