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1.
The effect of the application of acidified porous hydrate calcium silicate (APS) in nursery bed soil and porous hydrate calcium silicate (PS) in paddy fields on the growth of rice plants (Oryza sativa L. cv. Hitomebore) was examined in 2002 and 2003. The results revealed the following: 1) Shoot dry weight of rice seedlings increased by APS treatment in nursery bed soil. The tiller number of rice plants after transplanting in both years also increased by APS treatment in nursery bed soil, and in 2003, the tiller number in the treatment with a combination of APS in nursery bed soil and PS in paddy fields was significantly higher than that in the other treatments until the maximum tiller number stage. Furthermore, the root length of rice plants 14 d after transplanting increased by APS treatment in nursery bed soil. 2) Silicon concentration in the soil solution significantly increased by PS treatment in paddy fields, and the concentration of dissolved carbon oxide increased by APS treatment in nursery bed soil. 3) Only in the APS treatment the rice yield was 341 g m?2, while 400 and 450 g m?2 in the PS and both APS and PS treatments, respectively, in 2003. Percentages of ripened grains in the plots without PS treatment ranged from 57 to 63%, respectively, while, those in the PS treated plots were 82%. The numbers of panicles and ripened grains in both APS and PS treatments were the highest among the treatments. Based on the above results, we concluded that both APS in nursery bed soil and PS in paddy field treatments were effective in improving the silicon nutrition and growth of rice plants, and that this effect was enhanced by a combination of treatments with the two.  相似文献   

2.
不同脱沼泽阶段土壤中铁锰的比较研究   总被引：1，自引：1，他引：1       下载免费PDF全文
董元华  徐琪 《土壤学报》1991,28(4):382-389
本文以沼泽土、起源于沼泽土的潜育型水稻土和潴育型水稻土系列为研究对象，研究了土壤脱沼过程中铁锰的变化规律。根据铁锰的剖面分布特征、土体和各粒级硅铁率与钛锰率，以及游离铁和活性铁的变化规律，土壤脱沼过程可分为两个阶段：（1）铁锰强烈淋失阶段。脱沼过程初期，土壤有机质含量甚高，且随着有机质分解加速而破坏性有机物如酸、酚类等物质的含量增加，故土壤还原能力增强，加之随着排水而提高了渗漏性，铁锰便强烈淋失。主要是以较粗粒级中的铁锰，特别是以游离态和活性态淋失为主，然后较细粒级中的铁锰亦发生明显淋失。（2）铁锰再淀积阶段。当土壤有机质下降到一定程度之后，还原能力便减弱，铁锰则氧化淀积。主要是以铁锰新生体等游离态形式向较细粒级再淀积。由于长期渍水，阻碍了铁的老化，因而再淀积的铁活性甚高，其活化度达80%以上。  相似文献   

3.
磷在土壤中有效性的衰减   总被引：46，自引：3，他引：43  
培育试验表明,磷与红壤中有效性的衰减可分为快反应（3小时）阶段和慢反应阶段,前者有效磷以直线关系下降,后者则为一渐减性曲线。快反应阶段磷有效性的衰减量和土壤活性铝含量显著相关,但与活性铁和交换铝相关不显著。用红壤、潮土、板浆白土三种性质不同的土壤进行的生物试验表明,产量也随着土－磷作用时间延长而下降,而且有一个终止时间,中性水稻土在8个月培育后产量即可不再下降,石灰性潮土为16个月,而酸性红壤在28个月以上,影响产量衰减的可能和磷在土壤中的双核化（转化为环状双核结构）和吸收作用有关,它们在程度上和延续时间上不同土壤不同,在水稻土上最弱,延长时间最短,而在红壤上作用最强,延长时间最长,潮土处于两者之间。  相似文献   

