等离子体制备纳米晶相氮化硅粉体的研究

为了提高氮化硅材料的弹性模量和烧结后的强度和韧度,通过感应耦合等离子体技术产生尘埃等离子体,采用SiH4和N2为反应气体,气相沉积Si3N4纳米粉体材料。利用朗缪尔探针技术测得沉积室中离子密度分布,获得气压为53Pa时,不同射频功率和不同位置处离子密度分布规律。通过TEM、IR和XRD技术对Si3N4纳米粉体材料微结构进行了分析。结果表明:尘埃等离子体技术制备的纳米Si3N4粉体材料为球形,均匀分布在20nm,并且具有β-Si3N4晶相。     

三种测定园艺作物硅含量方法的比较研究（英文）

硅是一种在植物生命活动中起着重要生理作用的元素,由于多数园艺植物中硅含量极低,因而测定其含量非常困难,在本研究中,将三种现存方法改进后应用于园艺作物硅含量的分析.结果发现,利用高压消煮法虽然具有不使用危险化学品HF的优点,但对于含硅量较低的园艺作物,例如苹果,梨等,其回收率低,测定结果不稳定.利用HCl-HF混合液振荡过夜抽提其中的硅后,再利用ICAP分析,可以明显提高Si分析的敏感性和准确性,故适用于各种园艺作物硅的测定.     

水淬渣与钢渣硅肥对玉米硅、磷养分吸收及产量的影响

硅作为有益元素对促进作物生长发育及增强抗逆性等方面有显著效果。本研究在2013—2014年进行了2年田间小区试验,对比研究了水淬渣硅肥和钢渣硅肥对玉米生长发育及产量的影响,分析了施硅对玉米硅、磷营养吸收及硅肥利用率的效应。结果表明:施硅可显著提高土壤有效硅含量(P0.05),如在抽雄、乳熟及成熟期水淬渣硅肥处理的土壤有效硅含量分别比不施硅肥处理(CK)处理提高36.9%、15.3%和9.7%;施硅处理均显著提高了玉米叶面积指数、干物质量和产量(P0.05),水淬渣和钢渣硅肥处理的玉米产量为17 979 kg/hm2和17 134 kg/hm2,分别比CK处理提高18.9%和13.3%。2年结果均显示硅肥处理显著提高了成熟期玉米植株的吸硅量与吸磷量(P0.05),水淬渣与钢渣硅肥处理的年均吸硅量分别比CK处理增加14.6%和10.4%,其年均吸磷量分别比CK处理增加11.5%和8.7%。玉米吸硅量与吸磷量呈极显著正相关(P0.01),硅肥处理可显著改善玉米生育期内磷素营养,提高磷肥偏生产力;水淬渣硅肥和钢渣硅肥年均硅肥利用率分别达38.9%和27.8%,且水淬渣硅肥利用率明显高于钢渣硅肥。     

硅对红富士苹果植株~(15)N-尿素吸收和分配特性的影响

以15年生红富士/八棱海棠为试材,运用同位素示踪技术研究了施用硅肥对苹果植株15N-尿素吸收、利用与分配特性及果实品质的影响。结果表明,施硅处理可以提高苹果植株果实等器官中15N的含量及植株对15N利用率,同时施用硅肥能够明显提高果实单果质量、可溶性固形物含量和硬度。在一定范围,随着硅肥施入量的增加,硅对果实品质的提高越有效。     

Decomposition of rice residue in tropical soils

Nitrogen mineralization and immobilization of rice residue in Maahas clay soil under lowland and upland conditions were investigated by using ¹⁵N-labelled rice straw. The mineralization of residue-nitrogen was taking place even though the net mineralization was depressed by incorporation of rice residue.

There were some significant differences in the pattern of nitrogen transformation between lowland and upland soil conditions. The nitrogen transformation measured by mineralization of soil nitrogen and rice-residue nitrogen and the nitrogen immobilization into rice residue were more active under lowland conditions than under upland conditions, during the earlier period of residue decomposition.     

Influence of boron on other chemical elements in alfalfa

Abstract

The objectives of this study were to determine the effect of three boron rates applied to the soil on the distribution and relative abundance of 12 chemical elements in various alfalfa plant parts at four successive stages of growth.

Plant samples were separated into lower leaves, lower stems, upper leaves, upper stems, and tips. These plant parts were analyzed for Zn, B, Fe, Mn, Mg, Ca, P, K, Na, Al, Si, and Cu.

