Phosphate status of chernozem-like hydromorphic soils in the northern Tambov Plain

The phosphate status of chernozem-like soils in the northern forest steppe of the Tambov Lowland depends on soil waterlogging and hydrological conditions. Due to surface waterlogging and free effluent seep-age in podzolized, chernozem-like soils of open watershed depressions, the removal of bases and iron decrease the total phosphorus content by 10–15% because of the decrease in active mineral phosphates. Organic matter acts as a buffer preventing phosphorus from leaching. In podzolized, chernozem-like and podzolic, gleyic soils of closed watershed depressions, significant amounts of iron phosphates are accumulated in fine earth and ortsteins due to surface waterlogging and difficult effluent seepage. Under ground waterlogging, calcium phosphates prevail in the composition of active mineral phosphorus in the gleyed, gleyic, and gley chernozem-like soils of above-floodplain terraces.     

Manganese, iron, and phosphorus in nodules of chernozem-like soils on the northern Tambov Plain and their importance for the diagnostics of gley intensity

Nodules (nodules) forming in the chernozem-like soils of flat-bottomed closed depressions on the northern part of the Tambov Plain differ in their morphology and chemical composition as related to the degree of hydromorphism of these soils. The highest are the coefficients of Mn, P, and Fe accumulation in the nodules from these soils. The Fe to Mn ratio grows with the increasing degree of hydromorphism. Under surface moistening, the maximal amounts of mobile Mn and Fe compounds were extracted from the nodules of the most hydromorphic podzolic chernozem-like soils; under the ground moistening, their greatest amounts were extracted from the least hydromorphic soil—the weakly gley soil. In the first case, the content of organic phosphates in concretions amounted to 30–50%; in the second one, 2–3% of their total content. Under surface moistening, the proportion of active mineral phosphates becomes higher with the increasing hydromorphism: from 30 (podzolized soil) to 70% (gleyic podzolic soil). Under ground moistening, on the contrary, their proportion decreases from 70–89% in the weakly gley soil to 40–50% in the gley chernozem-like soil. The possibility to determine the degree of hydromorphism of chernozem-like soils based on the coefficients of bogging is shown. The expediency of using Schvertmann’s criterion in these studies is assessed.     

Ecological-hydrological and genetic features of chernozem-like soils of closed depressions in the northern Tambov Lowland

Specific features of the genesis and water regime of soils in closed depressions were studied in two catenas located on the interfluvial and terrace surfaces. In humid years and in the years with moderate precipitation, the surface flooding up to early May reduced the Eh values up to 60–100 mV in the soils of the interfluvial depressions. The contrasting stagnant-percolate water regime under the surface waterlogging caused podzolization of the soils manifested in the skeletans, iron nodules, humus cutans, and podzolic horizons. The pro-files acquired eluvial-illuvial differentiation, and the water-physical properties of the soils became less favorable. In the soils of the terrace depressions upon bogging due to the shallow ground water and stagnation of water up to mid-July, the Eh values decreased to ?20 to ?80 mV. The reductive conditions were responsible for the appearance of the morphochromatic signs of gley. The ground water of bicarbonate-calcium composition at a depth of 80–120 cm hindered podzolization. The soils with features of gley and podzolization are low-productive.     

Concretions in typical chernozem,gleyed chernozem-like,and solonetzic chernozem-like soils of the southern Tambov Lowland