4.
The effect of the application of acidified porous hydrate calcium silicate (APS) in nursery bed soil and porous hydrate calcium silicate (PS) in paddy fields on the growth of rice plants ( Oryza sativa L. cv. Hitomebore) was examined in 2002 and 2003. The results revealed the following: 1) Shoot dry weight of rice seedlings increased by APS treatment in nursery bed soil. The tiller number of rice plants after transplanting in both years also increased by APS treatment in nursery bed soil, and in 2003, the tiller number in the treatment with a combination of APS in nursery bed soil and PS in paddy fields was significantly higher than that in the other treatments until the maximum tiller number stage. Furthermore, the root length of rice plants 14 d after transplanting increased by APS treatment in nursery bed soil. 2) Silicon concentration in the soil solution significantly increased by PS treatment in paddy fields, and the concentration of dissolved carbon oxide increased by APS treatment in nursery bed soil. 3) Only in the APS treatment the rice yield was 341 g m−2, while 400 and 450 g m−2 in the PS and both APS and PS treatments, respectively, in 2003. Percentages of ripened grains in the plots without PS treatment ranged from 57 to 63%, respectively, while, those in the PS treated plots were 82%. The numbers of panicles and ripened grains in both APS and PS treatments were the highest among the treatments. Based on the above results, we concluded that both APS in nursery bed soil and PS in paddy field treatments were effective in improving the silicon nutrition and growth of rice plants, and that this effect was enhanced by a combination of treatments with the two.  相似文献   

5.
Elution of silicon (Si) from three types of slag fertilizers was tested in a paddy field. They were made from granulated blast furnace slag, dephosphorization slag and decarburization slag, respectively. Each fertilizer, embedded in epoxy resin to expose the cross section, was analyzed to get initial two-dimensional distribution images of Si, calcium (Ca), oxygen (O), magnesium (Mg), aluminum (Al), manganese (Mn) and iron (Fe) by electron probe micro-analyzer (EPMA). These resin specimens were set in a paddy field for 75 d. Then the second two-dimensional distribution images of Si, Ca, O, Mg, Al, Mn and Fe at the same site were analyzed again by EPMA. A comparison of the two-dimensional distribution images before and after setting in paddy field elucidated the following results: (1) Si eluted clearly from dephosphorization slag and decarburization slag; (2) Si, Ca, Mg and Al distributed homogeneously in granulated blast furnace slag. X-ray diffraction (XRD) clarified that granulated blast furnace slag was amorphous. The content of plant-available Si in each slag fertilizer was evaluated by the cation exchange resin extraction method. It was the highest in dephosphorization slag fertilizer. This result corresponded to Si elution from dephosphorization slag observed by EPMA. The content of plant-available Si was low in granulated blast furnace slag but high in air-cooled blast furnace slag. Although the content of plant-available Si in decarburization slag was low, the efficacy of Si elution was the highest in decarburization slag. From X-ray diffraction analyses, calcium silicate or larnite (Ca2SiO4) was considered to be the causative substance for efficient Si elution from decarburization slag and dephosphorization slag. Because of the high content of plant-available Si, dephosphorization slag and air-cooled blast furnace slag are recommended as silicate fertilizers in paddy fields.  相似文献   

6.
广东主要母质发育水稻土对硅的吸附特性   总被引：3，自引：0，他引：3  
Silicate adsorption in eight paddy soils developed from four different parent materials in Guangdong Province, China was examined to obtain fundamental knowledge of silicate adsorption to improve the efficacy of silicate fertilizer use in these areas. A correlation analysis showed that silicate adsorption did not obey the Langmuir equation （r = -0.664- 0.301） but did obey the Freundlich and Temkin equations （P〈0.01, r = 0.885-0.990）. When the equilibrium silicate concentration （Ci） was less than 45 mg SiO2 kg^-1, the adsorption capacity was in the following decreasing order of paddy soils： basalt-derived 〉 Pearl River Delta sediment-derived 〉 granite-derived 〉 sand-shale-derived. Stepwise regression and path analysis showed that for the investigated paddy soils amorphous MnO and Al2O3 were the two most important materials that affected silicate adsorption. Moreover, as Ci increased, amorphous Al2O3 tended to play a more important role in silicate adsorption, while the effects of amorphous MnO on silicate adsorption tended to decrease.  相似文献   

