Effect of slow releasing nitrogen fertilizers on nutrient status across wheat rhizosphere grown on volcanic ash

Abstract

The volcanic ash of the Mount Pinatubo in Philippines was used in this study. The major drawbacks of this ash for growing agricultural crops are nitrogen (N) and iron (Fe) deficiencies with low organic matter contents. The main objective of this study is to investigate the wheat grown on the volcanic ash to and determine the nutrient status across its rhizosphere using a rhizobox system. Either oxamide or polyolefinresin‐coated urea (PORCU) along with potash and phosphate fertilizers was applied to each rhizobox containing the volcanic ash. Plants were grown on the central compartment (CC) of the rhizobox. The nutrient status was examined by the assessment of distribution patterns of NH₄ ⁺‐N, NO₃ ^‐‐N, Ca²⁺, Mg²⁺, K⁺, Cl^‐, SO₄ ^2‐, PO₄ ^3‐, and associated pH. Although NH₄ ⁺‐N in both oxamide and PORCU treatments was accumulated to a somewhat considerable extent of the rhizosphere. The rhizosphere effect was more prominent in oxamide treatment. While NO₃ ^‐‐N concentrations in either of the treatment was low with a mere rhizosphere effect in PORCU treatment and a rugged distribution in oxamide treatment. Dominant anions and cations accumulated in the CC and the near by compartments of oxamide treatment were Cl^‐, SO₄ ^2‐ and Ca²⁺, respectively. In contrast, SO₄ ^2‐ and K⁺ were accumulated in the CC and the adjacent PORCU treated compartments. Thus the overall distribution of nutrients and pH across the wheat rhizosphere was rugged. Despite of this, it seems that with a rugged nutrient distribution and pH, the effects of slow releasing N fertilizers may well ensure the N benefit on plants while growing on the volcanic ash under circumstances of low N content.     

Nitrogen mineralization in soil amended with sewage sludge and fly ash

Summary The effect of fly ash on N mineralization in sewage sludge was studied during a 5-week aerobic incubation of soil-waste mixtures at different loading rates under controlled conditions. Periodically, the mixtures were leached with distilled water and the inorganic N released was determined in the percolates. The data were tested by an analysis of variance with repeated measures. Significant differences were found among different incubation periods and also between different treatments. The net N mineralization, expressed as a percentage of organic N added in the sludge, was drastically reduced when higher rates (500 Mg ha^-1) of fly ash were added.     

Soybean nodulation and nitrogen fixation on soil previously amended with sewage sludge

Summary A greenhouse study was conducted to examine the residual effects of sewage sludge on soybean Glycine max (L.) Merr., nodulation, and N fixation. Nodulating and nonnodulating isolines of Clark soybean were grown to the R2 stage in soils (Typic Paleudults) obtained from plots where heat-treated sludge had been applied in 1976 at rates equal to 0, 56,112, and 224 Mg ha^–1 high (7.0) and low (6.2) soil pH regimes were established by CaCO₃ additions. Sludge and soil pH treatments resulted in clearly defined differences in metal uptake by soybean shoots. Plant Zn, Cd, and Ni concentrations were greater on pH 6.2, sludge-amended soil than on the pH 7.0, amended soil. At low soil pH, soybean Zn and Cd concentrations, respectively, increased from 41 and 0.19 mg kg^–1 (control) to 120 and 0.58 mg kg^–1 at the 224 Mg hat sludge rate. At the high soil pH and 224 hg hat sludge rate, Zn and Cd concentrations were 45 and 0.15 mg kg^–1, respectively.Symbiotic N fixation provided 90% of the total N accumulation. Total N accumulation, shoot N concentration, dry matter, and N fixation by nodulating soybeans exhibited a significant linear increase with sludge rate. Total N accumulation, dry matter, and N fixation were significantly greater at high soil pH. For high and low soil pH, respectively, N fixation increased from 422 and 382 mg N per plant (control) to 614 and 518 mg N per plant at the 224 Mg ha^–1 sludge rate. While soybean nodulation also increased linearly on sludge-amended soil, a significant rate times pH interaction for nodule number indicated that nodulation was less strongly enhanced by sludge at low soil pH.     