A system for the diagnostics of chernozemic soils of the Tambov Lowland based on concretions is proposed for agricultural and reclamation purposes. The relationships between the structure and composition of the carbonate concretions, the long-term water regime of the soils, and the productivity of the crops have been established. The dense concretions in the typical chernozem testify to the depth of the seasonal wetting; the angular-rounded concretions in the deeply gleyed chernozem-like soil, to the upper boundary of the capillary fringe; and the angular concretions with sharp edges and cavities in the gleyic chernozem-like soils, to the groundwater table. In the chernozem-like soils that were waterlogged with bicarbonate-sodium water, the black angular concretions were formed in the solonetzic horizons, while the weakly compacted light-colored ones, in the zone of the capillary fringe. Humic acids were responsible for the color of the dark neoformations, and fulvic acids predominated in the light-colored ones. The appearance of black fine nodules indicated periodic surface water stagnation. Manganese predominantly accumulates in these nodules. The structure of the Mn-Fe concretions in the plow horizon observed at a magnification of 40–50 times has a diagnostic importance. The short-term (2–3 weeks) water stagnation leads to the formation of fine-stratified concretions, and the long-term (up to 1.5 months) stagnation promotes the formation of uniform porous ones. The solonetzic process induced by the bicarbonate-sodium water results in the appearance of mottled concretions.     

Methods for quantitative diagnostics of degree of hydromorphism of chernozem-like soils (based on example of soils of northern Tambov Plain)

The hydrologic features of chernozem-like soils of the northern Tambov Plain reflect the crystallinity of nonsilicate iron contained in ferromagnetic concretions, as well as the qualitative humus content and other properties. The possibility of using Schwertmann’s criterion and swampiness coefficient in the Zaidel’man-Ogleznev method as diagnostic indices of degree of hydromorphism is shown. A new diagnostic index is suggested, i.e., the hydromorphism criterion (K_I–II); the relation of the optical density of the extraction of alkaline and alkaline pyrophosphate from fine-earth arable land horizon is based on its definition.     

Chemical properties of soils in closed depressions of the northern Tambov Plain

Chemical properties of chernozem-like soils in closed depressions on different relief elements in the northern part of the Tambov Plain differ significantly. The soils with podzolic features in depressions on the watershed have a high acidity and a low degree of base saturation. The soils on the above-floodplain terrace are neutral and saturated with bases. When the degree of moistening increases, the share of magnesium in the total exchangeable bases increases to 30–35%. In the soils of surface flooding under gleyzation conditions, iron is leached from the fine earth, and iron nodules are formed. In the soils formed under the impact of groundwater, iron diffusion is observed in the surface layers. In the podzolic horizons of soils on the watershed, humus acquires a fulvic-humic character. In the soils formed under the impact of groundwater and water stagnation conditions typical for gleyed soils, the Cha: Cfa ratio is higher than 1.     

Clay minerals in chernozem-like soils of mesodepressions in the northern forest-steppe of European Russia

In the northern forest-steppe of European Russia, under the conditions of surface waterlogging (freshwater) and a stagnant-percolative regime, gleyic podzolic chernozem-like soils with thick light-colored eluvial horizons are formed. These horizons are close or similar to the podzolic horizons of bog-podzolic soils in many properties of their solid phase. They are bleached in color and characterized by the removal of Ca, Mg, Fe, Al, and Mn and the relative accumulation of quartz SiO₂. These soils differ from leached chernozems in their acid reaction and very low CEC, the presence of Fe-Mn concretions and coatings, and the significant decrease in the clay content in the A2 horizon as compared to the parent rock. The soils studied differ significantly from loamy podzolic and bog-podzolic soils by the composition of the clay minerals in the A2 horizons: (1) no essential loss of smectite minerals from this horizon was found as compared to the rest of the solum, (2) pedogenic chlorites (HIV and HIS) are absent, and (3) the distinct accumulation of illites is observed as compared to the subsoil and parent material, probably, due to the process of illitization.     

Genesis and properties of dark-colored chernozem-like soils of mesodepressions under fallow in the northern Caspian region

Specific features of the most fertile soils in the semidesert zone of the northern Caspian region—dark-colored chernozem-like soils of large mesodepressions—are analyzed. The recent regional rise in the groundwater level and the restoration of steppe vegetation in the fallowed soils of large mesodepressions, especially near forest strips and forest plantations, have led to certain changes in the microfabric and chemical composition of these soils, as well as in the soil organic matter properties.     

