STUDIES ON THE GROWTH IN SOIL AND THE PARASITIC ACTION OF CERTAIN RHIZOCTONIA SOLANI ISOLATES FROM WHEAT

1942 ◽  
Vol 20c (3) ◽  
pp. 174-185 ◽  
Author(s):  
I. D. Blair

An adaptation of the Rossi and Cholodny glass slide technique was found to be an effective means of measuring the growth of Rhizoctonia Solani in soil. After a 6 day and a 12 day period, the extent of growth of 11 isolates of this fungus was, for each growth period, less in a vertical than in a radial direction. Certain isolates grew faster than others. A comparison of the radial growth of a faster and of a slower growing isolate at soil depth of 2, 4, and 6 in. showed that the extent of growth decreased with depth, being significantly greater for both isolates at the 2 in. than at the 6 in. level.In pathogenicity tests on wheat with 10 of these isolates, the disease rating for each isolate was greater in natural than in steam sterilized soil, and in soil with a proportion of inoculum to soil of one to six than of one to three. The addition of cellulosic organic material, grass- or straw-meal, to unsterilized soil was effective in reducing the parasitic action of all isolates. Two distinct types of injury were observed: the one, a severe form of root injury, resulting in reduced plant growth; the other, a girdling of the coleoptile or lower stem tissue, usually unaccompanied by adverse effects on plant growth. The first type was produced by two slow growing isolates of English origin, the second by faster growing isolates of Canadian origin. On the basis of these differences, it is suggested that the root injuring isolates be regarded as a variety of R. Solani Kühn.

Author(s):  
Ramiro Remigio Gaibor Fernández ◽  
Abraham Adalberto Bayas Zamora ◽  
Galo Israel Muñoz Sánchez ◽  
Cristhian Adrián Rivas Santacruz

The objective of the present investigation was to evaluate the physical characteristics of the vermicompost and the quality of the purine of the red Californian (Eisenia foetida) using different substrates of feed for these worms. For this purpose, nine treatments were studied: 75% African palm rachis + 25% cattle manure, 50% African palm rachis + 50% cattle manure, 25% African palm rachis + 75% livestock manure, 50% manure of cattle, 50% of manure of cattle, 25% of manure of cattle, 50% of manure of cattle, 50% of manure of cattle, 50% of rach of coconut + 50% of manure of Livestock, 25% coccus rachis + 75% livestock manure. The substrate made up of 50% of rachis of coconut and 50% of livestock manure can be used in nurseries or nurseries for being the one that registered a value of pH 7.3 plus the closest to the neutral compared to the others, besides this (75% of oil palm rachis and 25% of cattle manure) showed a higher content of humic and fulvic acids (0.87 and 0.45 p / p, respectively), compounds that are important for agriculture by stimulating plant growth, in addition to this reflection 0.06% sulfur content, 4.0 ppm boron, 7.0 ppm copper, 47.5 ppm iron, 6.0 ppm manganese, with a presence of microorganisms of the species Trichoderma, Penicillium, Cladosporium sp. in amounts of 1.91x105 UFC / ml, however in this substrate was obtained between 13.3 and 43.5% less liquid slurry in Comparison with other treatments.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 628
Author(s):  
Hassan E. Abd Elsalam ◽  
Mohamed E. El- Sharnouby ◽  
Abdallah E. Mohamed ◽  
Bassem M. Raafat ◽  
Eman H. El-Gamal

Sewage sludge is an effective fertilizer in many soil types. When applied as an amendment, sludge introduces, in addition to organic matter, plant nutrients into the soil. When applied for cropland as a fertilizer, the mass loading of sewage sludge is customarily determined by inputs of N and/or P required to support optimal plant growth and a successful harvest. This study aims to examine the changes in organic matter contents and nitrogen forms in sludge-amended soils, as well as the growth of corn and faba bean plants. The main results indicated that there were higher responses to the corn and faba bean yields when sludge was added. Levels of organic carbon in soil were higher after maize harvest and decreased significantly after harvesting of beans, and were higher in sludge amended soils than unmodified soils, indicating the residual effect of sludge in soil. NO3−-N concentrations were generally higher in the soil after maize harvest than during the plant growth period, but this trend was not apparent in bean soil. The amounts of NH4+-N were close in the soil during the growth period or after the maize harvest, while they were higher in the soil after the bean harvest than they were during the growth period. Total nitrogen amounts were statistically higher in the soil during the growth period than those collected after the corn harvest, while they were approximately close in the bean soil. The total nitrogen amount in corn and bean leaves increased significantly in plants grown on modified sludge soil. There were no significant differences in the total nitrogen levels of the maize and beans planted on the treated soil.


Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1109-1109 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
M. L. Gullino

Lamb's lettuce or corn salad (Valerianella olitoria) is increasingly grown in Italy and used primarily in the preparation of mixed processed salad. In the fall of 2005, plants of lamb's lettuce, cv Trophy, exhibiting a basal rot were observed in some commercial greenhouses near Bergamo in northern Italy. The crown of diseased plants showed extensive necrosis, progressing to the basal leaves, with plants eventually dying. The first symptoms, consisting of water-soaked zonate lesions on basal leaves, were observed on 30-day-old plants during the month of October when temperatures ranged between 15 and 22°C. Disease was uniformly distributed in the greenhouses, progressed rapidly in circles, and 50% of the plants were affected. Diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 μg/liter of streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently and readily isolated and maintained in pure culture after single-hyphal tipping (3). The five isolates of R. solani, obtained from affected plants successfully anastomosed with tester isolate AG 4, no. RT 31, received from R. Nicoletti of the Istituto Sperimentale per il Tabacco, Scafati, Italy (2). The hyphal diameter at the point of anastomosis was reduced, and cell death of adjacent cells occurred (1). Pairings were also made with AG 1, 2, 3, 5, 7, and 11 with no anastomoses observed between the five isolates and testers. For pathogenicity tests, the inoculum of R. solani (no. Rh. Vale 1) was grown on autoclaved wheat kernels at 25°C for 10 days. Plants of cv. Trophy were grown in 10-liter containers (20 × 50 cm, 15 plants per container) on a steam disinfested substrate (equal volume of peat and sand). Inoculations were made on 20-day-old plants by placing 2 g of infected wheat kernels at each corner of the container with 3 cm as the distance to the nearest plant. Plants inoculated with clean wheat kernels served as controls. Three replicates (containers) were used. Plants were maintained at 25°C in a growth chamber programmed for 12 h of irradiation at a relative humidity of 80%. The first symptoms, consisting of water-soaked lesions on the basal leaves, developed 5 days after inoculation with crown rot and plant kill in 2 weeks. Control plants remained healthy. R. solani was consistently reisolated from infected plants. The pathogenicity test was carried out twice with similar results. This is, to our knowledge, the first report of R. solani on lamb's lettuce in Italy as well as worldwide. The isolates were deposited at the AGROINNOVA fungal collection. The disease continues to spread in other greenhouses in northern Italy. References: (1) D. Carling. Rhizoctonia Species: Pages 37–47 in: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. B. Sneh et al., eds. Kluwer Academic Publishers, the Netherlands, 1996. (2) J. Parmeter et al. Phytopathology, 59:1270, 1969. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN, 1996.


Author(s):  
Gebeyaw Tilahun Yeshaneh

The study was conducted at the Abuhoy Gara Catchment, which is located in the Gidan District of North Wello Zone. The aim of the study was to study farmers’ perceptions about the effect of farm land management practices and soil depth on the distribution of major soil physico-chemical properties in eroded soils of Aboy Gara watershed. To address this issue, semi-structured interviews were conducted in 64 households to gain insight into soil fertility management practices, local methods were used to assess the fertility status of a field, and perceived trends in soil fertility. Thirty-three farmers were then asked to identify fertile and infertile fields. According to farmers response, farmers’ fields were characterized as fertile where it comprise black color, cracks during dry season, good crop performance, vigorous growth of certain plants and presence of plants in a dry environment whereas the infertile is where it shows yellow/white and red colors, compacted soils, stunted plant growth, presence of rocks and stones and wilting or dying of crops in a hot environment. A total of eight indicators (soil color, texture, soil depth, topography, soil drainage, and distance from home, type of weeds grown and cultivation intensity) were found to be used by farmers to evaluate and monitor soil fertility. The results of administered questions showed that the principal indicators mentioned by farmers as very important were soil colour (82.8%), continuous cropping land (72.2%), soil texture (62.8%), distance from home (61%), type of weeds grown (56%), soil depth (55.6%), topography (51.1%), and soil drainage (28.7%) as very important. So, among sixty four interviewed farmers: deep soil (60 farmers), soils near to home (60 farmers), forest soil (59 farmers), smooth fine soil (59 farmers), black color soil (58 farmers) and gentle slope soil (57farmers) are categorized as fertile whereas 59, 57, 56, 55, and 44farmers said that Sandy/coarse soil, shallow soil depth, steep slope soils and yellow/white, red soils and continuously cultivated soils are infertile, respectively. The overall result showed that there was good agreement between farmers’ assessment of the soil fertility status of a field and a number of these indicators. The soil laboratory analysis also corresponded well with farmers’ assessment of soil fertility. Therefore, to design more appropriate research and to facilitate clear communication with farmers, researchers need to recognize farmers’ knowledge, perceptions about assessments of soil fertility. Because, as they included all soil factors affecting plant growth, farmers’ perceptions of soil fertility were found to be more long term day-to-day close practical experience finding than those of researchers.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Serge Lévesque ◽  
Thomas Graham ◽  
Dorin Bejan ◽  
Jamie Lawson ◽  
Ping Zhang ◽  
...  

