bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Harvesting for Afforestation: III. Dependence of Tree Growth on Amount and Distribution of Precipitation
Authors: Kowsar Ahang 
Published: July 2010

AbstractIrrigation of greenbelts being established around major Iranian cities constitutes an unnecessary burden on the overtaxed water supplies in this arid country. Water harvesting through surface application of asphalt is an answer to this pressing problem. Terraces, 2 m in width, were constructed on contour lines at 1.5‐m‐vertical intervals on a 30% slope. Hot, medium‐curing, cutback asphalt solution (MC2) was sprayed onto the soil surface between the terraces at the rate of 1 L/m2 in December 1969. Seedlings of Robinia pseudacacia L., Cupressus arizonica G., and Fraxinus rotundifolia Mill. were planted on the terraces in March 1970. The 509‐mm‐accumulated runoff from the treated microwatersheds in the 1970–1975 period did not substantially affect the survival of the tree seedlings but improved their growth significantly. The increases in height, crown cover, and stem cross section due to the runoff at the end of 1978 were 46.6, 46.2, and 54.4%, respectively, for R. pseudacacia L.; 16.4, 14.3, and 33.8%, respectively, for C. arizonica G.; and 17.6, 62.6, and 36.9%, respectively, for F. rotundifolia Mill.Regression equations were developed correlating growth with amount of water and age of trees. Height and crown growth of R. pseudacacia L., height growth of C. arizonica G., and crown growth of F. rotundifolia Mill. were influenced by water received in April and May of the previous and current years. Amount of water received in April and May of a given year influenced crown growth of C. arizonica G. for that year and height growth of F. rotundifolia Mill. during the following year. Amount of water received in April through October of a given year influenced stem cross‐section growth of R. pseudacacia L. and F. rotundifolia Mill. during the following year and that of C. arizonica G. 2 years later.
Influence of Fertilizer Nitrogen Source on Soil Physical and Chemical Properties
Authors: Intrawech A. , Stone L. R. , Ellis R. , Whitney D. A. 
Published: July 2010

AbstractThe soil‐dispersing potential of ammonium (NH+4) has caused concern about the possible negative influence of anhydrous ammonia (NH3) use on soil structure. In the fall of 1978, we collected disturbed and undisturbed soil samples to evaluate the influence of 10 years of annual application of four nitrogen (N) sources [NH3, ammonium nitrate (NH4NO3), urea, and urea‐ammonium nitrate solution (UAN)] on soil physical and chemical properties. A no‐N check was included during the 10‐year field study.Soil physical properties (saturated hydraulic conductivity, probe resistance at ‐⅓ bar soil water potential, core bulk density, water content at ‐⅓ and −15 bar soil water potential, particle‐size distribution, geometric mean diameter of water‐stable aggregates, and compactibility) were not significantly affected by fertilizer treatment. The application of all N sources reduced the soil pH significantly compared with the no‐N check. In the 6‐ to 14‐cm soil layer, the Zn concentration was significantly lower and the Mn concentration significantly higher in the N‐source plots than in the no‐N check. All treatments receiving fertilizer N yielded significantly more grain (1975 through 1977 mean) than the no‐N check, with no significant difference in grain yield among the four N sources.Our study found that 10 years of annual application of four N sources (included NH3) have had no measurable influence on soil structure and soil compactibility, compared with a no‐N check.
Effects of Nutrient Accumulation by Aspen, Spruce, and Pine on Soil Properties
Authors: Alban David H. 
Published: July 2010

