Specific features of water permeability in virgin and cultivated chernozems

The tendency and type of quantitative changes in the main characteristics of the water permeability of automorphic (typical and ordinary) chernozems in the central part of the Russian Plain have been studied in the system of virgin soil (long-term fallow), rainfed plowland, and irrigated plowland. It is shown that irrigation exerts the most pronounced adverse effect on the water permeability of chernozems. The revealed causes of unfavorable changes in the water permeability of chernozems in the region are related to their agricultural use.     

Bacterial composition and N2-fixation of some Egyptian soils cultivated with wheat (Triticum aestivum L.)

The composition of the microflora, N₂-fixing bacteria particularly, in different soils cultivated with wheat in Egypt was investigated in some samples collected from the fields after applying the agricultural practices recommended for wheat cultivation and just before sowing. The influence of carbon sources, mineral nitrogen and water regimes on potential dinitrogen fixation (acetylene reduction assay) in soils was investigated. The bacterial population densities including-N₂-fixing organisms were related to a number of environmental factors such as organic matter content. Among diazotrophs, Azotobacter spp. and Azospirillum spp. were encountered in higher densities in comparison with clostridia. Unamended soils showed a lower acetylene-reducing activity (0.5–61.5 nmoles C₂H₄ g^?1 h^?1). Addition of glucose (1% w/w) greatly enhanced such activity being the highest (86.9–2846.5 nmoles C₂H₄ g^?1 h^?1) in the clay soil with the highest organic carbon content (1.42%). Glucose amendment had no significant influence on acetylene reduction in the saline soil. N₂-fixation in barley straw-amended (1%) soils was not much higher than in unamended soils. Concentrations of up to 70 ppm ammonium-nitrogen depressed N₂-fixation in soils that received barley straw. Acetylene reduction in submerged soil increased after addition of cellulose. Non-flooded conditions favoured N₂-fixation in the fertile clay soil amended with sucrose.     

Basic composition and amino acid contents of mushrooms cultivated in Finland

The basic composition (moisture, total carbohydrates, dietary fiber, crude fat, ash, nitrogen, and protein) and amino acid contents were determined in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinula edodes, and Pleurotus ostreatus. In addition, nitrogen-to-protein conversion factors were calculated for each species by dividing the sums of amino acid residues with total (Kjeldahl) nitrogen contents. The dry matter contents of mushrooms varied from 7.7% to 8.4%. The dry matter of mushrooms contained large amounts of carbohydrates, from 4.5 (A. bisporus/white) to 5.8 g/100 g fresh weight (L. edodes). L. edodes proved to be an especially good source of dietary fiber (3.3 g/100 g fresh weight); the other mushrooms contained 1.5-2.4 g/100 g fresh weight. Crude fat, ash, and protein (based on amino acid analysis) contents of the mushrooms varied 0.31-0.35, 0.49-0.78, and 1.8-2.09 g/100 g fresh weight, respectively. Mushrooms proved to be good sources of almost all essential amino acids when compared with common vegetables. The mean nitrogen-to-protein conversion factor analyzed in the present study was 4.7 +/- 0.21. When using this factor, a very good estimation of protein contents could be obtained for the main species of mushrooms cultivated in Finland.     

Effect of growing and drying conditions on the phenolic composition of mate teas (Ilex paraguariensis)

Mate tea ( Ilex paraguariensis) has been used for centuries and is widely consumed in Brazil, Argentina, Paraguay, and Uruguay. The aim of the present study was to determine how growing and drying conditions affect the phenolic concentration and antioxidant capacity of 15 Mate teas from forest or plantation cultivations, dried either with hot air or wood smoke. The total polyphenol concentration determined with Folin-Ciocalteu ranged from 100.3 +/- 5.5 to 179.7 +/- 3.6 mg equiv chlorogenic acid/g dry leaves. The antioxidant capacity according to the oxygen radical absorbance capacity assay ranged from 1.5 +/- 0.3 to 4.1 +/- 0.1 mmol Trolox equiv/g dry leaves. Ten phenolic compounds were identified and correlated with antioxidant capacity ( R (2) = 0.80). Principle component analysis and multivariate linear regression were conducted to assess the effect of growing and drying conditions. Sun-exposed (plantation grown) Mate teas exhibited higher levels of all polyphenols as compared to shaded (forest grown) Mate teas ( P < 0.05). Lower rainfall, temperature, and drying conditions had varying effects on the phenolics. On average, plantation grown Mate teas had a greater concentration of phenolics than forest grown teas. Thus, plantation grown Mate teas represent better potential sources for their commercial extraction.     

