Showing papers in "Soil Science in 2000"
TL;DR: In this article, the authors summarize the recent literature about controls on dissolved organic matter (DOM) concentrations and fluxes in so-called "soil degraded organic matter" (SOCOM).
Abstract: Dissolved organic matter (DOM) in soils plays an important role in the biogeochemistry of carbon, nitrogen, and phosphorus, in pedogenesis, and in the transport of pollutants in soils. The aim of this review is to summarize the recent literature about controls on DOM concentrations and fluxes in soi
2,138 citations
TL;DR: Although urban and suburban soils are used for many purposes, some of them relevant to agricultural and forest sciences, that these intensively managed and disturbed soils have not been extensively investigated up to now is suggested by the white areas representing most urban zones on soil survey ma
Abstract: Although urban and suburban soils are used for many purposes, some of them relevant to agricultural and forest sciences, that these intensively managed and disturbed soils have not been extensively investigated up to now is suggested by the white areas representing most urban zones on soil survey ma
324 citations
TL;DR: The present world population of 6 billion will reach 8 billion by 2020 and 9.4 billion by 2050 as mentioned in this paper, and by then, the population will have increased by another 575 million in India, 300 million in China, 200 million in Nigeria, 200 millions in Pakistan, and 140 million in Ethiopia.
Abstract: The present world population of 6 billion will reach 8 billion by 2020 and 9.4 billion by 2050. By then, the population will have increased by another 575 million in India, 300 million in China, 200 million in Nigeria, 200 million in Pakistan, and 140 million in Ethiopia. Of the total world populati
222 citations
TL;DR: In this paper, the authors incubated intact peat cores from depth intervals of 5--15, 15--25, 25--35, and 35--45 cm from ombrotrophic bog, poor fen, and beaver pond margin sections of a cool-temperate peatland.
Abstract: The authors incubated intact peat cores from depth intervals of 5--15, 15--25, 25--35, and 35--45 cm from ombrotrophic bog, poor fen, and beaver pond margin sections of a cool-temperate peatland. CO{sub 2} production was measured over 12-day incubation periods at 4 and 14 C and under oxic and anoxic conditions. Rates ranged from 0.06 to 0.66 mg CO{sub 2} g{sup {minus}1} dry peat d{sup {minus}1} under oxic conditions and from 0.002 to 0.098 mg CO{sub 2} g{sup {minus}1} d{sup {minus}1} under anoxic conditions, and rates generally decreased with depth in the profiles. When expressed on a volumetric basis, production rates ranged from 0.3 to 23.4 g CO{sub 2} m{sup {minus}3} d{sup {minus}1}, and there was much less variation in CO{sub 2} production rates within profiles because the bulk density of peat increased with depth. The Q{sub 10} quotient, between 4 and 14 C, ranged from 1.0 to 7.7, depending on sample and incubation conditions, with an average of 2.0 for oxic and 2.7 for anoxic conditions. Oxic:anoxic ratios averaged 7:1, 16:1, and 12:1 for the bog, poor fen, and beaver pond margin samples, respectively. Degree of decomposition (von Post index) was the substrate property most strongly correlated with CO{sub 2}more » production. Based on temperature and incubation data for the peat profiles to a depth of 45 cm, annual decomposition values (k) ranged from 0.016 to 0.060 yr{sup {minus}1} under oxic conditions and from 0.001 to 0.007 yr{sup {minus}1} under anoxic conditions. A model of CO{sub 2} emission from the three sites, based on the incubation data and thermal and water table regime, gave good agreement with measured in situ CO{sub 2} emission rates, although summer emission rates were underpredicted, possibly because of the absence of a root production component in the incubations or because of underestimation of CO{sub 2} production rates in field conditions above the water table.« less
164 citations
TL;DR: In this paper, the distribution of heavy metals among various solid phase fractions in soil profiles from a 25-year poultry waste-amended soil was assessed, and it was found that the Cu and Zn in this long-term amended soil are potentially bioavailable and mobile.