AbstractNutrient analysis was done for adjacent, 40‐year‐old stands of pure quaking aspen (Populus tremuloides Michx.), white spruce (Picea glauca Moench Voss), red pine (Pinus resinosa Ait.) and jack pine (Pinus banksiana Lamb.) on two soils in Minnesota to determine the effects of tree species on soil properties. On both soils, aspen and spruce stands accumulated more of most nutrients than did pine stands, and these species differences were reflected in the litterfall. The weight of the forest floor did not differ among species, but nutrient accumulation and pH were greatest under aspen and spruce. Calcium content was about twice as high under aspen and spruce as under the pines. In the mineral soil, phosphorus (P) and potassium (K) did not differ among species; organic matter and nitrogen (N) tended to be lowest under aspen, and calcium (Ca) was much lower under aspen and spruce than under the pines. Soil pH and cation exchange capacity were highest under the pines; this was directly related to soil Ca contents. Mineral soil differences related to species were most pronounced in the top 10 cm; few differences occurred below 25 cm.The large species differences in the N, Ca, and Mg contents of vegetation, forest floor, and mineral soil show a redistribution of these nutrients, but their amounts in the entire ecosystem do not differ by species. In contrast, P and K in the ecosystem decrease in the order aspen>spruce>pines, and this is largely a reflection of their accumulation in the vegetation since their differences in the soil are minimal.
Influence of Soil Characteristics on the Survival of Rhizobium in Soils Undergoing Drying
Authors: Chao Wei‐Liang , Alexander Martin 
Published: July 2010

AbstractA study was conducted to establish whether certain soil characteristics could be correlated with the extent of survival of Rhizobium as the soils underwent drying. The numbers of R. meliloti and R. phaseoli fell markedly as the soils dried, but their abundance declined slowly in the soils maintained in an air‐dry state. The number of surviving cells increased if these bacteria were added to sterile soil and allowed to grow before desiccation was extensive. Survival of both species was poor in soils of pH values below 5.7. The number of survivors of R. meliloti but not R. phaseoli decreased as the content of clay and of water at 15 bar suction increased. At organic matter levels below but not above 2 to 3%, the abundance of survivors of these rhizobia was related to the organic carbon content of the soil. Survival of R. phaseoli was inversely related to the content of total available aluminum in the soils, but the number of survivors of the two species was not correlated with the available phosphorus levels.
Nutrient Availability under Trickle Irrigation: I. Distribution of Water and Bray no. 1 Phosphate
Authors: Bacon P. E. , Davey B. G. 
Published: July 2010

AbstractThe distribution of water and Bray no. 1 phosphate was measured in the surface soil of a Chromic Luvisol that had been under trickle irrigation for 5 years. The region of the soil reaching field capacity after 8 to 12 h of irrigation extended horizontally to at least 65 and up to 90 cm from the outlet and was no deeper than 12 cm from the surface. After irrigation had ceased soil water decreased with time but usually did not become significantly different from field capacity until after about 24 h.Where the soil had not been fertilized, Bray no. 1 phosphate decreased from 42 to 19 ppm over a 25‐cm depth immediately below the trickle outlet, while 65 cm away it decreased from 78 to 16 ppm. Banding fertilizer 50 to 80 cm from the outlet increased phosphate at the surface to 113 ppm but did not increase phosphate at depth. These results imply that trickle irrigation caused both horizontal and vertical movement of native soil phosphate near the outlet, and that phosphate fertilizer applied 50 to 80 cm away from the outlet remained near the soil surface and above the root zone.Irrigation of an 8‐ to 12‐h duration usually increased the concentration of Bray no. 1 phosphate by an average of 63% in a region of radius 30 cm from the outlet and about 12 cm in depth. The phosphate concentration remained above pre‐irrigation levels for between 6 to 23 h after the end of irrigation but fell to pre‐irrigation levels as the soil dried out.A series of linear regression equations of similar slope were found to describe the relationship between Bray no. 1 phosphate and soil water content for all 300 samples collected in the multicycle irrigation experiment. Differences in intercept values were related to the variable phosphate distribution with depth at various distances from the trickle outlet.Phosphate release probably resulted from reduction of amorphous iron phosphates during the anaerobic phase of the irrigation cycle. These results suggest that trickle irrigation leads to cyclic release of both native and applied phosphate during each irrigation cycle. Leaf analysis showed that under these circumstances there was no significant response to applied phosphate fertilizers at rates up to 78 g of P as single superphosphate per plant. Over the period studied trickle irrigation appears to be an agricultural management system with a much lower requirement for the application of phosphate fertilizer when tree crops are grown.
Soil Erosion Effects on Properties and Productivity of Two Kentucky Soils
Authors: Frye W. W. , Ebelhar S. A. , Murdock L. W. , Blevins R. L. 
Published: July 2010

