The relationship between phosphorus and copper concentrations in wheat

Abstract

Poorly managed kaolinitic soils are often too low in P and K for optimum agronomic crop production. Even though many of these soils have relatively high phosphate fixing capacities, P applied at sufficient rates to increase soil P to acceptable levels may induce micronutrient deficiencies. The purpose of this study was to evaluate the effects of applied and residual P on Mn, Zn, and Cu uptake by field grown wheat (Triticum aestivum). Treatments were a one‐time application of P (0, 64, 128, 256, and 384 kg/ha P) and K (0, 110, 220, 440, and 660 kg/ha K) rates arranged in a 5×5 complete factorial. The treatments were applied in October, 1977 and the study was continued through June, 1979. Potassium and P × K interactions did not have a significant effect on Mn, Zn, or Cu uptake. Phosphorus did not affect Mn concentration in the wheat tissue but Zn and Cu concentrations generally decreased as applied and residual soil P levels increased. The tissue Zn concentration at the various plant growth stages did not decrease below defined critical levels. The Cu concentration decreased linearly with applied P and curvilinearly with residual P. The tissue Cu levels often decreased below suggested critical levels. Total Cu in the wheat tissue indicated that the decrease in Cu concentration as P levels increased was not a simple dilution effect resulting from increased plant growth as applied and residual soil P increased.     

Heavy metal uptake by blue grama growing in a degraded semiarid soil amended with sewage sludge

Sewage sludge application to semiarid grassland may represent a beneficial means of utilizing this waste product for restoration of degraded sites. Consequently, dried municipal sewage sludge was applied at three rates (22.5, 45, and 90 Mg ha^–1) to a degraded semiarid grassland soil in order to determine the effects of sludge amendments on forage productivity, soil heavy metal content, and metal uptake by blue grama (Bouteloua gracilis).Soil and plant properties in control and amended plots were measured after 1, 2, and 5 growing seasons.Soil nutrients increased linearly with increased sludge application in the first two growing seasons. Consequently, forage quality and total production of blue grama improved significantly over the unamended control as the tissue levels of N, P, K, and crude protein increased. Cadmium and Pb in the sludge-treated plots did not increase significantly over the control after 1 and 2 growing seasons. Levels of DTPA-extractable soil micronutrients (Cu, Fe, Mn, Zn) increased linearly with increased sludge application rate to soil concentrations recommended for adequate plant growth. Soil N, P, and K concentrations remained higher in the sludge-amended soils after 5 growing seasons, while Cu and Cd increased to slightly above desireable limits as the soil pH decreased to 7.4 and 7.0 in the 45 and 90 Mg ha^–1 treatments, respectively. However, with the exception of Mn which remained within desirable limits, metal concentrations (including Cu and Cd) in blue grama tissue were not significantly different from the control treatment after five growing seasons. Based on soil and plant tissue metal concentrations, it appears that sludge applied at rates between 22.5 and 45 Mg ha^–1 will maintain the most favorable nutrient levels coupled with significant improvements in forage production in this semiarid grassland environment.     

蚯蚓对造纸污泥的养分和重金属处理效应研究

造纸污泥含有大量的养分和重金属等物质。试验采用室内培养试验,研究不同蚯蚓投放量对污泥中养分和重金属的处理效应。结果表明:蚯蚓的最佳投放量为中等投放量(22.5 g kg-1)。经过84天处理后,造纸污泥中有机质大量分解,最高分解率为24.95%;全量N、P、K的含量增加,其最大增量分别为2.65 g kg-1、0.64 g kg-1和0.32 g kg-1;碱解氮、速效磷、速效钾的最大减幅依次为24.78%、30.40%和10.77%。经蚯蚓处理后造纸污泥中重金属Mn、Cu和Zn的最大去除率依次为28.80%、28.80%和35.34%,蚯蚓体内Mn、Cu和Zn最高增加了8.03%、23.49%和27.06%,Mn、Cu和Zn的K值均小于1.0,其中Mn>Zn>Cu,说明蚯蚓对重金属Mn、Cu和Zn有明显的去除效应。     

