Non-volcanic Ash Soils Research Articles

Microbial ecology in tea soils

We determined the protease activity to analyze the mechanism of organic nitrogen decomposition (protein degradation) in tea soils. The hydrolyzing activities of N-benzoyl l-arginine amide (BAA), N-benzyloxycarbonyl l-phenylalanyl l-Ieucine (ZPL), and N-benzyloxycarbonyl glycyl l-phenylalanine (ZGP) were investigated at two depths in five acid tea soils, in upland crop Boils and in uncultivated soils (soils with near neutral pH) as controls. Sources of the enzymes and factors that influenced the activities were determined based on the relation between the protease activity and total N, total C, or microbial numbers. 1) In the assay with 0.2 M phosphate buffer (pH 8.1), the BAA-hydrolyzing activity in all the tea soils, upland crop soils and uncultivated soils was the highest, followed by the ZPL-hydrolyzing activity while the ZGP-hydrolyzing activity was the lowest. 2) Both magnitude of the protease activity and substrate specificity varied with depths and soil types. Proteases in the surface layers (0–20 cm) hydrolyzed all the used substrates faster than those in the lower layers (20–40 cm). The proteases in the lower layers hydrolyzed specifically BAA more than those in the surface layers. The BAA- and ZPL-hydrolyzing activities were higher in volcanic ash soils than in non-volcanic ash soils. 3) Tea, upland crop cultivation, and absence of cultivation affected the magnitude of protease activity. The soil cultivated with upland crops (hereafter referred to as “upland crop soils”) and uncultivated soils hydrolyzed specifically BAA more than the tea-cultivated soils (hereafter referred to as “tea soils”). 4) There were close relationships between the soil microbial group and BAA- or ZPL-hydrolyzing activity. It is therefore assumed that the enzymes hydrolyzing BAA and ZPL in the acid tea soils originated from the soil microorganisms.

Relationships between the Amount of Microbial Biomass and the Physicochemical Properties of Soil : Comparison between Volcanic and Non-Volcanic Ash Soils

Relationships between the Amount of Microbial Biomass and the Physicochemical Properties of Soil : Comparison between Volcanic and Non-Volcanic Ash Soils

A new method for measuring microbial biomass nitrogen in soils: Direct extraction after toluene treatment

Abstract Attempts were made to develop a new method for measuring the microbial biomass N in upland soils by direct extraction after toluene treatment. This method which involves the use of ninhydrin reagent for the estimation of nitrogenous compounds released by autolysis after incubation of the soil with buffered (pH 7.0) toluene at 30°C for 24 h, is rapid, sensitive, and precise. The factors responsible for the difference in the value of the K N nin factor between volcanic and non-volcanic ash upland soils were also examined. The results obtained can be summarized as-follows: 1. This method can be used to estimate the size of microbial biomass N in volcanic or non-volcanic ash upland soils. For 20 microorganisms (10 bacterial strains and 10 fungal strains) the mean value of the K N nin factor was 0.255 for volcanic ash soils and 0.343 for the non-volcanic ash soils. 2. The newly proposed toluene treatment method enabled to extract a much larger quantity of ninhydrin-reactive nitrogen than the chlorofor...

Survival of inoculant Bradyrhizobium japonicum in an Andosol

The survival of an antibiotic-resistant mutant of a commercial inoculant Bradyrhizobium japonicum strain, A1017ks, was studied in a volcanic ash soil (Andosol) in comparison with a non-volcanic ash soil (Fluvisol) over a period of 84 days. In a non-sterile soil system, the population decline in the Andosol (15% or 1.2 log units) was larger than in the Fluvisol (6% or 0.54 log units). In both soils, however, the inoculant bradyrhizobium survived at fairly high population levels after the period of incubation [106 and 107 colony-forming units (CFU) g-1 dry soil in the Andosol and Fluvisol, respectively]. In sterile control soil, viable bradyrhizobium cells could not be detected after 1 week of incubation in the Andosol, whereas in the Fluvisol population of introduced bradyrhizobium was maintained throughout the period of incubation. Overall changes in the population of indigenous bacteria and fungi were also monitored. However, no clear pattern of interaction between the inoculant Bradyrhizobium japonicum and the indigenous microbes could be identified. The antibiotic-resistant mutant maintained its resistance in the Fluvisol throughout the 3-month period of incubation, making it a useful model for conducting ecological studies in the soil.

Fluctuations in bacterial populations on the root surface of wheat (Triticum aestivum L.) grown under different soil conditions

Populations of several bacterial groups on the root surface of wheat and in root-free soil were investigated in volcanic ash soil and non-volcanic ash soil throughout a series of predetermined intervals. Over time, the populations changed similarly both on the root surface and in root-free soil. The numbers of total bacteria, fluorescent Pseudomonas spp., phosphate-solubilizing bacteria, and NH inf+ sup4 -oxidizing bacteria, were consistently lower in the plots with volcanic ash soil than with nonvolcanic ash soil, but the numbers of cellulose-decomposing bacteria were opposite to those of the other groups. Superphosphate application improved the growth of wheat in the volvanic ash soil. It did not, however, bring about any significant changes in the bacterial populations among the volcanic ash soils supplemented with three different levels of superphosphate, though there were some variations with plant age.

Relationship oetween the Shrinkage Behaviors and the Soil Structure on the Undisturbed Samples of Some Nonvolcanic Ash Soils

Relationship oetween the Shrinkage Behaviors and the Soil Structure on the Undisturbed Samples of Some Nonvolcanic Ash Soils

Physical Properties of Volcanic and Non-Volcanic Ash Soils in Japan

Physical Properties of Volcanic and Non-Volcanic Ash Soils in Japan

Specific gravity of allophane and volcanic ash soils determined with a pycnometer

Abstract The determination of the specific gravity of allophane is an interesting and important problem, but it is no exaggeration to say that we have no satisfactory answer to this question in spite of numerous studies. In this note, the specific gravities of allophane, weathered pumices and volcanic ash soil were determined with a pycnometer, and the values compared with those of the other clay minerals and non-volcanic ash soils.

Some factors affecting behaviour of boron in soil

Abstract It has been reported by many workers that various soil properties influence the retention of boron added to soils, but there is little infomration on the relative importance of these properties to boron retention and there is something controversial in the published results regarding the effects of different soil properties such as organic matter content, soil reaction, available calcium content and texture on boron retention (15). The present study was undertaken to obtain more detailed informations on the relationships between boron adsorption and different properties of soils, and on comparative contribution of soil constituents such as organic matter, sesquioxides and inorganic colloids to boron adsorption of soils. In Japan, boron deficiency symptoms of crops often appear in the fields of volcanic ash soils, and many experiments on boron application have been conducted to amend the boron deficiencies of the soils. It is considered that volcanic ash soils may have special characteristics concerning boron retention in comparison with nonvolcanic ash soils. In the present study, therefore, some volcanic ash soils were also taken as samples in addition to non-volcanic ash soils to confirm their speciality to boron retention.