7.
Porous hydrated calcium silicate (PS) is a by-product of autoclave light weight concrete and is being used as a silicon fertilizer in Japan. The impacts of this amendment on the yield and cadmium content of rice (Orzya sativa L. var. Kokoromachi), soil pH and the extractability of soil cadmium assessed by 1 M NH4OAc were compared with those of silica gel and CaCO3 by pot experiments. The application of PS at the rate of 2.0% and silica gel at the rate of 1.0% in Andosol and PS at the rate of 0.75% in Alluvial soil significantly increased the grain weight of rice. PS and CaCO3 treatment significantly increased soil pH, decreased the 1 M NH4OAc extractability of cadmium and reduced cadmium content in straw and brown rice in the two soils. However, cadmium content of rice of PS treatments was not significantly different from that of CaCO3 treatments in Andosol, while was significantly lower than that of CaCO3 treatments in Alluvial soil. Soil analysis showed that it was less effective in increasing soil pH and decreasing the extractability of cadmium by 1 M NH4OAc than CaCO3 at the same application rate in Andosol. Soil pH and 1 M NH4OAc extractability of cadmium were not significantly different between 2.0% of PS and CaCO3 treatments in Alluvial soil. The application of silica gel did not improve soil pH nor decrease the extractability of soil cadmium, but resulted in a significant decline of cadmium content in brown rice. These results demonstrate that the supply of silicon together with an increase in soil pH, as obtained by PS application, shows potential to reduce the cadmium content of rice.  相似文献   

8.
水分状况与供氮水平对土壤可溶性氮素形态变化的影响   总被引：3，自引：0，他引：3  
采用通气培养试验,研究比较了两种水稻土在不同水分和供氮水平下的矿质氮(TMN)和可溶性有机氮(SON)的变化特征。结果表明,加氮处理及淹水培养均显著提高青紫泥的NH4+-N含量;除加氮处理淹水培养第7 d外,潮土NH4+-N含量并未因加氮处理或淹水培养而明显升高。无论加氮与否,控水处理显著提高两种土壤的NO3--N含量,其中潮土始见于培养第7 d,青紫泥则始于培养后21 d;加氮处理可显著提高淹水培养潮土NO3--N含量,却未能提高淹水培养青紫泥NO3--N含量。两种土壤的SON含量从开始培养即逐步升高,至培养21～35 d达高峰期,随后急剧下降并回落至基础土样的水平;SON含量高峰期,潮土SON/TSN最高达80%以上,青紫泥也达60%。综上所述,潮土不仅在控水条件下具有很强硝化作用,在淹水条件下的硝化作用也不容忽视,因此氮肥在潮土中以硝态氮的形式流失的风险比青紫泥更值得关注;在SON含量高峰期,两种土壤的可溶性有机氮的流失风险也应予以重视。  相似文献   

9.
Implication of ureolytic biocalcification process as an efficient carbon dioxide sequestration technology was evaluated with Bacillus megaterium culture growing in a closed environment system. In three experimental sets containing either 35 % v/v CO2 in headspace (set 1) or 50 mM urea in solution (set 3) or both (set 2), change in headspace CO2, soluble calcium, and pH were monitored during 8 days of incubation. In absence of urea, headspace CO2 content continued to increase in set 1 (up to 48 % v/v) without any carbonate precipitation. However, carbonate precipitation were obvious in urea containing sets (sets 2 and 3) utilizing all the added calcium (25 mM) in just 2 and 6 days, respectively. No headspace CO2 could be detected in set 2 at the end of experimental period, and analysis suggested that this was majorly (>53 %) attributed to the solubility trapping phenomenon. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis revealed that the precipitates were made up of calcite and major fraction of vaterite polymorph of CaCO3.  相似文献   

