Showing 6 results for Rhizosphere
M. Mansourzadeh, F. Raiesi,
Volume 16, Issue 59 (4-2012)
Abstract
The application of herbicides as organic chemical compounds to control pest and weeds may affect the population and activity of microorganisms, and this may have an influence on biochemical processes that are important for soil fertility and plant growth. The primary objective of this study was to evaluate different loading rates of eradican (EPTC) on soil microbial biomass C and N, microbial biomass C/N ratio and the activities of urease and arylsulphatase under field conditions. In this experiment, loading rates of 6 and 9 L ha-1 eradican were applied to a calcareous soil cultivated with corn (Zea mays L.) and left uncultivated using split-plots arranged in a completely randomized block design with three replications. The experiment was conducted in the Kabootarabad’s Agricultural Research Center, Isfahan. Soil microbial biomass C and N were determined at 30th and 90th days after the onset of experiment and the activities of urease and arylsulphatase were assayed at 30th, 60th and 90th days. Results showed that in soils cultivated with corn microbial biomass C increased with increasing eradican levels and in both cultivated and uncultivated soils microbial biomass N and microbial biomass C/N ratios were increased over the control. At 30th day, urease activity at 6 L ha-1 level reduced, while at 9 L ha-1 level it increased compared with the control soils. At 60 day, there was no significant difference in the urease activity between the treatments. At 90th day, the activity of urease showed slight fluctuations. There was a reduction in arylsulphatase activity of the cultivated soils by increasing the loading rates of eradican during the experiment, and in uncultivated soils no trend was observed. Briefly, the use of eradican can cause either reduced or increased microbial biomass sizes and enzyme activities in calcareous soils These changes, however, depend largely upon the application rate of eradican, time elapsed since eradican application (i.e., sampling date) and the presence or absence of plant
H. R. Motaghian, A. R. Hosseinpur, F. Raiesi, J. Mohammadi,
Volume 18, Issue 67 (6-2014)
Abstract
Rhizosphere is a small zone and has quite different chemical, physical, and biological properties from bulk soil. This research was performed to study the available Zn and its fractions in the wheat rhizosphere and bulk soils by using rhizobox at greenhouse conditions. Total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and available Zn using 7 chemical procedures and Zn-fractions were determined in the rhizosphere and bulk soils. The results indicated that TOC, DOC and MBC in the rhizosphere were increased significantly (P<0.01). Zn extracted using several chemical extractants (except 0.01 M CaCl2) in the rhizosphere were significantly (p<0.05) higher than in the bulk soils. Also, concentrations of Zn-fractions (except carbonate-associated) in the rhizosphere were significantly (p<0.05) different from concentrations of Zn-fractions in the bulk soils. Results indicated that correlation between uptake index and extracted Zn using DTPA-TEA and Mehlich 3 were significant (p<0.05). Moreover, significant correlation (p<0.05) between uptake index and exchangeable Zn and Zn associated with iron-manganese in the wheat rhizosphere and bulk soils were found. The results of this research illustrated that available Zn and its fractions in the rhizosphere soils are different from the bulk soils. Therefore, application of the rhizosphere soil would be recommended in the study on these properties after planting.
Z. Mosleh, M. H. Salehi, M. Rafieiolhossaini,
Volume 18, Issue 68 (9-2014)
Abstract
Many studies have been carried out on pure minerals to study the effect of plant roots on minerals weathering, but information on mineral weathering that normally occurs in different soil fractions is limited. To investigate the effect of
German Chamomile (
Matricaria chamomilla L.) cultivation on mineral weathering of clay and silt fractions in five different soil series amended or not amended (control) with cattle manure, a factorial experiment was performed in a randomized complete block design (RCBD) with three replications. At harvest time, rhizosphere soil was separated and mineralogical studies were performed through X-ray diffraction (XRD) and compared to before cultivation Results showed that in clay sized particles, trioctahedral chlorite transformed to di-octahedral chlorite while kaolinite disappeared. In silt sized particles, feldspar transformed to amphibole and vice versa The pots amended with manure showed the same changes for clay and silt sized particles as the pots without manure.
