Evaluation of fly ash as a soil amendment for the Atlantic Coastal Plain: II. Soil chemical properties and crop growth

Crop yields in the Atlantic Coastal Plain of the U.S.A. are limited by the low moisture-holding capacities of the sandy soils common to the region. Corn was grown in a Hammonton loamy sand soil amended with fly ash (0, 5, 10, 20, 30, and 40%) to determine if the ash rates required to improve soil moisture holding capacity would adversely affect plant growth, or soil and plant levels of nutrients and heavy metals. Fly ash increased soil test levels of P, K, Ca, Mg, Mn, Cu, Zn, B, Cd, Cr, Ni, and Pb. Nutrient concentrations in plants grown in the ash-amended soils, except P, Mn, and B, remained within established sufficiency ranges. The 20 and 40% ash rates increased soil soluble salt (EC) levels from 0.2 to 1.1–1.5 and 1.7–2.1 mmho cm^?1, soil pH from 5.6 to 6.0–6.4 or 6.3–6.9, and extractable B from 0.2 to 2.2–5.9 and 2.2–9.0 mg kg^?1. Fly ash reduced corn germination, delayed seedling emergence, and reduced root and shoot dry weights. Plant B concentrations at the 40% ash rate were in the phytotoxic range (136–189 mg kg^?1). Management practices that allow for pre-leaching of B and soluble salts will likely be required to attain satisfactory corn growth in ash-amended soils.     

Aggregated fly ash as a medium amendment for the production of container grown nursery stock

Abstract

Royal beauty cotoneaster (Cotoneaster dammeri C. K. Schneid, ‘Royal Beauty') and Hicksii taxus (Taxus x media Rehd. ‘Hicksii') were grown in media amended with several levels of aggregated fly ash. In general, no differences in root or shoot growth was noted in either species as a result of the media in which they were produced. Higher than normal B levels were observed in the leaf tissue of taxus as the level of the aggregated fly ash in the media increased, while no differences in B levels were noted in the leaf tissue of the cotoneaster. Both Cu and B concentrations in the root tissue of taxus increased with increasing levels of aggregated fly ash in the media, while the level of P in the root tissue decreased under the same conditions.     

Nitrate leaching in an Atlantic Coastal Plain soil amended with poultry manure or urea-ammonium nitrate: Influence of thiosulfate

Nitrate leaching, which can lead to groundwater contamination, is a common occurrence, especially in sandy, well drained soils. Nitrogen from poultry manure (PM) and ammonium fertilizers has been shown to undergo rapid nitrification upon addition to soils, making it highly susceptible to nitrate leaching. Any management technique that could delay nitrification and thereby reduce nitrate leaching would be desirable. Ammonium thiosulfate has been shown to be an effective nitrification inhibitor in laboratory studies and may be useful in reducing nitrate leaching. Soil columns, 75 cm long and inner diameter 19.6 cm, were packed with a reconstituted profile of a Rumford loamy sand and amended with urea-ammonium nitrate (UAN) or PM. Corn was grown in the columns to create a dynamic soil/plant system. Columns were placed in a greenhouse and were leached periodically for a period of 10 weeks with deionized water in amounts intended to simulate early spring and summer rainfall patterns in the Atlantic Coastal Plain. Column leachates, as well as plant and soil samples were collected and analyzed for NO₃-N and NH₄-N. Nitrate-N leaching was largely dependent upon the amount of water moving through the system. Ammonium thiosulfate did not significantly decrease NO₃-N leaching or increase plant N uptake when used in combination with UAN or PM. Comparable amounts of NO₃-N leaching were observed for the UAN and the PM treated column. Additionally, large amounts of NO₃-N leaching were observed with the control columns, suggesting that residual soil N from previous crops can contribute significantly to NO₃-N leaching and may deserve further investigation.     

