Abstract:【Objective】 Albic soil is one of the main soil types with low productivity in Northeast China, mainly distributed in Sanjiang Plain. The soil profile is mainly composed of three layers, the black soil layer, the albic layer, and the illuvial layer. The albic layer has the physical characteristics of high bulk density, high strength, and poor aeration and water permeability, which is easily subjected to drought and waterlogging, thus, limiting crop root growth and yield formation. Its buried depth and thickness are closely related to the penetration depth and growth performance of crop roots, which are the key indexes to quantify the productivity of albic soil. However, little is known about the spatial distribution and driving factors of buried depth and thickness of the albic layer in the albic soil in Sanjiang Plain. The objective of this study was to investigate the spatial distribution pattern and driving factors of the buried depth and thickness of the albic layer in the albic soil in Sanjiang Plain. 【Method】 Based on classical statistics and geostatistics, the albic soil in the southeast of Sanjiang Plain ( Jidong County, Mishan City, Hulin City, and Baoqing County) was selected, and the soil profile of 0-60 cm was excavated. The thickness of the black soil layer and the albic layer was obtained by visual method, and the soils of the black soil layer, and the albic layer were taken for physical and chemical analysis. In addition, the meteorological, topographic, and parent material data of each sample point were collected. A total of 62 sampling points were obtained from 51 sampling points in the field and 11 points in the literature survey. 【Result】 (1) The average buried depth of the albic layer in the albic soil was 23.7 cm, and it gradually increased from southwest to northeast (13-37 cm). The average thickness was 18.5 cm, which gradually increased from southwest to northeast (8-35 cm), and the buried depth was opposite to the thickness of the albic layer in some local areas. (2) The burial depth of the albic layer was mainly affected by human tillage methods, and plough tillage increased the burial depth of the albic layer. (3) The thickness of the albic layer was negatively correlated with altitude ( r=–0.355, P<0.01), annual average evaporation ( r = –0.441, P<0.01), annual average temperature ( r=–0.273, P < 0.05), and clay mineral montmorillonite ( r=–0.432, P< 0.01), but positively correlated with annual average precipitation ( r=0.463, P<0.01), annual average humidity index ( r=0.461, P<0.01), coarse mineral hydromica (r=0.446, P<0.01), and coarse mineral quartz ( r=0.321, P<0.05). 【Conclusion】 The buried depth of the albic horizon in the Sanjiang Plain is related to tillage methods. The thickness of the albic horizon is mainly affected by meteorological topographic factors and soil minerals, resulting in a spatial distribution pattern of shallow and thin in the southwest and deep and thick in the northeast.

Abstract:【Objective】The purpose of this study is to illustrate effects of incorporation of organic material on organic carbon of the heavy fraction and composition of soil aggregates in the soil in the hope that the work may be of some important significance to scientific evaluation of the effects of incorporation of crop straw into the soil on soil fertility and the environment.【Method】An in-lab experiment was carried out incubating for 120 days columns of albic soil with corn stalk incorporated into top soil and parent material at a varying rate, and then analyses done for accumulation of organic carbon of heavy fraction, composition of soil aggregates and distribution of organic carbon in various fractions of soil aggregates as affected by incorporation rate of corn stalk.【Result】It was found that content of the organic carbon of heavy fraction in both the top soil and parent material increased simultaneously with the increasing incorporation rate of corn stalk. The two soils did not differ much in increment of the content of the organic carbon of heavy fraction, showing a slight difference of being only 0.34 g kg-1. However, they varied sharply in increasing rate of organic carbon. In the top soil, organic carbon increased by 85.51% only and in the parent material by 556.23%. It was also found that, the incorporation of stalk promoted transformation of small aggregates (<0.25 mm) to large aggregates (> 0.25 mm) in the soil. When the amount of corn stalk added is too high, > 2 mm size aggregates no longer increase but decrease. When corn stalk was incorporated at a rate of 3% and 2%, the fraction of large aggregates contributed the most to the content of organic carbon in the soil reaching up to 69.90% and 65.48%, respectively.【Conclusion】 In this study, the addition of stalk promoted accumulation of organic carbon of heavy fraction and formation of large-sized aggregates and increased organic carbon content in aggregates in various particle-size ,adding the appropriate amount of corn stalk can increase the contribution rate of organic carbon in the large-sized aggregates fractions. Compared to the top soil, that in the parent material soil had organic carbon increased by a far more high rate. The effect of the addition of extraneous carbon increasing organic carbon content in aggregates of all particle sizes was more apparent. The soil in the parent material layer was much higher than the top soil in carbon sequestration capacity, in the case that the former almost contained nil of organic carbon.