Abstract The capture and re-use of greenhouse fertigation water is an efficient use of fertilizer and limited water resources, although the practice is not without risk. Plant pathogens and chemical contaminants can build up over successive capture and re-use cycles; if not properly managed they can lead to reduced productivity or crop loss. There are numerous established and emerging water treatment technologies available to treat fertigation water. Electrochemical processes are emerging as effective means for controlling pathogens via in situ regenerative hypochlorination; a process that is demonstrated here to achieve pathogen control in fertigation solutions without leading to the accumulation of potentially phytotoxic free chlorine residuals associated with other chlorination processes. An electrochemical flow cell (EFC) outfitted with ruthenium dioxide (RuO2) dimensionally stable anodes (DSA) was characterized and evaluated for free chlorine production and Rhizoctonia solani inactivation in both irrigation and fertigation solutions. Pathogen inactivation was achieved at low current densities and short residence or cell contact times. Effluent free chlorine concentrations were significantly lower than commonly reported phytotoxic threshold values (approximately 2.5 mg/L) when fertilizer (containing ammonium) was present in the test solution; an effect attributable to reactions associated with breakpoint chlorination, including chloramine formation, as well as the presence of other oxidizable compounds in the fertilizer. Chloride concentrations were stable under the test conditions suggesting that the EFC was operating as a regenerative in situ electrochemical hypochlorination system. No significant changes to macronutrient concentrations were found following passage through the EFC.


2019 ◽  
Vol 65 (3-4) ◽  
pp. 92-105
Author(s):  
Xinguang Yang ◽  
Xilai Li ◽  
Mingming Shi ◽  
Liqun Jin ◽  
Huafang Sun

Replacement of topsoil to an appropriate depth is one of the key methods for ecological restoration. The objective of this study was to investigate the effects of topsoil replacement depth on vegetation and soil properties, and to identify the optimum soil depth for reclamation of coal mine spoils in a cold alpine mining area. We sowed 3 herbaceous species after coal mine spoil heaps were treated with topsoil to 3 depths (0, 20‒25, 40‒45 cm). The variations in vegetation community structure, plant growth, soil properties were measured at different replaced topsoil depths. The correlations between plant and soil properties were analyzed statistically. The results showed species richness, diversity and evenness were not significantly different among different depths of topsoil (P > 0.05). Vegetation coverage, density, height and aboveground biomass increased significantly (P < 0.05) with increasing topsoil depth. Soil properties did not change significantly with increasing topsoil depth (P > 0.05), but soil organic matter was significantly higher at 40‒45 cm topsoil depth than at other two depths (P < 0.05). All soil properties, with the exception of total potassium, were positively correlated with the plant growth parameters. The 40‒45 cm topsoil depth of replacement should be considered as effective method in reclaiming coal mine spoils. The use of both topsoil replacement to a depth of 40‒45 cm and sowing of suitable herbaceous seeds is found to be an effective restoration strategy. Additionally, fertilization might be used as a substitute for artificial topsoil replacement to improve soil quality and speed up revegetation process by the positive plant-soil interactions.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Savita Jandaik ◽  
Preeti Thakur ◽  
Vikas Kumar

The present study was conducted to determine antifungal activity of three different concentrations (5, 10, and 15%) of cow urine against three fungal pathogens (Fusarium oxysporum, Rhizoctonia solani, andSclerotium rolfsii) isolated from infected plants of Methi and Bhindi that showed symptoms of damping off and wilting disease by poison food technique. The extent of growth of test fungi in plates poisoned with cow urine was lesser when compared with the control plates. Among these concentrations cow urine at 15% concentration was most effective. When the three fungal organisms were compared, maximum growth suppression was observed inFusarium oxysporum(78.57%) at 15% concentration of cow urine followed byRhizoctonia solani(78.37%) andSclerotium rolfsii(73.84%). Finally we concluded that the cow urine has antifungal activities and the inhibitory activity can be used in the control of fungi. The nutritional effect of cow urine on plant growth was also tested withTrigonella foenum-graecum(Methi) andAbelmoschus esculentus(Bhindi) plants and the chlorophyll and protein content was also estimated.


2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 1333-1337 ◽  
Author(s):  
Y. T. Gan ◽  
J. Wang ◽  
L. B. Poppy

Node development of a crop plant can be used as a reference in making crop management decisions such as timing foliar fungicide application. A study was conducted in southwest Saskatchewan in 2001 and 2002 to characterize the nodal development, branching, and thermal time requirements on the main stem (MS) and on the branches of chickpea (Cicer arietinum L.). Large (9.1–11.0 mm) and small (8.1–9.0 mm) diameter seeds were planted at early-, normal-, and late-seeding dates in each year, and the crop was grown with recommended agronomic practices. The MS nodes were numbered upwards from the plant base, with the 1st node being the one immediately above the hypocotyls. All branches were identified and named in correspondence with their positions on the MS. The total number of nodes produced on the MS was 20 in the dry year of 2001 and 24 in the wet year of 2002, and their appearance was a function of growing-degree-days (GDD). The rate of the branch development in 2001 was greater compared with 2002 due to higher temperatures during the vegetative growth period. On average, branches No. 1 and 2 required 40 to 50 GDD units to emerge from the MS, while the emergence of branches No. 5 and 6 required 80 to 120 GDD units. Nodes on the branches that were positioned on the upper stems required more GDD units to develop compared with nodes on the branches that were positioned at the bottom of the MS. To use node development as a reference for crop management decisions in chickpea, one should bear in mind that the GDD requirements vary with node and branch positions on the culm. Key words: Cicer arietinum, legume, plant architecture, foliar fungicide, morphology


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