Assessment of chemical composition of plants cultivated on two different soils amended with sewage sludge compost using MANOVA

Abstract

Application of organic fertilizers may replenish soil organic matter, improve soil fertility and increase plant yield and its quality. This research deals with the effects of soil amendment with sewage sludge compost (SSC) on the chemical composition of plants (white mustard, triticale and white lupine) cultivated on two contrasting soils (light vs. medium). A 3-year pot experiment was conducted and SSC at the rate of 6?Mg ha^?1 was applied to the soils.The study clearly demonstrated that SSC as an organic fertilizer had a minor influence on the modification of the chemical composition of shoots and grain cultivated in crop rotation plants and it was more evident in medium soil. The statistically confirmed effect was mainfested in higher c ontents of N and P in grain of plants in the 2^nd and 3^rd year of the experiment.     

Possibilities of using sewage sludge as nitrogen fertilizer for maize

Abstract

The objective of this study was to determine the effects of nitrogen fertilizer sources of ammonium sulphate and municipal sewage sludge on yield, N content and uptake of the maize (Zea mays L.). Nutrient and heavy metals were determined in soil and plant. The experiment with three sludge rates (256, 513 and 1026 kg total N ha^?1 or 9.5, 18.0 and 38.1 t ha^?1 sludge), two nitrogen rates (80 and 160 kg N ha^?1) and zero-N control were conducted on a clay loam soils under irrigated conditions in Eastern Anatolia region in Turkey. Treatments were arranged in a randomized complete block design with four replications. Yield, N content and total N uptake of maize increased significantly with sludge application. 9.5 t and 19.0 t ha^?1 sewage sludge applications did not significantly affect heavy metal content of leaf and grain. However, 38.1 t ha^?1 sludge applications increased leaf Pb and Zn. DTPA-extractable Cd, Cu, Fe, Pb and Zn concentrations of the soil increased at applications of 38.1 t ha^?1 sewage sludge, whereas applications of 9.5 t and 19.0 t ha^?1 sludge only resulted in elevated levels of Cu and Zn, We conclude that if sewage sludge is to be used in production of maize, applications rate up to 19 t ha^?1 could be accepted. However, this means also that the N requirement of maize crop is not covered by the sludge; therefore, the rest of nitrogen could be supplied as inorganic N.     

Carbon and nitrogen mineralization of sewage sludge compost in soils with a different initial pH

Soil properties may affect the decomposition of added organic materials and inorganic nitrogen (N) production in agricultural soils. Three soils, Potu (Pu), Sankengtzu (Sk) and Erhlin (Eh) soils, mixed with sewage sludge compost (SSC) at application rates of 0 (control), 25, 75 and 150 Mg ha⁻¹ were selected from Taiwan for incubation for 112 days. The aim of the present study was to examine the effects of SSC application rates on the carbon decomposition rate, N transformation and pH changes in three soils with different initial soil pH values (4.8–7.7). The results indicated that the highest peaks of the CO₂ evolution rate occurred after 3 days of incubation, for all treatments. The Pu soil (pH 4.8) had a relatively low rate of CO₂ evolution, total amounts of CO₂ evolution and percentage of added organic C loss, all of which resulted from inhibition of microbial activity under low pH. For the Pu and Sk soils, the concentration of NH₄⁺-N reached its peak after 7–14 days of incubation, which indicated that ammonification might have occurred in the two soils with low initial pH values. NO₃⁻-N rapidly accumulated in the first 7 days of incubation in the Eh soil (pH 7.7). The direction and extent of the soil pH changes were influenced by the N in the SSC and the initial soil pH. Ammonification of organic N in the SSC caused the soil pH to increase, whereas nitrification of mineralized N caused the soil pH to decline. Consequently, the initial soil pH greatly affected the rate of carbon decomposition, ammonification and nitrification of SSC.     

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.     

基质肥料缓释基质的筛选及其氮素释放规律

为提高基质肥料的缓释性能,该文选用10种有机和无机基质制备基质肥料,通过砂柱间歇淋洗的方法研究了基质肥料的氮素释放规律,并根据Logistic方程的参数和氮素释放拐点的UPGMA聚类分析评价了10种基质的缓释效果,结果表明：基质肥料氮素累积释放率随时间的动态变化可用一级动力学方程、Elovich方程、抛物线扩散方程和Logistic方程表征,其中以Logistic方程拟合效果最好,这说明定量描述氮素养分释放规律的方程中以Logistic方程评价更具有实效性,而有机基质中氧化淀粉和木质素的缓释效果较好,无机基质中膨润土的缓释效果最好。     

The quantitative changes of nutrients in two contrasting soils amended with sewage sludge compost evaluated by various statistical tools

Introduction: The application of organic fertilisers to replenish soil organic matter and improve soil fertility and productivity has become common agricultural practice.