Abstract:A long-term plot experiment was conducted in the Sanjiang Plain to study the effect of applying organic manure for years in row on soil humus composition, transformations of Fe, Mn and Al oxides and phosphorus availability. The results indicated that soil humus, mainly loosely combined humus were increased after 4 years of adding cow feces, because of the supply of lowmolecule organic acid released from the added cow feces. The contents of DTPA-extractable and organo-chelated Fe, Mn, Al was also related to organic acid corroding soil coating and solublizing soil oxide. Some half-products derived from the fresh material can supply H+,and can chelate or solublize soil Fe, Mn, Al or compete for adsorption site on soil colloid, and form Fe, AI-OM-P or soil colloid-OM-compounds, thus bring about significant increase in soil available P. So the bio-measure is an effective strategy to ameliorate albic soil, enhance its nutrient, especially P, availability and its buffer capacity and stress-resistance.

Abstract:Minerological composition and chemical characteristics of albic soil in seven typical profiles all over the Jianghuai drainage basin were analyzed.The result showed that the albic soils in this region are silty loam or silty clay loam with a silt percentage of 45%~76%.Having inherited the characteristics of the loess, the main constituent of the clay is Hydromica, accounting 60%~80%.Sa and Saf of the soil are 7.70~14.65 and 6.43~10.24 respectively.But Sa and Saf of clay are 3.53~4.42 and 2.40~3.35 respectively.Compared with the other layers, Sa and Saf of the soil at the surface layer are higher or the highest,which manifests the phenomenon of surface silicon enrichment.Significant variations of Sa and Saf, together with that of clay composition and particle aistribution, show a parent material of the whitish layer not the same as that of the B horizon, which is due to the supposed alteration of alluviation and sedimention of loessial deposit in Holocene follow ed by leaching and illuviation.

Abstract:In this work, the characteristics of organic matter in different particle fractions of albic soil were studied by using Kumadas method. The results showed that the contnet of orc C in fertile soils and their particle fractions was higher than that in poor soil and it decreased with the increase of particle diameter. The decrement was smaller in fertile soil than that in poor soil. Soil organic matter and clay content the consistency between the storage curve of organic C and the content curve of particle fractions. Organic C storage of clay or fine sand particles in fertile soil was significantly higher than that in poor soil. The humus in soils and their particle fractions were mainly free form which can be extracted by 0.1 mol/L NaOH.Some indexes such as humic acid content and the PQ value of free form were higher in fertile soil than those in poor soil. But the degree of humification based on ΔlogK and RF values was lower in fertile soil.than that in poor soil. Those trends were much clear for silt and fine sand particles. With the increase of particle diameter, the contents of free humus and its humic acid. tended to decline, but the PQ1 value was higher in silt particle than that in other particle fractions. The type of free humic acid changed with the increase of particle diameter in the order of A type (clay)→B type(silt)→Rp (fine sand). The content of combined humus which was extracted by 0.1 mol/L Na4P2O7 and its humic acid content and the degree the humification were the highest in the silt particle, but PQ2 decreased with the increase of particle diameter. Both in fertile soil and in poor soil combined humic acid mainly belonged to A type in which the degree of humification was higher, only a few belonged to B type or P type.