污泥污水在棉花上的施用: Ⅰ.对土壤性质的影响

A field experiment with cotton was conducted on a well drained,calcareous,clay loamy Typic Xerochreph to investigate the utility of sewage sludge as a partial substitute for fertilizers and the influence of tis application on the basic soil properties and heavy metal concentrations.The experimental design was completely randomized blocks with five treatments replicated four times each.Sewage sludge came from the treatment plant of the municipality of Volos,Central Greece,with the following characteristics:organic matter content 36.6%,pH(H2O1:5)6.89,CaCO3 53.4g kg^-1,total N 265.g kg^-1,ttal P33.5g kg^-1,and total K 968mg kg^-1 soil.Heavy metal concentrations were Cd 5.24,Pb 442,Ni38,Cu 224,Zn1812,and Mn 260mgkg^-1 dry weight,respectively.The soil was high in potassium(K)and poor in available phosphorus(P).The results showed that sewage sludge application increased cotton yield and K and P concentrations in cotton leaves,Soil pH was reduced in the case of higher sewage sludge rate.Electrical conductivity,organic matter content,totalN,and avaiable P were significantly increased.Total concentrations of Zn,Pb,and Cu were slightly increased.DTPA-extractable Zn,Cu,and Mn were also significantly increased.Available forms of all heavy metals,except Cd,were significantly correlated with organic matter content in a positive way and negatively with soil pH.     

Sewage sludge incinerator ash effects on soil chemical properties and growth of lettuce and corn

Abstract

Incineration reduces sewage sludge volume, but management of the resulting ash is an important environmental concern. A laboratory incubation study and greenhouse pot experiments with lettuce (Lactuca sativa L.) and corn (Zea mays L.) were conducted to examine the potential for recycling elements in sewage sludge incinerator ash in agricultural systems. Ash rates in both the laboratory and greenhouse were 0, 0.95, 3.8, 15.2, and 61.0 g/kg soil (Typic Hapludoll). Ash was also compared to equivalent rates of citrate soluble P from superphosphate fertilizer in a soil‐less growth medium. During soil: ash incubation, Olsen P and DTPA extractable copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) increased with incubation time at the higher ash rates. Release rates diminished rapidly, however, and the limited release of these elements after 280 days was associated with decreasing pH. In the greenhouse, ash amendment increased extractable soil P, plant tissue P, and the growth of lettuce and corn. Ash was a less effective P source than superphosphate fertilizer in the soil‐less growth medium and Olsen P levels were more consistent with these differences than Bray P. Ash increased extractable soil levels and plant tissue concentrations of calcium (Ca), magnesium (Mg), sodium (Na), Cu, and Zn, but extractable soil manganese (Mn) and plant tissue Mn decreased. Ash increased soil pH and extractable SO₄‐S. DTPA extractable Cd and Pb increased, but chromium (Cr) and nickel (Ni) decreased. Lettuce accumulated higher amounts of these trace metals than corn, but tissue concentrations were at control levels or below detection limits in both crops.     

Heavy metals in mine soils amended with sewage sludge

In order to reclaim a clay quarry, a topsoil material was mixed with gravelly spoil at different ratios and with various rates of sewage sludge. The influence of three spoil/topsoil ratios (1:1, 2:1 and 3:1) and three sludge rates (40, 80 and 120 t ha⁻¹) on chemical properties of the resulting material was investigated, with emphasis on heavy metal (Fe, Cu, Mn, Ni and Zn) contents. The mixtures topsoil/spoil/sludge were water saturated and incubated for 15 or 30 days in a chamber under controlled conditions. The incubated samples were analysed for pH, total carbon and nitrogen, and total, available, exchangeable and soluble heavy metals. The addition of spoil to the topsoil increased the volume of material available, by utilizing an inert material unsuitable by itself to grow plants. The addition of sewage sludge repaired the disadvantages of the spoil, increasing the pH and the organic matter contents. The total heavy metal contents in the mixtures followed the sequence Fe>>Mn>>Zn, Cu>Ni. All except Cu were within the ranges allowed for agricultural lands. The available heavy metals constituted a small fraction of total contents and decrease with time due to complexation and immobilization processes. The exchangeable and soluble fractions were almost negligible; only small amounts of Mn, Zn and Cu were detected. Therefore, the risk of contamination by heavy metals is insignificant in the conditions investigated. Copyright © 1999 John Wiley & Sons, Ltd.     