10.
The precipitation of calcium carbonate is obtained from a bicarbonate solution added with silica gels, silico-mangnesian gels, ferric gels and clay minerals.Two methods have been performed. The first one consists of a quick removal of CO2; the second one refers to settled solutions. Identification of various carbonates is obtained by infra-red spectroscopy. Morphology of crystalline shapes are analysed with scanning electron microscope.It is etablished:
(i) silica gels are not good inhibitors of calcite;
(ii) silico-magnesian gels reduce the time of precipitation and promote the deposition of “disordered” calcite (intermediate hydrated form between amorphous calcium carbonate and calcite) and (OH) aragonite;
(iii) ferric gels inhibit very strongly calcite; then, vaterite and aragonite are deposited;
(iv) at the least, the presence of clay minerals promote the stabilization of amorphous calcium carbonate and “disordered” calcite.
The gels and the minerals which are here tested and recognized in soils take therefore an active part in the kinetics of precipitation and in the nature of the calcium carbonates.  相似文献   

11.
福建红壤性水稻土发生和分类的研究   总被引：4，自引：0，他引：4  
  相似文献   

12.
Soil organic carbon (SOC) is the most important carbon pool in the terrestrial ecosystem. However, temporal variations in paddy SOC under a temperate continental monsoon climate are poorly understood. Here, we demonstrate that significant SOC variations occur in meadow soil (MS), black soil (BS) and planosol (PS) paddy soils. Several soil samples were collected from different regions where rice was cultivated for 1, 6, 10, 23 and 40 years for MS samples; for 1, 6, 10, 20 and 35 years for BS samples and 1, 5, 10, 15 and 25 years for PS samples. The total organic carbon (TOC) content and humus organic carbon (HOC) content were found to increase as the rice cultivation duration increased, while the mineralizable organic carbon (MOC) content and carbohydrate organic carbon (COC) content exhibited the opposite trend. The relationships between the relative carbon accumulation (Y) in the three soil types and time (X) were consistent with the following models: YTOC = 0.9973X0.0245, YHOC = 0.9936X0.0457, YMOC = 1.023X−0.073, and YCOC = 1.040X−0.059, describing the temporal variation in the various forms of organic carbon in paddy soils under a temperate continental monsoon climate. The results of this study provide a reference for soil carbon pool management and fertilization management.  相似文献   

13.
Abstract

An anaerobic incubation experiment was conducted to investigate methane (CH4) production potential in soil samples collected from a paddy field after exposure to free-air CO2 enrichment (FACE). The FACE experiment with two CO2 levels, ambient and ambient + 200 p.p.m.v CO2 during the rice growing season, was conducted at Shizukuishi, Iwate Prefecture, Japan. The soil was a wet Andosol. Soil samples were taken from the surface (0–1 cm) and the sub-surface (1–10 cm) soil layers 2 months after rice harvest. Sub-samples of the fresh soils were put into glass bottles and submerged under N2 gas headspace during the incubation. The results showed that, prior to incubation, the contents of total C and dissolved organic C (DOC) were significantly greater in FACE soil than ambient soil. During the incubation, CH4 production potential was approximately 2–4-fold higher in FACE soil than ambient soil and approximately 500–1,000-fold greater in surface soil than sub-surface soil. In general, the FACE soil contained more DOC than ambient soil, particularly in the surface soil layer. These findings suggest that FACE treatment exerted long-term positive effects on CH4 production and increased organic C content in this paddy soil, particularly in the surface soil layer.  相似文献   

14.
Rice straw contains up to 2.3% K in dry matter, including potassium (K) subcompartmented in phytoliths, complex siliceous structures formed in plant tissue via precipitation of Si. Rice straw is usually returned to the soil as a conventional practice to sustain soil nutrients, and therefore, the K pool accompanied with rice straw phytoliths is also cycled. Based on phytoliths obtained by ashing of rice straw at 400 °C and dissolution experiments using batch extraction in combination with physical separation of phytoliths by heavy liquid, this study evaluated the phytolith K(phytK) pool in rice straw and aged phytoliths in paddy soils. Entrapped organic matter containing K within phytolith silica cells was visualized by X-ray tomographic microscopy, and releases of this phytK pool accompanying phytolith dissolution were quantified. A 1% Na2CO3 solution, which has been commonly used to extract amorphous Si and to quantify soil phytoliths, showed obvious responses for K derived from phytolith dissolution, indicating that the Na2CO3 method can be developed for measurement of phytK. In 13 soil samples, Na2CO3-dissolvable K content assignable to phytK was 0.55 ± 0.39 g kg?1 in the puddled horizon, suggesting the phytK pool is of high significance for the management of K in paddy soils.  相似文献   