The effects of fluctuations in atmospheric pressure on landfill gas migration and composition

Measurements of landfill gas emissions from a single site frequently show large variations in chemical composition and magnitude, often on the same time scale as the monitoring interval. These changes are generally ascribed to faulty instrumentation or mysterious alterations in the internal biological processes. This paper demonstrates a simple deterministic physical mechanism able to explain many of these changes, and discusses the implications this has for monitoring strategies. The main conclusions are that the total rate of gas venting depends linearly on the rate of change of the atmospheric pressure, with the stoichiometric variations depending additionally on the physical characteristics and moisture distribution within the site.     

Activity and composition of the methanogenic archaeal community in soil vegetated with wild versus cultivated rice

Wild rice (Oryza rufipogon) is a problematic weed in fields of cultivated rice (Oryza sativa). We hypothesized that the composition and/or the activity of the methanogenic microbial communities might be different in soil grown with cultivated versus wild rice. We used samples from Hainan, China, where wild rice grew on a field adjacent to cultivated rice. The composition of the methanogenic archaeal community was analyzed in samples of rice soil by targeting the 16S rRNA gene. Analysis of the terminal restriction fragment length polymorphism (T-RFLP) showed similar patterns in soil from wild versus cultivated rice. Sequences of archaeal 16S rRNA genes also showed similar composition in soil from wild versus cultivated rice, revealing the presence of Methanosarcinaceae, Methanosaetaceae, Methanobacteriales, Methanocellales (Rice Cluster I), Rice Cluster II, Crenarchaeota Group I.3 and Crenarchaeota Group I.1b. Incubation of soil samples under anoxic conditions generally resulted in vigorous CH₄ production after a lag phase of 7-8 days. Production of CH₄ was partially inhibited by methyl fluoride, a specific inhibitor of acetoclastic methanogenesis, resulting in nearly stoichiometric accumulation of acetate. CO₂ was produced without lag phase. The δ¹³C of the produced CO₂ was slightly lower in soil grown with cultivated rice versus wild rice, reflecting the δ¹³C of organic matter, which was about −29‰ for cultivated rice soil and about −24‰ for wild rice soil. The δ¹³C of the produced CH₄ and the acetate that accumulated in the presence of CH₃F was much more negative in cultivated versus wild rice soil, mainly since the isotopic fractionation factors for hydrogenotrophic methanogenesis were higher for soil from cultivated rice (α = 1.054) versus wild rice (α = 1.039). However, the percentage contribution of hydrogenotrophic methanogenesis to total CH₄ production was similar in both soils (27-35%). In conclusion, although the two soils exhibited different δ¹³C values of soil organic matter and derived products, they were similar with respect to rates and composition of the methanogenic communities.     

Clay mineral composition of some volcanogenous soils in Indonesia and the Philippines

Clay fractions of three Andosols and a Latosol occurring in Indonesia, and two Alluvial Soils derived from pyroclastic sediments in the Philippines were examined by means of chemical analyses, X-ray diffraction, differential thermal analysis, thermogravimetry, infrared absorption spectroscopy, and electron microscopy. The results are summarized as follows.

Allophane is a dominant clay mineral of young volcanogenous soils occurring in the tropics. Small amounts of halloysite, gibbsite, and imogolite are also found in some of the young volcanogenous soils. Halloysite and imogolite are relatively abundant in the surface soil, while gibbsite is more abundant in the subsoil. In the clay fraction of the young volcanogenous soils in the tropics, α-cristobalite is often present, but quartz occurs rarely. Small amounts of feldspars are also present in the Philippine soils. 2 : 1-type minerals are found to a small extent in some of the sample soils. The above results agree well with the results for Japanese Andosols, except for a difference in the primary mineral composition.     

Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms

The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.     

吉林省主要耕作土壤中含钾矿物组成及其与不同形态钾的关系

通过化学分析 ,X-射线衍射及镜检法研究了黑土、白浆土、黑钙土等吉林省主要耕作土壤的含钾矿物组成及不同形态钾的含量。结果表明 ,土壤中的含钾矿物以含钾长石和伊利石为主 ,钾长石主要集中在土壤砂粒部分 ,伊利石主要存在于土壤的粘粒部分。土壤的含钾矿物总量约占土壤矿物总量的 1/ 3多些 ,比南方土壤高 ;缓效钾含量丰富 ,供钾潜力大 ;速效钾含量在黑土、黑钙土中较高 ,而在白浆土中稍低。 3种土壤的全钾量与含钾矿物总量、粘粒中伊利石含量与粘粒含钾量、伊利石含量与缓效钾量、细砂中含钾长石含量与细砂中全钾量、缓效性钾与速效性钾之间呈极显著或显著相关。     

