Evaluation of levels and methods of zinc application to rice in sodic soils

Field experiments were conducted in zinc-deficient sodic soil to study the effect of levels and methods of zinc fertilization on yield, concentration and uptake of zinc by rice. Zinc was incorporated in the soil at the rate of 0, 5.6, 11.2 and 22.4 kg Zn per ha as zinc sulfate; sprayed on the plants at 1% and 2% zinc sulfate solution; and roots of rice seedlings were dipped in 2% and 4% ZnO suspensions in water. Grain yield, zinc content and its uptake increased in all the experiments up to 22.4 kg Zn per ha. Soil applied zinc was significantly correlated with yield of rice (r = 0.80^**) and zinc uptake (r = 0.89^**). Zinc content in 45-day old plants gave a significantly higher correlation with grain yield (r = 0.84^**) than the zinc content of rice straw and grain at maturity. Roots of rice seedlings dipped in 2% or 4% zinc oxide suspension in water were not only comparable with soil application of Zn at 5.6 and 11.2 kg Zn per ha, but also proved to be more economical for sodic soils showing moderate zinc deficiency.     

Zinc diffusion and extractability as affected by zinc carrier and soil chemical properties

This work was carried out to evaluate the effect of soil chemical properties, Zn carrier and time elapsed after fertilizer application on the diffusion and extractability of Zn. A soil block technique was used to study zinc diffusion and DTPA extractability from ZnEDTA and ZnSO₄ fertilizers in three soils that varied in texture, CaCO₃ content, organic matter content, and pH using Zn⁶⁵ tracer. ZnEDTA diffused readily in all soils, moving 20–25 mm from the fertilizer layer after three days. The rate of Zn diffusion and the extractability of Zn, however, varied among the soils and were lowest in Baha soil with the highest clay content, organic matter, and CEC despite its lower pH. The high pH and CaCO₃ content in Dirab soil did not restrict the diffusion or reduce the extractability of ZnEDTA in this soil. On the other hand, the diffusion of Zn from ZnSO₄ fertilizer was largely restricted in all soils and was confined to 5 mm from the fertilizer layer after 13 d. The extractability of ZnSO₄ fertilizer was largely affected by soil pH and CaCO₃ content and was lowest in Dirab calcareous soil. Organic matter amendment at 5% (as alfalfa) considerably reduced the diffusion and the extractability of ZnSO₄ in both Dirab calcareous and Bakyria noncalcareous soils. The application of 1% (w/w) elemental S reduced soil pH and increased Zn diffusion from ZnSO₄ fertilizer in Bakyria soil but had slight effect on Dirab calcareous soil.     

二甲酚橙光度法测定葡萄糖酸锌中锌含量

在pH=5~6弱酸性条件下,锌和二甲酚橙反应形成稳定的橙红色配合物,最大吸收波长为568 nm,锌含量在0~2.5μg/mL范围内与吸光度呈良好的线性关系。方法用于测定葡萄糖酸锌中锌含量,结果满意。     

EDTA容量法测定氧化锌锡粉末材料中的锌

采用 EDTA容量法测定氧化锌锡粉末中的锌含量.以酒石酸为掩蔽剂掩蔽锡,用氨水调节pH值并加入六亚甲基四胺-HCl缓冲溶液,将pH值控制在 5.10,以二甲酚橙为指示剂直接滴定锌.锌的回收率在97.6%～100.5%之间,标准偏差和相对标准偏差都符合分析要求.     

差示扫描量热法测定锌粉和富锌底漆中的锌含量

采用差示扫描量热法（DSC）测定了锌粉与富锌底漆中的金属锌含量。分析了测试过程中可能出现测定误差的原因,提出了提高分析精度的方法。     

离子软硬度对锌合金电沉积的影响

一般说来,金属离子的电沉积基本上决定于金属与相应离子的电极电位,但是在混合离子溶液中有时会遇到电极电位较负的金属优先析出的“异常现象”.作者利用循环伏安法测定了混合溶液的析出电位.并根据离子的软酸碱原理计算了Ahrland标度.对比这个标度,发现金属离子的电沉积不仅与它们的电极电位有关,还与它们的软硬度有关.提出了软度较大的金属离子在双电层中更加贴近阴极的假设.     