Effects of N-enriched sewage sludge on soil enzyme activities

Sewage sludge is increasingly used as an organic amendment to soil, especially to soil containing little organic matter. However, little is known about utility of this organic amendment with N-enriched or adjusted C:N ratios in soil. We studied the effects of adding of different doses (0, 100, 200 and 300 t ha⁻¹) and C:N ratios (3:1, 6:1 and 9:1) of sewage sludge on enzyme activities (β-glucosidase, alkaline phosphatase, arylsulphatase and urease) in a clay loam soil at 25 °C and 60% soil water holding capacity. Nitrogen was added in the form of (NH₄)₂ SO₄ solution to the sludge to reduce the C:N ratio from 9:1 to 6:1 and 3:1. The addition of different doses and C:N ratios of the sludge caused a rapid and significant in the enzymatic activities in soils, this increase was specially noticeable in soil treated with high doses of the sludge. In general, enzymatic activities in sludge-amended soils tended to decrease with the incubation time. All activities reached peak values at 30 days incubation and then gradually decreased up to 90 days of incubation. Sewage sludges also the increased available metal (Cu, Ni, Pb and Zn) contents in the soils. However, the presence of available soil metals due to the addition of the sludge at all doses and C:N ratios did negatively affect all enzymatic activities in the soils. This experiment indicated that all doses and C:N ratios of sewage sludge applied to soil would have harmful effects on enzymatic activity. Some heavy metals found in sewage sludge may negatively influence soil enzyme activities during the decomposition of the sludge.     

Application of High Copper and Zinc Compost and Its Effects on Soil Properties and Growth of Barley

Abstract

A compost of high copper (Cu) and zinc (Zn) content was added to soil, and the growth of barley (Hordeum vulgare L.) was evaluated. Four treatments were established, based on the addition of increasing quantities of compost (0, 2, 5, and 10% w/w). Germination, plant growth, biomass production, and element [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), iron (Fe), Cu, manganese (Mn), and Zn] contents of soil and barley were determined following a 16‐week growing period. Following harvesting of the barley, analysis of the different mixtures of soil and compost was performed. Micronutrient contents in soils as affected by compost additions were determined with diethylene–triamine–pentaacetic acid (DTPA) (Cu, Mn, Fe, and Zn) or ammonium acetate [Ca, Na, Mg, K, cation exchange capacity (CEC)] extractions, and soils levels were compared to plant uptake where appropriate. Increasing rates of compost had no affect on Ca, Mg, or K concentration in barley. Levels of Cu, Zn, Mn, and Na, however, increased with compost application. High correlations were found for DTPA‐extractable Cu and Zn with barley head and shoot content and for Mn‐DTPA and shoot Mn content. Ammonium acetate–extractable Na was highly correlated with Na content in the shoot. High levels of electrical conductivity (EC), Cu, Zn, and Na may limit utilization of the compost.     

Soil micronutrient availability to crops as affected by long-term inorganic and organic fertilizer applications

