湖南省土壤中硅的形态与土壤性质的关系

湖南省几种主要土壤中各种形态硅的含量顺序为无定形硅 > 活性硅 > 有效硅 > 水溶性硅。土壤pH、粘粒含量和CEC是影响土壤有效硅及活性硅的正效应因素,而有机质含量为负效应因素。盆裁试验结果表明,大部分土壤施硅后水稻籽粒产量显著提高,其增产率与土壤有效硅及活性硅均呈明显负相关,表明土壤活性硅也可作为衡量土壤供硅能力的指标。     

西天目集约经营雷竹林土壤硅存在形态与植物有效性研究

在雷竹主产地临安西天目选取了集约经营下不同种植年限(1、5、10、15 a)的雷竹林地,采集不同深度(0～10 cm、10～20 cm和20～40 cm)土样,运用逐级化学提取等技术,研究集约经营雷竹林土壤硅素含量与形态随种植年限和土壤剖面深度的变化规律,为雷竹林地土壤有效态硅调控提供理论依据。研究结果表明:(1)雷竹林土壤不同土层有效态硅的含量(0.084～0.318 g kg-1)和所占的比例(1.60%～12.3%)随种植年限和有机物覆盖年限的增加呈先下降后上升趋势;(2)雷竹林表层土壤无定形硅含量(2.58～5.15g kg-1)和所占比例(75.1%～87.7%)随种植年限的增加呈上升趋势;(3)覆盖有机物可同时促进无定形硅向有效态硅、有机结合态硅、铁锰(氢)氧化物结合态硅转变。     

酸化与富磷影响农田土壤硅的移动性

硅是水稻等禾本科作物生长发育不可或缺的营养元素,pH影响着土壤中硅的有效性和形态转化,而土壤磷与硅之间存在明显的竞争吸附效应。以常年水稻-瓜/菜轮作农田土壤为研究对象,进行等摩尔硅磷竞争吸附试验、土壤培养试验和硅分组试验,模拟探究土壤酸化和磷富集对土壤硅的有效性及移动性的影响,以期为农田硅、磷养分管理提供一定的理论依据。结果表明,在pH 3.5～6.4范围内,同时加入等摩尔浓度的硅和磷时,磷的存在会抑制土壤吸附硅,使土壤对硅的吸附量降低78%～350%。土壤对硅的吸附小于对磷的吸附,磷的添加导致了土壤中硅的解吸。土壤酸化和磷添加均降低了土壤对硅的吸附,且在pH较高时添加磷对降低土壤吸硅的效果更为显著。土壤酸化降低了可移动态硅、吸附态硅、有机结合态硅和铁铝锰（氢）氧化物结合态硅的含量,但增加无定形态硅含量。与pH 6.4相比,酸化使可移动态硅和吸附态硅含量分别降低了22.47%～54.32%、10.72%～33.40%;磷添加使可移动态硅含量增加了4.07%～9.40%,吸附态硅含量降低了1.19%～3.53%。pH可调控土壤硅的溶解与吸附-解吸过程,从而影响土壤硅的移动性;磷富集促进土...     

安徽省水稻土有效硅状况及硅肥效果

安徽省水稻土有效硅含量具有明显区域分布特征。不同母质发育的水稻土有效硅含量顺序为：黄土性古河湖相沉积物〉近代黄泛〉淮河冲积〉石灰岩〉湖积物〉下蜀黄土〉长江冲积〉紫色砂页岩和第四纪红土〉板页岩和花岗岩。土壤ＰＨ值，土壤物理性粘粒含是与土壤有效硅含量呈极显著显著正相关。     

不同栽培年限日光温室土壤磷素累积特性研究

测定了陕西关中地区不同栽培年限日光温室土壤不同形态磷素的含量,以评价土壤磷素累积特性。结果表明:与农田土壤相比,日光温室栽培土壤全磷、有效磷、水溶性磷含量显著增加,土壤表层Olsen-P和水溶性磷平均含量分别达227 mg kg-1和8.45 mg kg-1;0～20 cm土层土壤全磷、Olsen-P和水溶性磷含量平均分别为农田的1.78倍,8.00倍和3.70倍,20～40 cm土层的分别为农田的0.62倍,3.24倍和2.53倍;且随日光温室栽培年限的增加,不同形态磷的累积量呈逐年递增的趋势。日光温室土壤全磷、有效磷、水溶性磷三者关系呈显著线性相关关系,有效磷与水溶性磷达极显著正相关。表明研究地区日光温室栽培下土壤磷素过量累积带来的淋溶风险值得关注。     

