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2021 ◽  
Author(s):  
Xiaoli Chang ◽  
Huiting Xu ◽  
Li Yan ◽  
Dan Zhu ◽  
Wei Wang ◽  
...  

Abstract BackgroundThe dynamic of soil-borne disease is closely related to the rhizosphere microbial communities. Maize-soybean intercropping can suppress soybean root rot as compared to monoculture. However, it is still unknown whether rhizosphere microbial community participates in the regulation of intercropped soybean root rot.MethodsIn this study, the difference of rhizosphere Fusarium and Trichoderma community was compared between healthy or root-rotted soybean rhizosphere soil from soybean monoculture and maize-soybean intercropping, and the inhibitory effect of potential biocontrol Trichoderma against pathogenic Fusarium were examined.ResultsThe abundance of rhizosphere Fusarium was remarkably different between intercropping and monoculture, while Trichoderma was largely accumulated in healthy rhizosphere soil of intercropping rather than monoculture. Four rhizosphere Fusarium species identified were all pathogenic to soybean but displayed distinct composition and isolation proportion in the corresponding soil types. As the dominant and most aggressive species, F. oxysporum was more frequently isolated in diseased soil of monoculture. Furthermore, of three Trichoderma species identified, T. harzianum dramatically increased in the rhizosphere of intercropping rather than monoculture as compared to T. virens and T. afroharzianum. For in-vitro antagonism test, Trichoderma strains had antagonistic effects on F. oxysporum with the percentage of mycelial inhibition ranging of 50.59%-92.94%, and they displayed good mycoparasitic abilities against F. oxysporum through coiling around and entering into the hyphae, expanding along cell-cell lumen and even dissolving cell walls of target fungus.ConclusionThese results indicate maize-soybean intercropping significantly increase the density and composition proportion of beneficial Trichoderma to antagonist the pathogenic Fusarium species, thus contributing to the suppression of soybean root rot under intercropping.


Author(s):  
Balla Ratan Sharmila ◽  
Syed H Mazhar ◽  
Dipak Kumar Bose ◽  
Jahanara Jahanara

Okra (Abelmoschus esculentusL.) also known as Lady’s Finger is an economically important summer vegetable crop that belongs to the family Malvaceae. It is known to have originated in tropical Africa. The crop is quite popular due to its easy cultivation, dependable yield and resistant to drought & water logging adaptability to varying moisture conditions & soil types. (Maurya et al., 2013). the major findings are 74.16 percent of the respondents have knowledge on soils that are Loose, loamy soils are required for Okra cultivation, followed by 64.16 percent of the respondents are saying that they cultivate Okra crop throughout the year. Okra plant produces fiber by 20.2 to 7.2 percent. (Chauhan 1972) East-godavari district of Andra pradesh state was selected purposively based on the maximum farmers’ availability. Descriptive research design was used for the present study. A total of 120 respondents were selected purposively as a sample for the present investigation. The data was collected by using pre-tested schedule and analyzed using appropriate statistical tools. Karl Pearson’s Co-efficient of Correlation test was applied to find out the association between farmers socio-economic profile with independent variables. It was concluded that the socio-economic status of the respondents constitute medium level. It was observed that majority of the respondents belonged to the high level of perception and towards improved okra cultivation practices. There was a positive and significant relationship between independent variables with dependent variables.


Author(s):  
Koffi Djaman ◽  
Komlan Koudahe ◽  
Houteta D. Koubodana ◽  
Aminou Saibou ◽  
Samuel Essah

Potato is one of the main crops grown worldwide under different climatic conditions. Potato is conventionally produced under intensive tillage practices under the same or different soil types. Research has shown some contrasting effects of the tillage practices on the soil properties, crop growth, yield, and quality. Under the reducing available freshwater for food production, soil management practices are more targeting conservation and system sustainability. It is therefore critical to revisit literature on the tillage practices and their impact on the soil, crop, and crop yield. This review presents research results of studies conducted exclusively on potatoes comparing different types of tillage practices and is a valuable source of information for potato growers and scientists as it is not only focused on the impact of tillage practices on soil properties but also on potato tuber yield and grade, tuber specific gravity, and the impact of tillage practices on diseases in potatoes.