15.
Calcite and dolomite were differentiated quantitatively from calcite-dolomite mixtures and limestones by a method based on the quantitative dissolution of calcite in pH 5.85N citrate buffer. The acidity and chelating ability of citrate favoured greatly the dissolution of calcite to that of dolomite. The method consisted of determination of citrate-soluble Ca and Mg which, in conjunction with a Ca and Mg analysis of the residue, or a determination of total CO3 in the system, allowed calculation of the calcite and dolomite contents of the sample. Analyses of artificially prepared mixtures and limestone samples gave essentially the same calcite and dolomite contents when determined by the residue and total CO3 methods. The residue method is to be preferred because error can be reduced by determination of the actual Ca:Mg ratio of the dolomite. However, the total CO3 method would be superior for heterogeneous systems, such as soils, since dissolution of dolomite in the residue by strong acid treatment may introduce errors from the dissolution of non-carbonate Ca and Mg minerals.  相似文献   

16.
Amine-functionalized SiO2/TiO2 photocatalytic films have been synthesized using the peroxo titanic acid (PTA) approach coupled with the sol-gel dip-coating method. The 3-aminopropyl-trimethoxysilane (APTMS) and methyltrimethoxysilane (MTMOS) were employed as the amine functional groups and silica precursor. The effects of the ratio of APTMS/MTMOS, PTA refluxed time, and pH of prepared sol on the characteristics and the formaldehyde degradation efficiency were investigated. Physicochemical properties of prepared photocatalysts were characterized with nitrogen adsorption–desorption isotherm measurement, SEM, X-ray diffraction (XRD), UV-vis spectrophotometer, and Fourier transform infrared (FTIR) spectroscopy. The XRD and FTIR results indicated that the obtained photocatalysts consisted of –NH2 groups, SiO2, and anatase TiO2. The photocatalytic films showed high transmittance of 80–90% in the visible light region. The obtained film prepared with the APTMS/MTMOS ratio of 0.03, pH of 1.8, and 10 h of refluxed time possessed high specific surface area (604.0 m2 g?1) and 85% formaldehyde degradation efficiency. The enhancement of formaldehyde degradation efficiency was observed when increasing the PTA refluxed time. The repeatability of photocatalytic film was also tested, and the degradation efficiency was 92.0% of initial efficiency after seven cycles.  相似文献   

17.
Abstract

Rice is a plant that requires high levels of silica (Si). As a silicate (SiO2) source to rice, coal fly ash (hereafter, fly ash), which has an alkaline pH and high available silicate and boron (B) contents, was mixed with phosphor‐gypsum (hereafter, gypsum, 50%, wt wt?1), a by‐product from the production of phosphate fertilizer, to improve the fly ash limitation. Field experiments were carried out to evaluate the effect of the mixture on soil properties and rice (Oryza sativa) productivity in silt loam (SiL) and loamy sand (LS) soils to which 0 (FG 0), 20 (FG 20), 40 (FG 40), and 60 (FG 60) Mg ha?1 were added. The mixture increased the amount of available silicate and exchangeable calcium (Ca) contents in the soils and the uptake of silicate by rice plant. The mixture did not result in accumulation of heavy metals in soil and an excessive uptake of heavy metals by the rice grain. The available boron content in soil increased with the mixture application levels up to 1.42 mg kg?1 following the application of 60 Mg ha?1 but did not show toxicity. The mixture increased significantly rice yield and showed the highest yields following the addition of 30–40 Mg ha?1 in two soils. It is concluded that the fly ash and gypsum mixture could be a good source of inorganic soil amendments to restore the soil nutrient balance in rice paddy soil.  相似文献   