Micronutrient status in soils and crops can be affected by different fertilization practices during a long-term field experiment. This paper investigated the effects of different fertilization treatments on total and DTPA-extractable micronutrients in soils and micronutrients in crops after 16 year fertilization experiments in Fengqiu County, Henan Province, China. The treatments of the long-term experiment included combinations of various rates of N, P and K in addition to two rates of organic fertilizer (OF) treatments. Winter wheat and summer maize were planted annually. Soil macro- and micronutrients along with pH and organic matter (OM) were analyzed. Grains and above ground parts of both crops in the final year were harvested and analyzed for Cu, Zn, Fe and Mn. The results showed that soil Cu, Zn, Fe and Mn concentrations did not change among the different treatments to a significant level, except for a slight decrease of soil Zn in the CK (no fertilizer application) compared to the OF treatment. The DTPA-extractable soil Zn, Fe and Mn concentrations increased from 0.41 to 1.08 mg kg⁻¹, from 10.3 to 17.7 mg kg⁻¹, and from 9.7 to 11.8 mg kg⁻¹, respectively, with increasing soil OM content, thus showing the importance of soil OM in micronutrient availability for crops. The NPK treatment also had higher DTPA-extractable micronutrient concentrations in soil. Deficiency of N or P resulted in a low yield but high micronutrient concentrations in crops except Cu in maize stalks. Higher available soil P significantly decreased crop micronutrients, possibly because of their precipitation as metal phosphates. Maize stalks contained higher concentrations of micronutrients than those of wheat straw, whereas wheat grain had higher micronutrients than those of corn grain. The transfer coefficients (TCs) of micronutrients from straw to grain were significantly different between winter wheat (1.63–2.52 for Cu; 2.31–3.82 for Zn; no change for Fe; 0.55–0.84 for Mn) and summer maize (0.24–0.50 for Cu; 0.50–1.21 for Zn; 0.02–0.04 for Fe; 0.07–0.10 for Mn). In conclusion, application of organic matter significantly increased the DTPA-extractable concentrations of Zn, Fe and Mn compared to the CK, grain and vegetative tissue in the CK and NK had higher micronutrient concentrations than those in other treatments.     

Effect of Organic Materials on Yields and Nutrient Accumulation of Wheat

ABSTRACT

This experiment was conducted under greenhouse conditions using a sandy clay loam treated with garbage and mushroom composts, cattle and chicken manures, or municipal sludge at rates of 0, 30, or 60 ton ha^?1. The organic materials were applied to the pots and incubated for 15 d. The soil samples were watered at field capacity. In this experiment, wheat (Triticum aestivum L.) was used as a test crop. At the end of the experiment, it was found that treating sandy clay loam with the organic materials increased plant total and grain yields, protein content, 1000-kernel weight, number of grains in spike, and accumulation of nitrogen (N), phosphorus (P), potassium (K), iron (Fe), zinc (Zn), and manganese (Mn) by wheat compared with the control treatment, depending on the organic material applications. Thus, the increases were found to be statistically significant (P ≤ 0.05). Among the types of organic materials, the sewage sludge was the most effective material in increasing N, P, K, Fe, Zn, and Mn content of leaf, grain, and stem samples of the wheat plant. It was followed by mushroom compost and cattle manure. Based on the results, sewage sludge and garbage compost are suggested for use as an amendment for the soil studied. Comparing the beneficial effects of the organic materials applied for improving plant growth and nutrient accumulation, the materials can be arranged in the following descending order: municipal sludge > chicken manure > cattle manure > garbage compost > mushroom compost. It is suggested that recycling of organic materials for agricultural usage as an organic-matter resource is an alternative, organic fertilization option in Turkey.     

添加黏土及植物残体混合物对沙质土壤中呼吸作用和微生物量碳、氮有效性的影响

Crop yields in sandy soils can be increased by addition of clay-rich soil, but little is known about the effect of clay addition on nutrient availability after addition of plant residues with different C/N ratios. A loamy sandy soil(7% clay) was amended with a clay-rich subsoil(73% clay) at low to high rates to achieve soil mixtures of 12%, 22%, and 30% clay, as compared to a control(sandy soil alone) with no clay addition. The sandy-clay soil mixtures were amended with finely ground plant residues at 10 g kg~(-1): mature wheat(Triticum aestivum L.) straw with a C/N ratio of 68, mature faba bean(Vicia faba L.) straw with a C/N ratio of 39, or their mixtures with different proportions(0%–100%, weight percentage) of each straw. Soil respiration was measured over days 0–45 and microbial biomass C(MBC), available N, and p H on days 0, 15, 30, and 45. Cumulative respiration was not clearly related to the C/N ratio of the residues or their mixtures, but C use efficiency(cumulative respiration per unit of MBC on day 15) was greater with faba bean than with wheat and the differences among the residue mixtures were smaller at the highest clay addition rate. The MBC concentration was lowest in sole wheat and higher in residue mixtures with 50% of wheat and faba bean in the mixture or more faba bean. Soil N availability and soil p H were lower for the soil mixtures of 22% and 30% clay compared to the sandy soil alone. It could be concluded that soil cumulative respiration and MBC concentration were mainly influenced by residue addition, whereas available N and p H were influenced by clay addition to the sandy soil studied.     