Author(s):  
Stefan Hay ◽  
Ingo Weidlich ◽  
Ingo Wolf ◽  
Felipe A. Villalobos

The development of a monitored district heating piping system has allowed the study of axial displacement variations in a buried pipeline. This piping system includes four instrumented sections of piping within an in use district heating network. There are also different conditions under testing such as thickness of expansion cushions, temperature ranges and bedding soil types. The pipe axial displacements were on-line monitored by means of extensometers in six positions along each of the four sections of the pipeline. Measured maximum pipe axial displacements were 24 and 25 mm in the corners of the 41 m long monitored pipelines, while estimated values were 23 mm using current recommendation procedures and 27 mm using calibrated commercial computer programs. One temperature unloading-reloading caused displacements to not return to the same values as before, but around 3 mm smaller. Therefore, several unloading-reloading temperature cycles may affect the pipe deformation behaviour in the short and long term.


SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 785-809
Author(s):  
Carrie L. Thomas ◽  
Boris Jansen ◽  
E. Emiel van Loon ◽  
Guido L. B. Wiesenberg

Abstract. Despite the importance of soil organic matter (SOM) in the global carbon cycle, there remain many open questions regarding its formation and preservation. The study of individual organic compound classes that make up SOM, such as lipid biomarkers including n-alkanes, can provide insight into the cycling of bulk SOM. While studies of lipid biomarkers, particularly n-alkanes, have increased in number in the past few decades, only a limited number have focused on the transformation of these compounds following deposition in soil archives. We performed a systematic review to consolidate the available information on plant-derived n-alkanes and their transformation from plant to soil. Our major findings were (1) a nearly ubiquitous trend of decreased total concentration of n-alkanes either with time in litterbag experiments or with depth in open plant–soil systems and (2) preferential degradation of odd-chain length and shorter chain length n-alkanes represented by a decrease in either carbon preference index (CPI) or odd-over-even predominance (OEP) with depth, indicating degradation of the n-alkane signal or a shift in vegetation composition over time. The review also highlighted a lack of data transparency and standardization across studies of lipid biomarkers, making analysis and synthesis of published data time-consuming and difficult. We recommend that the community move towards more uniform and systematic reporting of biomarker data. Furthermore, as the number of studies examining the complete leaf–litter–soil continuum is very limited as well as unevenly distributed over geographical regions, climate zones, and soil types, future data collection should focus on underrepresented areas as well as quantifying the transformation of n-alkanes through the complete continuum from plant to soil.


Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2382
Author(s):  
Jana Reinhardt ◽  
Pia Hilgert ◽  
Moritz Von Cossel

Industrial crop cultivation on marginal agricultural land limits indirect land-use change effects that pose a threat to food security. This review compiles results from 91 published crop-specific field trial datasets spanning 12 relevant industrial crops and discusses their suitability for cultivation on unfavorable soil types (USTs). It was shown that the perennial species Miscanthus (Miscanthus Andersson) and reed canary grass (Phalaris arundinacea L.) performed well on USTs with both high clay and/or high sand contents. Information on stoniness (particles sizes > 2 mm), where mentioned, was limited. It was found to have only a small impact on biological yield potential, though it was not possible to assess the impact on mechanization as would be used at a commercial scale. For soils with extreme clay or sand contents, half of the crops showed moderate suitability. The large yield variations within and between crops revealed large knowledge gaps in the combined effects of crop type and agronomy on USTs. Therefore, more field trials are needed on diverse USTs in different climates with better equipment and more consistent measurements to improve the accuracy of potential yield predictions spatially and temporally. Additionally, larger trials are needed to optimize cultivation and harvesting.


