Laboratorial incubation and field experiments were conducted on soils ranging in texture from sandy loam toclay and in PH from 3 .6 to 9.0 to determine the agronomic effectiveness of single superphosphate (SSP), fused...Laboratorial incubation and field experiments were conducted on soils ranging in texture from sandy loam toclay and in PH from 3 .6 to 9.0 to determine the agronomic effectiveness of single superphosphate (SSP), fused magne-sium phosphate (FMP)and partially acidulated phosphate rock (PAPR)on 8 field crops. The results showed that thepottern of available P released from SSP was fixing -releasing-fixing-steady state, while that of PAPR was shortlyfixing-slowly releasing-fixing-steady state And the PAPR . SSP and FMP were equally effective as judged by yield, Puptake by plants and extractable P in soils after crop harvesting. The PAPR used as basal fertilizer was more effectivethan that as top dressing, and its residual effect was also obvious.展开更多
A glasshouse experiment was conducted to evaluate the agronomic potential of four partially acidulatedrock phosphates (PARP) in three representative soils sampled from subtropical China. The PARPs weremanufactured by ...A glasshouse experiment was conducted to evaluate the agronomic potential of four partially acidulatedrock phosphates (PARP) in three representative soils sampled from subtropical China. The PARPs weremanufactured by attacking a moderately reactive phosphate rock either with sulfuric acid alone or withcombination of sulfuric and phosphoric acids at 30 or 60 percent of acidulation. Shoot dry weight and Paccumulation of six successive cuttings of ryegrass were used to compare the agronomic potential of thesefertilizers with that of the raw rock phosphate (RP) and monocalcium phosphate (MCP). Results indicatedthat the effectiveness of various phosphates was determined both by the solubility of the phosphates andby the acidity and P-fixing capacity of the soils. The higher the watersoluble P contained, the better theeffectiveness of the fertilizer was. Although plant P accumulation of PARP treatments was constantly lowerthan that of MCP treatment, some PARPs could still get a dry matter production similar to that of MCPtreatment. PARP SP60, which was acidulated with a mixture of sulfuric acid and phosphoric acid at 60percent of acidulation and contained the highest soluble P, was as effective as MCP in terms of dry matterproduction on all the soils. 560 and C1, which were both acidulated with sulfuric acid with the formerat 60 percent of acidulation and the latter at 30 percent but with a further addition of monoarninoniumphosphate, were more than 80 percent as effective as MCP. Raw RP also showed a reasonable effectivenesswhich increased with soil acidity. It was suggested from the study that some of these PARPs could beexpected to have a comparable field performance as soluble P fertilizers in the acid soil regions.展开更多
Phosphorus (P) and Nitrogen (N) deficiencies are recognized as the major constraint of agricultural productivity in developing countries including Zambia. While N deficits can be restored at least in part through the ...Phosphorus (P) and Nitrogen (N) deficiencies are recognized as the major constraint of agricultural productivity in developing countries including Zambia. While N deficits can be restored at least in part through the application of crop residues and manure, the restoration of soil P can only be achieved by use of phosphate fertilizers which are unaffordable by the small scale farmers. The aim of the study was to assess the availability of P for crop use from rock phosphate (RP), partially acidulated by acid produced by sulfur oxidizing bacteria. The RP was obtained from Keren Mining Limited at Sinda district, Zambia;the Pyrite rock (iron sulfur) and bacteria culture were obtained Nampundwe mine dump. The pyrite and PR were ground and mixed with the bacterial culture to produce the Partially Acidulated Rock Phosphate (PARP). A pot experiment was set up in a CRB design in a greenhouse on four soil types with four treatments of: soil alone (control), soil with GRP, soil with PARP and soil with super single phosphate (SSP) replicated four times. The results showed that the plant height, biomass yield and P uptake across the different P sources showed significant differences (p < 0.01);particularly, the PARP and SSP were significantly higher than the both control and the GRP. A comparison of PARP and SSP within each soil based on both biomass yield and P uptake showed no significant difference between them. Despite the fact that the RAE values based on biomass yield were in most cases higher than those base on the P uptake, the trend was the same. On average the PARP was >90% effective within and across the four soils indicating that the PARP is reactive and suitable for direct application for crop production.展开更多
This paper presents results that illustrate the recycling of a bamboo derived sorbent used for the capture of elemental mercury (Hg0). The bamboo derived sorbent used is essentially a HCl functionalized activated carb...This paper presents results that illustrate the recycling of a bamboo derived sorbent used for the capture of elemental mercury (Hg0). The bamboo derived sorbent used is essentially a HCl functionalized activated carbon prepared from carbonization and CO2 activation of raw bamboo, that could potentially provide an alternative way to existing methods in removing mercury from flue gases from coal-fired plants. In this study, the bamboo derived sorbents were tested in a batch test using a mercury permeation tube as the source and nitrogen as a carrier gas. The recycling or regeneration of an activated carbon is an important issue to address from a coal-fired power plant point of view, and an attempt has been made to test the behavior of bamboo derived sorbents with various treatments including carbonized, carbonized-activated, carbonized-activated-acidulated, and then a follow-up recycled run after sample treatments in gas phase. From the study, it was found that bamboo derived activated carbon can be successfully acidulated using various normalities of HCl where weak solutions can be very effective in functionalizing the surface of the sorbent and capturing mercury. In order to recycle and reuse bamboo derived sorbents, stronger normalities of HCl would be desired.展开更多
文摘Laboratorial incubation and field experiments were conducted on soils ranging in texture from sandy loam toclay and in PH from 3 .6 to 9.0 to determine the agronomic effectiveness of single superphosphate (SSP), fused magne-sium phosphate (FMP)and partially acidulated phosphate rock (PAPR)on 8 field crops. The results showed that thepottern of available P released from SSP was fixing -releasing-fixing-steady state, while that of PAPR was shortlyfixing-slowly releasing-fixing-steady state And the PAPR . SSP and FMP were equally effective as judged by yield, Puptake by plants and extractable P in soils after crop harvesting. The PAPR used as basal fertilizer was more effectivethan that as top dressing, and its residual effect was also obvious.
