scholarly journals Agricultural Practices Modulate the Beneficial Activity of Bacterial-Feeding Nematodes for Plant Growth and Nutrition: Evidence from an Original Intact Soil Core Technique

2021 ◽  
Vol 13 (13) ◽  
pp. 7181
Author(s):  
Jean Trap ◽  
Mahafaka Patricia Ranoarisoa ◽  
Sariaka Raharijaona ◽  
Lilia Rabeharisoa ◽  
Claude Plassard ◽  
...  
Keyword(s):  
Plant Growth ◽  
Agricultural Practices ◽  
Soil Core ◽  
Rice Seed ◽  
Soil Cores ◽  
Beneficial Effects ◽  
Positive Effects ◽  
Growth And Nutrition ◽  
Intact Soil Core ◽  
Intact Soil

Free-living nematodes have beneficial effects on plant growth and nutrition. Exploring how agricultural practices modulate these beneficial effects is still challenging. A study was conducted in Ferralsols from Madagascar from one unmanaged grassland and 16 upland rainfed rice fields, representative of different agricultural practices: rotation, agroforestry and monoculture. Intact soil cores in plastic cylinders were sampled in the field to assess the effects of agricultural practices on changes in plant growth and nutrition induced by the presence of bacterial-feeding nematodes. The soil cores were fumigated to kill the nematodes and moistened with a filtered fresh soil suspension containing only microbial cells. A rice seed was introduced in the core, which was then incubated under natural climatic conditions for 40 days with or without inoculation of the bacterial-feeding nematode Acrobeloides sp. The inoculation of the nematodes induced lower, similar or higher plant biomass and nutrient content in comparison to the control according to the agricultural practices. Positive effects of Acrobeloides sp. on plant functions were frequent in soil cores sampled from fields with high plant diversity, especially from agroforestry systems. The intact soil core technique appears to be a robust means of mimicking field conditions and constitutes a promising tool to assess effects on soil processes of the ecological intensification of agricultural practices.

MEASUREMENT OF EVAPORATION FROM SOIL BENEATH CROP CANOPIES

1983 ◽  
Vol 63 (1) ◽  
pp. 137-141 ◽  
Author(s):  
G. K. WALKER
Keyword(s):  
Zea Mays ◽  
Key Words ◽  
Leaf Area ◽  
Energy Supply ◽  
Zea Mays L ◽  
Growing Season ◽  
Soil Core ◽  
Crop Cover ◽  
Intact Soil Core ◽  
Intact Soil

Evaporation rates beneath maize canopies were measured using an intact soil core technique. Early in the growing season evaporation rates were periodically high (4.0 mm∙day−1) following rain, but declined rapidly. At full crop cover, when energy supply normally limits evaporation, significant differences in evaporation were detected between canopies with leaf area indices of 3.0 and 4.0. Key words: Evaporation measurement, energy supply, Zea mays L., leaf area, soil evaporimeter, lysimeter

Intact soil-core microcosms compared with multi-site field releases for pre-release testing of microbes in diverse soils and climates

2001 ◽  
Vol 47 (3) ◽  
pp. 237-252 ◽  
Author(s):  
Joel V Gagliardi ◽  
J Scott Angle ◽  
James J Germida ◽  
R Campbell Wyndham ◽  
Christopher P Chanway ◽  
...  
Keyword(s):  
Low Cost ◽  
Soil Microbiology ◽  
Soil Core ◽  
Wheat Roots ◽  
Fallow Soil ◽  
Site Field ◽  
Intact Soil Core ◽  
Regression Slopes ◽  
Field Plots ◽  
Intact Soil

Intact soil-core microcosms were used to compare persistence of Pseudomonas chlororaphis 3732RN-L11 in fallow soil and on wheat roots with field releases at diverse sites. Parallel field and microcosm releases at four sites in 1996 were repeated with addition of one site in 1997. Microcosms were obtained fresh and maintained at 60% soil water holding capacity in a growth chamber at 70% relative humidity, a 12-hour photoperiod, and constant temperature. Persistence of 3732RN-L11 was measured at each site in field plots and microcosms at 7–21 day intervals, and in duplicate microcosms sampled at an independent laboratory. Linear regression slopes of field plot and microcosm persistence were compared for each site, and between identical microcosms sampled at different sites, using log10transformed plate counts. Microcosm persistence closely matched field plots for wheat roots, but persistence in fallow soil differed significantly in several instances where persistence in field plots was lower than in microcosms. Analysis of weather variations at each site indicated that rainfall events of 30–40 mm caused decreased persistence in fallow soil. Cooler temperatures enhanced persistence in field plots at later time points. Inter-laboratory comparison of regression slopes showed good agreement for data generated at different sites, though in two instances, longer sampling periods at one site caused significant differences between the sites. Soil characteristics were compared and it was found that fertility, namely the carbon to nitrogen ratio, and the presence of expanding clays, were related to persistence. These microcosm protocols produced reliable data at low cost, and were useable for pre-release risk analyses for microorganisms.Key words: microcosm, soil, microbiology, risk assessment, 3732RN-L11.

scholarly journals The First Evidence of the Beneficial Effects of Se-Supplementation on In Vitro Cultivated Olive Tree Explants