Author(s):  
Heather A. Ford ◽  
Maximiliano J. Bezada ◽  
Joseph S. Byrnes ◽  
Andrew Birkey ◽  
Zhao Zhu

Abstract The Crust and lithosphere Investigation of the Easternmost expression of the Laramide Orogeny was a two-year deployment of 24 broadband, compact posthole seismometers in a linear array across the eastern half of the Wyoming craton. The experiment was designed to image the crust and upper mantle of the region to better understand the evolution of the cratonic lithosphere. In this article, we describe the motivation and objectives of the experiment; summarize the station design and installation; provide a detailed accounting of data completeness and quality, including issues related to sensor orientation and ambient noise; and show examples of collected waveform data from a local earthquake, a local mine blast, and a teleseismic event. We observe a range of seasonal variations in the long-period noise on the horizontal components (15–20 dB) at some stations that likely reflect the range of soil types across the experiment. In addition, coal mining in the Powder River basin creates high levels of short-period noise at some stations. Preliminary results from Ps receiver function analysis, shear-wave splitting analysis, and averaged P-wave delay times are also included in this report, as is a brief description of education and outreach activities completed during the experiment.


2021 ◽  
Author(s):  
Yafei Huang ◽  
Jonas Weis ◽  
Harry Vereecken ◽  
Harrie-Jan Hendricks Franssen

Abstract. Droughts can have important impacts on environment and economy like in the year 2018 in parts of Europe. Droughts can be analyzed in terms of meteorological drought, agricultural drought, hydrological drought and social-economic drought. In this paper, we focus on meteorological and agricultural drought and analyzed drought trends for the period 1965–2019 and assessed how extreme the drought year 2018 was in Germany and the Netherlands. The analysis was made on the basis of the following drought indices: standardized precipitation index (SPI), standardized soil moisture index (SSI), potential precipitation deficit (PPD) and ET deficit. SPI and SSI were computed at two time scales, the period April-September and a 12-months period. In order to analyze drought trends and the ranking of the year 2018, HYDRUS 1-D simulations were carried out for 31 sites with long-term meteorological observations and soil moisture, potential evapotranspiration (ET) and actual ET were determined for five soil types (clay, silt, loam, sandy loam and loamy sand). The results show that the year 2018 was severely dry, which was especially related to the highest potential ET in the time series 1965–2019, for most of the sites. For around half of the 31 sites the year 2018 had the lowest SSI, and largest PPD and ET-deficit in the 1965–2019 time series, followed by 1976 and 2003. The trend analysis reveals that meteorological drought (SPI) hardly shows significant trends over 1965–2019 over the studied domain, but agricultural droughts (SSI) are increasing, at several sites significantly, and at even more sites PPD and ET deficit show significant trends. The increasing droughts over Germany and Netherlands are mainly driven by increasing potential ET and increasing vegetation water demand.


Koedoe ◽  
2021 ◽  
Vol 63 (1) ◽  
Author(s):  
Isiah Nthenga ◽  
Rinus Knoetze ◽  
Antoinette P. Malan

Entomopathogenic nematodes (EPNs) are microscopic roundworms that are found in soil worldwide. They deliver an important ecosystem service through preventing natural flares in insect reproduction by means of utilising the soil stages of insects as a food source and by acting as natural biocontrol agents. A survey of EPNs was conducted in the JS Marais Nature Reserve, Stellenbosch, in the Western Cape province of South Africa. Soil samples were baited with the larvae of three susceptible hosts, codling moth (Cydia pomonella), wax moth (Galleria mellonella) and mealworm (Tenebrio molitor) to determine the presence of EPN. Of the 76 soil samples collected across the reserve, 39 were found to be positive for the presence of EPN (51.32%). Among the positive samples, 87% contained Steinernema isolates, 8% contained Heterorhabditis and 5% contained the Oscheius sp. Morphological and molecular studies were performed to characterise the isolates to species level. The Steinernema species were identified as Steinernema khoisanae in 34 samples, and as Steinernema nguyeni in five samples. The only species of Heterorhabditis found was H. safricana, which was identified from three samples. An unknown Oscheius sp. was found in two samples. The reserve’s population of S. khoisanae showed interesting inter-individual variation (93%) early in the internal transcribe spacer (ITS) region, leading to short single-usable sequences, which, in most cases, included only the ITS1 or ITS2 region. However, using the D2D3 confirmed their identity as S. khoisanae, with such occurring in all areas and soil types of the reserve.Conservation implications: The undisturbed alluvial fynbos and renosterveld of the JS Marais Nature Reserve showed high EPN abundance and diversity in stark contrast to the agro-ecosystems present in the Cape floristic region. This finding, on a micro level, should be conserved for future bioprospecting in the fynbos for EPNs with potential as biocontrol agents.


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