Characteristics of the soils developed under broad-leaved evergreen forests in okinawa prefecture and the kinki district with special reference to their pedogenetic processes

Abstract

Properties of sesquioxides, clay mineralogical composition, and charge characteristics of the soils developed under broad-leaved evergreen forests in Okinawa Prefecture (subtropical climate) and the Kinki District (warm temperate climate) were studied with special reference to their pedogenetic processes in order to reexamine the corresponding parameters of Brown Forest soils and related soils in Japan.

The soils in Okinawa Prefecture were characterized by a higher degree of weathering as compared to the soils in the Kinki District. Major differences involved the values of the Fed/Fet ratio for the soil samples throughout the profile, and those of the ratios of (Fed-Feo)/Fet, CEC/clay, and (Feo + Alo)/ clay and the content of CaO plus Na₂O for the B horizon. The soils in the Kinki District did not show andic soil properties, nor Al translocation in the profile and, both of which were characteristic of Brown Forest soils developed under cool temperate climatic conditions at high altitudes in the same District.

The difference in the degree of weathering were reflected on the charge characteristics at the very surface of the soils, i.e., the surface of the particles of the soils in Okinawa Prefecture exhibited a lower reactivity as compared with those of the soils in the Kinki District.     

On the initial process of horizon differentiation from a uniform parent material

In a preceding paper (5) the authors proposed a hypothesis that the movement of iron in a soil profile is regulated by the ratio of the amount of the mobilizing agent to the amount of the iron to be mobilized.     

Charge characteristics of soil organo-mineral complexes and their effect on phosphate fixation

Soil is a complex system of mineral and organic components. The main reactive constituent of the mineral portion of soil is clay and of organic portion is humus from the microbial transformation of organic materials in the soil. Most of the biological and physico-chemical properties and the reactions of soil are due to clay and humus, the colloidal fraction of which being the most important. Many soil phenomena of great practical and fundamental importance such as sorption and exchange of ions, interaction with organic materials etc. originate from the surface charge of clay. The presence of organic matter in the soil and its union with the mineral portion affects these charge characteristics thus affecting many important physicochemical reactions in the soil.     

A soil core sampler for paddy soils and some physical properties of the soils under waterlogged condition

Introduction

Recent investigations in soil science have shown that physical properties of paddy soils are of great importance to rice-production. There is extensive literature on the chemical property of paddy soils, but little information on the physical property of paddy soils, especially under waterlogged condition. For studying the physical property of flooded paddy soils, it is necessary to collect the soil cores under an undisturbed condition.     

A method of capability evaluation for upland soils

As one of the important capability determinants of upland soils, fertility was taken up as the object of evaluation in this study.

On the basis of correlation analysis, factor analysis (FA) was applied to a set of 12 variates (humus, total nitrogen, available nitrogen, clay. sand, total phosphorus, Bray-P. HC1-P, CEC, percentage base saturation. exchangeable calcium, and pH).

Four mutually independent and clearly definable fertility component factors were consistently extracted from the 12 variates for the entire set of 94 surface soil samples and for different strata of the samples. The fertility status of each sample soil could be objectively designated by the scores of the four factors.

As a means of summarizing the information obtained, taxonomic distances between all pairs of the samples were computed from these 4 factor scores and subjected to numerical taxonomy. Six fertility groups were formulated, each of which was characterized by one or more of the fertility components. This fertility classification based on the present state of soil properties could be of use in pointing to the proper direction of fertility amelioration and improvement for each group of Boils.     