Evaluation of pumice as a perlite substitute for container soil physical amendment

Abstract

Shallow‐drained horticultural soils utilized in containers, sporting areas, and landscape sites tend to retain excess water and be poorly aerated as a consequence of capillary retention following irrigation or precipitation. This problem is usually corrected by soil physical amendment with coarse‐textured particulates which add pores sufficiently large to drain and provide adequate aeration. A variety of materials are used for soil physical amendment. One of the most common and successful amendments is perlite. This study examined the feasibility of using pumice, a very similar mineral, as a substitute for perlite in soil amendment.

The physiochemical properties of pumice important to its use as a container soil amendment were found similar to those of perlite.     

Spatial variability of Southeastern U.S. Coastal Plain soil physical properties: Implications for site-specific management

Our objectives were to describe the field-scale horizontal and vertical spatial variability of soil physical properties and their relations to soil map units in typical southeastern USA coastal plain soils, and to identify the soil properties, or clusters of properties, that defined most of the variability within the field. The study was conducted on a 12-ha field in Kinston, NC. A 1:2400 scale soil survey had delineated three soil map units in the field: Norfolk loamy sand, Goldsboro loamy sand, and Lynchburg sandy loam. These are representative of millions of hectares of farmland in the Coastal Plain of the southeastern USA. Sixty soil cores were taken to ∼ 1-m depth, sectioned into five depth increments, and analyzed for: soil texture as percentage sand, silt, and clay; soil water content (SWC) at − 33 and − 1500 kPa; plant available water (PAW); saturated hydraulic conductivity (Ksat); bulk density (BD); and total porosity. A penetrometer was used to measure cone index (CI) at each sample location. Variography, two mixed-model analyses, and principal components analysis were conducted. Results indicated that soil physical properties could be divided into two categories. The first category described the majority of the within-field variability and included particle size distribution (soil texture), SWC, PAW, and CI. These characteristics showed horizontal spatial structure that was captured by soil map units and especially by the division between sandy loams and finer loam soils. The second class of variables included BD, total porosity, and Ksat. These properties were not spatially correlated in the field and were unrelated to soil map unit. These findings support the hypothesis that coastal plain soil map units that delineate boundaries between sandy loams versus finer loam soils may be useful for developing management zones for site-specific crop management.     

Evaluation of wood ash disposal on agricultural land. I. Potential as a soil additive and liming agent

Abstract

This study evaluated wood ash as an agricultural fertilizer and liming material. Winter wheat (Triticwn aestivum) and poplar (Populus sp.) were grown in a greenhouse on six different Idaho soils amended with different ash concentrations. At ash levels equal to or lower than 2%, no detrimental plant growth effects were observed. In fact, the biomass of the wheat and the caliper and height of the poplar cuttings increased more at 2% ash (40 mt/ha) than with the control soil. These results suggest that wood ash could be used in agricultural applications as a low analysis fertilizer containing K and/or a liming agent. Land application of wood ash could be less expensive and more environmentally sound than present landfilling practices.     

Improvement of physical and hydraulic properties of desert soil with amendment of different biochars

Purpose

The objective of this study was to investigate the effects of amendment of different biochars on the physical and hydraulic properties of desert soil.

Materials and methods

Biochars were produced with woodchip, rice straw, and dairy manure at temperatures of 300 and 700 °C, respectively. Each biochar at 5% (w/w) was mixed with desert soil, and the mixtures were incubated for 120 days.

Results and discussion

The different biochar treatments greatly reduced soil bulk density and saturated hydraulic conductivity. Especially the rice straw biochar addition resulted in the lowest saturated hydraulic conductivities among the treatments. Biochar addition significantly increased water retention of desert soil at any suction. At the same suction and experimental time, the treatment with the rice straw biochar produced at the lower temperature resulted in higher water content than the other treatments. The biochar additions slightly enhanced formation of soil macro-aggregates in the early experimental time. However, the aggregate contents gradually decreased with time due to the lack of effective binding agents (e.g., soil organic matter and clay minerals).