AbstractFew attempts have been made to identify the yield‐limiting effects of soil erosion and to quantify losses in soil productivity. The objective of our study was to determine the effects of moderate erosion on certain physical and chemical soil properties and on the productivity of two soils. Soils were the Maury soil at Lexington, Ky., and the Crider soil at Princeton, Ky. Both have strongly developed profiles and are in the family of Typic Paleudalfs, fine‐silty, mixed, mesic. The soils were known to vary in degree of past erosion at the sites. For moderately eroded and uneroded areas of the soils, we determined several physical and chemical properties and measured corn grain yields on both soils and cover crop yields on the Maury soil. Corn grain yields on eroded soils compared to uneroded soils were 12% lower for the Maury soil and 21% lower for the Crider soil. Lower yields of winter cover crops attributed to erosion on the Maury soil were 17, 30, 36, and 27%, respectively, for rye, crimson clover, big flower vetch, and hairy vetch. Available water‐holding capacity (0.33 minus 15 bar water) averaged 4 to 5% lower (volume basis) in the surface layer of the eroded soils. In general, the Ap horizon of eroded compared to uneroded soils had higher clay content, higher bulk density, lower organic matter content, and lower fertility status. Erosion substantially decreases the productivity of strongly developed soils, such as the Maury and Crider soils, and the effect is long lasting and difficult to ameliorate. Probably the most important yield‐limitng effect of soil erosion is the decrease in available water‐holding capacity caused by the increased clay content of the Ap horizon.
Managing Early Season Soil Temperatures in the Northern Corn Belt Using Configured Soil Surfaces and Mulches
Authors: Radke J. K. 
Published: July 2010

AbstractSoil temperatures in the northern Corn Belt are often too low at planting time to allow optimum germination, emergence, and early seedling growth. Crop residues, which are beneficial for erosion protection or are the result of minimum tillage, generally retard the rate of drying and warming of the seedbed. We found that ridged soils dried faster starting at the peak of the ridges and continuing down their southerly exposed slopes. Maximum seedbed temperatures occurred either under the ridge peak or under the southerly exposed slope. The time of the diurnal maximum temperatures depended on the slope aspect. For example, a southeast‐facing slope reached maximum temperature over 2 h earlier than a southwest‐facing slope, although the southwest slope reached a higher maximum temperature. Mulch decreased daytime soil temperatures, but a combination of mulch and ridging offset this temperature decrease so that there was no difference between a seedbed temperature under a mulch‐covered ridge and a conventionally tilled soil without mulch. Mulch with ridging provides a limited means of managing soil water and soil temperature in the seedbed.
The Mechanism of Raindrop Splash on Soil Surfaces
Authors: Al‐Durrah M. M. , Bradford J. M. 
Published: July 2010

AbstractFrom the results of high‐speed photography of 4.6‐mm‐diam drops impacting various soil materials and from soil mechanics principles, a new concept in describing the mechanism of soil detachment from raindrops impacting on saturated soil surfaces is proposed. The impulsive loading caused by the impacting drop does not permit time for drainage; thus there is no change in total soil volume or bulk density. The soil surface is deformed under the impulsive load application of the drop; however, the vertical strain under the impact area is compensated by a bulge around the perimeter of the depression. The vertical force of the drop is transformed to lateral shear caused by radial flow of the impacting drop. Splash angle is determined by the depth of the cavity and the size of the bulge surrounding it.Splash angle was highly correlated with soil shear strength as measured by the fall‐cone method. Low soil strength resulted in (i) a larger cavity and surrounding bulge, (ii) a greater detachment of soil particles due to the shear stress of the radial flow, and (iii) a greater splash angle with the horizon.
Rapid Method for Determining the Adsorption of Nickel‐63 to Kaolinite
Authors: Angle J. S. 
Published: July 2010

AbstractA supernatant isolation system was investigated as a means to assay 63Ni adsorption to kaolinite. The Titertek Supernatant Collection System utilizes microtiter wells as the reaction chamber and cellulose‐acetate cartridges to separate kaolinite from supernatant. The 63Ni absorbed into the cartridge was assayed on a scintillation counter.The supernatant of 96 wells could be separated from the kaolinite in under 5 min. The coefficient of variation for all measurements averaged 6.83%. The primary limitation of this system is the lengthy equilibration time.
A New Method for Determination of 15N‐Labeled Nitrous Oxide
Authors: Mulvaney R. L. , Kurtz L. T. 
Published: July 2010

