Showing papers on "Soil organic matter published in 1970"
TL;DR: Methane is a gas occurring in nature as a product of anaerobic bacterial decemposition of organic matter under water as mentioned in this paper, and it arises not only from stagnaat and putrescent, pools but also from soils used in rice culture during summer (1,2.3).
Abstract: Methane is a gas occurring ap~ndantly in .nature as a product of anaerobic bacterial decemposition of organic matter under water. Methane arises not. only from stagnaat and putrescent, pools but also from soils used in rice culture during summer (1,2.3).
196 citations
TL;DR: A study of the effects of various soil pretreatments on soil arylsulfatase activity showed that storage at − 10C is a satisfactory method of preserving field-moist soil samples for assay of aryl sulfase activity as discussed by the authors.
Abstract: A study of the effects of various soil pretreatments on soil arylsulfatase activity showed that storage at — 10C is a satisfactory method of preserving field-moist soil samples for assay of arylsulfatase activity. Storage of field-moist soils at 5C or 22-24C for 3 months led to a decrease in arylsulfatase activity (average, 8% at 5C, 18% at 22-24C), but storage at — 10C for the same period did not significantly affect this activity. Air-drying of field-moist soils at 22-24C caused a marked increase in arylsulfatase activity (average, 43% ), and ovendrying (105C) caused a marked decrease (average, 54%). A slow decrease in arylsulfatase activity was observed when air-dried soils were stored at 22-24C. Arylsulfatase activity decreased markedly with depth in six soil profiles examined. This decrease was associated with a decrease in organic matter content, and studies with surface soils differing markedly in physical and chemical properties showed that soil arylsulfatase activity was significantly correlated with soil organic matter content. Soil arylsulfatases were not deactivated by most of the reagents used to study the sulfur status of soils. Additional
157 citations
150 citations
TL;DR: In this paper, it was shown that organic soil constituents are responsible for the reduction of nitrite to N 2 and N 2 O and for the fixation of Nitrite N observed on treatment of soils with nitrite and that inorganic soil constituents were not involved in these reactions.
Abstract: Studies of the gaseous products formed by chemical decomposition of nitrite in soils showed that substantial amounts of N 2 and NO 2 and small amounts of N 2 O were evolved on treatment of neutral and acidic soils with nitrite, the largest amount of N 2 being formed in an acidic soil having a high organic matter content. The amount of NO 2 produced was inversely related to soil pH, but significant amounts of NO 2 were evolved from soils having pH values above 7. The failure of some investigators to detect NO 2 as a product of nitrite decomposition in acidic soils can be attributed to use of closed experimental systems that promoted sorption of this gas by moist soil and conversion of NO 2 to nitrate. A study of the selfdecomposition reaction of nitrous acid showed that this reaction does not proceed according to the classical equation 3HNO 2 = HNO 3 + 2NO + H 2 O and is better represented by the equation 2HNO 2 = NO + NO 2 + H 2 O. Evidence was obtained that organic soil constituents are responsible for the reduction of nitrite to N 2 and N 2 O and for the fixation of nitrite N observed on treatment of soils with nitrite and that inorganic soil constituents are not involved in these reactions. Several experiments indicated that most of the NO 2 evolved on treatment of soils with nitrite is formed by self-decomposition of nitrous acid and by atmospheric oxidation of NO produced by this reaction.
133 citations
TL;DR: The earlier conclusions which indicated that soil organic matter could reduce the phytotoxicity of s-triazines and other preemergent herbicides were drawn from the analysis of data by simple correlation analysis and by multiple regression analysis, but Bailey and White (1964) have pointed out that these and other soil properties which can be highly or significantly correlated with the lowering of herbicides can also behighly or significantly inter-correlated.