Mechanisms and processes of crust formation on artificial aggregates

Crust formation process initiates from aggregate disinategration occurred through the combined effects of inherent soil properties and external actions. Rainfall plays a major role in determining the moisture conditions of the soil surface and in triggering aggregate disintegration mainly through slaking and the impact off raindrops. To analyze the relations between rainfall characteristics and crust formation, three artificially granulated aggregates were exposed to natural rainfall events. The rainfall characteristics were expressed in terms of the distribution pattern of rainfall intensity, I _10min; mean weighted drop diameters, D _n; raindrop concentration, N _Dn,; rainfall energy, Et;and kinetic energy, KE; as well as conventionally used parameters, such as total amount and mean intensity of rainfall. The degree of crusting was evaluated in terms of the water permeability and morphological observation just after the rainfall treatment. Based on a comparison of the rainfall characteristics and degree of crusting, we confirmed the following relations. Rainfall characteristics at the onset of the event considerably influence the degree of crusting, i.e. initial rainfall with high I _10min; and large drop size promotes aggregate disintegration by slaking due to rapid wetting, whereas initial gentle rainfall prevents slaking by slow wetting and subsequent crusting. When initial rainfall is not saaficient for slaking but Beads to a weakening sf the aggregates, subsequent disintegration and crusting are promoted by impact together with the residual influence of slaking. Impact is a dominant factor for aggregate disintegration under wet conditions after initial rainfall which is so gentle that slaking never occurs. Responses of the soils under different natural rainfall conditions were almost consistent with the results under simulated rainfall reported in the previous papers (Tanaka et $1.1997: Soil Sci. Plant Nutr., 43, 99-107, 109-115). Crusting was not observed in the Fujino 1–3 soil gender any rainfall events. In the Wokuei 1–3 soil, characterized by a susceptibility to slaking and stability to impact, crusting was only formed under the rainfall with high I _{10 min} at the onset. For the Shimazu 1 soil, impact played a dominant role in crusting under any rainfall events, and a larger degree of crusting was found when the effects of impact and slaking were combined. The characteristics of rainfall monitored in this study may be within a normal range as natural rainfall in terms of the amount and the mean intensity, suggesting that crusting likely to occur if the aggregate stability of soils is Bower than or similar to that sf the Shimaza 1 and the Hokuei 1–3 soils.     

Trace elements in tropical Asian paddy soils

Attempts were made to evaluate correlations of total trace elements with various soil characters in the hope that such correlations would allow prediction of the trace element status of paddy soils in Tropical Asia.

Among the 11 trace elements studied, Ni and Cr showed by far the highest correlation, followed by the pairs of V and Zn, Ni and Zn, and Cr and Zn.

High positive correlations of trace elements with soil characters were found for the following pairs: total Fe₂O³, and V and Zn, total K₂0 and Rb, total CaO and Sr, total TiO₂, and V, total Al₂0³ and Zn, 10 Å clay content and Rb, clay and V, and sand and Zr. Among the negative correlations, the highest was between total SiO₂ and V, followed by those between total SiO₂ and Zn and sand and Zn.

Soil material classes and inherent potentiality ratings previously established were found to have some value for the prediction of the status of certain trace elements in soil.     

乳酸菌制剂在黑毛和牛育肥中的使用效果

[目的]旨在通过黑毛和牛（Japanese Blackcattle）育肥后期投服乳酸菌制剂Entero—coccus faecalis FK-23粉末,探讨付与牛肉的附加价值和该制剂的实用性。[方法]供试牛10头,随机分为试验组和对照组,试验组5头,每头每日投服乳酸菌制剂8．0g。测量体重（BW）,静脉采血检测白细胞数（WBC）,维生素A（VA）,维生素E（VE）．总胆固醇（TC）,谷草转氨酶（GOT）,血尿素氮（BUN）及血糖（GLC）浓度;HPLC测验中性脂肪的脂肪酸成分。[结果]试验组与对照组比较。食欲亢进,日增重（DG）明显增加（P〈0．05）,血清VE和TC明显升高（P〈0．05）,VA维持预计水平走向不变。中性脂肪的不饱和脂肪酸比例出现增高趋势,出栏体重增长4．3％,胴体重增加9．3kg。[结论]结果提示,黑毛和牛育肥后期投服乳酸菌E．faecalisFK-23制剂可以获得VE含量较高的高附加价值牛肉并能提高其生产性能。