Specific surface area and surface charges of some argentinian soils

The specific surface areas of nine argentinian soils obtained by adsorption followed the order N₂ < ethylene glycol < H₂O, attributed to the presence of smectites (verified by XRD analysis) and some organic coating. The H₂O₂ treatment of these soils modified the former order of surface area determined by different absorbents. This order was modified because the mineral surface was evidenced and an increase of cation adsorption was produced by organic matter removal. This fact was supported by the decrease of PZC values of soils after H₂O₂ treatment. The specific surface area of initial soils obtained by water and ethylene glycol adsorptions showed a good correlation with carbon content and CEC of untreated soils and with the PZC of protonated soils.     

Vitamin C and elemental composition of some bushfruits

Vitamin C and elemental analysis of a range of indigenous bushfruit from the Northern Territory, Darwin, Australia, was carried out. The results suggest that bushfruit may be a valuable food resource. In the majority of cases, vitamin C and elemental composition of bushfruits were comparable to those of western fruits in the same fruit category. Billy goat plums (Terminalia fertinandiana) have the highest vitamin C content, while K concentration is generally high as compared to other elements. Morinda citrifolia gave strong test for the presence of terpenes.     

Soil microbial community composition and land use history in cultivated and grassland ecosystems of coastal California

Phospholipid ester-linked fatty acid (PLFA) profiles were used to evaluate soil microbial community composition for 9 land use types in two coastal valleys in California. These included irrigated and non-irrigated agricultural sites, non-native annual grasslands and relict, never-tilled or old field perennial grasslands. All 42 sites were on loams or sandy loams of similar soil taxa derived from granitic and alluvial material. We hypothesized that land use history and its associated management inputs and practices may produce a unique soil environment, for which microbes with specific environmental requirements may be selected and supported. We investigated the relationship between soil physical and chemical characteristics, management factors, and vegetation type with microbial community composition. Higher values of total soil C, N, and microbial biomass (total PLFA) and lower values of soil pH occurred in the grassland than cultivated soils. The correspondence analysis (CA) of the PLFA profiles and the canonical correspondence analysis (CCA) of PLFA profiles, soil characteristics, and site and management factors showed distinct groupings for land use types. A given land use type could thus be identified by soil microbial community composition as well as similar soil characteristics and management factors. Differences in soil microbial community composition were highly associated with total PLFA, a measure of soil microbial biomass, suggesting that labile soil organic matter affects microbial composition. Management inputs, such as fertilizer, herbicide, and irrigation, also were associated with the distinctive microbial community composition of the different cultivated land use types.     

Determination of leghemoglobin components and xylem sap composition by capillary electrophoresis in hypernodulation soybean mutants cultivated in the field

The hypernodulation soybean mutant lines (NOD1-3, NOD2-4, NOD3-7) and their parent Williams, and the mutant En6500 and its parent Enrei were cultivated in a sandy dune field in Niigata, and the nodules and root bleeding xylem sap were sampled at 50, 70, 90, and 120 d after planting (DAP). The nodule size distribution patterns and concentration of leghemoglobin components were determined. The number of nodules of the hypernodulation mutant lines was about two to three times higher than that of the parent lines irrespective of the sampling date. At 50 DAP the nodule size was relatively smaller in the hypernodulation mutant lines, and the total dry weight of the nodules was almost the same in the mutant lines and their parents. At 70 DAP and 90 DAP, the size distribution of the hypernodulation mutant nodules became .almost the same as that of the parent lines, and both the number and total dry weight of the nodules were higher than those of the parent lines. The concentration of four Lb components was separately measured by capillary electrophoresis. The concentration of the Lb components in the hypernodulation mutant lines tended to be lower than in the parents, but the component ratios were not different between the hypernodulation mutants and their parents. Under field conditions, plant growth and nodulation characteristics were more similar between mutants and parents than in the hydroponic culture reported previously, although the mutants did exhibit hypernodulation traits. These findings suggest that the decrease in the Lb concentration and the different Lb components ratios in the mutants may be caused by secondary effects of excess nodulation, such as photosynthate deficiency, rather than by a genetic defect in mutation. The concentration of major nitrogenous compounds (allantoic acid, allantoin, asparagine, aspartic acid, and nitrate) in the xylem sap was also measured by capillary electrophoresis. The concentration of ureides and nitrate in xylem sap decreased with the plant age, but the asparagine concentration increased during the same period. The concentrations of ureides and asparagine were higher, and the nitrate concentration was lower in the mutant lines than in their parents, possibly due to the higher dependence on N₂ fixation than N0₃ ^- utilization. In the xylem sap, nitrate was the major inorganic anion followed by phosphate, sulfate, and chloride, and potassium was the major cation followed by calcium or magnesium and sodium.     

