Effect of different environmental conditions on bacterial chemotaxis toward fungal spores

1993 ◽  
Vol 39 (10) ◽  
pp. 922-931 ◽  
Author(s):  
Dilip K. Arora ◽  
Sushma Gupta
Keyword(s):  
Soil Ph ◽  
Sandy Soil ◽  
Sandy Loam ◽  
Fungal Spores ◽  
Bacterial Chemotaxis ◽  
Chemotactic Response ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Matric Potential ◽  
Loam Soil

The chemotactic response of four common soil bacteria, Agrobacterium radiobacter, Bacillus subtilis, Pseudomonas fluorescens, and Xanthomonas malvacearum, was observed in natural soil to conidia of Cochliobolus sativus, chlamydospores of Fusarium oxysporum f.sp. ciceri, sclerotia of Macrophomina phaseolina, and oospores of Phytophthora drechsleri f.sp. cajani. All bacteria migrated through soil toward fungal spores. Chemical analysis of fungal exudates demonstrated the presence of various amino acids and sugars that served as chemoattractants. The effect of temperature, pH, soil water matric potential, and soil texture on bacterial chemotaxis toward fungal spores was also investigated. In general, the response of bacteria to different types of fungal spores was significantly greater (P = 0.05) at higher water matric potential (0 and −5 kPa) than at lower soil water potential (−10 and −20 kPa). The chemotactic response was greatest in sandy soil, followed by sandy loam and clay loam soil. High temperature (40 °C) was not favourable for bacterial chemotaxis. The chemotactic response decreased by 4 to 28 times when soil pH decreased from 7 to 5 or increased from 7 to 9. The relative concentration response of the exudate of fungal spores and the motility or chemotaxis of bacteria were assessed. A significant positive correlation (P = 0.05; r = 0.89–0.92) was recorded between motility and relative concentrations of exudate. The swimming speed and tumbling frequency of Pseudomonas fluorescens cells was observed at different pH values and temperatures. The swimming speed of bacteria increased with increasing temperature, but decreased with an increase in pH from 5 to 7. The tumbling frequency had a sharp peak at 30 °C and pH 7. Bacteria were able to stimulate the release of exudate from the fungal spores. The amount of exudation was also affected by temperature, pH, and soil texture. A positive significant correlation (P = 0.05; r = 0.79–0.85) was recorded between exudation and a progressive increase in temperature. The amount of exudation also increased with an increase in soil pH from 5 to 8, but further increases in pH decreased the rate of exudation. In general, fungal spores exuded the greatest amounts of carbon compounds in sandy soil, followed by sandy loam and clay loam soil. Exudation in sandy soil was often greatest in the presence of A. radiobacter cells, while the greatest exudation in sandy loam and clay loam soils was induced by B. subtilis cells.Key words: chemotaxis, chemoattractants, fungal spores, motility.

Influence of soil matric potential on 14C exudation from fungal propagules

1987 ◽  
Vol 65 (10) ◽  
pp. 2084-2089 ◽  
Author(s):  
A. B. Filonow ◽  
D. K. Arora
Keyword(s):  
Water Content ◽  
Sandy Loam ◽  
Macrophomina Phaseolina ◽  
Sandy Loam Soil ◽  
Soil Matric Potential ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Matric Potential ◽  
Fungal Propagules ◽  
Loam Soil

The influence of soil matric potential (ψm) on 14C exudation from labeled fungal propagules incubated in two soils over 5 days was determined, using tensiometers set at 0, −50, −100, and −200 mbar ψm (1 bar = 100 kPa). In general, 14C exudation to soil (as a percent of initial label) tended to be greatest at 0 mbar and decreasing ψm. In a sandy loam soil, the range of 14C exudation from conidia of Bipolaris victoriae or sclerotia of Macrophomina phaseolina was 18.4–20.9 or 4.4–5.5% at 0 mbar. At −200 mbar, it was 5.5–6.0 or 1.2–1.7%, respectively. In a clay loam soil at 0 mbar, conidia of B. victoriae or B. sorokiniana lost 17.6–19.9 or 7.3–9.2%, respectively, of total 14C label as exudate. At −200 mbar 14.6 or 5.9–7.2% was lost, respectively. Sclerotia of M. phaseolina lost 5.1–5.7% 14C-labeled exudate to the clay loam soil at 0 mbar and 4.3–4.6% at −200 mbar. 14C exudation at ψm less than saturation was about 2–3 times greater in the clay loam soil than in the sandy loam soil. Calculated ratios of evolved 14CO2/total 14C-labeled exudate were lowest at 0 mbar and increased as ψm decreased, suggesting that oxygen availability and soil water content as regulated by ψm were related to soil respiratory utilization of exudate.