火焰原子吸收光谱法测定硫酸锌中的铁

采用火焰原子吸收光谱法测定硫酸锌中的微量的铁,考察了HCl、SO42-对测定的影响。在选定条件下,方法线性相关系数为0.9998,检测限为0.0072mg/L,标准偏差为0.0008,变异系数为2.0%,回收率为95.2%～104.8%。     

Experimental study and PC-SAFT simulations of sorption equilibria in polystyrene

The knowledge of sorption equilibria of blowing agents in polystyrene (PS) is necessary for the optimization of PS foam production. The sorption equilibria were studied experimentally using a gravimetric apparatus and simulated by the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state. As chlorinated and fluorinated hydrocarbons are being phased out, alternative blowing agents are important. We place emphasis on n-pentane, as sorption data for the PS+n-pentane system are scarce in the literature. The measured n-pentane and iso-pentane sorption isotherms were used to evaluate the PC-SAFT binary interaction parameters. The sorption of CO₂, N₂ and He in PS was also studied. Cosorption of pentanes in PS was predicted and comparison of the results with our experimental data proved good performance of the PC-SAFT model. The industrially interesting sorption enhancement and inhibition effects were studied using both experimental and simulated ternary data.     

Deep Purification of Zinc Ammoniacal Leaching Solution by Cementation with Zinc Dust

Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied.The effects of relative amount of metallic impurities,dosage of zinc dust,purification time,temperature,pH value and total ammonia concentration in the solution on the purification of the solution were investigated.The results indicate that total ammonia concentration in the solution had no effect on the purification,but relative amount of metallic impurities,dosage of zinc dust,purification time,temperature and pH value of the solution were the main factors influencing the purification.Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium.Nevertheless,the presence of cobalt went against the cementation of cadmium and cobalt.All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage,1 h of purification time,35℃,pH value 9.03 of zinc ammoniacal leaching solution.The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.     

二氧化碳和醇类体系相平衡的研究进展

CO2和醇类混合物的高压相平衡是化工、食品及药品工业设计和运行过程中的基础数据。笔者对CO2-醇类二元体系相平衡的实验测定和理论模型方面的进展进行了总结,并分析了适用于CO2和醇类体系高压相平衡计算的交叉缔合模型的发展方向。     

Burning of a Cotton Fabric Impregnated by Synthetic Zinc Carbonate Hydroxide as a Flame Retardant

Zinc carbonate hydroxide [ZnCO₃·Zn(OH)₂] synthesized by means of the multiple-bath method was deposited onto a cotton fabric, and its uniformity was ensured by means of squeeze rolls. Prolonged burning was observed on treated specimens: 200.5 sec for 20.20% of ZnCO₃·Zn(OH)₂ added to 100 g of a dry fabric increased to 337.5 sec for a 45.39% addition. The ashes of the treated specimens were subjected to X-ray diffraction analysis, and the result was compared with data for zinc and zinc-oxide powders. The existence of zinc oxide was detected in the ashes, but no traces of the metallic zinc were discovered. Therefore, it can plausibly be assumed that a reduction-oxidation reaction occurs during the smoldering process.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 4, pp. 73–77, July–August, 2005.     

Chemical assessment of the zinc status of some soils of the semi-arid region of India

To find critical tissue levels of Zn for wheat, and to evaluate various chemical extractants, a screen-house experiment was conducted on 21 diverse soils representing semi-arid regions in Haryana State, India. The extractants differed in the amounts of Zn extracted and the order was: 0.1 N HC1 > EDTA-NH₄OAc > EDTA-(NH₄)₂CO₃ > DTPA + CaCl₂. The amounts (mg kg^–1) of extractable Zn associated with a yield reduction of 20% were: DTPA + CaCl₂, 0.60; EDTA — (NH₄)₂CO₃, 0.80; EDTA-NH₄OAc, 0.92 and 0.1 N HCl, 1.20. The corresponding critical Zn concentration in ten weeks old plants was found to be 17 mg gm^–1. The DTPA + CaCl₂ method gave the best correlation (r = 0.85) between extracted Zn and Bray's per cent yield. It is recommended for assessing Zn status of soils of semi-arid region.     