Abstract: The earlier conclusions which indicated that soil organic matter could reduce the phytotoxicity of s-triazines and other preemergent herbicides were drawn from the analysis of data by simple correlation analysis and by multiple regression analysis These techniques also indicated that the cation-exchange capacities and, in some instances, the clay contents of soils could also be inversely correlated with preemergent herbicide phytotoxicity Bailey and White (1964) have pointed out, however, that these and other soil properties which can be highly or significantly correlated with the lowering of herbicide phytotoxicity can also be highly or significantly inter-correlated
127 citations
TL;DR: Zinc adsorption by calcareous soils, Zinc adaption by calc calcineous soils as mentioned in this paper, مرکز فناوری اطلاعات و اسلاز رسانی
Abstract: Zinc adsorption by calcareous soils , Zinc adsorption by calcareous soils , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
105 citations
TL;DR: Large amounts of nutrients from the L-H horizons and 0.2 cm of mineral soil were either redistributed at mineral soil depths or removed by leaching within a 15-month period after severe fire in jac...
Abstract: Large amounts of nutrients from the L-H horizons and 0–2 cm of mineral soil were either redistributed at mineral soil depths or removed by leaching within a 15-month period after severe fire in jac...
97 citations
71 citations
TL;DR: In this article, a modification of the scanning method for uptake sites along roots showed translocation to occur from all parts of the root with rather less translocation from the apical centimetre than from other parts.
Abstract: At 3 weeks, uptake of phosphate along roots of seedlings grown in soil at 25°C was greatest in the apical centimetre and decreased sharply along the roots. By contrast uptake was markedly more sustained along the roots of seedlings grown in soil at 14°C and here the greatest uptake occurred several centimetres behind the apex. No one pattern of ion uptake along roots can be assumed to hold for all conditions of growth when constructing mathematical models of ion uptake from soil. Increasing soil temperature from 15°C to 25°C approximately doubled total root length of 3-week seedlings of Pinus radiata; primary root length was increased but the main effect was due toa marked increase in the number and length of lateral roots. Lateral root growth of the 3-week seedlings was almost completely suppressed in the soil at 11°C. Roots of 3-week sterile seedlings growing in phosphate-deficient nutrient solution were considerably smaller than those of pine grown in complete nutrient solution at 15°C but not at 25°C. This interaction of temperature and phosphate deficiency did not occur with soil grown seedlings. The sustained phosphate uptake along roots grown at the low soil temperature did not compensate for greater root growth (and therefore soil exploration) at higher temperatures, for P content of 3-week seedlings grown in soil at 25°C was considerably greater than that of seedlings grown in soil at 15°C. In phosphate poor soils low temperature depression of root growth will seriously restrict phosphate uptake. A modification of the scanning method for uptake sites along roots showed translocation to occur from all parts of the root with rather less translocation from the apical centimetre than from other parts.
62 citations
TL;DR: In this article, the amounts and distribution of C, N, S, and organic P accumulated over a period of 10, 000 years of soil development on wind-blown sand.
Abstract: Summary
A study was made of the amounts and distribution of C, N, S, and organic P accumulated over a period of 10 000 years of soil development on wind-blown sand. After initial rapid rates of accumulation of C, N, and organic P during the first 1000 years, subsequent rates of gain were slower, but steady states for C, N, and S had still not been reached after 10 000 years. Sulphur declined during the first 50 years of soil development but then increased in a parallel fashion to organic C. During 10 000 years, gains of organic C, total N, total S, and organic P were 204 000, 9800, 1180, and 1170 kg/ha m profile, respectively. Gains in total N and S in the older soils are readily accounted for by returns in precipitation. Pronounced changes in soil organic matter composition during 10 000 years are reflected in the widening of the C/N ratio (8 to 20) and the C/organic P ratio (39 to 159).
61 citations
TL;DR: In this article, a simplified mathematical model describing soil temperatures under grass fires is presented, where it is assumed that, for grass fires that are short-lived in any one spot, the soil temperature just beneath the surface does not rise above 100°C.
Abstract: A simplified mathematical model describing soil temperatures under grass fires is presented. It is assumed that, for grass fires that are short-lived in any one spot, the soil temperature just beneath the surface does not rise above 100°C. Data are presented for two experiments in which temperatures just above the soil surface and at depths ranging from 0.3 to 4 cm were measured. These results are compared with the results predicted by the theory and reasonable agreement is found. Predicted maximum temperature profiles for two soil thermal diffusivities and two fire durations are given.