TOLERANCE OF EARLY-MATURING SOYBEAN CULTIVARS TO METRIBUZIN

1986 ◽  
Vol 66 (1) ◽  
pp. 125-130 ◽  
Author(s):  
G. H. FRIESEN ◽  
D. A. WALL
Keyword(s):  
Sandy Loam ◽  
Controlled Environment ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Soybean Cultivars ◽  
Early Maturing ◽  
Glycine Max L ◽  
Loam Soil ◽  
Environment Chamber ◽  
Chamber Studies

McCall, Maple Presto, Maple Amber and OT80-3 soybean (Glycine max (L.) Merr.) cultivars were evaluated under field conditions for their response to metribuzin. Maple Amber was found to be less tolerant than the other cultivars. In controlled environment chamber studies, injury to this cultivar was more severe on a sandy loam soil than on a clay loam soil. Fall applications of metribuzin, alone or tank-mixed with trifluralin, were tolerant to Maple Amber soybeans and such applications may offer a practical alternative to spring treatments for broad spectrum weed control in the less tolerant soybean cultivars grown in Manitoba.Key words: Metribuzin, trifluralin, preplant incorporation, fall treatments, soybean cultivars

scholarly journals Biochar Improves Plant Growth and Reduces Nutrient Leaching in Red Clay Loam and Sandy Loam

2012 ◽  
pp. 86-90 ◽  
Author(s):  
Kalpana Pudasaini ◽  
Nanjappa Ashwath ◽  
Kerry Walsh ◽  
Thakur Bhattarai
Keyword(s):  
Sandy Loam ◽  
Vegetable Production ◽  
Clay Loam ◽  
Plant Establishment ◽  
Clay Loam Soil ◽  
Red Clay ◽  
Green Waste ◽  
Loam Soil ◽  
Shoot Weight ◽  
Water Holding

A factorial pot experiment was conducted using two types of soils (sandy loam and red clay loam) that are commonly used for commercial vegetable production in Bundaberg, region of Central Queensl and Australia. The soils were amended with 0, 25, 50 and 75 t/ha of green waste biochar and minimum doses of N, P and K (30 kg/ha, 30 kg/ha and 40 kg/ha respectively). After two weeks of plant establishment, the pots were leached with 1.5 litres of deionised water at week intervals, and cation concentrations of the leachate were determined. In 25 t/ha biochar treatment, there was a significant (P<0.05) reduction in K and Ca leaching by 40% and 26% respectively from sandy loam, and of Ca by 23% from the red clay loam. Soil water holding capacity and soil organic carbon were also increased in both biochar treated soils. After 12 weeks of growth, shoot weight was signifi cantly (P<0.05) higher in 25 t/ha biochar-treated sandy loam and red clay loam (32% and 31% respectively). These results clearly demonstrated that a higher yield of capsicum can be achieved from green waste biochar application in sandy loam and red clay loam at 25 t/ha biochar.DOI: http://dx.doi.org/10.3126/hn.v11i1.7221 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.86-90

scholarly journals Effect of growing media on mat type seedling raised for mechanical rice transplanting 

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 157-167
Author(s):  
Hossen Anwar M ◽  
Hossain Mosharraf M ◽  
Haque Enamul M ◽  
Bell Richard W
Keyword(s):  
Rice Straw ◽  
Rice Bran ◽  
Sandy Loam ◽  
Organic Fertilizer ◽  
Poultry Litter ◽  
Cow Dung ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Loam Soil ◽  
Rolling Quality

Mechanical transplanted seedling must meet the requirements of standard seedling block with uniform distribution of seedlings and inter-twisting roots for rolling. This study was conducted to identify the effect of growing media on mat type seedling raised for mechanical transplanting at Bangladesh Rice Research Institute (BRRI), Gazipur during the period of 2012–2014 covering two dry and cold seasons (Boro) and one wet season (Aman). Seedling were raised on plastic tray using sandy loam and clay loam soil mixed with decomposed cow-dung, mustard cake, rice straw organic fertilizer, rice bran, poultry litter and vermicompost at the rate of 0.0, 10, 20, 30 and 40%. Rolling quality of the seedling mat decreased and seedling height increased with the increased of mixing rate of organic fertilizer except rice bran and mustard cake. Averaged across three seasons, 10 to 30% cow-dung, rice straw organic fertilizer, vermicompost, 10% poultry litter and 20 to 30% rice bran with both types of soil was found suitable for seedling mat and seedling height. However, seedling varied among the organic fertilizers with both types of soil in the order of cow-dung &gt; rice bran &gt; vermicompost &gt; poultry liter &gt; rice straw organic fertilizer &gt; mustard cake. Clay loam soil showed better performance on rolling quality over sandy loam soil.