Morphology and composition of some soils under cultivation in Saudi Arabia

Twelve profiles representing the principal soils of five major agricultural areas (Al-Kharj, Gassim, Hofuf, Taif and Wadi Dawasir) in Saudi Arabia were described and sampled by horizons. Laboratory analyses were then made of the samples to characterize the profiles more completely. Analyses were also made for certain nutrient elements to get some measure of their levels in the soils.The profiles are tentatively classified in the Entisol and Aridisol orders of the American taxonomy. Five Entisol profiles were considered to be Fluvents and two Psamments. Four Aridisol profiles were considered to be Argids and one an Orthid.All of the profiles are saline and calcareous and most are also sandy. Furthermore, amounts of nutrient elements such as phosphorus, iron and zinc in surface layers are below minimum levels established for similar soils in earlier investigations in other countries. Consequently, the soils are believed to lack sufficient quantities of several elements for optimum plant growth. Successful use of the soils will thus require reductions in salinity, increased levels of nutrient elements, and skillful irrigation to provide adequate moisture.     

印度酸性耕作土中总锰、铁以及可提取态锰、铁的水平、分布及其与土壤性质的关系研究

A total of 400 surface soil(0–15 cm) samples were collected from cultivated soils representing four soil series,namely,Hariharapur,Debatoli,Rajpora and Neeleswaram in Orissa,Jharkhand,Himachal Pradesh and Kerala states of India,respectively,and were analyzed to measure the contents of total and extractable Mn and Fe,to establish the relationship among total and extractable Mn and Fe and soil properties,and to characterize the spatial distribution pattern of Mn and Fe in some cultivated acid soils of India. The contents of total as well as extractable Mn and Fe varied widely with extractants and soil series. However,the amounts of Mn or Fe extracted by diethylene triamine penta-acetic acid(DTPA),Mehlich 1,Mehlich 3,0.1 mol L-1 HCl and ammonium bicarbonate DTPA(ABDTPA) were significantly correlated with each other(P 0.01). Based on the DTPA-extractable contents and the critical limits(2 mg Mn kg-1soil and 4.5 mg Fe kg-1 soil) published in the literature,Mn and Fe deficiencies were observed in 7%–23% and 1%–3% of the soil samples,respectively. The content of soil organic carbon(SOC) had greater influence on total and DTPA-extractable Fe than did soil pH. Geostatistical analysis revealed that total and DTPA-extractable Mn and Fe contents in the acid soils were influenced by soil pH,SOC content,and exchangeable cations like potassium,calcium and magnesium. Spatial distribution maps of total and DTPA-extractable Mn and Fe in soil indicated different distribution patterns.     

Plant elemental composition and element ratio in some crops at the flowering stage

Abstract

The elemental composition of winter wheat, spring barley, oat, rye, buckwheat and potato at flowering stage as well as the molar ratio of elements to each other in these crops were determined. Presented is a new theoretical approach to fertilization based on the view that knowing the ratio of elements in crops at the flowering stage can be useful in determining the appropriate ratios of fertilizer components in plant nutrition and fertilization.     

The sources and composition of humus in some soils of West Antarctica

Original data on humus-forming substances and their elemental and biochemical compositions in Antarctic soils are discussed. Mosses, lichens, algae, remains of higher vascular plants, and penguin guano of two types differ considerably in their chemical compositions. This leads to significant differences in the formation of humic substances in plant materials themselves in the course of their transformation. However, no significant differences in the composition of humus in the fine earth of soils developing under different humus-forming materials have been revealed, which may be related to the extremely low rates of humification. Significant differences between the soils of Antarctic landscapes proper and the soils of the Subantarctic King George Island are only observed in the humus enrichment with nitrogen. The soils of Antarctica are low-humus soils with the humate-fulvate or fulvate types of humus.     

Mineralogy and chemical composition of some laterites of Sri Lanka

Laterite samples have been collected from different parts of Sri Lanka and analysed mineralogically and chemically. The samples studied were collected from layers within individual vertical sections. Mineralogical analyses were made using XRD, DTA, DTG and TG methods whereas chemical analyses were made with wet chemical techniques. The laterites studied overlie several rock types differing in chemical composition. The analyses show that gibbsite is the most significant free aluminium mineral, whereas geothite and hematite are the main iron minerals. Even though bauxite composition is approached in some samples, the existence of sufficient commercial grade bauxite is still to be established.