AbstractA procedure is described that permits determination of nitrous oxide (N2O) evolved from soils treated with 15N‐labeled fertilizer. This procedure involves dilution of 15N‐labeled N2O with a known amount of unenriched dinitrogen (N2), reduction of the N2O to N2 in a heated tube containing reduced copper, and determination of the ratios, 29N2/28N2 and 30N2/(28N2 + 29N2), with a dual‐inlet ratio mass spectrometer. The procedure described is accurate and precise; it permits measurement of 15N‐labeled N2O without interference by CO2; it allows calculation of the average 15N enrichment of the nitrogen pool from which this N2O is derived; and it permits N2O analysis of an atmospheric sample previously analyzed for 15N‐labeled N2.
Soil Profile and Site Characteristics Related to Winter Wheat Response to Potassium Fertilizers
Authors: Schaff Bernard E. , Skogley Earl O. 
Published: July 2010

AbstractEighteen sites throughout Montana were selected to study soil and climatic factors that influence the response of winter wheat (Triticum aestivum L.) to K fertilizer. Rates of 0, 22, 45, 90, and 135 kg K/ha were applied with 45 and 56 kg/ha of N and P, respectively. The sites were characterized according to Soil Taxonomy classification parameters. Fourteen chemical and physical properties were determined for each genetic horizon and seven site characteristics were identified. A stepwise multiple linear regression analysis was used to determine the relationship of the chemical, physical, and site characteristics to percent yield response of winter wheat to applied K. The genetic horizon variables were analyzed by major horizon as well as by sequence of horizons. Statistically significant variables (p < 0.1) from the major horizon analyses were grouped with significant site characteristics in a combined overall analysis. Variables with the highest correlation to percent yield response in the combined analysis, in decreasing order, were: (i) mean annual soil temperature at 50 cm as derived from SCS estimates; (ii) moist consistence of the Ap; (iii) moist and (iv) dry consistence of the B horizon; and (v) the clay content of the ca horizon. For these five variables an R2 of 0.88 was obtained.
A Laboratory Method for Predicting the Size Distribution of Sediment Eroded from Surface Soils
Authors: Rhoton F. E. , Meyer L. D. , Whisler F. D. 
Published: July 2010

AbstractA laboratory method was developed to reproduce size distributions of sediment eroded from field plots during simulated rainstorms. Using samples of surface soil from the field plots, sediment size data were generated in the laboratory by agitating soil suspensions on an orbital shaker after wetting the sample under tension. Once agitated, the samples were separated into 10 size groups ranging from >1,000 to <4 µm by wet sieve and sedimentation procedures. Size distribution curves were prepared from these data and compared with appropriate field sediment curves. Agitation times were adjusted until most points on the laboratory curves were within ±1 SD of corresponding points on the field curves. Soils high in sand and silt produced laboratory and field curves which were quite similar, but curves from soils high in clay and organic matter were less similar. Results from the 17 soils studied indicate that laboratory generated sediment size data can be used to predict size distributions of sediment eroded by simulated rainfall from interrill areas.
Dry Soil‐Aggregate Stability: Energy‐Based Index
Authors: Skidmore E. L. , Powers D. H. 
Published: July 2010

