scholarly journals Antifungal Activity of Western Australian Soil Actinomycetes against Phytophthora and Pythium Species and a Mycorrhizal Fungus, Laccaria laccata

1983 ◽  
Vol 36 (2) ◽  
pp. 191 ◽  
Author(s):  
D Keast ◽  
C Tonkin
Keyword(s):  
Antifungal Activity ◽  
Phytophthora Cinnamomi ◽  
Mycorrhizal Fungus ◽  
Organic Matter Content ◽  
Phytophthora Species ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Soil Actinomycetes ◽  
High Degree

Soil pH, soil moisture content and soil organic matter content did not appear to influence significantly the total numbers of actinomycetes isolated from sample sites in Western Australia. However, seasonal influences exist with summer conditions leading to higher spore isolation. Substantial but non-specific antifungal activity against Phytophthora cinnamomi, P. cryptogea, P. nicotiana, Pythium proli/erum and L. laccata was detected in vitro from many of the 2367 actinomycetes isolated. Antifungal activity mayor may not occur in members of the same actinomycete group, suggesting segregation of antifungal capacity within all groups. A limited number of actinomycete groups was isolated from the rhizosphere of plants and these exhibited similar properties to their counterparts in soil or litter. Actinomycetes isolated from the rhizosphere of Pinus radiata produced a high degree of in vitro antifungal activity against the Phytophthora species but, in general, actinomycetes isolated from root surfaces exhibited antibiosis against all the fungi tested. More actinomycetes showed antifungal activity from soils where P. cinnamomi was causing dieback of jarrah and other understorey species.

Effects of Copper Salts on Growth and Survival of Phytophthora cinnamomi in vitro and on the Antifungal Activity of Actinomycete Populations From the Roots of Eucalyptus marginata and Banksia grandis

1985 ◽  
Vol 33 (2) ◽  
pp. 115 ◽  
Author(s):  
D Keast ◽  
C Tonkin ◽  
L Sanfelieu
Keyword(s):  
Antifungal Activity ◽  
Phytophthora Cinnamomi ◽  
Copper Ion ◽  
Copper Cation ◽  
Copper Salts ◽  
Eucalyptus Marginata ◽  
Growth And Survival ◽  
Fungistatic Activity ◽  
Soil Actinomycetes

Seven copper salts and 10 isolates from both mating types of Phytophthora cinnamomi have been tested, in vitro, for copper cation toxicity to mycelial mat growth and to the germination of chlamydospores. It has been shown that while the copper ion is toxic, extended periods of exposure (9-23 days) to the cation are often required to change the fungistatic activity to that of a true fungicide. This observation applies to both mycelial growth and to chlamydospore germination of P. cinnamomi. Soluble copper (CuS02.5H20) gave short-term protection of both Eucalyptus marginata and to a lesser degree Banksia grandis against infection by P. cinnamomi but insoluble copper (CuO) gave none. The rhizospheres of seedlings of E. marginata and B. grandis grown in pots contained populations of soil actinomycetes different from each other and the parent soil population. These actinomycetes showed substantial antifungal activity against Phytophthora cinnamomi in vitro. Moreover, the actinomycete populations were modified by the presence of copper and by the infection of the roots by P. cinnamomi. It is suggested that both the actinomycetes and the copper contributed to the protection against invasion by P. cinnamomi.