Abstract: Various metals are added to poultry diets to facilitate weight increase and disease prevention. The large amounts of poultry waste produced annually are dispersed intensively over relatively small areas of land, resulting in accumulations that pose potential environmental risks to the surface and groundwater. The focus of this study was to assess the distribution of heavy metals among various solid-phase fractions in soil profiles from a 25-year poultry waste-amended soil. Copper and Zn accumulated close to the soil surface where the total amounts of Cu and Zn in waste-amended soils were significantly higher than in nonamended soils. The total metal concentrations in amended soils were not critically high. Copper in the amended soil was present mostly in the organic matter (OM) fraction (46.9%), whereas Zn was found in the easily reducible oxide (ERO) fraction (47.3%). This suggests that the Cu and Zn in this long-term amended soil are potentially bioavailable and mobile. We observed the mobility of Zn through much of the soil profile of the long-term waste-amended soil. Zinc in this soil profile was found primarily in forms of the residual (RES) and crystalline iron oxide bound (CryFe) fractions, followed by the organic matter-bound and exchangeable (EXC) fractions.
148 citations
TL;DR: Soil Science integrates specific contributions from physics, chemistry, biology, and the human sciences during the last 2 decades into a single integrated approach to ecology.
Abstract: Soil Science integrates specific contributions from physics, chemistry, biology, and the human sciences During the last 2 decades, these approaches, which had primarily developed separately and at different speeds, have been progressively integrated Ecology has contributed a significant number of
122 citations
TL;DR: In this paper, long-term weathering rates are determined by comparing the chemistry and mineralogy of soil profiles of known age and the fresh source rock composition, based on enrichment/depletion factors determined using immobile element contents.
Abstract: Long-term weathering rates are determined by comparing the chemistry and mineralogy of soil profiles of known age and the fresh source rock composition. Such calculations are based on enrichment/depletion factors determined using immobile element contents, usually Ti or Zr. For convenience, both pos
121 citations
TL;DR: In this article, the authors identify and prioritize research needs in soil physical management in the tropics, including assessing soil physical constraints at farm scale, managing soil structure and tilth to minimize the risks of crusting, compaction, and hard-setting, quantifying and controlling soil erosion by water and wind, developing a cause-effect relationship between soil and climate factors, and evaluating the effects on productivity.
Abstract: Increasing agronomic productivity and improving the quality of the environment are among the important goals of soil physical management in the tropics. Several perceptions, created by insufficient scientific data and misunderstanding of the basic processes, are being resolved by an improved data base and better understanding of the dynamics of soil physical properties and processes. Principal issues in the tropics for the 21st century include: (i) achieving food security; (ii) curtailing soil degradation and restoring degraded soils; and (iii) improving environment quality. These issues can be addressed by identifying and prioritizing research needs in soil physical management. Important among these are: (i) assessing soil physical constraints at farm scale; (ii) managing soil structure and tilth to minimize the risks of crusting, compaction, and hard-setting; (iii) quantifying and controlling soil erosion by water and wind, developing a cause-effect relationship between soil and climate factors, and evaluating the effects on productivity; (iv) managing soil-water, controlling soil salinity in irrigated agriculture, and developing water harvesting techniques in rain-fed agricultural systems; (v) studying the dynamics of soil physical properties in puddled soils of rice-based cropping systems; (vi) developing conservation tillage and residue management methods to improve soil tilth; (vii) understanding soil moisture retention characteristics in relation to plant available water capacity; and (viii) developing indicators of soil physical quality. Important environmental issues relevant to soil physical management are transport of agricultural chemicals into surface and ground waters, emission of greenhouse gases from soils to the atmosphere, and disposal of urban and industrial wastes. Soil physical management in the tropics must be based on a holistic approach to solve practical problems. It is also important to make the public aware of the contributions of soil science to society's well-being. In addition to enhancing food production, soil physical management needs to address environmental, engineering, social, legal, and archeological issues. Achieving these goals necessitates soil scientists working in close collaboration with engineers, climatologists, geologists, biologists, and specialists in GIS and geostatistics.
113 citations
TL;DR: In this paper, the existence of natural soil phosphorus thresholds as expressed by Quantity/Intensity relationships is explored, where the authors consider the role of soil phosphorus in environmental risk assessment.
Abstract: Concern over the transport of phosphorus from agricultural soils to surface waters has focused attention on the role of soil phosphorus in environmental risk assessment. This study explores the existence of natural soil phosphorus thresholds as expressed by Quantity/Intensity relationships. Fifty-ni
96 citations
TL;DR: In this article, the effect of organic matter (pig manure, Sus scrofa) addition on solubility and free Cd(II) and Zn(II)- speciation was studied in two mineral soils.