Aim of the study: This research deals with the effects of soil amendment with sewage sludge compost (SSC) on organic carbon, nitrogen total, nitrogen mineral and available P, K, S and Mg mineralisation in two contrasting soils. The various statistical tools used in this study have allowed us to present another conceptualisation of nutrient increments or losses as an effect of SSC applied. In order to distinguish groups of nutrients which are similar, a cluster analysis was used. A two-way analysis of variance was applied to compare the increments of the content of nutrients in the soils.

Material and Methods: A 3-year pot experiment was conducted, employing a randomised, factorial design with two soils (light and medium) and one amendment treatment as a compost at a rate equivalent to 6 Mg ha^?1. The following parameters of chemical soil properties were determined: contents of organic carbon (Corg), total nitrogen (Ntot), amounts of available P, K, Mg, S and mineral nitrogen (Nmin).

Results: The SSC showed a similar influence on the fertility of both soils. It was affirmed that application of SSC results in a statistically significant increase in the contents of soil organic carbon. The amounts of total and mineral N, as well as available P and S were subjected to different patterns of quantity changes expressed by both increase and loss. Moreover, a statistically significant loss of available K amounts was observed in both soils.

Conclusions: The findings of the study indicated that mature SSC becomes a long lasting fertiliser, slowly subjected to decomposition processes. Therefore, it may influence small increases in nutrient amounts in soils, in relation to the contents obtained for the control soil.     

Runoff and losses by erosion in soils amended with sewage sludge

In order to promote the transformation of a burnt Mediterranean forest area into a dehesa system, 10 t ha⁻¹ of dry matter of the same sewage sludge in three different forms: fresh, composted and thermally‐dried, were added superficially to field plots of loam and sandy soils located on a 16 per cent slope. This application is equivalent to 13ċ8 t ha⁻¹ of composted sludge, 50 t ha⁻¹ of fresh sludge and 11ċ3 t ha⁻¹ of thermally‐dried sludge. The surface addition of a single application of thermally‐dried sludge resulted in a decrease in runoff and erosion in both kinds of soil. Runoff in thermally‐dried sludge plots was lower than in the control treatment (32 per cent for the loam soil and 26 per cent for the sandy soil). The addition of any type of sludge to both soil types also reduces sediment production. Significant differences between the control and sludge treatments indicate that the rapid development of plant cover and the direct protective effect of sludge on the soil are the main agents that influence soil erosion rates. Results suggest that the surface application of thermally‐dried sludge is the most efficient way to enhance soil infiltration. Copyright © 2003 John Wiley & Sons, Ltd.     

Comparison of biological and chemical methods to determine available nitrogen in sewage sludge amended soil

Summary Two biological and two chemical methods were tested to quantify the available N of two sewage sludges in two soils. Sewage sludges increased the quantified available N of soil according to the rate for any tested method. A significant correlation between available N determined by biological methods (leaching and non-leaching incubation procedures) was observed, while no significant correlation between chemical methods (acidic hydrolysis and 2 N KCl extraction) was reported. With the exclusion of the method based on acid hydrolysis, the other procedures were correlated significantly with the available N determined in field experiments. It is concluded that the method based on NH₄ ⁺-N released by KCl gives an easy and accurate estimation of the sewage sludge available N.[/ab]     

Nitrous oxide and carbon dioxide emissions from grassland amended with sewage sludge

Abstract. Land disposal of sewage sludge in the UK is set to increase markedly in the next few years and much of this will be applied to grassland. Here we applied high rates of digested sludge cake (1–1.5×10³ kg total N ha⁻¹) to grassland and incorporated it prior to reseeding. Using automated chambers, nitrous oxide (N₂O) and carbon dioxide (CO₂) fluxes from the soil were monitored 2–4 times per day, for 6 months after sludge incorporation. Peaks of N₂O emission were up to 1.4 kg N ha⁻¹ d⁻¹ soon after incorporation, and thereafter were regularly detected following significant rainfalls. Gas emissions reflected diurnal temperature variations, though N₂O emissions were also strongly affected by rainfall. Although emissions decreased in the winter, temperatures below 4 °C stimulated short, sharp fluxes of both CO₂ and N₂O as temperature increased. The aggregate loss of nitrogen and carbon over the measurement period was up to 23 kg N ha⁻¹ and 5.1 t C ha⁻¹. Losses of N₂O in the sludge-amended soil were associated with good microbial conditions for N mineralization, and with high carbon and water contents. Since grassland is an important source of greenhouse gases, application of sewage sludge can be at least as significant as fertilizer in enhancing these emissions.     