01 Jun 1970
TL;DR: In this article, a control of plant parasitic worms with organic soil amendments is discussed. But the authors focus on the control of plants and do not address the problem of weeds.
Abstract: (1970). Control of Plant Parasitic Nematodes with Organic Soil Amendments. PANS Pest Articles & News Summaries: Vol. 16, No. 2, pp. 287-297.
TL;DR: Isolates of heterotrophic organisms from a Teak soil were tested for their ability to produce nitrite and/or nitrate in a glucose-peptone medium, soil organic matter extract, and in sterilized soils as mentioned in this paper.
Abstract: Isolates of heterotrophic organisms from a Teak soil were tested for their ability to produce nitrite and/or nitrate in a glucose-peptone medium, soil organic matter extract, and in sterilized soils. The amounts of nitrite and nitrate formed varied with the medium used. The ability to produce nitrite and/or nitrate was more common and more efficient among the fungi where up to 4.76 ppm nitrite-nitrogen and 12.88 ppm nitrate-nitrogen were obtained after 14 days incubation.
TL;DR: In this paper, the average recovery by chemical analysis of N applied as manure to a Plainfield sand at relatively high rates and incubated for 37 weeks was 77% for aerobic conditions and 24% for anaerobic conditions.
Abstract: Nitrate production under aerobic conditions was directly related to rate of manure application, period of incubation, and soil pH but was stopped under anaerobic conditions. Average recovery by chemical analysis of N applied as manure to a Plainfield sand at relatively high rates and incubated for 37 weeks was 77% for aerobic conditions and 24% for anaerobic conditions. The addition of manure tended to increase soil pH and the contents of organic N, available P and exchangeable K, Ca, and Mg, particularly at the higher rates. They also increased the field moisture capacity of a Plainfield sand. However, on an acid Ella loamy sand the two highest rates of manure caused a reduction of the values for field moisture capacity, apparently the result of formation of a waxy material that tended to repel water absorption.
TL;DR: Preliminary estimates of the root biomass and of the amounts of plant nutrients contained within the rooting zone of a lowland heath ecosystem and to consider them in relation to the above ground vegetation and litter are provided.
Abstract: Nutrient budgets have been described for the above-ground components of the vegetation of a dry heath ecosystem in the south of England (Chapman 1967). In that paper the plant nutrients contained in the rooting system and in the soil were not considered. There is no need to emphasize the importance of the root system in the ecosystem but in the past it has not been so well studied or described mainly because of the practical difficulties involved. Methods of estimating root production have been discussed by Newbould (1968), and by a number of authors in the proceedings of an international symposium (U.S.S.R. Academy of Sciences 1968). Some past work on heathland and moorland has included studies of the root systems of Calluna or associated vegetation, but very little includes estimates of root biomass or the nutrient content of the root system. Brien (1950) measured the root volume of plants of Calluna on a variety of soils. Rennie (1953, 1957) and Boggie (1956) studied the distribution of Calluna roots within the soil profile. Boggie, Knight & Hunter (1958) studied the activity of roots of species including Calluna by use of radioactive phosphorus. This present paper is intended to provide preliminary estimates of the root biomass and of the amounts of plant nutrients contained within the rooting zone of a lowland heath ecosystem and to consider them in relation to the above ground vegetation and litter.
TL;DR: In this article, unusual features of red earth and red-brown earth soils associated with layered parna deposits in the Eastern Riverina, N.S.W. were identified and traced for identification and tracing of individual layers, modern soils, and paleosols in different landscapes.
Abstract: Attention is drawn to unusual features of red earth and red-brown earth soils associated with layered parna deposits in the Eastern Riverina, N.S.W., which facilitate identification and tracing of individual layers, modern soils, and paleosols in different landscapes, and subsequent elucidation of distribution, stratigraphic relations, and relative age of these and associated deposits and soils. These features include mechanical composition, subplasticity, and the occurrence of secondary calcite, magnesian calcite, barytes, dolomite, and palygorskite.
TL;DR: A surface soil can apparently have a good structure as measured by the slaking (break-up) of dry aggregates in water and yet after shearing, as in tillage, it may still crust badly.