18.
室内恒温条件下稻田土壤中菌渣的分解过程及CO2释放特征   总被引：1，自引：0，他引：1  
菌渣是栽培食用菌后的下脚料,可作为有机肥再利用。本文通过实验室条件下培养不同比例的菌渣和稻田土壤混合物[不施用菌渣(TS),土壤与菌渣质量比为10∶1(SM1)、5∶1(SM2)和2∶1(SM3),全部菌渣(TM)],研究不同处理有机碳和全氮的变化,探讨菌渣在稻田土壤中的分解过程,并分析CO_2释放特征,为菌渣合理利用提供参考。结果表明,在相同培养时间,添加不同比例菌渣处理有机碳和氮含量均比TS处理高,其中TM处理的有机碳和全氮分别比TS处理提高了10.7倍和11.0倍。有机碳、氮含量的提高量主要依赖于菌渣的添加量。总体来说,各处理随培养时间的延长,由于碳氮的分解,有机碳、氮均有下降趋势;在35 d后TM处理有机碳氮下降较快。添加菌渣越多,有机碳残留率也越大。在培养63 d后,菌渣有机碳(YC)和氮(YN)的分解残留率与菌渣添加量(X)的关系式分别为:YC=71.26X-0.607 5,r2=1.000 0**和YN=74.039X-0.413 3,r2=0.999 9**。各处理土壤CO_2释放速率均表现出先增后降然后趋于稳定趋势。菌渣用量越高,CO_2释放速率越高,各处理在不同培养时间CO_2释放速率均表现为TMSM3SM2SM1TS。在第7 d时各处理CO_2释放速率最高,在第14 d时渐渐处于平稳下降状态,培养35 d后,各处理土壤有机碳矿化强度很小,大部分有机碳被固定在土壤中,其中TM处理有机碳矿化强度最小。总之,还田菌渣越多,土壤中被固定的碳越多。  相似文献   

19.
THE ADSORPTION AND PRECIPITATION OF PHOSPHATE ONTO CALCITE   总被引：11，自引：0，他引：11  
Scanning electron micrographs show that the reaction products of solution phosphate and calcite are hemispherical, coral-like growths on calcite surfaces. Electron probe micro-analysis indicates that these are a calcium phosphate, and solution data plotted against solubility isotherms suggest that dicalcium phosphate (DCP) is formed rapidly and slowly changes to octa-calcium phosphate (OCP). X-ray diffraction shows that DCP and OCP are present with DCP predominating. The ratio of Ca:P in the treated calcite, after allowing for the CaCO3 present, is that in DCP, and a surface coating of OCP on DCP is likely. The exchangeability of the reacted P falls from 100 per cent for small amounts (0–10 μg P per g calcite) to a constant 30 per cent when larger amounts are present (200–1000 μg/g) resulting from the porous structure of the coral-like growths. These cover only a small fraction of the calcite surface even when large amounts of P are present so allowing calcite to control solution pH.  相似文献   

20.
In this investigation, the photocatalytic activity of α-Bi4V2O11 in the degradation of 2-naphthol under simulated solar light was evaluated. Bismuth vanadate α-Bi4V2O11 was synthesized by the solid-state reaction method and by co-precipitation in aqueous media, with the aim of comparing their performance in the photodegradation of the aromatic pollutant. The latter method (co-precipitation) has not been previously reported for the synthesis of α-Bi4V2O11. Structural evolution of the oxides precursors was determined by X-ray diffraction. Morphology and optical properties of the solids were analyzed by scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectroscopy (UV-vis), respectively. The results showed that at 800 °C, only α-Bi4V2O11 was formed in both preparations. The SEM micrographs revealed that the powders were composed of agglomerates with sizes between 0.8–2 μm for those synthesized by co-precipitation and 2–10 μm for those obtained by solid-state reaction. The optical properties indicated that α-Bi4V2O11 was activated with visible light during the photocatalytic process. The photocatalytic degradation of 2-naphthol was largely influenced at basic pH, degrading 79% of the contaminant in 240 min, with the powder obtained by co-precipitation; meanwhile, for the solid-state preparation, the degradation reached only 55%.  相似文献   

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