scholarly journals Influence of wood-derived biochar on the physico-mechanical and chemical characteristics of agricultural soils

2018 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ahmed S.F. Ahmed ◽  
Vijaya Raghavan
Keyword(s):  
Agricultural Soils ◽  
Sandy Loam ◽  
Chemical Properties ◽  
Dry Weight ◽  
Crop Productivity ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Loam Soil ◽  
Specific Influence ◽  
And Chemical Properties

AbstractAmendment of soil with biochar has been shown to enhance fertility and increase crop productivity, but the specific influence of biochar on soil workability remains unclear. Select physico-mechanical and chemical properties of clay loam and sandy loam soils were measured after amendment with wood-derived biochar of two particle size ranges (0.5-425 and 425-850 µm) at five dosages ranging from 0.5 to 10% dry weight. Whereas the clay loam soil workability decreased when the finer wood-derived biochar was applied at rates of 6 or 10%, soil fertility was not enhanced. The sandy loam soil, due to Proctor compaction, significantly decreased in bulk density with 6 and 10% wood-derived biochar amendments indicating higher soil resistance to compaction.

scholarly journals The Effect of Phosphate Rocks on Spring Barley Shoot Yield in a Pot Trial 

2006 ◽  
Vol 55 (1) ◽  
pp. 193-202 ◽  
Author(s):  
Péter Csathó ◽  
E. Osztoics ◽  
J. Csillag ◽  
T. Lengyel ◽  
L. Gonda ◽  
...  
Keyword(s):  
Sandy Soil ◽  
Spring Barley ◽  
Ammonium Citrate ◽  
Acidic Ph ◽  
Clay Loam ◽  
Phosphate Rocks ◽  
Clay Loam Soil ◽  
Single Superphosphate ◽  
Ammonium Lactate ◽  
Loam Soil

Depending on their origin, sedimentary phosphate rocks (PRs) may differ in their P solubility, and, as a consequence, in their agronomic effectiveness. The effect of six phosphate rocks (PR) - originating from Algeria (ALG), North Florida (FLO), North Carolina (NCA), Senegal (SEN) Morocco (MOR) and Hyperphosphate (HYP) with various P solubility (evaluated by 2% formic acid, 2% citric acid, and neutral ammonium citrate) - as well as single superphosphate (SSP) and superphosphate + lime (SSP + Ca) (each P source on 4 P levels, with doses of 0, 100, 400 and 1600 mg P 2 O 5 ·kg -1 soil) on the shoot yield of tillering stage spring barley, soil available P (i.e. H 2 O, Olsen, Bray1, Lakanen-Erviö (LE) and ammonium lactate (AL) extractable P contents) were studied in pot experiments set up with acidic sandy soil (Nyírlugos, Hungary) and acidic clay loam soil (Ragály, Hungary), both with low P supplies.  The average spring barley shoot yield at the beginning of shooting was 95% higher on the colloid-rich acidic (pH KCl : 4.5) clay loam soil than on the colloid-poor acidic (pH KCl : 3.8) sandy soil. The differences in the solubility of phosphate rocks showed close correlation to the differences in P responses. On both soils, the correlation between total PR-P added and P responses in spring barley shoot yield was much weaker than that between neutral ammonium citrate soluble PR-P added and P responses in spring barley shoot yield. When phosphate rocks were applied as P sources, the comparison of soil test P methods showed a different picture on the two soils. In the case of the acidic sandy soil (Nyírlugos), the strongly acid LE-P (r² = 0.83) and AL-P (r² =0.74) tests gave the highest correlation coefficients with spring barley responses to P, while on the acidic clay loam soil (Ragály) these were achieved by the Olsen-P (r² = 0.88) and Bray1-P (r² =0.88) methods. 

scholarly journals Trace Metal Concentrations in the Liquid Phase of  Phosphate Rock-Treated Soils

2006 ◽  
Vol 55 (1) ◽  
pp. 203-212 ◽  
Author(s):  
Julianna Csillag ◽  
A. Lukács ◽  
E. Osztoics ◽  
P. Csathó ◽  
Gy. Baczó
Keyword(s):  
Soil Solution ◽  
Sandy Soil ◽  
Phosphate Rock ◽  
Toxic Elements ◽  
Time Frame ◽  
Potentially Toxic Elements ◽  
Clay Loam ◽  
Phosphate Rocks ◽  
Clay Loam Soil ◽  
Loam Soil