In vitro studies on the relative availability and mobility in soil of natural hatching factors for the potato cyst nematodes, Globodera rostochiensis and G. pallida

Nematology ◽  
2001 ◽  
Vol 3 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Peter Jones ◽  
John Byrne ◽  
Ken Devine
Keyword(s):  
Solid Phase ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Samples ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Potato Root ◽  
Soil Matrix ◽  
Soil Organic Matter Content

AbstractThe fractionation of root leachates from tomato and potato on a Sephadex G-10 column revealed many similarities between the elution profiles of hatching activities towards potato cyst nematodes (PCN). When aliquots of either tomato or potato root leachate were mixed with different soil samples, hatching factors exhibiting G. pallida-selective hatching activity showed less affinity for the soil matrix than did those selective for G. rostochiensis . This was confirmed by the earlier elution of G. pallida-selective hatching factors from columns in which soil was used as the solid phase in low pressure liquid chromatography. The selectivity of the earliest-eluting hatching factors towards G. pallida, relative to G. rostochiensis, was found to increase significantly as the percentage soil organic matter content increased.

scholarly journals Soil nitrogen supply of peat grasslands estimated by degree days and soil organic matter content

2020 ◽  
Vol 117 (3) ◽  
pp. 351-365
Author(s):  
J. Pijlman ◽  
G. Holshof ◽  
W. van den Berg ◽  
G. H. Ros ◽  
J. W. Erisman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Nitrogen ◽  
Organic Matter Content ◽  
Matter Content ◽  
Nitrogen Supply ◽  
Degree Days ◽  
Soil Organic Matter Content ◽  
Soil Nitrogen Supply

scholarly journals Microbial Respiration and Enzyme Activity Downstream from a Phosphorus Source in the Everglades, Florida, USA

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 696
Author(s):  
Sanku Dattamudi ◽  
Saoli Chanda ◽  
Leonard J. Scinto
Keyword(s):  
Nutrient Dynamics ◽  
Microbial Respiration ◽  
Organic Matter Content ◽  
Physicochemical Analysis ◽  
Matter Content ◽  
Enzyme Assays ◽  
Co2 Efflux ◽  
Soil Organic Matter Content ◽  
Phosphorus Source ◽  
P Distribution

Northeast Shark River Slough (NESS), lying at the northeastern perimeter of Everglades National Park (ENP), Florida, USA, has been subjected to years of hydrologic modifications. Construction of the Tamiami Trail (US 41) in 1928 connected the east and west coasts of SE Florida and essentially created a hydrological barrier to southern sheet flow into ENP. Recently, a series of bridges were constructed to elevate a portion of Tamiami Trail, allow more water to flow under the bridges, and attempt to restore the ecological balance in the NESS and ENP. This project was conducted to determine aspects of soil physiochemistry and microbial dynamics in the NESS. We evaluated microbial respiration and enzyme assays as indicators of nutrient dynamics in NESS soils. Soil cores were collected from sites at certain distances from the inflow (near canal, NC (0–150 m); midway, M (150–600 m); and far from canal, FC (600–1200 m)). Soil slurries were incubated and assayed for CO2 emission and β-glucoside (MUFC) or phosphatase (MUFP) activity in concert with physicochemical analysis. Significantly higher TP contents at NC (2.45 times) and M (1.52 times) sites than FC sites indicated an uneven P distribution downstream from the source canal. The highest soil organic matter content (84%) contents were observed at M sites, which was due to higher vegetation biomass observed at those sites. Consequently, CO2 efflux was greater at M sites (average 2.72 µmoles g dw−1 h−1) than the other two sites. We also found that amendments of glucose increased CO2 efflux from all soils, whereas the addition of phosphorus did not. The results indicate that microbial respiration downstream of inflows in the NESS is not limited by P, but more so by the availability of labile C.

scholarly journals Effect of Clay, Soil Organic Matter, and Soil pH on Initial and Residual Weed Control with Flumioxazin

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Weed Control ◽  
Soil Ph ◽  
Organic Matter Content ◽  
Amaranthus Retroflexus ◽  
Matter Content ◽  
Weed Species ◽  
Soil Organic Matter Content ◽  
Field Soils

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.

scholarly journals Assessment of Potato Farmland Soil Nutrient Based on MDS-SQI Model in the Loess Plateau

2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Fertility ◽  
Soil Quality ◽  
Soil Nutrients ◽  
Organic Matter Content ◽  
Soil Nutrient ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Farmland Soil

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.

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