基于废弃物的潞安煤矿废弃地改良土壤基质配比研究

为解决潞安矿区煤矸石山、塌陷地生态修复缺土少肥问题,本研究将粉煤灰、污泥与垃圾堆肥以5%、10%、20%体积比例正交混合配制改良土壤基质进行盆栽试验,观测不同配比土壤的理化性质、养分及重金属含量、高羊茅与紫叶小檗生长状况,并用主成分–聚类分析法筛选最优配比。结果表明:添加垃圾堆肥可以提高土壤有效养分与有机质含量,对土壤理化性质改良有明显效果;添加污泥仅提升土壤有效磷含量;添加粉煤灰在降低土壤容重、增大总孔隙度与非毛管孔隙度上效果明显,但对土壤p H、阳离子交换量(CEC)与碱解氮的改良具有显著负效应。各废弃物改良基质的碱解氮、有效磷、速效钾、有机质等含量均较高,土壤重金属含量也处在安全范围,而土壤容重、非毛管孔隙、pH、电导率(EC)与CEC等指标性质较优的处理组为粉煤灰∶污泥∶垃圾堆肥∶土=5%∶20%∶20%∶55%、10%∶10%∶20%∶60%、20%∶5%∶20%∶55%3个处理。经过综合筛选,本研究基质最优混合配比为粉煤灰∶污泥∶垃圾堆肥∶土=5%∶20%∶20%∶55%,可作为当地矿区废弃地生态修复客土材料推荐方案。     

Impacts of biochar and processed poultry manure,applied to a calcareous soil,on the growth of bean and maize

Direct use of poultry manure on agricultural lands may cause environmental concerns, so there is a need to establish the suitability of the application of biochar derived from poultry manure for calcareous soil chemical properties and plant growth. The purpose of this study was to evaluate the effects of processed poultry manure (0, 5, 10 and 20 g/kg) and its biochar (0, 2.5, 5, 10 and 20 g/kg) on soil chemical properties of a calcareous soil and growth of bean (Phaseolus vulgaris) and maize (Zea mays) plants. In the incubation experiment, both processed poultry manure (PPM) and biochar decreased pH and the concentration of plant‐available Fe of soil but increased plant‐available P, Zn, Cu and Mn concentrations. PPM and biochar increased the concentrations of exchangeable cations (K, Ca and Mg) in soil. PPM and biochar applications increased the growth of maize and bean plants. PPM and biochar resulted in increased concentrations of N, P, K, Ca, Fe, Zn, Cu and Mn in bean plants. In maize plants, PPM and biochar applications increased the N, P, K, Zn, Cu and Mn but decreased the Ca and Mg concentrations. Results of this study reveal that poultry manure biochar can be used effectively for agricultural purposes.     

