Allelopathic Effects of Different Plant Water Extracts on Yield and Weeds of Wheat

Abstract

Use of synthetic herbicides to control weeds poses serious threats to sustainable agricultural production around the globe. The phytotoxic effect of different plant water extracts (i.e., sorghum, sunflower and mulberry) against weeds has been previously studied; however, their combined effects at different rates are yet to be explored. In this study, mixtures of allelopathic water extracts of sorghum + sunflower and sorghum + sunflower + mulberry were sprayed each at 12, 15, 18 and 21 L ha-1 at 40 and 55 days after sowing in wheat to control wild oats (Avena fatua), little seed canary grass (Phalaris minor), lamb’s quarters (Chenopodium album) and swine cress (Coronopus didymus). A synthetic herbicide Affinity 50 WP (Carfentrazone-ethyl 0.75% + Isoproturon 50% applied at 1000 g a.i., ha-1) and a weedy check were kept as a control treatment. The increasing order of water extract dose 12-21 L ha-1 showed substantial reduction in total weed density and their dry biomass production of both narrow and broad-leaved weeds in all the treatment combinations. Mixture of sorghum + sunflower + mulberry water extracts each at 18 L ha-1 applied at 40+55 DAS resulted in an 87.14% decrease in total weed dry matter with a 19.5% increase in grain yield of wheat and higher net benefits of Rs. 100525 with 777.5% marginal rate of return. Nonetheless, application of sorghum + sunflower water extracts each at 12 L ha-1 at 40+55 DAS was more economical than the other treatments in terms of higher marginal rate of return of 799.82%. Based on this study, it can be suggested that the use of allelopathic plant water extracts in a mixture may act as a potential weed control strategy in wheat.

Phytotoxic Potential and Phenolic Profile of Extracts from Scrophularia striata

“…fresh biomass was reduced by 100 and 90%, respectively, as a result of the allelopathic effects of sorghum (15 L/ha) [ 94 ]. In another investigation, sunflower aqueous extract (100% concentration) reduced the total dry weight of weeds, including Avena fatua L., Phalaris minor Retz., C. album, and C. didimus [ 95 ].…”

Comparative Evaluation of the Allelopathic Effects of the Leaf Extracts of Three Asteraceae Species (Ageratum conyzoides, Vernonia amygdalina, Artemisia annua)

“…Herbicides are frequently utilised to enhance crop yield through effective weed control, but excessive and non judicious use of herbicides has posed environmental and health problem [10] Interestingly, some allelopathic crops have proven to be efficient in weed control with little or no environmental and health risk [12]. In this study, a comparative evaluation of the allelopathic effects of leaf extracts of A. conyzoides, V. amygdalina and A. annua on seedlings of Lactuca sativa was carried out on the following parameters; percentage germination, average root length, average height, mitotic index and mitotic inhibition after 28 days.…”

“…An allelopathic crop can potentially be used for weed control by planting a variety, either as a smother crop in a rotational sequence or when left as a residue or mulch, especially in low-till systems to control subsequent weed growth [9]. Concerns about chemicals in the environment, prohibitive cost and other limitations have threatened the sustainability of chemical weed control measures [10]. Hence, the allelopathic suppression of weeds which is natural, environmental friendly and cost effective may prove to be an amazing alternative for weed control [11].…”

Allelopathic properties of plant extracts as potential bioherbicides

“…Pove anje doze primene, zna ajno uti e na smanjenje ukupne gustine korova i proizvodnju njihove biomase u obe kombinacije, dok je tako e zabeležen pove an prinos pšenice za oko 20%. Na osnovu ove studije može se sugerisati da upotreba biljnih ekstrakata sa alelopatskim karakteristikama u mešavini može da se koristi kao potencijalna strategija za suzbijanja korova u pšenici (Naeem et al, 2018). Uticaj ekstrakta biljke Brassica nigra iz razli itih biljnih delova, lista, stabljike, cveta i korena ispitivani su na divlju zob, gdje je utvr eno da su alelohemikalije ispoljile uticaj na inhibiciju klijanja i porast klijanaca.…”