Fractional composition of humus in leached chernozems and gleyed podzolized chernozem-like soils of the northern forest-steppe zone

The composition of humus in leached chernozems differs from that in gleyed podzolized chernozem-like soils in the northern forest-steppe zone of European Russia. Leached chernozems have the fulvate-humate humus. Gleyed podzolized chernozem-like soils have the humate-fulvate humus. A more aggressive composition of humus in the latter soils is caused by their overwetting and the development of gley processes under conditions of a stagnant-percolative soil water regime.     

Ecological-hydrological and genetic features of the soils of the Tambov Plain

Specific features of the genesis of chernozem-like, solonetzic chernozem-like soils, and hydromorphic chernozem-like solonetzes were investigated on the southern Tambov Plain. Typical chernozems occupy well drained areas. The yield of cereals is limited by the amount of precipitation. On the flat surface of weakly drained watersheds, deeply gleyed chernozem-like soils are formed under the influence of bicarbonate-calcium ground water and water stagnation on the plow sole. In closed depressions with the 1.5- to 2.0-month long stagnation of surface water on the compact lower horizons, podzolized gleyic chernozem-like soils are formed. They have favorable physical properties, weak eluvial differentiation, and rather high acidity. In humid and moderately humid years, the cereals on these soils are waterlogged; in dry years, their yield increases by 20% as compared to that on the typical chernozem. In the low undrained areas of the watersheds, solonetzic chernozem-like soils and hydromorphic chernozem-like solonetzes are formed under the influence of bicarbonate-sodium water. Despite the unfavorable physical properties of the solonetzic horizons, their better supply with moisture determines the possibility to obtain stable high yields of cereals on the solonetzic chernozem-like soils. The productivity of the gleyic chernozem-like solonetzes is low irrespective of the humidity of the year.     

固体废弃物及土壤中磷的形态分析技术

畜禽粪便等固体废弃物及土壤中磷的形态分析对于管理固体废弃物、提高磷素利用率、减少磷素流失风险具有重要意义。自20世纪初以来,已提出多种固体废弃物及土壤中磷素形态分析的方法,包括化学分级、酶水解法、X射线衍射(XRD)、红外光谱(FT-IR)3、1P核磁共振(31P NMR)、X射线吸收近边结构(XANES)等。本文系统总结了一些固体废弃物及土壤中磷素形态分析的方法,比较了其特点,指出只靠单一的方法并不能很好地鉴定固体废弃物及土壤中磷素的形态,必须综合考虑运用多种方法,从而为磷素形态分析提供方法选择的依据,同时为进一步发展固体废弃物及土壤中磷素形态分析新技术奠定基础。     

EDTA extractable phosphorus in soils as related to available and inorganic phosphorus forms

Abstract

Twenty surface soil samples, representing two major soil orders alfisols and vertisols were extracted with 0.01N Na₂ EDTA solution (pH 4.8) at a soil/solution ratio of 1:25. Phosphorus in the extract was determined following ammonium molybdate‐stannous chloride colorimetric method. The EDTA extractable P showed significant positive correlations with extractable P according to the Olsen, Morgan, Bray 1 and 2 and also with inorganic phosphorus fractions associated with Al, Ca and Fe.     

北方耕地和蔬菜保护地土壤磷素状况研究

以北方一般耕地和蔬菜保护地为供试土壤 ,研究了不同种植条件下土壤磷素状况 ,蔬菜保护地土壤磷素的空间分布特性。结果表明 ,蔬菜保护地土壤全磷、无机磷、有机磷、Olsen-P的平均含量是一般耕地土壤的 2.7～14.0倍 ,土壤Olsen P占全磷的比率 ,Ca2-P ,Ca8-P ,Al-P占土壤无机磷的比率显著高于一般耕地土壤。蔬菜保护地土壤各形态磷素主要积累在 0～20cm土层 ,并随土层深度的增加各形态磷素的含量逐渐降低 ,各土层Olsen-P ,Ca2-P ,Ca8-P ,Al-P含量降低幅度明显高于Fe-P ,O-P ,Ca10-P含量的降低值     