Abstract: The effect of organic matter (pig manure, Sus scrofa) addition on solubility and free Cd(II) and Zn(II) speciation was studied in two mineral soils. The soils were extracted with ultra pure 0.01 M KNO3, and the extracts were analyzed for total dissolved Cd and Zn by graphite furnace AAS and ICP, res
86 citations
TL;DR: In this article, the molecular weight (MW) of humic materials is a key factor controlling proton and metal binding and organic pollutant partitioning, and several studies have suggested preferential adsorption of higher MW, more aromatic moieties to mineral surfaces; quantification of such processes is fundamental to develo
Abstract: Molecular weight (MW) of humic materials is a key factor controlling proton and metal binding and organic pollutant partitioning. Several studies have suggested preferential adsorption of higher MW, more aromatic moieties to mineral surfaces; quantification of such processes is fundamental to develo
TL;DR: In the interplay of the soil and the atmosphere, the soil can be both a contributor to and a recipient of the impacts of climate change as mentioned in this paper, and the task of soil management should be to restore soil organic carbon in order to enhance soil structure and fertility and to help counter the atmospheric greenhouse effect.
Abstract: In the interplay of the soil and the atmosphere, the soil can be both a contributor to and a recipient of the impacts of climate change. In the past, land management has generally resulted in considerable depletion of soil organic matter and the release into the atmosphere of such radiatively active gases as carbon dioxide, methane, and nitrous oxide. Global climate change, to the extent that it occurs, will strongly impact all soil processes. At this time, the task of soil management should be to restore soil organic carbon in order to enhance soil structure and fertility and to help counter the atmospheric greenhouse effect. Widely varying estimates of the soil's organic carbon content and of the potential for soil carbon sequestration point to the need to conduct a comprehensive inventory of this important property.
TL;DR: In this paper, field evaluation of nutrient release from composts is important to estimate nutrient contribution to crops, potential leaching of nutrients, and, ultimately, to determine optimum application rates, timing, and placement of composts.
Abstract: Field evaluation of nutrient release from composts is important to estimate nutrient contribution to crops, potential leaching of nutrients, and, ultimately, to determine optimum application rates, timing, and placement of composts. Field incubation and laboratory analyses were conducted to evaluate
TL;DR: In this paper, the authors examined the adsorption and desorption characteristics of metolachlor in two Louisianian soil regions and found that metolACHlor is susceptible to runoff or movement in the soil profile.
Abstract: Adsorption and desorption of herbicides are important processes that influence the amount of herbicide retained by the soil and that which is susceptible to runoff or movement in the soil profile In this study, we examined the adsorption and desorption characteristics of metolachlor in two Louisian
TL;DR: In this paper, a mechanistic submodel, which is incorporated in the model NLOSS, designed to predict the soil biogen is presented, and the model is used to predict soil microbial denitrification.
Abstract: Soil microbial denitrification is a significant source of atmospheric nitrous oxide (N2O), a trace gas important in global climate change and stratospheric ozone depletion. In this paper we describe a mechanistic submodel, which is incorporated in the model NLOSS, designed to predict the soil biogen
TL;DR: In this article, an alternative procedure for calculating root water extraction from different depths of a soil profile is proposed, based on the concept that the root extraction entails energy expenditure by the plant and that the plant seeks to minimize the total rate of energy expenditure during water uptake.
Abstract: An alternative procedure for calculating root water extraction from different depths of a soil profile is proposed. The procedure is based on the concept that the root water extraction entails energy expenditure by the plant and that the plant seeks to minimize the total rate of energy expenditure during water uptake. The model, therefore, considers root water extraction to be a minimization problem whose solution can be sought using a dynamic programming framework. We tested the model by simulating the variations of the soil water content using the time and depth of a maize-sorghum intercrop experiment reported for an 8-day drying cycle by Ozier-Lafontaine et al. (Plant and Soil 204:183-201, 1998). Simulated patterns follow the observed water content distribution quite well. Furthermore, results from numerical experiments show that the model is capable of simulating a range of water extraction patterns in a realistic manner. Patterns of water extraction from uniformly wet soil profiles follow those of the root distribution with depth. The extraction rate is highest in the section where the root length density is also highest. Once the soil profile dries out, water extraction patterns cease to bear any similarity to root distribution. Model simulations also show increased root activity at greater depths when the top sections of the soil dry out. Generally, the model avoids the need to make any prior assumptions about the pattern of the root water extraction.