V. Shahrokh, H. Khademi, H. Shariatmadari,
Volume 23, Issue 2 (9-2019)
Abstract
Despite the great importance of potassium applied as a fertilizer in the orange orchards, no information is currently available regarding the rate of potassium release from rhizosphere and the bulk soils of such trees. The objectives of this study were to investigate the weathering of micaceous minerals and their non-exchangeable K release and also, to examine the status of different forms of K in the rhizosphere and bulk soils of orange orchards with different ages in Darab, Fars Province. Samples were, accordingly, taken from the rhizosphere and bulk soils of orange orchards with the ages of 5, 10 and 20 years; also, virgin soils (control) were obtained from three soil depths including 0–30, 30–60, and 60–100 cm. Water soluble, exchangeable and nonexchangeable K, and the clay mineralogy of the soils were determined. The results demonstrated that the concentration of soluble and exchangeable K in the cultivated soils was less than that in the control soil and that the concentration of nonexchangeable K in the soils of 20-year-old orchards was less, than that in other soils. Soluble and exchangeable K values decreased with depth in all soils. Clay mineralogy investigation also showed that the quantity of illite decreased and that of smectite and illite-smectite increased as the age of orange trees was raised. With increasing the age of orange trees and root development, more potassium could be taken up from soil and more changes occurred in the soil minerals. In order to avoid a very high decline in the reserved K in the soils under orange trees, particularly in the orchards with older trees, K fertilization has to be taken more seriously based on the soil testing results.
R. Vahedi, M. H. Rasoili-Sadaghiani,
Volume 23, Issue 4 (2-2020)
Abstract
Synergistic relationships between mycorrhizal fungi (AMF) and organic compounds affect the mobility of the micronutrient elements in the rhizosphere and improve their bioavailability. In order to evaluate the effect of biochar and pruning waste compost of apple and grape trees, as well as AMF, on micronutrient bioavailability in calcareous soil at the wheat rhizosphere, an experiment was carried out in a completely randomized design under greenhouse conditions in a rhizobox study. Some factors including the organic sourses (pruning waste biochar, pruning waste compost and control), microbial inoculation (AMF and no inoculation) were considered. At the end of the growth period, Organic matter (OM) content and bioavailability of micronutrients including iron (Fe), Zinc (Zn), Copper (Cu) and Manganese (Mn) in the rhizosphere and their uptake by wheat plant were determined. The results indicated that OM, Fe, Zn, Mn and Cu were significantly increased in the rhizosphere soil under the influence of organic sources and mycorrhizal inoculation. Furthermore, biochar application in the mycorrhizal tratment resulted in 74.73% and 19.28% increase in Fe and Mn, as compared to non-inoculated conditions, in rhizosphere. The presence of mycorrhizal fungi increased the bioavailability of 94.66% and 29.54% Zn and Cu in the compost treatment, as compared to non-inoculated ones. Application of organic sources and mycorrhizal inoculation increased the micronutrient uptake and plant dry weight.
R. Rezaeinejad, H. Khademi, Sh. Ayoubi, H. Jahanbazy Goujani,
Volume 24, Issue 2 (7-2020)
Abstract
In arid and semi-arid ecosystems, isolated trees significantly influence the soil properties and can have a great impact on the soil fertility as well as the conservation and improvement of soil quality. This investigation was conducted to examine the influence of wild almond (Amygdalus arabica Olive.) trees having different ages on the physical and chemical soil properties. Soil samples were taken from the depths of 0-20, 40-60, 80-100 and 120-140 cm at two distances from the tree crown including the basal area (referred to as the rhizosphere) and the canopy edge in 3 replications for the 30, 50, and 130 year-old stands and also, in a control site, all in the Anjarak area, southeast of Baft city, Kerman Province. Soil properties including pH, EC, organic matter, calcium carbonate equivalent, available and non-exchangeable potassium and soil texture were measured in all samples. The results indicated that the measured soil properties in different depths in the study area had been influenced by the age and the canopy size of the wild almond trees. The highest and the lowest amount of pH were found in the control soil and the soils covered by 130 year-old trees, respectively. Besides, the electrical conductivity of the soil under the tree crown was more than that of the soil in the canopy edge. The accumulation of C, N, and other nutrients under the tree canopies resulted in the creation of fertility islands surrounding the trees. Furthermore, the soil physical and chemical properties were greatly improved with the increase in the tree age of Amygdalus arabica Olive. As the conclusion, wild almond trees could have very positive effects on soil properties. Therefore, it is essential to protect the trees. Otherwise, the risk of soil quality reduction would be increased and soils might become more susceptible to soil erosion.