北方耕地和蔬菜保护地土壤磷素状况研究

以北方一般耕地和蔬菜保护地为供试土壤 ,研究了不同种植条件下土壤磷素状况 ,蔬菜保护地土壤磷素的空间分布特性。结果表明 ,蔬菜保护地土壤全磷、无机磷、有机磷、Olsen-P的平均含量是一般耕地土壤的 2.7～14.0倍 ,土壤Olsen P占全磷的比率 ,Ca₂-P ,Ca₈-P ,Al-P占土壤无机磷的比率显著高于一般耕地土壤。蔬菜保护地土壤各形态磷素主要积累在 0～20cm土层 ,并随土层深度的增加各形态磷素的含量逐渐降低 ,各土层Olsen-P ,Ca₂-P ,Ca₈-P ,Al-P含量降低幅度明显高于Fe-P ,O-P ,Ca₁₀-P含量的降低值     

Mountainous meadow chernozem-like soils of high mountains in the North Caucasus region

Original and literature data on the soil-forming conditions and the morphology, physicochemical properties, and bulk chemical and mineralogical composition of mountainous meadow chernozem-like soils of the North Caucasus region indicate that these soils are developed from the coarse-textured pebbly colluvium of calcareous bedrock under the impact of humus accumulation and clay formation. The intensity of these processes is directly related to the activity of soil biota. Suggestions aimed at improving the classification of high-mountain soils are discussed.     

Available phosphorus forms in forest soils and their possible ecological significance

Abstract

For a range of northern N.S.W. forest soils typical of Australian east coast forests, both inorganic and organic P have been determined on sequential soil extracts. Organic P was present in each extract, and in most extracts was a high proportion of the total P, regardless of soil type. Using the sum of the P concentrations in the most neutral extracts as an index of available P, the organic component ranged from 352 to 88% of the total available P. Soil parent material appeared to exert the strongest influence on both soil total P and on the proportion of organic P/total P which ranged from 26% to 81%. The results have been discussed in relation to soluble organic P and its availability in forest ecosystems. The soil organic P results have been discussed in relation to P availability and supply within the forest ecosystem.     

低磷红壤无机磷组分特征及间作调控作用

为明确间作和施用磷肥对低磷红壤无机磷组分的影响,促进酸性土壤磷肥高效利用,通过田间小区定位试验,采用玉米单作（MM）、玉米//大豆间作（MI）2种种植模式,在4个施磷水平（P2O5 0、60、90、120kg·hm-2,分别记作P0、P60、P90、P120）下,研究玉米//大豆间作根际土壤无机磷组分变化特征,探讨间作对红壤玉米产量及其可持续性、磷吸收和磷素收支平衡、土壤无机磷组分的调控作用。结果表明,玉米籽粒产量及其可持续性指数（SYI）、磷吸收量随着施磷水平的增加而增加,在P90水平达到最大值。低磷红壤无机磷组分以O-P和Fe-P为主,二者占无机磷库的71.44%～80.18%,施用磷肥显著提高了红壤Fe-P和Al-P的含量与占比。玉米//大豆间作显著提高玉米产量,促进磷的吸收利用,减少土壤磷素盈余量,显著降低红壤O-P、Fe-P、Al-P含量。与单作相比,在P60、P90、P120水平下,间作玉米产量分别显著提高66.70%、52.44%、74.14%,SYI分别显著提高55.31%、42.18%、78.00%,磷吸收量分别显著提高61.97%、48.67%、74.33%,土壤磷...     