TL;DR: In the vineyards of the Anoia-Alt Penedes region of NE Spain, erosion problems arising from a combination of soil and climate characteristics and their relief have been accelerated in the last few decades as a consequence of new cropping/planting patterns and soil management practices involving cont
Abstract: In the vineyards of the Anoia-Alt Penedes region of NE Spain, erosion problems arising from a combination of soil and climate characteristics and their relief have been accelerated in the last few decades as a consequence of new cropping/planting patterns and soil management practices involving cont
TL;DR: In this paper, the authors measured total and dissolved trace element concentrations, including potentially toxic heavy metals, in the contaminated 0 to 5-cm surface soil layer of a long-term, no-till continuous bromegrass experiment about 18 years after the last application of three chemically different sewage sludges.
Abstract: To understand the long-term fate of heavy metals applied to agricultural soils via sewage sludges, it is necessary to measure metal speciation and solubility in the soil for many years after application. With this as our objective, we measured total and dissolved trace element concentrations, including potentially toxic heavy metals, in the contaminated 0 to 5-cm surface soil layer of a long-term, no-till continuous bromegrass experiment about 18 years after the last application of three chemically different sewage sludges. For each particular sludge, long-term heavy metal solubility was generally linearly correlated to the remaining heavy metal concentration in the soil, with the nature of the sludges applied affecting the partition coefficient (K D ) for some elements and heavy metals. Most of the dissolved Cu and Pb (generally >75%) was not labile by anodic stripping voltammetry (ASV), indicating a high degree of complexation of these two metals by soluble organic matter. A smaller degree of complexation (<50%) of dissolved Cd and Zn in nonlabile organic complexes was measured. Some reduction of both organic matter content and heavy metal concentrations in the 0 to 5-cm layer was measured in the time interval between 1979 and 1997. The K D values for Cu, Zn and Cd were all close to 10 4 for the sludge-treated soils with the highest organic matter content, indicating a strong metal retention that may be attributable to binding to organic matter, but free calcium carbonate in the soil was probably important in limiting metal lability and solubility. A strong linear correlation between total Cd and sulfur in these soils suggests that Cd may be associated with organosulfur ligands. Heavy metal ion activities in the high-organic matter surface layer at this site were low compared with activities measured at other sites with comparable total metal loadings, suggesting the importance of the role of continuous grass and no-till management in maintaining high organic matter and consequent low metal activity in high-lime soils.
TL;DR: In this paper, a multidimensional model describing water flow in variably saturated soil and evapotranspiration was used to simulate successfully 3-years of local hydrology for a cypress pond located within a relatively flat Coastal Plain pine forest landscape.
Abstract: WETLANDS, a multidimensional model describing water flow in variably saturated soil and evapotranspiration, was used to simulate successfully 3-years of local hydrology for a cypress pond located within a relatively flat Coastal Plain pine forest landscape. Assumptions included negligible net regional groundwater flow and radially symmetric local flow impinging on a truncated conical pond, deciduous cypress trees and shallow-rooted perennial undergrowth in the pond area, and pine trees in the upland area as well as within the outer 20% of the wetland area. A minimal observed parameter set of daily rainfall, daily air temperature, soil characteristics, and pond geometry provided model input. The model described temporal patterns of daily pond water and groundwater table elevations with relatively small average signed deviations of -2 and +ll cm, respectively. Potential exists for the model to be utilized as a predictive tool for wetland hydrology, even for conditions where available empirical data for a given site is minimal and appropriate simplifjring assumptions are utilized. (Soil Science 2000;165:384-397)
TL;DR: In this article, FT-IR, FT-Raman, and 1 H-NMR spectroscopies were applied to investigate molecular changes in soil organic matter (SOM) treated with different biomasses.
Abstract: FT-IR, FT-Raman, and 1 H-NMR spectroscopies were applied to investigate molecular changes in soil organic matter (SOM) treated with different biomasses. The experiment consisted of several plots of soil treated over a 22-year period (from 1972 to 1994) with different amendments: cattle manure (CM), cow slurries (CS), and crop residues (CR). Samples taken from these plots were analyzed and compared with the unamended soil (C), which was used as the control sample. The samples were analyzed for both total organic carbon (TOC) and total nitrogen (N) content, both at the beginning of the study and after 22 years of treatments. The plots amended with CS and CR and the unamended plots showed a decrease in TOC and N after 22 years when compared with the control at the beginning of the experiment. However, the amended soil with CM showed a linear increase in TOC and N in relation to the control. The above mentioned spectroscopic procedures were employed to characterize both the unfractionated SOM and the low molecular weight (LMW) fraction extracted in an acidic medium. This spectroscopic analysis revealed that the composition of the soils amended with CM varied significantly in relation to the other amendments in the sense that the more aliphatic and aromatic moieties are resistant to the degradation. This is corroborated by the spectroscopic analysis of the LMW fraction, which is richer in small aromatic and aliphatic carboxylic acids in the soil amended with CM. The results shown in this work reveal that the SOM formed during the amendment with CM might be more resistant to the process of decomposition.
