scholarly journals Phytotoxic Substances Involved in Teak Allelopathy and Agroforestry

2021 ◽  
Vol 11 (8) ◽  
pp. 3314
Author(s):  
Hisashi Kato-Noguchi

Teak (Tectona grandis L.f.) is one of the most valuable timber species, and is cultivated in agroforestry systems in many countries across the tropical and subtropical regions of the world. The species is also one of the most essential trees in home gardens in South Asia due to its wood quality and medicinal value in folk remedies. It is a deciduous tree species, and the amount of litter that falls from teak trees is huge. The decomposition rate of the litter is relatively fast in tropical humid conditions. The interactions between teak and weeds, or crops, under the teak trees have been evaluated in terms of allelopathy. Evidence of allelopathy is documented in the literature over the decades. The leachate and extracts of teak leaves suppress the germination and growth of several other plant species. Phytotoxic substances, such as phenolics, benzofurans, quinones, terpens, apocarotenoids and phenylpropanoids, in the teak leaves, were isolated and identified. Some phytotoxic substances may be released into the soil under teak trees from leaf leachate and the decomposition of the litters, which accumulate by annual leaf fall and can affect the germination and growth of undergrowth plant species as allelopathic substances. The allelopathy of teak is potentially useful for weed management options in agroforestry and other agriculture systems to reduce commercial herbicide dependency. It was also reported that agroforestry systems with teak enhance income through the production of crops and woods, and provide energy efficiency for crop cultivation.

2021 ◽  
pp. 096703352199911
Author(s):  
SR Shukla ◽  
S Shashikala ◽  
M Sujatha

Near infrared (NIR) spectroscopy is developing as an advanced and non-invasive tool in the wood, wood products and forestry sectors. It may be applied as a rapid and cost effective technique for assessment of different wood quality parameters of timber species. In the present study, NIR spectra of heartwood samples of Tectona grandis (teak) were collected before measuring fibre morphological parameters (fibre length, fibre diameter and fibre lumen diameter)and main chemical constituents (cellulose, hemicellulose, lignin and extractives) using maceration and wet chemistry methods respectively. Multivariate partial least squares (PLS) regression was applied to develop the calibration models between measured values of wood parameters and NIR spectral data. Pre-processing of NIR spectra demonstrated better predictions based on higher values of correlation coefficient for estimation (R2), validation (Rcv 2 ), ratio of performance to deviation (RPD), and lower values of root mean square errors of estimation (RMSEE), cross-validation (RMSECV) and number of latent variable (rank). Internal cross-validation was used to find the optimum rank. Robust calibrations models with high R2 (>0.87), low errors and high RPD values (> 2.93) were observed from PLS analysis for fibre morphological parameters and main chemical constituents of teak. These linear models may be applied for rapid and cost effective estimation of different fibre parameters and chemical constituents in routine testing and evaluation procedures for teak.


2021 ◽  
Author(s):  
Razia Sultana ◽  
ASM Saifullah ◽  
Rahat Khan Khan ◽  
Mir Talas Mahammad Diganta

Abstract The litters in the forest floor are the principal contributor for regulating the cycling of necessary elements, primary productivity and maintain soil fertility within the forest ecosystems. Therefore, this study was conducted in a deciduous forest of Bangladesh to ascertain the leaf-litter production and decomposition along with elemental dynamics (K, Ca, Mn, Fe, Co and Zn). Leaf-litter samples from five deciduous plant species and soil samples were collected from the Madhupur Sal Forest for about six months (July-December) in 2018. Production of leaf-litter during the dry season (December) was found in an order of Shorea robusta>Dipterocarpus indicus>Terminalia bellirica>Tectona grandis>Grewia microcos. The decomposition rates were higher for the long sampling period (90 days) followed by the intermediate (60 days)> short(30 days) sampling period. The nutrient release pattern from the leaf-litter was similar (Ca>K>Mn>Fe>Zn>Co) for all plant species except for Terminalia bellirica and Tectona grandis. The Pearson correlation coefficients showed a significant relationship between K and Fe (r=0.54; p<0.05), Ca and Co (r=0.59; p<0.01), Fe and Co (r=0.97; p<0.05) in leaf-litters. Analysis of variance (ANOVA) revealed significant variation in the litter production, decomposition and nutrient content (except Zn; p>0.05) among the different plant species (p<0.05). There revealed a significant dynamic of necessary elements from soil to trees and vice-versa.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel K. N’Woueni ◽  
Orou G. Gaoue