Conclusions

The changes of hydraulic properties of desert soil were attributable to the biochar properties. The higher fine particle content, porosity, and surface hydrophilicity of rice straw biochars were the most beneficial properties to increase soil water retention and to reduce water flow in the desert soil. The improvement of hydraulic properties by biochar addition may provide a potential solution to combat desertification.

     

粉煤灰与糠醛渣混合人工土壤的主要化学性质

To solve soil shortage in reclaiming subsided land of coal mines, the principal chemical properties of artificial soil formed by mixing organic furfural residue and inorganic fly ash were examined. The results indicated that the artificial soil was suitable for agriculture use after irrigation and desalination, the available nutrients in the artificial soil could satisfy the growth demand of plants, and the pH tended to the neutrality.     

Use of organic amendment as a strategy for saline soil remediation: Influence on the physical, chemical and biological properties of soil

The effectiveness of adding two organic wastes (cotton gin crushed compost, CGCC, and poultry manure, PM) to a saline soil (Salorthidic Fluvaquent) in dryland conditions near Seville (Guadalquivir Valley, Andalusia, Spain) was studied during a period of 5 years. Organic wastes were applied at rates of 5 and 10 t organic matter ha⁻¹. One year after the assay began, spontaneous vegetation had appeared in the treated plots, particularly in that receiving a high PM dose. After 5 years the plant cover in this treated plot was around 80% (compared with the 8% of the control soil). The effect on the soils physical and chemical properties, soil microbial biomass, and six soil enzymatic activities (dehydrogenase, urease, protease, β-glucosidase, arylsulfatase, and phosphatase activities) were ascertained. Both added organic wastes had a positive effect on the physical, chemical and biological properties of the soil, although at the end of the experimental period, the soil physical properties, such as bulk density, increased more significantly in the CGCC-amended soils (23%) and the exchangeable sodium percentage (ESP) decreased more significantly in the CGCC-amended soils (50%) compared to the unamended soil. Water soluble carbohydrates and soil biochemical properties were higher in the PM-amended soils compared to the CGCC-amended soils (by 70% for water soluble carbohydrates, and by 34, 18, 37, 39, 40 and 30% for urease, protease, β-glucosidase, phosphatase, arylsulfatase and dehydrogenase activities, respectively). After 5 years, the percentage of plant cover was >50% in all treated plots and 8% in the control soil.     

Soil amendment with seed meals: Short term effects on soil respiration and biochemical properties

In the last decades, worldwide biofuel production increased up to 105 billion liters in 2010; in this year, the world's first biodiesel producer was the European Union. Biodiesel is produced from a variety of oils, mainly soybean, Brassicaceae and sunflower. One of the most important biodiesel production byproducts are seed meals. The most common use of seed meals is for animal nutrition, but another potential use is agricultural soil organic amendments. Soil biological and biochemical properties have been widely used as soil quality indicators, due to their quick response to changes in soil management. Although there are many studies on the effects of regular amendments on respiration and enzymatic activities of the soil, very few papers refer to the effect of seed meals. Therefore, the aim of this study was to investigate the short-term effect of seed meal amendment on soil respiration and enzymatic activities (alkaline phosphatase, dehydrogenase, fluorescein diacetate hydrolase, arylsulphatase and β-glucosidase). The two seed meals used were obtained from Brassica carinata (A.) Braun (Ethiopian mustard) and sunflower (Helianthus annuus L.). The study was carried out, from June 2007 to October 2007, at an experimental farm of CRA-ORT, Battipaglia, in the Sele River (Plain Salerno, Campania Region, Italy). The results of this study support an alternative use of seed meals as organic amendments. Generally, a significant positive response of enzymatic activities, evaluated in this study, to the addition of seed meals, indicates a beneficial effect on soil quality as regards microbial activity.     

