Allelopathic potential of oil seed crops in production of crops: a review

Soil fertility management on sesame (Sesamum indicum L.) production in Northern Ethiopia: A review

Sesame (Sesamum indicum L.) is an important cash crop and plays a vital role in many people's livelihoods in Ethiopia. However, its production is low due to many constraints, and low soil fertility is among the major. The previous fertilizer recommendation was a blanket recommendation regardless of the soil fertility status. Hence, the objective of this review is to synthesize the different recommendations and forward to the sesame growing areas. R statistical software and Python programming language used to analyze the chemical and physical soil properties, association among the chemical and physical soil properties and association with soil depth. The organic carbon, total N (Nitrogen), available P (Phosphorus), S (Sulfur) and Zn (Zinc) are below optimum value while K is sufficient in the soil and moderately alkaline soil. The soil particle size is dominantly clay (58.5 %). The clay particle size and pH increased while the sand and silt particle sizes, organic carbon, total N, available P and S decreased as the soil depth increased. 204,558.8 ton of sesame stack residue are burned every year, and from this, 7360.03 ton of NPK is lost every year in Western Tigray. The recommended N, P and S for sesame are: (i) 64 and 41 kg ha -1 N for low N content areas and for medium N content areas respectively; 46 and 23 kg ha -1 P2O5 for low and medium P content areas; (iii) 60 and 30 kg ha -1 S for low medium S content areas may be recommended to boost sesame production.

A Scientometric Analysis of Worldwide Intercropping Research Based on Web of Science Database between 1992 and 2020

Intercropping has been practiced worldwide in both traditional and sustainable agriculture to feed the growing population. This study aims to analyze the research status and evolution of intercropping, to identify the influential authors, research centers, and articles, and to reveal the main research topics between 1992 and 2020 based on the Web of Science Core Collection database. The results show that the volume of publications in this field has increased rapidly over the past three decades. The analysis identifies the top three authors (i.e., Meine Van Noordwijk, Wenyu Yang, and Teja Tscharntke), top three contributing organizations (i.e., the World Agroforestry Center (ICRAF), the Chinese Academy of Science, and the INRA), and three most productive countries (i.e., the USA, India, and China). Co-occurrence analysis demonstrates that studies on intercropping can be divided into four clusters as centered by keywords of intercropping/maize, biodiversity/conservation, agroforestry, and carbon, respectively. Lal 2004 is the most influential study with the greatest number of citations and Agroforestry Systems is the most utilized journal. Perspectives on future studies were also given. This study helps researchers to clarify the current research status in the field of intercropping and put forward its future research.

Sustainable Weed Control and Enhancing Nutrient Use Efficiency in Crops through Brassica (Brassica compestris L.) Allelopathy

Weed–crop competition and reduced soil fertility are some of the main reasons for decreased crop yields in Pakistan. Allelopathy can be applied to combat the problems of environmental degradation by reducing pesticide use and through reduction of herbicide-resistant weeds. A two-year field experiment (2014–2015) was conducted to assess the impact of incorporation of various levels of brassica residues and brassica water extract on the growth of mung bean and soil attributes. Two brassica water extract levels (10, 20 L/ha) and two residue levels (4, 6 t/ha) were tested, and a treatment with no water extract and residue incorporation was used as the control. The results showed that the water extract and residue incorporation had diverse impacts on soil fertility indices and weed dynamics, where treatment with 6 t/ha had more significant impacts. Compared with the control, reductions of 61% in dry weight of weeds and 52% in weed density were observed. After cropping, improved soil properties in terms of available potassium, available phosphorus, soil organic matter, and total nitrogen were higher in the rhizosphere (0–15 cm) soil after the treatments of residue incorporation, i.e., 59–91%, 62–84%, 29–45%, and 52–65% higher than the control, respectively. Meanwhile, alkaline phosphatase and dehydrogenase concentrations in the rhizosphere soil were 26–41% and 52–74% higher than with the control, respectively. The highest economic return with a high benefit–cost ratio was recorded with residue incorporation. In conclusion, addition of crop residues at 6 t/ha was the most effective and economical treatment with the highest net benefit rate of returns. This approach can provide a potential alternative for implementing sustainable weed control in mung bean with significant improvement in soil properties and can be a part of sustainable and eco-friendly agriculture.