AbstractThe conversion of natural systems into farms and agroecosystems is the main cause of biodiversity loss. In human-dominated landscapes, understanding the interactions between agroforestry systems and adjacent natural vegetation is fundamental to developing sustainable agricultural systems. Species can move between these two systems with natural systems providing the regional pool of species that shape the agricultural values and conservation value of the agroforestry systems. We investigated the influence of neighboring natural habitats on traditional agroforestry systems in the buffer zone of Pendjari Biosphere Reserve in Benin to understand the contribution of regional processes on the quality of agroforestry systems. We expected that agroforestry parklands adjacent to natural vegetation with high species diversity will also have higher plant species diversity. We found no similarity in plant species composition between agroforestry systems and adjacent natural habitats. A small proportion of species in adjacent natural habitats were found in agroforestry systems. The proportion of shared species was not significantly influenced by plant diversity in adjacent natural habitats or the distance from the agroforestry systems to the natural adjacent habitat. However, plant diversity in agroforestry systems was strongly associated with site ethnobotanical values indicating that farmers act as a supplemental but severe environmental filter of the regional species pool. Our study suggests that promoting the plantation of plants with high ethnobotanical use-value is a potentially viable strategy for sustainable agriculture and ecological restoration in Biosphere reserves.


Author(s):  
Weixue Mu ◽  
Jinpu Wei ◽  
Ting Yang ◽  
Yannan Fan ◽  
Le Cheng ◽  
...  

Nyssa yunnanensis is a deciduous tree in family Nayssaceae within the order Cornales. As only 8 individuals in 2 sites recorded in Yunnan province of China, the species was listed as the China&rsquo;s national grade-I protection species in 1999, and also as one of 120 PSESP(Plant Species with Extremely Small Populations) in Implementation Plan of Rescuing and Conserving China&rsquo;s Plant Species with extremely Small Populations(PSESP) (2011-2-15). N. yunnanensis was also been evaluated as Critically Endangered in IUCN red list and Threatened Species List of China's Higher Plants. Hence understanding the genomic characteristics of this highly endangered Tertiary relict tree species is essential, especially for developing conservation strategies. Here we sequenced and annotated the genome of N. yunnanensis using 10X genomics linked-reads sequencing data. The de novo assembled genome is 1474Mb in length with a scaffold N50 length of 985.59kb. We identified 823.51Mb of non-redundant sequence as repetitive elements and annotated 39,803 protein-coding genes in the assembly. Our result provided the genomic characteristics of N. yunnanensis, which will provide valuable resources for future genomic and evolutionary studies, especially for conservation biology studies of this extremely threatened tree species.


2016 ◽  
Vol 6 (3) ◽  
pp. 95-100
Author(s):  
Nadi Awwad Al Harbi

The aim of the present study was to investigate the potentials for utilization of Artemisia herba-alba and Anthemis arvensis shoot aqueous extract at different concentrations (1%, 3%, and 5%) to suppress the germination and growth of Panicum turgidum and Portulaca oleracea (weeds of crop fields) in Petri dish experiment. Results indicated that the degree of inhibition on seed germination and growth of the recipient species was largely dependent on the concentration of A. herba-alba and A.arvensis shoot aqueous extract. The aqueous extract of A.herba-alba showed the highest allelopathic effect on the germination of the seeds of P. turgidum, (10%,10% and 0%) while the effect of A. arvensis shoot aqueous extract was greater on the germination of the seeds P. oleracea (40%,0% and 0%). Percentage germination of the two selected crop species Triticum aestivum and Hordeum vulgare also de-creased as the A.herba-alba and A.arvensis shoot aqueous extract concentra-tion increased from 1% to 5% (90%,80% and 70%),(40%,40% and 20%). But the inhibition percentage was largely less than that of weed species. The results also showed that H.vulgare was more sensitive than T. aestivum and responds more strongly to the increase of concentration of A. herba-alba shoot aqueous extract . Results also showed that the radicle length of almost all tested species was more sensitive to allelochemicals from A.herba-alba and A.arvensis shoot aqueous extract than plumule length. Therefore, A. herba-alba and A. arvensis shoot aqueous extract may offer promises for their usefulness as a tool for weed management.


2020 ◽  
Author(s):  
Esteban García‐Ruiz ◽  
Guillermo Cobos ◽  
Ismael Sánchez‐Ramos ◽  
Susana Pascual ◽  
María‐Cristina Chueca ◽  
...  

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 548 ◽  
Author(s):  
Panagiotis Kanatas ◽  
Ilias S. Travlos ◽  
Ioannis Gazoulis ◽  
Alexandros Tataridas ◽  
Anastasia Tsekoura ◽  
...  