Results of this study indicated: i. application of B to the soil resulted in increases in concentration of B in alfalfa tissue proportional to the rate of B applied. For most elements, a decrease in concentration was generally obtained when the rate of soil‐applied boron was increased from 6.3 to 12.6 kg/ha;

ii. a continual increase in the B concentration from early vegetative to bloom stage of growth and then, a decrease in the B concentration from bloom to seed set was observed for the entire alfalfa plant;

iii. the concentration of an element found in leaf tissue was generally greater than the concentration in stem tissue. Furthermore, the concentration of an element found in the lower leaves was generally greater than the concentration found in the upper leaves.

     

Release of silicon from rice straw under flooded conditions

It is estimated that nearly 20 kg of SiO₂ is removed from the soil by rice plants for producing 100 kg brown rice (Takahashi 1987). Although there is a large amount of silicon in soil, little is available to the rice plant. To supply a sufficient amount of silicon to the rice plant for healthy growth, therefore, it is nccessary to supply various silicon materials to the soil. Rice straw application to the soil is one of the means.     

Silicon pools and fluxes in soils and landscapes—a review

Silicon (Si) is the second‐most abundant element in the earth's crust. In the pedosphere, however, huge spans of Si contents occur mainly caused by Si redistribution in soil profiles and landscapes. Here, we summarize the current knowledge on the different pools and fluxes of Si in soils and terrestrial biogeosystems. Weathering and subsequent release of soluble Si may lead to (1) secondarily bound Si in newly formed Al silicates, (2) amorphous silica precipitation on surfaces of other minerals, (3) plant uptake, formation of phytogenic Si, and subsequent retranslocation to soils, (4) translocation within soil profiles and formation of new horizons, or (5) translocation out of soils (desilication). The research carried out hitherto focused on the participation of Si in weathering processes, especially in clay neoformation, buffering mechanisms for acids in soils or chemical denudation of landscapes. There are, however, only few investigations on the characteristics and controls of the low‐crystalline, almost pure silica compounds formed during pedogenesis. Further, there is strong demand to improve the knowledge of (micro)biological and rhizosphere processes contributing to Si mobilization, plant uptake, and formation of phytogenic Si in plants, and release due to microbial decomposition. The contribution of the biogenic Si sources to Si redistribution within soil profiles and desilication remains unknown concerning the pools, rates, processes, and driving forces. Comprehensive studies considering soil hydrological, chemical, and biological processes as well as their interactions at the scale of pedons and landscapes are necessary to make up and model the Si balance and to couple terrestrial processes with Si cycle of limnic, fluvial, or marine biogeosystems.     

Effects of slag silicate fertilizer on silicon content of rice plants grown in paddy fields on the Shounai Plain,Yamagata, Japan

Abstract

Slag silicate fertilizer (SSF) is applied to paddy fields with different soil chemical properties to increase silicon (Si) concentration in rice (Oryza sativa L.) plants. However, the effects of soil chemical properties on Si availability of SSF to rice Si uptake is poorly understood. To investigate the relationships between chemical properties of soils and the effects of SSF application on the Si concentration in rice plants, a field experiment was conducted in 2007 and 2008 at 18 paddy fields on the Shounai Plain, Yamagata, Japan. Two treatments were implemented: SSF applied at 1.5 t ha^?1 and a no-SSF control. The Si concentrations of rice tissues were measured at the tillering and ripening stages. The difference in the Si concentrations of rice tissues between treatments (ΔSi concentration) was used to evaluate the effect of SSF. The Si concentrations in the shoots and aboveground parts of the rice plants were significantly increased by the SSF application in six or more of the fields at the two growth stages, whereas the Si concentrations in the panicles of the rice plants at the ripening stage were not increased significantly in most fields. Results of two-way analysis of variance evidenced a significant effect of field on the ΔSi concentrations in the shoots and aboveground parts at both growth stages. Furthermore, the ΔSi concentrations in the same rice plant tissues and at the same growth stages in the first year and in the second year were found to be positively correlated. These results indicate that the effect of SSF on the Si concentration in shoots and aboveground parts of rice plants varies from field to field. The ΔSi concentrations in shoots and aboveground plant parts at both growth stages were also found to be negatively correlated with soil chemical properties, i.e., available Si, Si adsorption capacity, contents of Si adsorbents (acid oxalate-extractable iron and manganese) and the pH under flooded soil conditions. These findings imply that those soil chemical properties of paddy fields should be taken into account for better prediction of ΔSi concentration of rice plants.     

北方酸性水稻土上氮磷硅肥配施对水稻产量影响的研究

用盆栽的方法,采用三因素五水平D-饱和优化设计,以采自于辽宁东部的酸性水稻土为供试土壤。对氮、磷、硅肥用量与水稻产量之间的关系进行研究,建立了水稻产量函数模型;结果表明,氮、磷、硅肥均能显著地影响水稻产量,其作用大小依次为氮肥>磷肥>硅肥,获得最高产量的施肥方案N、P2O5和SiO2分别为0.248、0.129和0.0001g/kg土。