Use of rice straw biochar simultaneously as the sustained release carrier of herbicides and soil amendment for their reduced leaching

The sustained release and reduced leaching of herbicides is expected for enhancing their efficacy and minimizing their pollution. For this purpose, the rice straw biochar made at a relatively low temperature (350 °C) (RS350) was used simultaneously as the carrier for incorporating herbicides besides as the soil amendment. In this way, the sustained release of herbicides acetochlor and 2,4-D was obtained in the release experiments, due to the high and reversible sorption by RS350 biochar. Besides, the RS350 biochar significantly reduced the leached amount of herbicides by 25.4%-40.7% for acetochlor, and by 30.2%-45.5% for 2,4-D, depending on the depth (50 or 100 mm) of biochar-amended soil horizon. The high retention of both herbicides in the biochar-amended topsoil makes it possible to extend their efficacy. The results suggest a potential way of using low temperature biochars to reduce the leaching of herbicides without impacting their efficacy.     

Soil fulvic acid properties as a means to assess the use of pig slurry amendment

Soil amendment with animal manures is a common practice for either increasing soil organic matter (SOM) and nutrient content or disposing of wastes from intensive animal industries. However, the application of organic amendments that are not sufficiently mature and stable may adversely affect soil properties, especially the content and quality of SOM pools. In this work, the effect of the consecutive annual additions of pig slurry (PS) at rates of 0 (control), 90 and 150 m³ ha⁻¹ per year over a 4-year period on the soil fulvic acid (FA) fraction of SOM was investigated in a field plot experiment conducted under semiarid conditions on a Calcic Luvisol in Toledo province, Spain. The FAs isolated from PS and control and amended soils were characterized for chemical, compositional, structural and functional properties by use of elemental and functional group analysis, and ultraviolet/visible, Fourier transform infrared (FT IR), fluorescence and electron spin resonance (ESR) spectroscopies. PS-FA was characterized by a prevalent aliphatic character, large contents of acidic functional groups, S- and N-containing groups and polysaccharide components, extended molecular heterogeneity, small organic free radical (OFR) contents and small degrees of aromatic ring polycondensation, polymerization and humification. With respect to the control soil FA, the PS-amended soil FAs were characterized by a smaller extraction yield, O and OFR contents and ratios of absorbances at 465 and 665 nm, and larger C, N, S, COOH and phenolic OH contents, C/N ratios and aliphaticity. Statistical analysis of experimental data showed that, with some exceptions, these effects generally increased with increasing cumulative amount of PS applied to soil over time. In conclusion, cumulative PS application to soil over time modifies the content and properties of the FA fraction of SOM. Thus, this material should not be considered as a mature organic amendment and should be treated appropriately before it is applied to soil, so as to increase the degree of humification and enhance its potential as a soil organic fertilizer.     

Log yard fines as a soil amendment: Pot and field studies

Abstract

This study evaluated the application of high levels of log yard fines (LYF), produced by the screening of log yard residues, as a soil amendment/additive. In both pot and field studies, plant growth decreased as LYF application rate increased. LYF immobilized nitrogen (N) and reduced its availability to plants. In the pot study, both alfalfa (Medicago sativa) and orchard grass (Dactylis glomerota L.) had low yields at the first harvest but much higher yields at the second harvest, indicating that N immobilization decreased with time. Alfalfa growth was superior to orchard grass in the LYF‐amended pot soil due to its ability to fix N. LYF provided mineral nutrients and organic matter, lowered soil density, and also improved soil moisture retention properties. This study suggested that LYF could be used as a N‐immobilizing mulch or as a soil amendment/additive for marginal farmland when fertilized adequately and allowed to stabilize in the soil.     