Concentrations of potentially toxic elements were determined in the soil solution of two soils (acidic sandy and slightly acidic clay loam) treated with phosphate rocks having high Cd content in a pot experiment. Relative concentrations characterizing the mobility of metals (expressed as soil solution concentrations in percentage of their “total” amounts in the phosphate rock-treated soil) decreased with increasing phosphate rock rates in the sandy soil. Mn@Sr>Cd@Co were the most, while Pb and Cr the least mobile elements. The relative concentrations in the clay loam soil were much lower than in the sandy soil and they practically remained constant with increasing phosphate rock rates. It was concluded that in the experimental time frame the environmental risk did not increase with the increase of phosphate rock rate. 

scholarly journals Carrot Yield and Shape Altered by Seeding Rate and Raised Beds in Clay-loam Soil

HortScience ◽  
2021 ◽  
pp. 1-8
Author(s):  
Charlie L. Rohwer
Keyword(s):  
Sandy Loam ◽  
Specific Yield ◽  
Clay Loam ◽  
Seeding Rate ◽  
Clay Loam Soil ◽  
Soil Penetration Resistance ◽  
Heavy Soil ◽  
Loam Soil ◽  
Raised Bed ◽  
Plot Design

Carrots (Daucus carota L. var sativus) in the midwestern United States are generally raised commercially on sandy-loam or muck soils. Some smaller growers may not have the luxury of an ideal soil type, so raised beds are often recommended to improve taproot growth. To determine specific yield and shape responses of carrots to raised-bed culture in heavy soil, three hybrids (‘Cupar’, ‘Envy’, and ‘Naval’) were grown in 2019 and 2020 on raised or flat beds in clay-loam soil. In addition, two seeding rates (high or low) were incorporated into the split-split plot design. ‘Cupar’ was larger and less misshapen than the other hybrids, but total marketable yields were similar among all three. ‘Naval’ was the most cylindrical. High seeding rate generally resulted in more numerous but smaller marketable roots and no change in total marketable weight. Raised beds caused a 10.6% increase in total marketable weight by allowing more marketable roots classified as “short” (between 76 and 127 mm long, diameter >25 mm) to grow to lengths more than 127 mm long. The average taproot cylindricity was increased and diameter decreased by growing on raised beds. Soil penetration resistance at 7.6 cm was correlated with many of the measured responses.

Performance Evaluation of Surface Overlaid EN-42 Steel for Tillage Applications

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Jagseer Singh ◽  
Sukhpal Singh Chatha ◽  
Buta Singh Sidhu
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Moisture Content ◽  
Sandy Loam ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Wear Performance ◽  
Sandy Clay Loam ◽  
Actual Field ◽  
Loam Soil

Abstract Wear of tools is a key problem in the farming sector. The objective of this study was to evaluate the wear performance of untreated steel (EN-42) and two hardfacings, namely H1 and VB. Hardfacing H1 (0.86Cr0.22C) fall in the basic buildup iron–carbide alloy category and hardfacing VB (3.19Cr2.51C2.7Si) is categorized as martensitic alloy steel. Abrasive wear performance of untreated, as well as hardfaced steel specimens, was evaluated in the laboratory and actual field conditions. The tests were conducted in the laboratory, and actual field trials were conducted in sandy loam and sandy clay-loam soil. The performance of the untreated and hardfaced steel was analyzed using various techniques such as weight loss, microhardness, microstructure and scanning electron microscopy (SEM). The results revealed that H1 and VB overlaid steel exhibited better wear performance than the untreated steel, and the least wear-rate was found in sandy clay-loam soil. VB overlaid steel experienced lesser cumulative weight loss (g) and wear-rate (g/km) and thus displayed better abrasive wear behavior under all the conditions of the study. Further, it has been observed that the moisture content in soil exerts a stronger effect on ploughshare wear than soil type. For actual field conditions, untreated and overlaid ploughshares tested in sandy loam soil with low moisture content (0–3%) experienced almost three times higher wear-rate (4.078 g/km, 3.699 g/km, and 3.055 g/km for untreated, H1, and VB overlaid steel, respectively) than the same ploughshares tested in soil having high (14–17%) moisture content (1.296 g/km, 1.178 g/km, and 0.913 g/km for untreated, H1, and VB overlaid steel, respectively).

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