Behaviour of cadmium and nickel in a soil amended with sewage sludge

Various urban and industrial sewage sludges were applied to a soil at two doses (50 and 100 t ha⁻¹ y⁻¹) during eight years in a field experiment. The soil was analysed at two depths (0–30 and 30–60 cm) for extractable cadmium and nickel. In general these trace metal increased with dosage. However, cadmium formed complexes with organic matter and nickel bound to iron and manganese oxides. Hence, the available fractions of these metals constituted a small proportion of the total content. The results obtained show a low risk of contamination due to the available fractions of these metals at sludges dosages of up to 100 t ha⁻¹. Copyright © 2001 John Wiley & Sons, Ltd.     

Initial organic matter transformation of soil amended with composted sewage sludge

 An incubation experiment with composted sewage sludge (CSS) just added to the soil was conducted to determine its initial effects on C decomposition, N nitrification and the transformation of organic matter. CSS was mixed with a sandy loam soil from uncultivated ochric epipedon of a Typic Haploxeralf at rates of 0, 40 and 80 t ha^–1 (dry weight). The data obtained showed that with regard to the unamended soil, both the 40 and the 80 t ha^–1 treatments produced the same result in decreasing respiratory activity, but the addition of increasing amounts of CSS progressively delayed C decomposition. The nitrification index (NI), defined as the relation between nitrate-N and nitrate-N + ammonium-N, increased in correlation with the C mineralization coefficient. Total organic matter decreased after incubation whereas the humic substances increased in relation to the total C mineralized. Received: 28 October 1999     

Biological and physical resilience of soil amended with heavy metal-contaminated sewage sludge

Stability and resilience of a variety of soil properties and processes are emerging as key components of soil quality. We applied recently developed measures of biological and physical resilience to soils from an experimental site treated with metal‐contaminated sewage sludge. Soils treated with cadmium‐, copper‐ or zinc‐contaminated, digested or undigested sewage sludge were studied. Biological stability and resilience indices were: (i) the time‐dependent effects of either a transient stress (heating to 40°C for 18 hours) or a persistent stress (amendment with CuSO₄) on decomposition, and (ii) the mineralization of dissolved organic carbon (DOC) released by drying–rewetting cycles. Physical stability and resilience measures were: (i) compression and expansion indices of the soils, and (ii) resistance to prolonged wetting and structural regeneration through drying–rewetting cycles. Soil total carbon and DOC levels were greater in the sludge‐amended soils, but there were no differential effects due to metal contamination of the sewage sludge. Effects of metals on physical resilience were greater than effects on soil C, there being marked reductions in the expansion indices with Cd‐ and Cu‐contaminated sludge, and pointed to changes in soil aggregation. The rate of mineralization of DOC released by drying and wetting was reduced by Zn contamination, while biological resilience was increased in the Zn‐contaminated soil and reduced by Cd contamination. We argue that physical and biological resilience are potentially coupled through the microbial community. This needs to be tested in a wider range of soils, but demonstrates the benefits from a combined approach to the biological and physical resilience of soils.     

Partial replacement of rock phosphate by sewage sludge ash for the production of superphosphate fertilizers

Thermal utilization of sewage sludge through mono‐incineration or gasification results in phosphorus (P) rich sewage sludge ash (SSA) that must be returned to agricultural production systems to fulfill the need for recycling of P resources contained in wastewater streams. As the plant‐availability of P contained in SSA is low, we propose feeding SSA directly into the production of superphosphate fertilizers, thereby opening a further pathway for the recycling of phosphorus (P) from wastewater streams to agricultural production systems by using available technologies. We carried out laboratory‐scale production of superphosphate test‐products, in which rock phosphate (RP) was partially replaced with SSA (gasification) before digestion with concentrated sulfuric acid, and evaluated these products with regard to the solubility of P in H₂O and neutral ammoniumcitrate solution. We further carried out a growth‐chamber experiment (28 d) using maize (Zea mays L. cv. Sulano) as a model plant on a low P (0.4 mg P_CAL 100g^?1), high pH (7.6) substrate to evaluate plant P availability of the test products. Our laboratory‐scale results show that at least 8% of P from RP can be replaced by P from SSA while maintaining both the high solubility of P in the fertilizer product and the growth of maize compared to pure RP digested with concentrated sulfuric acid. Further substitution of RP through SSA decreased the total P concentration of the test products, as well as the relative amounts of P soluble in H₂O and neutral ammoniumcitrate solution, which affected early plant development of maize.     