Mudflat soil amendment by sewage sludge: Soil physicochemical properties,perennial ryegrass growth,and metal uptake

Abstract

The fast pace of cropland loss in China is causing alarm over food security and China’s ability to remain self-reliant in crop production. Mudflats after organic amendment can be an important alternative cropland in China. Land application of sewage sludge has become a popular organic amendment to croplands in many countries. Nevertheless, the land application of sludge to mudflats has received little attention. Therefore, the objective of the present work was to investigate the impact of sewage sludge amendment (SSA) at 0, 30, 75, 150 and 300 t ha^?1 rates on soil physicochemical properties, perennial ryegrass (Lolium perenne L.) growth and heavy metal accumulation in mudflat soil. The results showed that the application of sewage sludge increased organic matter (OM) content by 3.5-fold while reducing salinity by 76.3% at the 300 t ha^?1 rate as compared to unamended soil. The SSA reduced pH, electric conductivity (EC) and bulk density in mudflat soil, increased porosity, cation exchange capacity (CEC) and contents of nitrogen (N), phosphorus (P), exchangeable potassium ions (K⁺), sodium ions (Na⁺), calcium ions (Ca²⁺) and magnesium ions (Mg²⁺) in comparison to unamended soil. There were 98.0, 146.6, 291.4 and 429.2% increases in fresh weight and 92.5, 132.4, 258.6 and 418.9% increases in dry weight of perennial ryegrass at 30, 75, 150, and 300 t ha^?1, respectively, relative to unamended soil. The SSA increased metal concentrations of aboveground and root parts of perennial ryegrass (p < 0.05). The metal concentrations in perennial ryegrass were Zn > Cr > Mn > Cu > Cd > Ni, and the metal concentrations in roots were significantly higher than aboveground parts. The metal accumulation in perennial ryegrass correlated positively with sludge application rates and available metal concentrations in mudflat soil. Land application of sewage sludge was proved to be an effective soil amendment that improved soil fertility and promoted perennial ryegrass growth in mudflat soil. However, heavy metal accumulation in plants may cause food safety concern.     

华北山前平原农田土壤硝态氮淋失与调控研究

本文依托中国科学院栾城农业生态系统试验站小麦-玉米一年两熟长期定位试验, 应用土钻取土和土壤溶液取样器取水的方法, 研究了不同农田管理措施下土壤硝态氮的累积变化, 计算了不同氮肥处理通过根系吸收层的硝态氮淋失通量。结果表明, 小麦-玉米生长季土壤硝态氮累积量和淋失量随着施氮量的增加显著增加, 相同氮肥水平下增施磷、钾肥增加了作物的收获氮量, 施磷肥增加的作物收获氮量最高可达123kg·hm^-2·a^-1, 施钾肥增加的作物收获氮量最高为31 kg·hm^-2·a^-1。不同灌溉水平下0~400 cm 土体累积硝态氮随着灌溉量的增加而降低, 控制灌溉(小麦季不灌水, 玉米季灌溉1 水)、非充分灌溉(小麦季灌溉2~3 水, 玉米季按需灌溉)、充分灌溉(小麦季灌溉4~5 水, 玉米季按需灌溉)各处理剖面累积硝态氮量分别为1 698 kg·hm^-2、1148 kg·hm^-2 和961 kg·hm^-2。与非充分灌溉和充分灌溉处理相比, 控制灌溉在100~200 cm 土层硝态氮累积量显著高于其他层次, 2003~2005 年间控制灌溉剖面增加的硝态氮量占施肥总量的23%; 非充分灌溉处理剖面增加的硝态氮量占施肥总量的22%; 充分灌溉处理剖面增加的硝态氮量占施肥总量的47%。免耕措施降低了作物产量, 影响土壤水的运移, 增加了硝态氮的淋失风险。根据作物所需降低氮素投入(N 200 kg·hm^-2·a^-1), 增施磷、钾肥, 控制灌溉量是减少华北山前平原地区硝态氮淋失, 保护地下水的有效措施。     