Abstract:This paper deals with the primary and secondary mineralogical properties of seven pedons of albic soils from the northern subtropical region of China. The contents of heavy and light minerals show that the soils inherit the parent material properties, the parent material between albic E horizon and argillic horizons are lithologically uncountinous, and the former horizons are weathered strongly than latter ones. The surface of the arenaceous quartz shows albic E horizons result from the loess reaccumulation. Hydromica dominates the clay fraction of albic soils, the kaolinite formation and clay mineral crystallinity show the desilicification and depotassication, the clay minerals can collapse to some extent. The dominant iron oxides are hematite and geothite, these iron oxides are proved to have formed under the conditions consistent with present ones.

Abstract:Four typical profiles of albic soils in China were collected to study the properties and geochemical variability of amorphous oxides collected to study the properties and geochemical variability of amorphous oxides of iron, manganese and aluminum.

Abstract:With the study of physical,chemical,morphological and mineralogical properties of three pedons of typical albic soils from the Three River plain of Heilongjiang Province,we discussed the pedogenetic characteristics.The profiles were found to be lithologically countinuous by the comparsion of Zr/Sr and Ti/Zr ratio within the pedons.The albic soils study was characterized by a mollic epipedon,an ablic E horizon and a thick argillic horizon.Through this study,it was indicated that lessivage was a dominant pedogenetic process.Pedogenic Fe Mn nodules were found abundant in Ah and E horizons and were apparently forrned by weathering of Fe-Mn primary minerals,and the nodules may have developed in situ.The maximum amounts of pyrophosphate extractable Fe and AI appeared it Bt2 horizons were smaller than the values required for podzols.Vermiculite,which had not previously been recognized,dominated the clay fraction of albic soils.The clay mineral assemblage was qualitatively similar but quantitively differentiated throughout the profile.Finally,we suggested that the albic soils could be classified as mollie planosols in the FAO-UNESCO system and Typical Argialbolls in Soil Taxonomy.

Abstract:The characteristics of phosphate(P) adsorption and desorption by 4 albic soils collected from the Three-River Plain.The experimental results showed that the soils had very strong ability to adsorb P.The whole process of adsorption was divided into the initially fast reaction (within 24 hours) and the slow reaction thereof ter.In all kinetic models examined in this study, the Langmuir-type equation most perfectly modeled the kinetic processes of P sorption.The properties of P adsorption suggested that there were two populations of adsorbed sites which differed in the affinity for P,and therefore the sorption of P may be described using two-surface Langmuir equation.The process of P desorption had high P concentration.The characteristics of succe.ssrve an evident hysteresis phenomenonn at desorption further indicated the presence of two forms of adsorbed sites or regions,one adsorbed P tightly,another loosely.Organic matter (O.M.) significantly affected P sorbtion by soils.The addition of O.M.could increase the amount of P adsorbed but it could be conductive to P desorption as well.The higher the content of O.M.the more easily the adsorbed P,especially at low P concentration.After O.M.was removed,P was more tightly adsorbed by soils,and therefore the desorption rate decreased evidently.

Abstract:Three pedons of typical albic soils in the Three River Plain of Heilongjiang Provence were chosen far the study of elemental geochemistry.The background levels of trace element and rare earth element were established for these undisturbed soils.The redistribution and differentiation of these elements during soil forming process were analyzed.We found that Br,Cl,I and Hg were possibly accumulated in Ah Horizons,due to dust deposition and their affinity for soil organic matter.Mn,As,Sb,Th and U were associated with amounts of oxalate and dithionite extractable Mn and Fe in E horizons.The Cr,Rb,Sc,V and Zn Were closely related to clay particles and enriched in Ba horizons.The B,Ba,Hf,Sr,Ti and Zr exist generally in weathering-resistant minerals and have a relatively even distribution in soil profiles.