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1630
Author(s):  
Luca Regni ◽  
Maurizio Micheli ◽  
Alberto Marco Del Pino ◽  
Carlo Alberto Palmerini ◽  
Roberto D’Amato ◽  
...  
Keyword(s):  
Plant Growth ◽  
Dry Weight ◽  
Olive Tree ◽  
Adaptation Effect ◽  
Beneficial Effects ◽  
Experimental Scheme ◽  
Positive Effects ◽  
Olive Cultivars ◽  
Aseptic Conditions

Selenium is an essential micronutrient that provides important benefits to plants and humans. At proper concentrations, selenium increases plant growth, pollen vitality, the shelf life of fresh products, and seems to improve stress resistance; these effects can certainly be attributed to its direct and indirect antioxidant capacity. For these reasons, in the present work, the effects of selenium at different dosages on in vitro cultivated olive explants were investigated to observe possible positive effects (in terms of growth and vigor) on the proliferation phase. The work was carried out on four different olive cultivars: “San Felice”, “Canino”, “Frantoio”, and “Moraiolo”. The explants were cultured in aseptic conditions on olive medium (OM), with the addition of 4 mg·L−1 of zeatin, 30 g·L−1 of sucrose, and 7 g·L−1 of agar. The experimental scheme included a comparison between explants grown with five different concentrations of Na2SeO4 (0, 10, 20, 40, and 80 mg L−1) added to the medium during three successive subcultures. Interesting information has emerged from the results and all varieties responded to different concentrations of Selenium. The optimal Se dosages varied for each cultivar, but in general, Se concentration between 10 and 40 mg L−1 increased fresh and dry weight of the explants and shoot lengths. Se treatment induced in all cultivars and for all dosages used an increase in total Se content in proliferated explants. Furthermore, as the subcultures proceeded, the ability of the explants to absorb Se did not diminish. The Se content ranged from 8.55 to 114.21 µg kg−1 plant DW in ‘Frantoio’, from 9.83 to 94.85 µg kg−1 plant DW in ‘Moraiolo’, from 19.84 to 114.21 µg kg−1 plant DW in ‘Canino’, and from 20.97 to 95.54 µg kg−1 plant DW in ‘San Felice’. In general, the effect of selenium tends to decrease with the progress of subcultures and this suggests a sort of “adaptation” effect of the explants to its presence. The present study highlights for the first time the possibility of using in vitro cultures as biotechnological support to study supplementation with selenium and its effects on in vitro olive plant growth.

Field Extraction of Large Intact Soil Cores for Leaching Studies in the Laboratory

1996 ◽  
Vol 10 (1) ◽  
pp. 210-216 ◽  
Author(s):  
She-Kong Chong ◽  
Suling Zhao ◽  
Brian P. Klubek
Keyword(s):  
Hydraulic Conductivity ◽  
Low Cost ◽  
Sampling Procedure ◽  
Soil Horizon ◽  
Soil Core ◽  
Soil Cores ◽  
Intact Soil Cores ◽  
Large Soil ◽  
Intact Soil

Various samplers have been developed for taking intact soil cores. Very often, the sampler was used once or twice to take only a few soil cores then it became either obsolete or a burden for maintenance and storage. An economic portable hand-operated soil core sampler was developed to obtain large soil cores with a diameter of 19 cm and a length of 120 cm. The quality of large soil cores was evaluated and compared with that obtained from short cores from each soil horizon. In addition, the large intact column was used to evaluate atrazine transport under the saturated condition. Results showed that the hydraulic conductivity of the large cores were of the same magnitude as that of short cores, except for the A horizon; the hydraulic conductivity of the large cores was about 10 times greater than the short cores. Even though the sampling procedure is labor intensive, the soil sampler has the flexibility to collect different size soil cores and can be constructed at a very low cost (less than $200 including labor). Lastly, the sampler is maintenance free and can be stored easily in a limited space.

scholarly journals Deciphering the Symbiotic Plant Microbiome: Translating the Most Recent Discoveries on Rhizobia for the Improvement of Agricultural Practices in Metal-Contaminated and High Saline Lands

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 529 ◽  
Author(s):  
Agnese Bellabarba ◽  
Camilla Fagorzi ◽  
George C. diCenzo ◽  
Francesco Pini ◽  
Carlo Viti ◽  
...  
Keyword(s):  
Plant Growth ◽  
Crop Yield ◽  
Heavy Metal Contamination ◽  
Agricultural Practices ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Genome ◽  
Biotic And Abiotic Stresses ◽  
Beneficial Effects ◽  
Plant Growth Promoting ◽  
Growth Promoting

Rhizosphere and plant-associated microorganisms have been intensely studied for their beneficial effects on plant growth and health. These mainly include nitrogen-fixing bacteria (NFB) and plant-growth promoting rhizobacteria (PGPR). This beneficial fraction is involved in major functions such as plant nutrition and plant resistance to biotic and abiotic stresses, which include water deficiency and heavy-metal contamination. Consequently, crop yield emerges as the net result of the interactions between the plant genome and its associated microbiome. Here, we provide a review covering recent studies on PGP rhizobia as effective inoculants for agricultural practices in harsh soil, and we propose models for inoculant combinations and genomic manipulation strategies to improve crop yield.

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