蚌壳用作土壤改良剂：对根际和非根际土壤和草地生产力的影响

Large quantities of mussel shells(66 000-94 000 t year 1),an alkaline material that can be used as a soil amendment,are generated as waste in Galicia,NW Spain.A field trial was carried out by planting different pasture species in a Haplic Umbrisol using a randomized block design with four blocks and six treatments(not amended control or soil amended with lime,finely ground shell,coarsely ground shell,finely ground calcined shell or coarsely ground calcined shell) to compare the effects of lime and mussel shells additions on a soil with a low cation exchange capacity and high Al saturation.The trial was established in March 2007,and samples of plants and soil were collected when plots were harvested in summer 2008(separating the bulk and rhizosphere soil).The soils were analyzed for pH,total C,total N,available P,exchangeable cations,effective cation exchange capacity and available micronutrients.Dry matter yield was measured in all plots and plants were analyzed for nutrients.Application of mussel shells and the commercial lime resulted in an increase in pH and exchangeable Ca and a decrease in exchangeable Al and Al saturation.The stability of pH over time was high.These effects were most noticeable in the rhizosphere.The amendment also had a positive effect on dry matter yield and concentration of Ca in the plant.     

Use of palm-mat geotextiles for soil conservation: I. Effects on soil properties

Despite geotextile-mats having the potential for soil conservation, field studies on the effects of geotextiles on soil properties are limited. Hence, the utilization of palm-mat geotextiles as a potential soil conservation technique was investigated at Hilton, east Shropshire, U.K. (52°33′5.7″ N, 2°19′18.3″ W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Field experiments were conducted at Hilton during 2007–2009, to study the impacts of Borassus and Buriti mats on selected properties of the topsoil (0–5 cm). Ten fixed plots (10 × 1 m on a 15° slope) were established, with duplicate treatments. The treatments were: (i) bare soil; (ii) permanent grassed; (iii) bare soil with 1 m Borassus-mat buffer strips (area coverage ~ 10%) at the lower end of the plots; (iv) bare soil with 1 m Buriti mat buffer strips (area coverage ~ 10%) at the lower end of the plots; and (v) completely-covered with Borassus mats. Initial and final soil samples of the topsoil were collected and analysed for bulk density, aggregate stability, soil organic matter (SOM), total soil C (TSC), total soil N (TSN) and pH. Results indicate that, apart from Borassus completely-covered plots, soil bulk density increased and aggregate stability decreased in all plots after two years. Despite decreases in SOM contents in bare plots, SOM content did not change after two years in the grassed and geotextile treated plots. Treatments had no effects on changes in pH, TSC or TSN. Both Borassus and Buriti mat-covers within the buffer strip plots had little impact on SOM, TSC and TSN changes compared with bare soils within the same plots. Thus, Borassus buffer strip plots were very effective in maintaining some soil properties (i.e. SOM, TSC, and TSN) after two years of erosion by water. In summary, utilization of Borassus mats as buffer strips was very successful in conserving soil properties on a loamy sand soil.     

Surface measurements of the hydraulic properties of a tilled and untilled soil

The surface characteristics of soil can have a profound effect on the hydrology of tilled land. Apposite measurements of the surface hydraulic properties of Plainfield sand (Wisconsin, U.S.A.), a Typic Udipsamment, were used to assess the hydrologic impact of 5 years tillage by either moldboard plow or no-till. The crop was always corn (Zea mays L.). The “mean” pore size (λ_m), weighted in a way relevant to the flow of water through the soil surface, was computed here from saturated and unsaturated measurements of sorptivity (S₀) and hydraulic conductivity (K₀). Disc permeameters of dissimilar radii were used at two unsaturated supply-potential heads of ψ₀=−100 mm and −20 mm to find S₀ (ψ₀) and K₀ (ψ₀). At saturation (ψ₀=0), infiltration rings of contrasting radii were employed. The saturated and unsaturated values for S₀ and K₀ of the plowed soil were either the same as, or greater than the corresponding values for the no-till soil. Combination of the values for the saturated S₀ and K₀ showed that the no-till soil had a λ_m=1.34 (±0.67) mm, while in the plowed soil the “mean” pore size during saturated flow was only 0.19 (±0.18) mm. The large λ_m, and the high coefficient of variation, for the no-till soil was presumed to be related to the macropore network associated with the decay of crop residue in the less-sorptive matrix. The small homogeneous λ_m of both the saturated and unsaturated plowed soil reflects the annual pulverization of the soil surface by tillage.