Abstract: SURFACE soils with good structure consist of aggregates that do not disintegrate on sudden wetting with water to form a crust when re-dried. Crusting is most severe when disintegration proceeds down to the level of clay sized particles. The beneficial effect of soil organic matter in reducing the break-up of initially dry soil aggregates when wetted with water is well known. Equally well known is the deleterious effect of exchangeable sodium in causing spontaneous dispersion of clay from aggregates if the external electrolyte concentration is reduced when the soil is wetted. Spontaneous dispersion does not occur if the exchange complex of a soil is effectively saturated with Ca ions or if sufficient organic matter is present1. If external work is performed on such soils when they are wet, however, then spontaneous dispersion may occur2. Thus a surface soil can apparently have a good structure as measured by the slaking (break-up) of dry aggregates in water and yet after shearing, as in tillage, it may still crust badly3.
TL;DR: A series of mono-and di-valent cation hydroxides, and certain strong acids, were allowed to react with a two and a three-layer clay mineral (kaolin and montmorillonite) under conditions simulating those for normal soil stabilization in field practice as discussed by the authors.
Abstract: A series of mono- and di-valent cation hydroxides, and certain strong acids, were allowed to react with a two- and a three-layer clay mineral (kaolin and montmorillonite) under conditions simulating those for normal soil stabilization in field practice, i.e. mixed, remoulded, and moist-cured at a moisture content and density approximating optimum compaction conditions. The progress of reaction was followed over extended periods of time, up to two years. Changes in strength and volume were correlated with chemical and mineralogical changes in order to identify those bonding mechanisms which contribute to inorganic soil stabilization. For an additive level of 10% by weight dry clay basis (9.1% total dry solids basis) it was shown that several distinct stabilization mechanisms exist. One major mechanism is the surface coating of fabric units, and another the reinforcement of the soil by product formation in crevices, angularities, pore constrictions, and similar defects which influence the mechanical properties of the whole sample. The importance of these reactions to practical soil stabilization is thus demonstrated.
Journal Article•
TL;DR: The results of a soil investigation conducted in February 1967 in some widely distributed saline alkali soils of Vrijbhumi Afforestation Division of Uttar Pradesh to determine the range of tolerance of some important forest species for salinity and alkali status have been reported in this paper.
Abstract: The results of a soil investigation conducted in February 1967 in some widely distributed saline alkali soils of Vrijbhumi Afforestation Division of Uttar Pradesh to determine the range of tolerance of some important forest species for salinity and alkali status have been reported in this paper. These soils vary widely in several morphological, physical and chemical characteristics and accordingly, the forest species have shown varying growth response. In general, all planted species have failed to grow on the soils which are compact and indurated with a cemented bed of Kankar nodules, are highly calcareous and have pH >10 and soluble salts >3.42% and >1.14% in the top soil and sub-soil respectively. P. juliflora is able to grow on the calcareous soils which have on the average a maximum pH value of 9.5 and soluble salt content of 0.54%, though a soil having pH up to 10 and soluble salts up to 1% with compact sub-soil can also be tolerated. A. arabica thrives satisfactorily on the sa1ine alkali soils which have pH value below 9 and soluble salt content below 0.3%. Azadirachta indica, Butea monosperma, Dalbergia sissoo, Pongamia pinnata and Terminalia arjuna have grown on the moderately calcareous soils which are generally non-saline and non-alkali in the top 60 cm depth but have pH up to 9.8 and soluble salts up to 0.45% in the sub-soil. Out of the species studied, Albi ia lebbek and Ailanthus excelsa appear to be the least tolerant to salinity and alkali status and require comparatively better structured soil. Further, the growth of P. juliflora brings about some improvement in the fertility status and reduction in the salinity and alkali level of the surface layer only. The trenchridge method is effective in lowering the salt concentration of the soil in the ridge by leaching. Although the technique of filling the planting pit with good imported soil helps in establishment of the planted species, it entails the possible danger of subsequent alkali development due to salt diffusion from the surrounding soil. In view of the varying degree of tolerance shown by different forest species and also wide variations encountered in the soil conditions, the paramount importance of a judicious selection of forest species according to the salinity and alkali status and morphological features of the soil is quite obvious, before any afforestation programme of saline alkali soils is undertaken.