Evaluation of Coal Fly Ash-Based Synthetic Aggregates as a Soil Ameliorant for the Low Productive Acidic Red Soil

A potential new way of producing coal fly ash-based granular synthetic aggregates (CSA) using waste coal fly ash (CFA), paper waste, lime, and gypsum and their utilization as a soil ameliorant to improve crop production in low productive acidic red soil in Okinawa, Japan were studied. The red soil was amended with CSA at three different mixing ratios (i.e., CSA/soil—1:1, 1:5, and 1:10) for the cultivation of Brassica rapa var. Pervidis commonly known as Komatsuna, and the physico-chemical parameters of CSA–soil mixtures and plant growth were analyzed. Incorporation of CSA to the red soil improved the physical and chemical properties of the soil such as water holding capacity, hydraulic conductivity, bulk density, pH, exchangeable cation concentration, cation exchange capacity, particle size distribution, soil pH, electrical conductivity, and carbon content. CSA amendment at ratios of 1:1, 1:5, and 1:10 decreased bulk density by 29.39%, 14.28% and 11.11%, respectively, compared to the original red soil. The acidic pH of the red soil (5.12) was increased to 7.13 and 6.37 by CSA/soil ratios of 1:5 and 1:10, respectively. CSA amendment in soil at 1:5 ratio increased water holding capacity, saturated hydraulic conductivity, electrical conductivity, cation exchange capacity, carbon, potassium (K), magnesium (Mg), and calcium (Ca) content by 0.06 kg kg^?1, ten times, 15.95 mS m^?1, 1.76 cmol_c kg^?1, 6.07 g kg^?1, 0.42 g kg^?1, 0.24 g kg^?1, and 3.38 g kg^?1, respectively, in comparison to the original red soil. Heavy metal contents of the CSA–soil mixtures were below the maximum pollutant concentrations suggested by the US Environmental Protection Agency. Moreover, Na, K, Mg, Ca, copper (Cu), and zinc (Zn) contents in the CSA–soil mixtures increased in comparison with the original red soil. CSA amendment in soil at the ratio of 1:5 and 1:10 resulted in an increase in plant height and plant fresh weight by three and 12 times, respectively, and there was increase in N, K, Mg, Ca, Cu, and Zn contents of the shoots. The results suggest that utilization of eccentric CSA as soil amendment agent can be regarded as an effective waste management practice.     

不同轮作体系土壤残留硒锌对小麦产量与营养品质的影响

采用盆栽试验,通过玉米-小麦和大豆-小麦轮作,探讨了不同种植模式中,土壤残留硒锌对小麦产量与营养品质的影响。结果表明,土壤中残留硒锌对小麦生物量和产量的影响与作物轮作体系有关。玉米-小麦轮作,土壤残留硒锌并没有表现出增加小麦产量的趋势,而大豆-小麦轮作,土壤残留硒锌对小麦生物量和产量呈增加趋势。土壤残留硒锌可改变作物体内元素组成。玉米-小麦轮作,土壤残留硒锌有利于小麦籽粒对氮、钾、硫、钙、铁、锌、硒、铜元素的吸收累积。大豆-小麦轮作,土壤残留硒锌促进小麦对钾、硫、镁、铁、锌、硒、铜、锰、硼的吸收,而氮、磷、钙吸收减少。     

长期施肥对潮土耕层土壤和作物籽粒微量元素动态的影响

Micronutrient status in soils can be affected by long-term fertilization and intensive cropping.A 19-year experiment (1990-2008) was carried out to investigate the influence of different fertilization regimes on micronutrients in an Aquic Inceptisol and maize and wheat grains in Zhengzhou,China.The results showed that soil total Cu and Zn markedly declined after 19 years with application of N fertilizer alone.Soil total Fe and Mn were significantly increased mainly due to atmospheric deposition.Applications...     

Enzyme Activities in a Sandy Soil Amended with Sewage Sludge and Coal Fly Ash

Previous studies showed that coal fly ash could stabilize sewage sludge by reducing metal availability, but fly ash may cause an adverse effect on soil microbial activities. Therefore, an experiment was performed to evaluate the effects of amendment of soil with anaerobically digested dewatered sewage sludge, stabilised with alkaline coal fly ash, on soil enzyme activity and the implications for soil nutrient cycling. Sewage sludge was amended with 0, 5, 10, 35 and 50% w/w of fly ash, and then the ash-sludge mixtures were incubated with a sandy soil at 1:1 (v/v). Dehydrogenase activity decreased with an increase in fly ash amendment level and the time of incubation. Soil receiving 5% ash-sludge amendment had a higher dehydrogenase activity than other treatments. Soil receiving 10% ash-sludge mixture had the highest urease activity and in general, urease activity decreased with increasing incubation time. Phosphatase activity was the highest at 5% ash-sludge mixture amended soil and no general trend was observed with time. Water-soluble Zn, Mn and Cu contents were suppressed by the addition of fly ash. The present experiment indicated that addition of 10% ash-sludge mixture should have a positive benefit on the activity of soil microorganisms, N and P nutrient cycling, and reduce the availability of heavy metals.     