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

The phytotoxic potential of the legume shrubs Ulex europaeus L. (gorse) and Cytisus scoparius (L.) Link. (Scotch broom) is studied in this work for the first time. On the basis of their richness in active principles, the previous evidence of biological activity, and the abundance of biomass in their native range and invaded areas, a question arose: can U. europaeus and C. scoparius be considered as potential sources of natural herbicides for sustainable agriculture? By means of volatile bioassays, the flowering fresh plant material of both shrub species was shown to produce and emit volatile organic compounds (VOCs) able to inhibit the germination and/or early growth of two agricultural weeds: Amaranthus retroflexus and Digitaria sanguinalis. Novel complete VOCs profiles from the volatile extracts of the shrub species were obtained by GC and GC/MS. A total of 20 compounds were identified from U. europaeus flowering biomass, theaspirane and eugenol, among others, being described in gorse for the first instance. The chemical profile of C. scoparius yielded 28 compounds and was rich in oxygenated monoterpenes such as terpinen-4-ol, verbenol, α-terpineol, and verbenone, which were also identified in this species for the first time. Using dose-response bioassays with pure compounds, these VOCs were argued to be involved in the phytotoxicity observed for the plant materials, even at very low concentrations. The phytotoxic effects were predominantly irreversible, particularly for D. sanguinalis, since the seeds exposed to the VOCs produced damaged seedlings, were unable to recover germination capacity after removing the phytotoxin or, when recovered, produced unviable seedlings. Our results extend the interest of the abundant U. europaeus and C. scoparius for the obtention of natural products with bioherbicide potential, or to be used as allelopathic biomass in the development of new sustainable agricultural practices.

Biorational substitution of piperonyl butoxide in organic production: effectiveness of vegetable oils as synergists for pyrethrums

Piperonyl butoxide is a semi-synthetic synergist for natural pyrethrum and synthetic pyrethroid insecticides in phytochemicals and biocides. As such it is used in large quantities for crop treatments, stored grain protection, disinfestation of grain storage facilities and indoor uses. Piperonyl butoxide is consequently a regular contaminant in stored grains, and subsequently in corresponding cereal food products and meat via feed uses. Therefore it is regularly monitored and its MRL is ongoing a reassessment. It is also considered as a possible human carcinogen and a suspected endocrine disruptor. For all these reasons and considerations most of the countries have already banned its use in Organic Farming as France in 2017. Thus, ecological substitution of with biorational and sustainable solutions is required. Vegetable oils have been described as exhibiting similar potency and synergistic effects. We have reviewed the literature and have proceeded to ecotoxicological efficacy tests in order to determine the best and most durable substitution candidates. Sesame and rape seed oil were determined to be the most efficient.

Primary Structure Analysis of Antifungal Peptides from Cultivated and Wild Cereals

Cereal-derived bioactive peptides with antimicrobial activity have been poorly explored compared to those from dicotyledonous plants. Furthermore, there are a few reports addressing the structural differences between antimicrobial peptides (AMPs) from cultivated and wild cereals, which may shed light on significant varieties in the range and level of their antimicrobial activity. We performed a primary structure analysis of some antimicrobial peptides from wild and cultivated cereals to find out the features that are associated with the much higher antimicrobial resistance characteristic of wild plants. In this review, we identified and analyzed the main parameters determining significant antifungal activity. They relate to a high variability level in the sequences of C-terminal fragments and a high content of hydrophobic amino acid residues in the biologically active defensins in wild cereals, in contrast to AMPs from cultivated forms that usually exhibit weak, if any, activity. We analyzed the similarity of various physicochemical parameters between thionins and defensins. The presence of a high divergence on a fixed part of any polypeptide that is close to defensins could be a determining factor. For all of the currently known hevein-like peptides of cereals, we can say that the determining factor in this regard is the structure of the chitin-binding domain, and in particular, amino acid residues that are not directly involved in intermolecular interaction with chitin. The analysis of amino acid sequences of alpha-hairpinins (hairpin-like peptides) demonstrated much higher antifungal activity and more specificity of the peptides from wild cereals compared with those from wheat and corn, which may be associated with the presence of a mini cluster of positively charged amino acid residues. In addition, at least one hydrophobic residue may be responsible for binding to the components of fungal cell membranes.

An Overview of Biotransformation and Toxicity of Diterpenes

Diterpenes have been identified as active compounds in several medicinal plants showing remarkable biological activities, and some isolated diterpenes are produced at commercial scale to be used as medicines, food additives, in the synthesis of fragrances, or in agriculture. There is great interest in developing methods to obtain derivatives of these compounds, and biotransformation processes are interesting tools for the structural modification of natural products with complex chemical structures. Biotransformation processes also have a crucial role in drug development and/or optimization. The understanding of the metabolic pathways for both phase I and II biotransformation of new drug candidates is mandatory for toxicity and efficacy evaluation and part of preclinical studies. This review presents an overview of biotransformation processes of diterpenes carried out by microorganisms, plant cell cultures, animal and human liver microsomes, and rats, chickens, and swine in vivo and highlights the main enzymatic reactions involved in these processes and the role of diterpenes that may be effectively exploited by other fields.