AbstractMost methods used to estimate aggregate stability apply an unmeasured force, or a measured force without knowledge of transfer, to a single or a group of aggregates. A technique is needed to estimate aggregate stability based on quantitative transfer of energy. This paper presents an energy‐based procedure for evaluating dry‐aggregate stability. Soil aggregates were crushed by diametrically loading them between parallel plates. The energy of crushing was determined by integrating the area under the force against distance curve. The aggregate‐surface area after comminution was calculated from aggregate‐size distribution and aggregate density; the aggregates were assumed to be spherical. The results are expressed as energy per unit of surface area, joules per meter squared (J/m2). Example values obtained from field‐sampled aggregates for several soil series ranged from 3.7 ± 0.7 for Hotlake silt loam (coarse‐silty, mixed, mesic Aquic Haploxerolls) to 43.9 ± 7.5 for Bearden silt loam (fine‐silty, frigid Aeric Calciaquolls). The wide range of aggregate stabilities among different soils made it possible to distinguish among them even though variability among aggregates of the same soil was relatively large. The results were relatively insensitive to initial aggregate size but sensitive to crushing end point.
Comparison of Fall and Spring Applications of 15N‐Labeled Urea to Douglas‐Fir: II. Fertilizer Nitrogen Recovery in Trees and Soil after 2 years
Authors: Heilman P. E. , Dao T. H. , Cheng H. H. , Webster S. R. , Christensen L. 
Published: July 2010

AbstractThirteen separate tree components were sampled for estimation of dry weight and for analysis for total N and 15N on relatively high site quality plots that had been treated with 224 kg N/ha as 15N‐labeled urea. Although the increase in volume growth from fertilization was significant, we were unable to demonstrate a significant increase in weight of any tree component including foliage and boles. Specific gravity of bole wood was significantly reduced by urea fertilization. Fertilization significantly increased concentration of N in the 1977 and older foliage, in bole wood, and in bole bark, but not in other biomass components including roots. The only component in which total weight of N was significantly increased by fertilizer was bole wood.Fertilizer N in individual components as a percent of the total N in those components averaged 22.3% in 1979 foliage, 27.5% in 1978 foliage, 17.1% in 1977 and older foliage, 13 to 17% in twigs and branches, 19% in bole wood produced since fertilization, 19% in bole bark, and 16% in roots. Foliage contained an average of 55% of the total fertilizer taken up by the trees.Fertilizer N in the total tree varied from 25 to 36% of the application. Volume growth response directly corresponded to the quantity of fertilizer N recovered in trees. Differences both in N fertilizer in trees and in volume growth response appeared related to pattern of rainfall soon after treatment. Fertilizer accounted for in soils and trees at the end of two growing seasons averaged 68% of the application. Lowest recovery (52%) corresponded to the treatment which had lowest rainfall after application. Real and apparent N loss averaged 32 ± 6% of the application. Causes of apparent losses likely include litter falling outside of the plots, transport of N beyond the plots by roots passing below the plot barriers, and leaching to deeper soil depths than sampled but still in the rooting zone. Relative magnitudes of real and apparent losses of N were not determined.
Seasonal Variation in Nutrients of Floodplain and Upland Forest Soils of Central Illinois
Authors: Peterson David L. , Rolfe Gary L. 
Published: July 2010

AbstractVariation in nutrients was studied over a two‐year period in adjacent floodplain and upland forest soils in central Illinois. Nutrient pools of all elements except Na were greater in floodplain soils than in upland soils and were in the following order at both study sites: exchangeable Ca > exchangeable Mg > exchangeable K > available P. Seasonal variation in nutrient content of soils was the result of several environmental factors. Available P in floodplain soils was highly dependent on pH, which was in turn influenced by flooding, but there was no evidence of seasonal variation in available P for upland soils. Soil pH was positively correlated with the concentration of exchangeable bases in both soils, especially Ca and Mg in upland soils. Exchangeable Na was highly variable at both floodplain and upland sites and may have been influenced by leaching and variation in tree root exudation. The seasonal variation in nutrient pools of forest soils in this study has implications for tree growth, site evaluation, and nutrient cycling in forest stands.
Measurement of a Cation Exchange Isotherm from Elution Curves Obtained in a Soil Column: Preliminary Results
Authors: Schweich D. , Sardin M. , Gaudet J‐P. 
Published: July 2010

AbstractIt is shown how successive column experiments allow the measurement of exchange capacity and a composition‐dependent selectivity factor for the calcium‐potassium exchange process on a natural soil. The method is based on a simple model which describes (i) the coupling between the steady flow and the exchange process, and (ii) the solubility of calcite which is taken into account by assuming that the resulting excess in calcium is already in the feed. Comparison with classical batch measurements shows that the column experiments give more reliable results. Nevertheless, the accuracy of the method is limited by the efficiency of the packing of the column.