Transformations and Availability of Iron to Wheat as Influenced by Phosphorus and Manganese Fertilization in a Typic Haplustept Soil

An investigation was conducted using Typic Haplustept, sandy loam soil, to investigate the interactive effects of phosphorus (P) and manganese (Mn) fertilization on native iron (Fe) pools in soil and their availability to wheat (cv. PBW-343) crop. Phosphorus fertilization moved Fe from residual mineral fraction of Fe to manganese oxides (MnOX), organic matter (OM), amorphous (AMPOX), and crystalline (CRYOX) Fe and Al oxide fractions. However, Mn application decreased specifically adsorbed (SAD)–Fe and CRYOX–Fe but increased OM–Fe and mineral fraction of Fe. Available Fe in soil decreased as Olsen P and P:Mn ratio increased in the soil. Higher Olsen P (>60 mg P kg^?1soil) reduced mean Fe uptake by shoot. P content and P:Mn ratio in soil as well as in root and shoot were inversely related to Fe concentration in both the plant parts. The role of soil Fe associated with oxides and organic matter was found most notable in Fe nutrition of wheat.     

Direct and residual effects of pulp and paper mill sludge on crop yield and soil mineral N

Abstract. Paper sludge composted or stored in static piles for six months was compared to raw and lime-stabilized sludge in a three-year pot experiment (loam) and a four-year field experiment (silt loam) at rates of up to 40 t DM ha^-l. The original sludge contained equal amounts of fibre sludge and biological sludge, mixed with bark in 1:1 ratio to improve the structure. The N content in composted sludge (1.30%) was markedly lower than that of the uncomposted piles (1.98%), indicating significant loss during composting. The yield results were generally inversely proportionate to the C:N ratios of the sludges applied. Sludge from the uncomposted piles gave significant grain yield increases in the year following sludge application, while the other sludge types gave variable results. In the residual years there was, generally, a small but positive effect on yield from all the sludge types. The N and P content in grain generally increased with sludge application, but only the higher rates gave statistically significant increases. Sludge application also increased the Zn content in grain, while Mn, B and Cu was less affected. The increase in Cd content was very small. The 40 t ha^-l sludge rate tended to increase the residual mineral N in soil at the field site and thus the risk of nitrate leaching.     

Growth of apple seedlings on sludge‐amended soils in the greenhouse

Abstract

Open pollinated ‘York Imperial’ apple (Malus domestica Borkh.) seeds were germinated and grown for a period of 7 months in: (1) sand with complete nutrient solutions added; (2) limed and unlimed soil, (3) limed and unlimed soil amended with two different sewage sludges at rates of 25, 50 or 100 dry kg ha^‐1. A third composted, lime stabilized sludge was added either sieved or non‐sieved (to remove wood chips) at the same rates. The sludge materials used were: (1) a high metal, composted sludge from Baltimore, MD (BALT); (2) a high Cd sewage sludge (CITY) and (3) a low metal, composted sewage sludge from Washington, D.C. (DC).

Germination was unaffected by treatments. After 7 months, the best growth was obtained from the sand plus nutrient solution media. Two of the three sludge materials increased seedling growth over that of the soil, either limed or unlimed. The BALT compost treated soils produced the lowest growth, particularly when unlimed. Elevated tissue metal levels indicated that Mn, Zn, Cu and Ni were the probable causes of reduced growth noted from the BALT compost treatment. The use of soil with or without low metal sludges as media for early apple seedling growth when compared to standard sand culture is not recommended.