文摘A glasshouse experiment was conducted to evaluate the agronomic potential of four partially acidulatedrock phosphates (PARP) in three representative soils sampled from subtropical China. The PARPs weremanufactured by attacking a moderately reactive phosphate rock either with sulfuric acid alone or withcombination of sulfuric and phosphoric acids at 30 or 60 percent of acidulation. Shoot dry weight and Paccumulation of six successive cuttings of ryegrass were used to compare the agronomic potential of thesefertilizers with that of the raw rock phosphate (RP) and monocalcium phosphate (MCP). Results indicatedthat the effectiveness of various phosphates was determined both by the solubility of the phosphates andby the acidity and P-fixing capacity of the soils. The higher the watersoluble P contained, the better theeffectiveness of the fertilizer was. Although plant P accumulation of PARP treatments was constantly lowerthan that of MCP treatment, some PARPs could still get a dry matter production similar to that of MCPtreatment. PARP SP60, which was acidulated with a mixture of sulfuric acid and phosphoric acid at 60percent of acidulation and contained the highest soluble P, was as effective as MCP in terms of dry matterproduction on all the soils. 560 and C1, which were both acidulated with sulfuric acid with the formerat 60 percent of acidulation and the latter at 30 percent but with a further addition of monoarninoniumphosphate, were more than 80 percent as effective as MCP. Raw RP also showed a reasonable effectivenesswhich increased with soil acidity. It was suggested from the study that some of these PARPs could beexpected to have a comparable field performance as soluble P fertilizers in the acid soil regions.
文摘Phosphorus (P) and Nitrogen (N) deficiencies are recognized as the major constraint of agricultural productivity in developing countries including Zambia. While N deficits can be restored at least in part through the application of crop residues and manure, the restoration of soil P can only be achieved by use of phosphate fertilizers which are unaffordable by the small scale farmers. The aim of the study was to assess the availability of P for crop use from rock phosphate (RP), partially acidulated by acid produced by sulfur oxidizing bacteria. The RP was obtained from Keren Mining Limited at Sinda district, Zambia;the Pyrite rock (iron sulfur) and bacteria culture were obtained Nampundwe mine dump. The pyrite and PR were ground and mixed with the bacterial culture to produce the Partially Acidulated Rock Phosphate (PARP). A pot experiment was set up in a CRB design in a greenhouse on four soil types with four treatments of: soil alone (control), soil with GRP, soil with PARP and soil with super single phosphate (SSP) replicated four times. The results showed that the plant height, biomass yield and P uptake across the different P sources showed significant differences (p < 0.01);particularly, the PARP and SSP were significantly higher than the both control and the GRP. A comparison of PARP and SSP within each soil based on both biomass yield and P uptake showed no significant difference between them. Despite the fact that the RAE values based on biomass yield were in most cases higher than those base on the P uptake, the trend was the same. On average the PARP was >90% effective within and across the four soils indicating that the PARP is reactive and suitable for direct application for crop production.
文摘This paper presents results that illustrate the recycling of a bamboo derived sorbent used for the capture of elemental mercury (Hg0). The bamboo derived sorbent used is essentially a HCl functionalized activated carbon prepared from carbonization and CO2 activation of raw bamboo, that could potentially provide an alternative way to existing methods in removing mercury from flue gases from coal-fired plants. In this study, the bamboo derived sorbents were tested in a batch test using a mercury permeation tube as the source and nitrogen as a carrier gas. The recycling or regeneration of an activated carbon is an important issue to address from a coal-fired power plant point of view, and an attempt has been made to test the behavior of bamboo derived sorbents with various treatments including carbonized, carbonized-activated, carbonized-activated-acidulated, and then a follow-up recycled run after sample treatments in gas phase. From the study, it was found that bamboo derived activated carbon can be successfully acidulated using various normalities of HCl where weak solutions can be very effective in functionalizing the surface of the sorbent and capturing mercury. In order to recycle and reuse bamboo derived sorbents, stronger normalities of HCl would be desired.