TL;DR: In this paper, the authors investigated the catalytic power of oxides in the ring cleavage of pyrogallol and the polycondensation of the resulting fragments in air and N 2 atmosphere.
Abstract: The nature of oxide in soil and associated environments in influencing the abiotic transformations of polyphenols still remains to be established. The objective of this study was to investigate the catalytic power of Mn(IV), Fe(III), Al, and Si oxides in the abiotic ring cleavage of pyrogallol and the polycondensation of the resulting fragments in air and N 2 atmosphere. The catalytic power varied greatly with the nature of the oxides. The synergistic effects of oxygen molecules and oxides also played an important role in affecting the transformations of pyrogallol. The results indicate that the release of CO 2 as a result of ring cleavage of pyrogallol enhanced the development of carboxylic group contents of humic polymers formed in the reaction systems. The abiotic ring cleavage of polyphenols catalyzed by soil inorganic components such as short-range ordered oxides of Al and especially Fe and Mn may account, in part, for the carboxylic group contents and the origin of the aliphaticity of humic substances in soils.
TL;DR: In this paper, the effects of aqueous Pb (initial [Pb a ] = 0.185 mM) on the kinetics of apatite dissolution were investigated.
Abstract: Apatite has been used to remediate Pb contamination; apatite dissolution releases phosphate, which combines with Pb to form highly insoluble Pb-phosphate minerals. This research focused on the effects of aqueous Pb (initial [Pb a ] = 0.185 mM) on the kinetics of apatite dissolution. Synthetic microcrystalline hydroxylapatite (HAP) and natural chlorapatite (CAP) and fluorapatite (FAP) were used in batch experiments at 22°C, with pH within the range of 4.2-7.0, and in the presence of aqueous Cl. In these batch experiments, apatites followed linear (zeroth-order) dissolution kinetics. Dissolution experiments were performed using 1 g apatite/L for all three apatites. When dissolution rate constants (k AP ) are adjusted for particle specific surface area (A s ), k CAP > k FAP > k HAP . In the presence of Pb aq and Cl, all three apatites reacted to form pyromorphite (PY; Pb 10 (PO 4 ) 6 Cl 2 ). Rates of Pb a uptake by the apatites decreased in the same order as the apparent (not normalized for A s ) dissolution rate constants of apatite (k Ap ○): HAP > CAP > FAP, suggesting that Pb aq uptake is controlled by the total amount of dissolved phosphate in the system. While HAP and CAP removed more than 98% of Pb aq during 2 weeks of the experiment, FAP decreased the initial [Pb aq ] by ∼30%. Pb uptake rates calculated on a molar basis correlated with Ca release rates. Concentration of dissolved phosphate during the reaction with Pb aq was below the detection limit of 10 -7 mol/L. Phosphate concentration was probably controlled by solute equilibrium with precipitating PY, which has very low solubility (log K sp = -167). This indicates that the rate-controlling step was apatite dissolution. The presence of Pb aq increased apatite batch dissolution rates, most probably because formation of PY acted as a sink for dissolved phosphate, hence increasing the thermodynamic drive for dissolution. Although PY formed heterogeneously on the surfaces of apatite particles, the PY did not prevent continued apatite dissolution.
TL;DR: In this paper, the microporous properties of five organic soil materials and two agricultural topsoils were studied and compared to other topsoil materials. But the results were limited.
Abstract: Microporous properties of soil materials are considered important to the physical sequestration processes of contaminants and the influence on risk assessment for chemicals in the environment. We studied the microporous properties of five organic soil materials and two agricultural topsoils and thei
TL;DR: In this article, the potential of these two-dimensional NMR spectroscopy techniques to the study of soil humic structures has been outlined, with multitudes of cross-peaks produced from both TOCSY and HMQC experiments.