施用钢渣对水稻土硅素肥力的影响

施用钢渣种植水稻的贫栽试验结果表明，与对照相比，施用钢渣使土壤pH升高，土壤水溶态硅和无定形硅的含量降，活性硅及有效硅含量上升，水稻植株含硅量上升，水稻植株含硅量增加，除水溶态硅外，上述影响随钢渣用量增加或粒度变细而增强。     

酸化与富磷对农田土壤硅有效性的影响

目前，大量农田土壤及其生态功能正经受着土壤酸化的严重威胁，而土壤pH深刻影响着土壤中硅、磷养分的移动性及两者间的相互作用。关于硅肥施用可有效提升土壤磷素植物有效性的研究已有大量报导，但在农业集约化生产区，土壤磷素已大量累积的背景下，磷富集对土壤硅移动性与有效性的影响及其机制尚不清楚。选取2种不同有效硅水平的农田土壤（低有效硅土壤LASi：有效硅28.20 mg?kg-1；高有效硅土壤HASi：有效硅253.6 mg?kg-1），通过等摩尔浓度硅磷竞争吸附试验、土壤培养试验等，探究人工酸化与磷添加对土壤硅吸附性能与移动性的影响及其机制。结果表明，酸化土壤pH在3.5~8.0范围内，当硅与磷等摩尔浓度同时添加时，磷的存在会降低硅的吸附，各相应pH的LASi与HASi 2种土壤对硅的吸附量分别降低26%~74%、31%~84%。这说明，土壤对磷的吸附大于对硅的吸附。设置土壤pH3.5~8.0范围内，降低pH可降低土壤对硅的吸附；磷添加降低土壤硅吸附的效应，在高pH条件下更为显著。土壤酸化与磷添加降低了土壤对硅的吸附，降低了土壤有效硅（HOAc-NaOAc-Si）水平；不同类型土壤移动性硅（CaCl2-Si）水平对酸化与磷添加的响应不同，具体机理尚需进一步研究。     

江西省旱地土壤有效硅含量的分布特征及其影响因素

了解江西旱地土壤有效硅含量分布规律及影响因素,可为今后江西省旱地土壤采取合理的硅肥施用措施提供理论依据。本研究采用柠檬酸浸提—硅钼蓝比色法测定了江西省旱地耕层185个土样的有效硅含量,结果表明:(1)江西旱地土壤有效硅含量范围在12.7～192.0 mg·kg~(-1),空间分布存在较大差异,整体表现为北高南低,西高东低,赣东北最低的分布特征。(2)赣东北、赣北、赣西土壤中有效硅含量随着土壤pH值升高而显著(P0.05)增加;赣南旱地土壤有效硅含量随碱解氮、有效磷的升高而显著(P0.05)降低。(3)江西省除赣东北土壤有效硅平均含量稻田高于旱地,其他4个区旱地土壤有效硅平均含量均高于稻田。且旱地土壤有效硅含量主要集中在25～115 mg·kg~(-1),而稻田土壤有效硅含量主要集中在25～70 mg·kg~(-1),旱地有效硅含量缺(25～70mg·kg~(-1))与极缺(25 mg·kg~(-1))的土壤占比分别比稻田低7.09%和6.03%。但江西省旱地土壤有效硅含量缺和极缺的也占57.3%,超过一半,急需通过合理施肥提高其含量,保证作物的产量和品质。     

缙云山4种林分土壤植硅体碳分布特征

森林生态系统中丰富的植硅体可以将部分有机碳封存于土壤中,形成稳定的碳库,对全球碳平衡起到重要作用。以重庆市缙云山的竹林、阔叶林、针叶林和针阔叶混交林4种亚热带森林植被为研究对象,研究不同林分下土壤植硅体及植硅体碳在0～20、20～40、40～60和60～100 cm土壤剖面上的分布规律。结果表明,整个土壤剖面(0～100 cm)上,不同林分下竹林土壤有机碳含量和储量、土壤植硅体和植硅体碳含量及植硅体碳储量均最高,显著高于其他3种林分(P<0.05)。4种林分下有机碳和植硅体碳含量呈现一定的表层(0～20 cm)富集现象,并呈现随土层深度增加含量减少的趋势。相关性分析发现,植硅体和植硅体中的有机碳存在显著的负相关关系(P<0.05),而与植硅体碳存在极显著的正相关关系(P<0.01)。缙云山4种林分中,竹林土壤有机碳含量、储量,植硅体、植硅体碳含量、储量均为最高,是较好的富碳森林类型。     