TL;DR: In this paper, the variability of a range of chemical properties in the profiles of four Great Soil Groups, viz. yellow podzolic, red earth, red-brown earth, and grey clay, is described.
Abstract: Statistical procedures are described for the characterization and comparison of profiles within soil classification units. Profile trends in a measured characteristic are represented by the coefficients of orthogonal polynomials in depth, and these coefficients are used as observations for standard statistical procedures. The mean of the respective coefficients provides estimates of the mean profiles for the classification units, and the variance-covariance matrix of the coefficients can be used to calculate the confidence intervals of these means. Differences between the mean profiles can be tested by analyses of variance. The variability of a range of chemical properties in the profiles of four Great Soil Groups, viz. yellow podzolic, red earth, red-brown earth, and grey clay, is described. The characterization is based on the analysis of profiles sampled from areas of about 0.4 ha chosen to represent cultivated examples of the groups in southern New South Wales. Variability of most soil properties is greater between these areas than within them, notable exceptions being exchangeable calcium and magnesium within the grey clay Group. This high localized variability is attributed to the gilgaied nature of this group in this region. Also variation between the soil groups is generally greater than within the groups. The differences seem, however, of limited importance from the point of view of soil fertility.
TL;DR: The application of pyrolysis gas chromatography (P.G.C) for comparative studies of soil organic matter is discussed in this article, along with the possible use of the technique for further elucidation of organic matter composition and structure.
TL;DR: In this article, an N15-labelled Chester silt loam surface soil was analyzed for total carbon, total nitrogen, and nitrogen extractable at 100°C by 0.5N sodium pyrophosphate.
Abstract: SummaryOrgano-mineral sedimentation fractions of an N15-labelled Chester silt loam surface soil were analyzed for total carbon, total nitrogen, and nitrogen extractable at 100°C by 0.5N sodium pyrophosphate. The nitrogen of the pyrophosphate extract was fractionated into: I, NaOH-distillable N; II, 6N H2SO4-hydrolyzable NaOH-distillable N following I; III, ninhydrin-reactive NaOH-distillable N following II; and IV, total N on the extract residue following III. Nitrogen not extractable by pyrophosphate treatment was designated from V. Subsamples of each soil fraction were incubated under waterlogged conditions, and MgO-distillable nitrogen was determined on the extracted incubate as an estimate of nitrogen mineralization capacity. The distillate from each nitrogen determination was analyzed for N15 by mass spectrometry.Total nitrogen and per cent nitrogen mineralization increased, and C/N ratios decreased, as fraction particle size decreased. In contrast, total nitrogen and nitrogen mineralization generally decreased, and C/N ratios increased, for a given particle size, with an increase in intensity of ultrasonic dispersion treatment. Atom per cent excess N15 data revealed that a general labelling of all soil nitrogen forms examined had occurred, and that the degree of labelling decreased in those materials which required greater intensities of ultrasonic vibration for dispersion. Apparently, fertilizer N15 had been incorporated in a wide range of soil nitrogen components, from the most readily extractable to those which remained in extracted residues, at each level of microaggregate stability. Tagging was highest in the nitrogen of the > 53 µ organic separate, in the water-solubilized NaOH-distillable nitrogen, and in the nitrogen mineralized during incubation. Allocation of the various total and N15-labelled nitrogen forms among soil fractions for the maximum dispersion treatment, t180 min, showed that the <2 µ plus water-solubilized materials contained 85 per cent of the NaOH-distillable soil nitrogen, the form concluded to be most active biologically in light of the high correlations obtained between it and mineralized nitrogen (r ranged from 0.90 to 0.98). It was also shown that the sum of the amounts of nitrogen mineralized by soil fractions separated at a given dispersion intensity became equivalent to the amount mineralized by the whole soil only when the quantity of NaOH-distillable nitrogen extracted by water during the fractionation step was added. This finding further supported the hypothesis that the two forms of nitrogen probably have a common source, or sources, among soil nitrogen components.