Abstract: Humic substances are the most abundant organic macromolecules in soils, and comprehension of their chemical structure is essential to understanding their role in terrestrial ecosystems. The one-dimensional nuclear magnetic resonance (NMR) spectroscopy techniques now used widely to study humic substances have provided important insight into humic structures, but the complexity of these macromolecules gives rise to resonance signals that are broad and have spectral overlap. This has prevented the definitive functional group assignments necessary for structural determination. Hence, interest has focused on more powerful two-dimensional NMR experiments, such as the homonuclear TOtal Correlation SpectroscopY (TOCSY) and Heteronuclear Multiple Quantum Coherence (HMQC), which were employed in the study of a soil humic acid standard. The purpose of this paper is to outline the potential of these techniques to the study of soil humic structures. The 2-D spectra produced were extremely encouraging, with multitudes of cross-peaks produced from both TOCSY and HMQC experiments. The identification of fatty ester/acid chains and amino acid couplings are given as examples. Results obtained with these NMR experiments indicate substantial improvements in functional group assignment capabilities and the potential for marked progress in the determination of the chemical structure of soil humic substances.
TL;DR: In this paper, the effects of soil water content on denitrification during hairy vetch (Vicia villosa) decomposition were investigated. But they did not consider the effect of water augmentation.
Abstract: Experiments were conducted to assess the effects of soil water content on denitrification during hairy vetch (Vicia villosa) decomposition. Hairy vetch plants were grown from seed to maturity in soil cores. Before and after kill, simulated rainfall was applied to cores weekly and leachate was analyz
TL;DR: In this article, the applicability of inverse modeling to the water regime of a layered field soil was investigated, and the authors found that fitting alone, even with 20 to 30 parameters, could not account satisfactorily for the soil hydraulic behavior.
Abstract: Identification of soil hydraulic parameters is an important step for modeling soil water flow and transport behavior. Parameter fitting by inverse modeling is becoming increasingly attractive as a way to avoid experimental difficulties. In this study, the authors linked the inverse program SUFI (Sequential Uncertainty domain FItting) with the one-dimensional flow model HYDRUS5 to investigate the applicability of inverse modeling to the water regime of a layered field soil. Measured pressure head and water content data from an irrigation and drainage experiment were used. The soil profile at the experimental site consisted of at least five soil layers, including a compacted pan. They formulated a total of eight inverse scenarios in an effort to explain the observed pressure head and water content data. Important processes in the experiment included, among others, air entrapment and preferential flow. The authors obtained a relatively precise simulation of pressure head and water content only after accounting for a pan layer and treating the irrigation and the drainage phases separately. They found that fitting alone, even with 20 to 30 parameters, could not account satisfactorily for the soil hydraulic behavior. Rather, correct accounting of the soil hydraulic processes as well as the soil system provedmore » to be essential.« less
TL;DR: Soils are relevant to society in diverse ways, supplying various economic and cultural services or functions as well as being the substrate for plants and a life-support system as discussed by the authors, and efforts are now being made to institute an internationally secured global treaty or soil convention for better soil care and sustainable use of soils.
Abstract: Soils are relevant to society in diverse ways, supplying various economic and cultural services or functions as well as being the substrate for plants and a life-support system. Attitudes to the diverse kinds of soil resources and resulting land-use practices throughout human history indicate that mankind has frequently used other than the most fertile or easiest accessible soils. Many special techniques, such as terracing, have been developed to utilize and preserve less accessible land and shallow soil on slopes. Soil degradation and erosion following deforestation have frequently been a problem in the past, especially when some land was abandoned for cultural or economic reasons. Better data on current degree and extent of soil degradation are needed. Man has made soils fertile on a large scale, providing more secure food resources for the ever growing population. Yet, there is a growing threat to soils, in many instances, on marginal soils or in less resilient soil regions. A good environmental ethic requires equally good soil care of open spaces and of forests, woods, and deserts for better quality of life and for future generations of town and country populations. For this purpose an Eleventh Commandment was formulated a generation ago, and efforts are now being made to institute an internationally secured global treaty or soil convention for better soil care and sustainable use of soils. Soil scientists need to support such proposals and to bridge the gaps and differences between local and governmental efforts.
TL;DR: In this article, the effects of conservation tillage on P speciation were examined by examining the distribution of P in inorganic and organic chemical pools, and depth-incremented soil samples were collected from long-term (9- an
Abstract: Conservation tillage results in the concentration of plant-available P near the soil surface. We studied the effects of conservation tillage on P speciation by examining the distribution of P in inorganic and organic chemical pools. Depth-incremented soil samples were collected from long-term (9- an