温室土壤硅素释放动力学特征的研究

施硅可以促进园艺作物生长、提高其抗逆性和改善果实品质,但关于温室土壤硅素供应特征及其影响因素、合理调控土壤硅素肥力的研究却鲜有报道。采用淹水培养试验与化验分析结合的方法,研究温室土壤的硅素释放特征及其影响因素。结果表明,幂函数方程y=kxm能很好地描述土壤硅素的累积释放特征,方程参数k(硅素初始释放量)、m(硅素释放速率系数)、km(初始释放速率)受土壤pH和有机质的显著影响,均与土壤pH、有机质含量呈极显著的直线正相关关系;此外,参数k和km还分别与土壤游离氧化铁含量呈显著的指数和幂函数正相关关系。应用释放动力学方程求得的100天硅素累积释放量与土壤pH、有机质含量分别呈极显著的指数和直线正相关关系,但多元逐步回归分析结果表明硅素累积释放量与土壤有机质含量关系更为密切。应用释放动力学方程及其参数评价温室土壤的供硅能力具有可行性,值得进一步深入研究。     

应用硅素释放动力学方程评价水稻土供硅能力 Ⅰ硅素释放动力学方程参数与水稻相对产量的关系

在淹水培养条件下,进行了12种不同pH水稻土硅素累积释放试验,结合田间试验的效果,研究了土壤有效硅、水稻土硅的累积释放特征及其与硅肥肥效之间的关系。结果表明:1mol L-1HAc-NaAc(pH=4)缓冲液法不能直接判断碱性水稻土供硅能力。不同pH水稻土中硅素的释放过程可以用方程y=kxm来描述。土壤硅素120日累积释放量、硅素释放初始速率km与水稻相对产量具有显著的线性正相关关系。因此,应用土壤硅素释放动力学方程参数能够评价不同pH水稻土的供硅能力。     

硅钙钾镁肥及引入柠檬酸对红壤和潮土pH值及养分含量的影响

通过土壤培养试验研究了硅钙钾镁肥(SCPM)及引入柠檬酸的复混肥(CA-SCPM)在酸性红壤和石灰性潮土上的养分供给和酸碱度调节能力.硅钙钾镁肥添加量设置为6 g/kg,硅钙钾镁肥与柠檬酸(CA)的比例为88％:12％.与对照处理相比,培养至150 d时,SCPM肥及CA-SCPM肥提高红壤pH值约1.16个单位,提高...     

Increase of Available Phosphorus by Fly‐Ash Application in Paddy Soils

Abstract

Fly ash from the coal‐burning industry may be a potential inorganic soil amendment to increase rice productivity and to restore the soil nutrient balance in paddy soil. In this study, fly ash was applied at rates of 0, 40, 80, and 120 Mg ha^?1 in two paddy soils (silt loam in Yehari and loamy sand in Daegok). During rice cultivation, available phosphorus (P) increased significantly with fly ash application, as there was high content of P (786 mg kg^?1) in the applied fly ash. In addition, high content of silicon (Si) and high pH of fly ash contributed to increased available‐P content by ion competition between phosphate and silicate and by neutralization of soil acidity, respectively. With fly‐ash application, water‐soluble P (W‐P) content increased significantly together with increasing aluminum‐bound P (Al‐P) and calcium‐bound P (Ca‐P) fractions. By contrast, iron‐bound P (Fe‐P) decreased significantly because of reduction of iron under the flooded paddy soil during rice cultivation. The present experiment indicated that addition of fly ash had a positive benefit on increasing the P availability.     