Decision support systems (DSS) have the potential to support farmers to make the right decisions in weed management. DSSs can select the appropriate herbicides for a given field and suggest the minimum dose rates for an herbicide application that can result in optimum weed control. Given that the adoption of DSSs may lead to decreased herbicide inputs in crop production, their potential for creating eco-friendly and profitable weed management strategies is obvious and desirable for the re-designing of farming systems on a more sustainable basis. Nevertheless, it is difficult to stimulate farmers to use DSSs as it has been noticed that farmers have different expectations of decision-making tools depending on their farming styles and usual practices. The function of DSSs requires accurate assessments of weeds within a field as input data; however, capturing the data can be problematic. The development of future DSSs should target to enhance weed management tactics which are less reliant on herbicides. DSSs should also provide information regarding weed seedbank dynamics in the soil in order to suggest management options not only within a single period but also in a rotational view. More aspects ought to be taken into account and further research is needed in order to optimize the practical use of DSSs for supporting farmers regarding weed management issues in various crops and under various soil and climatic conditions.


Weed Science ◽  
2012 ◽  
Vol 60 (2) ◽  
pp. 244-253 ◽  
Author(s):  
Lauren N. Kolb ◽  
Eric R. Gallandt ◽  
Ellen B. Mallory

Effective in-season weed management options are limited for organic cereal farmers. Two alternatives to current farmer practices are improving efficacy of physical weed control through use of interrow cultivation or increasing the competitive ability of the crop through elevated seeding rates and more uniform spatial planting patterns. It is unknown how these two methods affect yield, quality, and economic returns. Field experiments were conducted in the northeast United States to determine whether the yield gain from increased weed control from these contrasting weed management strategies resulted in increased net returns and how these different systems affected grain quality. Wheat was planted at two seeding rates (400 and 600 plants m−2), in three row spacings (11, 18, and 23 cm). A fourth crop arrangement that approaches a more uniform spatial distribution through a combination of drilling and broadcasting seed was included. For weed control, treatments received tine harrowing. Wheat sown in wide rows also received interrow cultivation. Each system was sown in the presence and absence of condiment mustard, which was sown as a surrogate weed. Increased seeding rate reduced weed density 64% compared to a crop-free check and 30% compared to regional farmers' practices of 18-cm rows and 400 plants m−2. Increased seeding rates lowered grain protein 5% compared to standard seeding rates. Wide rows, in combination with interrow cultivation, reduced weed density 62%, increased yield 16%, and net returns 19% compared to regional organic practices. Significant increases in grain N were limited to weed-free plots. While increased seeding rates improved weed suppression, the high input cost of organic seed make this an unsatisfactory alternative to interrow cultivation and current farmer practices, as yield would need to be. 15 t ha−1higher at elevated density to offset the extra cost of seed.


2015 ◽  
Vol 74 ◽  
pp. 18-23 ◽  
Author(s):  
Navneet Kaur ◽  
Makhan S. Bhullar ◽  
Gurjeet Gill

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 954-961 ◽  
Author(s):  
Martin M. Williams

Edamame, a specialty food-grade soybean popular among health-conscious consumers, is growing in popularity worldwide. Despite a well-developed soybean industry, most edamame consumed in the United States is imported from Asia. Considerable interest exists in growing edamame domestically; however, weed interference is a major problem, and until recently, only a single herbicide was registered for use on the crop. The objectives of this work were (1) to compare effectiveness of weed management treatments that utilize herbicides currently registered for use on edamame or that may be registered in the near future, (2) to determine the significance of edamame cultivar on performance of these treatments, and (3) to identify potential relationships between the crop and weed. Ten different weed management treatments were tested in three edamame cultivars over a 3-yr period. All weed management treatments increased marketable pod yield relative to the nontreated control, but only treatments with saflufenacil orS-metolachlor combinations were comparable to the hand-weeded weed-free treatment. Of the treatments studied,S-metolachlor followed by imazamox was among the greatest yielding, had the least weed density and biomass, and did not reduce crop population density. Also, cultivars differed in their weed-suppressive ability. Path analysis indicated certain relationships were consistent across cultivars, such as weed population density having a direct negative association with crop biomass; however, other edamame–weed interactions were not identical across cultivars. Although more improvements are needed, the vegetable industry is beginning to have nascent weed management options in edamame, which will likely reduce reliance on hand weeding and result in crop-production costs that are more competitive in the global market.


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