Carbon sequestration in a limestone quarry mine soil amended with sewage sludge

To reclaim a limestone quarry, 200 and 400 Mg/ha of municipal sewage sludge were mixed with an infertile calcareous substrate and spread as mine soil in 1992. Soil samples were taken 1 week later and again after 17 yr of mine soil rehabilitation so as to assess changes in the amount and persistence of soil organic carbon (SOC). Sludge application increased SOC as a function of the sludge rate at both sampling times. Seventeen years after the sludge amendments, the nonhydrolysable carbon was increased in the 400 Mg/ha of sludge treatment. The recalcitrance of SOC was less in sludge‐amended soils than in the control treatment at the initial sampling, but 17 yr later this trend had reversed, showing qualitative changes in soil organic carbon. The CO₂‐C production had not differed between treatments, yet the percentage of mineralized SOC was less in the high sludge dose. When the size of active (C_active) and slow (C_slow) potentially mineralizable C pools was calculated by curve fitting of a double‐exponential equation, the proportion of C_active was observed to be smaller in the 400 Mg/ha sludge treatment. Soil aggregate stability, represented by the mean weight diameter of water‐stable soil aggregates, was significantly greater in mine soil treated with the high dose of sludge (18.5%) and SOC tended to be concentrated in macro‐aggregates (5–2 mm). Results suggest that SOC content in sludge‐amended plots was preserved due by (i) replacement of the labile organic carbon of sludge by more stable compounds and (ii) protection of SOC in aggregates.     

Mineralization of nitrogen in permanent pastures amended with fertilizer or dung

 Nitrogen mineralization was measured in three permanent pastures – either fertilized or unfertilized grass, or a mixed grass-clover sward – which were further amended with either fertilizer or cattle dung over a summer growing season. Measurements were made at 4-weekly intervals from June to October. Rates of net mineralization were similar in each of the background treatments (overall mean 0.99±0.091 kg N ha^–1 day^–1) and did not change markedly during the experiment. From the second sampling (July) onwards, rates of mineralization in all the dung treatments were higher than in the control by a factor of up to 2. In the fertilizer-amended treatments, rates were also consistently (but not significantly) higher than in the control. However, the relatively small effect of fertilizer detected at each sampling had a significant cumulative effect by the end of the experiment. There was no interaction between the background and current treatments. Potential mineralization, measured by anaerobic incubation, increased in all the treatments over the period of the experiment, showing an accumulation of readily mineralizable residues. Total N mineralized and the N accumulated during the experiment were calculated and compared. This approach suggests that potential measurements could provide a good estimate of changes in soil N supply that would not be otherwise detectable in changes in soil total N in the short-term. Received: 12 June 2000     

Labile and stable pools of organic matter in soil amended with sewage sludge biochar

One of the main advantages of using biochar for agricultural purposes is its ability to store carbon (C) in soil for a long-term. Studies of labile and stable fractions of soil organic matter (SOM) may be a good indicator of the dynamics of biochar in soils. This study evaluated the effects of applying sewage sludge biochar (SSB) in combination with mineral fertilizer on fractions of SOM. To conduct this evaluation, 15 Mg ha^?1 of SSB combined or not with mineral fertilizer (NPK) was applied to the soil in two cropping seasons. Apart from total organic C (TOC), the labile and stable fractions of SOM were also determined. The combined use of SSB and NPK resulted in higher TOC, a 22% to 40% increase compared to the control and to the NPK treatments, respectively. The SSB produced at a lower temperature increased the labile fractions of SOM, especially the microbial biomass C, showing its capacity to supply nutrients in the short-term. The stable pools of SOM are increased after adding SSB produced at a higher temperature. It was concluded that pyrolysis temperature is a key-factor that determines the potential of SSB to accumulate C in labile and stable fractions of SOM.