环洞庭湖区稻田土壤中硅分布特征及其影响因素

[目的]研究环洞庭湖区稻田土壤中有效硅的空间分布特征及其变化规律,以期为环洞庭湖区精准农业的发展、农田的保养提供科学依据和实践指导。[方法]运用地统计学与GIS技术相结合的方法开展研究。[结果]环洞庭湖区土壤中有效硅的含量与水稻产量呈显著的正相关,硅是水稻生长所需的重要营养元素。环洞庭稻田土壤有效硅平均含量为155.1mg/kg,多集中于100~200mg/kg。有效硅含量变幅大,最低与最高含量相差27倍,在研究区域空间上呈中间高四周低,西北最低的分布格局。土壤有效硅具有较强的空间相关性,其空间变异主要受土壤类型、土壤酸碱度、成土母质等因素影响。[结论]硅在水稻生长发育中起着重要的作用。不同的土壤类型所处的自然地理环境不一样,土壤有效硅含量各异,土壤有效硅的丰缺程度受土壤成土母质的影响并与土壤pH值成显著的正相关。     

Measurement of Si adsorption and “Active Si” in a soil amended with slag fertilizers by using stable isotope 30SP

The silicic acid adsorption by a soil (Eutric Gleysols) where slag fertilizers were applied was measured by the addition of a silicic acid solution labelled with ³⁰Si after soil incubation, in order to study the effect of slag application on the specific Si adsorption by the soil and to estimate the amount of Si in the soil solid phase which can easily enter the soil solution. It was evident that the application of slags increased the ability of soil to adsorb Si. It was also shown that the ³⁰Si added was diluted with not only the Si present in the soil solution but also the Si dissolved from the soil solid phase. We proposed the use of the term “active” for Si in soil which can take part in the isotopic dilution within 1 h. The amount of active Si in the soil solid and liquid phases (D ₆₀ - value) was calculated from the ³⁰Si content in the soil solution and compared with the amount of Si taken up by rice plant (Oryza sativa L.), which was determined in our previous study. The buffering capacity of the soil for Si, which can reflect the ability of soil to maintain the Si concentration in the soil solution constant when Si is added to or removed from the soil, was also determined. The D ₆₀ - value and the Si buffering capacity of the soil increased by slag application. These increases were large when the alkalinity of the applied slags was high. The correlation study revealed that the D ₆₀ - value was a better index of Si availability of the soil than the amount of Si dissolved from the soil solid phase during the incubation when the slags were previously applied.     

Changes in Extractable Si,Fe, and Mn as Affected by Silicon,Salinity, and Waterlogging in a Sandy Loam Soil

Silicon (Si) is one of the most abundant elements in the earth's crust, although its availability may be affected by some edaphic and abiotic factors such as soil moisture and salinity. In a laboratory experiment, effects of silicon (Si), salinity, and soil moisture on changes of extractable Si, iron (Fe), and manganese (Mn) concentrations were investigated on a sandy loam calcareous soil. The experiment was arranged as a factorial completely randomized design with three replications. Two levels of Si (8 and 200 mg per kg of soil), three salinity levels [0.46 dS m^?1, 8 dS m^?1 as sodium chloride (NaCl), and 8 dS m^?1 as four-salt combination], two soil moisture regimes (–20 kPa and waterlogged), and four incubation times (0, 7, 30, and 45 days) were applied. Salt composition consisted of sodium chloride, sodium sulfate, calcium chloride, and magnesium sulfate at a molar ratio of 4:2:2:1. Acetic acid–extractable Si, Fe, and Mn were determined after 0, 7, 30, and 45 days of incubation. Waterlogging caused significant increase in the extractable Si, Fe, and Mn. Soil salinity of 8 dS m^?1, only in the form of sodium chloride, resulted in a marked decrease in extractable Si, Fe, and Mn. Silicon addition enhanced the soil Si concentration, with no effect on Fe and Mn. Equilibrium time for Si and Fe was 30 days, whereas Mn concentration reached to a constant level after 1 week of waterlogging. It was concluded that Si, Fe, and Mn fertilizers should be applied in sufficient amounts to the saline soils to prevent their deficiencies in plants. Meanwhile, overfertilization in waterlogged conditions must be avoided, because of the probability of nutrient imbalance or toxicity.     

SLAG EFFICACY AS A LIME AND SILICON SOURCE FOR RICE CROPS THROUGH THE BIOLOGICAL METHOD

There is little information about the best silicon (Si) sources for agricultural use, and yet some products have already been marketed as sources of this element. One of these products is slag, which is used as a source for Si and lime. This study evaluated the silicon supply availability and efficacy of different silicate slag types for rice crops. The experiment was conducted in a greenhouse, used Entisol Quatzipsamment soil and was set up in randomized blocks with three replications. Si source reactivity was evaluated using five metallurgic slag types and Wollastonite, which is considered a standard in Si studies. Doses of each Si source were 1000 and 2000 mg dm^?3 of Si and a control (additional treatment). Soil data [soluble Si, calcium (Ca²⁺), magnesium (Mg²⁺) and pH] and rice growth and yield were recorded. Data were evaluated by analysis of variance and contrasts were made for comparisons between each slag type and the additional treatment. Averages were compared by the Scott Knott test at 5% with the statistics program SISVAR. The efficacy of the slag types in supplying Si for the plants (ESSi) and in increasing Si availability in the soil (ESiA) was determined from the values of contrast estimates. Slag E3 and Wollastonite were effective in increasing soil silicon availability and, consequently, the efficacy of supplying silicon for the plants, while the other slag types had low efficacy.     