间作作物菌根菌丝对红壤磷形态的影响

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)在植物与土壤系统中扮演着重要的角色,能促进寄主植物对养分尤其是磷(P)的吸收。间作在提高土壤P素利用及增产增收等方面具有重要作用。本研究通过三室隔网分室盆栽模拟试验,在玉米/大豆间作种植体系下,对菌丝室进行不同形态P处理[不施P(P0)、施用无机磷(IOP50)、施用有机磷(OP50)],同时在根室进行不同AMF处理[不接种(NM)、接种Funneliformis mosseae(FM)],研究了不同外源形态P添加和AMF处理下,菌根作物对菌丝室红壤中不同形态P吸收利用的影响。结果表明:与单作-FM-IOP50处理相比,间作-FM-IOP50处理下的玉米P吸收量显著增加150.2%,大豆P吸收量增加24.5%;除大豆单作-P0处理外,接种FM均明显降低菌丝室土壤有效磷含量。除大豆单作-FM处理外,施用IOP50使土壤有效磷含量在单作条件下最高,而在间作条件下则最低。对红壤P形态的分级结果表明,接种AMF均一定程度增加了Ca_2-P、Al-P、Org-P、O-Al-P、Ca_(10)-P的含量,而间作则显著提高了作物对土壤Ca_2-P、Fe-P的吸收;相比其他处理,土壤Ca_2-P、Org-P、O-Al-P含量在间作-FM-IOP50组合处理下较高(P0.05)。相关分析显示,Ca_2-P与玉米植株P吸收量呈显著负相关,而O-Al-P与大豆植株P吸收量呈显著负相关。总之,接种FM、磷肥施用与间作均在一定程度上促进了宿主作物对P的吸收累积。其中间作-FM-IOP50组合是促进间作玉米生长、P素吸收及Ca_2-P、Org-P、O-Al-P增加的最佳组合,通过促进无机磷的活化而改善作物对P素的吸收利用,有效削减土壤P素的残留,若将其应用于滇池流域,可望减少P素的流失。     

蔬菜地肥熟表层土壤中各形态磷的可淋洗性研究

肥熟表层是长期培肥形成的富磷表土层.为了解该类土层中积累磷的释放特性,本文选择了酸碱度和质地相差较大的5个代表性肥熟表层土壤样品,采用室内模拟淋洗和磷形态分析方法,研究了该类土层中磷的可淋洗性.结果表明,该类土层有很强的磷释放能力,从中释放出来的磷主要为无机态磷,其占总释放磷的86.68%～94.44%.可释放土壤磷的形态除水溶性磷(H2O-P)外,还有胶体表面吸附的无机磷(NaHCO3-Pi)、钙、镁结合态磷(HCl-P)、有机态P和土壤铁铝氧化物吸附的磷(NaOH-Pi)等形态;在淋洗过程中,H2O-P、NaHCO3-Pi和HCl-P的下降率分别达45.8%～58.1%、30.5%～43.2%和3.6%～49.0%.淋洗过程中磷的稳定性由低到高依次为水溶性磷和NaHCO3-Pi,而后期可能来自HCI-P.     

Hydrolysis of organic and inorganic phosphorus compounds added to soils

The rates of hydrolysis of seven organic and two inorganic phosphorus compounds applied to soils at a rate of 500 ppm P and incubated at 20°C for various times under aerobic and waterlogged conditions were studied. Monomethyl phosphate, β-glycerophosphate, and α-D-glucose-1-phosphate were hydrolyzed at similar rates in the three soils used, but the rates were somewhat faster under aerobic than under waterlogged conditions. Organic P compounds in which two hydrogens of the orthophosphoric acid are replaced (e.g., diphenyl phosphate) were hydrolyzed at slower rates than those in which one hydrogen is replaced (e.g., phenyl phosphate). The rate of hydrolysis of diphenyl phosphate was lower than that of bis-p-nitrophenyl phosphate. Of the two inorganic P compounds studied, ammonium tetrametaphosphimate did not hydrolyze in soil, and the rate of hydrolysis of phosphonitrilic hexaamide was very small (6–13% hydrolyzed in 7 days) compared with those of the organic phosphates (30–98%).