Evaluation of available silicon content and its determining factors of agricultural soils in Japan

To evaluate the available silicon (Si) content in agricultural soils in Japan and to investigate the determining factors of this content, we collected 180 soil samples from the surface layer of paddies and upland fields in Japan and determined their available Si contents. A phosphate buffer (PB; 0.02 M, pH 6.9) or an acetate buffer (AB; 0.1 M, pH 4.0) was used to extract available Si from the soil samples, and the Si concentrations in the extracts were determined by inductively coupled plasma-atomic emissions spectroscopy (ICP-AES). The total Si content and selected physicochemical properties were also determined for the soil samples. The median values of the available Si contents by the PB and AB methods were 48.8 and 79.7 mg kg^?1 and corresponded to 0.017% and 0.027% of the total Si content, respectively. The overall data showed log-normal distributions. The available Si content of the upland soils was significantly higher than that of the paddy soils by both the PB (p < 0.01) and AB methods (p < 0.05). The available Si contents by the PB and AB methods had a significant positive correlation (p < 0.01) and they had significant negative correlation with the total Si content (p < 0.01). The values of the available Si contents by the PB and AB methods correlated positively with the pH, total carbon (C) content, and dithionite-citrate bicarbonate extractable iron (Fed) and aluminum (Ald), acid oxalate extractable iron (Feo) and aluminum (Alo), Fed-Feo and Alo+1/2Feo values (p < 0.01). A multi-regression analysis indicated that pH, amorphous minerals and crystalline iron (Fe) oxides were the dominant determining factors of available Si in the soils, and these three variables explained approximately two thirds of the variation of available Si content in agricultural soils in Japan. In terms of soil type, Terrestrial Regosols, Dark Red soils and Andosols had relatively high available Si contents, whereas Sand-dune Regosols, Red soils and Gray Lowland soils had relatively low contents. In terms of region, the soils in the Kanto and Okinawa regions had relatively high available Si contents and those in the Kinki, Shikoku and Chugoku regions had relatively low contents. In conclusion, the available Si content and its determining factors for agricultural soils in Japan were quantitatively elucidated, and this will contribute to the establishment of rational soil management?—including the application of silicate materials, taking into account the Si-supplying power of the relevant soils—for sustainable and productive agriculture in Japan.     

Bioavailability of Silicon from Different Sources and Its Effect on the Yield of Rice in Acidic,Neutral, and Alkaline soils of Karnataka,South India

Several silicon (Si) sources have been reported to be effective in terms of their effectiveness on rice growth and yield. Apart from that, it is crucial to understand the bioavailability of silicon from different silicon sources for adequate plant uptake and its performances in varying types of soils. In this point of view, a pot experiment was conducted to assess the bioavailability of silicon from three Si sources and its effect on yield of rice crop in three contrasting soils. Acidic (pH 5.86), neutral (pH 7.10), and alkaline (pH 9.38) soils collected from different locations in Karnataka were amended with calcium silicate, diatomite, and rice husk biochar (RHB) as Si sources. Silica was applied at 0, 250, and 500 kg Si ha^?1, and the pots were maintained under submerged condition. There was a significant increase in the yield parameters such as panicle number pot^?1, panicle length pot^?1, straw dry weight pot^?1, and grain weight pot^?1 in acidic and neutral soils with the application of Si over no Si treatment, whereas only straw dry weight pot^?1 increased significantly with the application of Si sources over control in alkaline soil. Higher Si content and uptake was noticed in neutral soil followed by acidic and alkaline soils. The bioavailability of Si increased with the application of Si sources but varied based on the types of soil. Application of calcium silicate followed by diatomite performed better in acidic and neutral soils whereas RHB was a better source of Si in alkaline soil. A significant difference in plant-available silicon status of the soil was noticed with the application of Si sources over control in all three studied soils.