氯化锌催化合成二异亚丙基-D-甘露醇

以甘露醇为原料,氯化锌作催化剂合成二异亚丙基-D-甘露醇,考察了影响反应的因素,结果表明反应的最佳条件为:n(D-甘露醇)∶n(丙酮)∶n(氯化锌)=1∶21·4∶1·85,反应温度为30~35℃,反应时间12h,产率可达62·8%。     

Organic and inorganic phosphorus forms in soil as affected by long-term application of organic amendments

Organic amendments contribute significantly to the phosphorus (P) supply in agroecosystems. However, their long-term effects on specific P forms in soils are not completely understood. The objective of this study was to investigate the concentration of organic P forms and inorganic P pools in soil and the activity of enzymes involved in the P turnover in a long-term field experiment running since 1998 in Northern Germany as affected by P amendments. The following treatments with different P supplies were sampled in 2012, 14 years after the establishment of the experiment: control (no P), cattle manure (manure), biowaste compost (compost), and biowaste compost in combination with triple-superphosphate (compost + TSP). The classification of organic P forms by using enzyme additions to NaOH–EDTA soil extracts showed non-hydrolyzable organic P as the dominant form in soil followed by inositol hexakisphosphate (Ins6P)-like P. Non-hydrolyzable and total organic P concentrations in soil were highest in the combined compost + TSP treatment, which received the highest amount of inorganic P. The values of the bioavailable P pools (water-extractable P and double lactate-extractable P) were in accordance with the P balance (P addition with the amendments minus P removal with harvested crops) independently of the type of amendment. The results of this research suggest that the distribution of soil P forms is more reliant on the turnover processes in the soil than on the forms of P added.     

An economic evaluation of a long-term experiment on phosphorus and manure amendments to sandy Sahelian soils: Using a stochastic dominance model

Poor fertility status of sandy Sahelian soils represents a major constraint to cereal and legume production. Soil amendment options were evaluated, using a stochastic efficiency framework. Dominance analyses showed that in the presence of annual applications of 30 kg N ha^–1 and 30 kg K ha^–1, efficient soil amendment options comprise of either the annual application of 8.7 kg P ha^–1 in the form of single superphosphates in combination with 5 tonnes manure ha^–1 applied every three years or the annual application of 17.5 kg P ha^–1 in the form of single superphosphates. Choice between these two efficient options depends on the availability of manure, deficiencies in sandy soils and farmer resource endowments.Submitted as JA no. 1133 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).     

利用氯化锌废泥渣生产硫酸锌的研究

以合锌废泥渣和硫酸为原料生产工业级硫酸锌，经试验锌利用率90％以上，硫酸锌质量达到HG／T2326－92标准的要求。     

氢化物发生—流动注射电热原子吸收法测定电解锌溶液中的微量砷,锑

采用氢化物发生—流动注射电热原子吸收光谱分析测定湿法冶金过程中电解锌溶液中的微量砷、锑。其灵敏度可达：Ａｓ为０．０００８μｇ／ｍｌ、Ｓｂ为０．０００６μｇ／ｍｌ。线性范围是：０～０．１μｇ／ｍｌ     

无氰碱性镀锌溶液中锌的分析方法

制定了测定无氰碱性镀锌溶液中锌质量浓度的新方法。在p H=10的条件下用三乙醇胺掩蔽镀液中的铁和铝杂质,以铬黑T作指示剂,用EDTA标准滴定溶液滴定锌。实验表明,方法的相对平均偏差为0.2%,回收率为99.12%。与以氰化钾作掩蔽剂的测定方法相比,该方法简单,操作安全,无污染。     

利用低品位含锌原料湿法制取氧化锌的研究

探索了利用低品位含锌原料采用湿法直接制取氧化锌产品，技术关键是提高浸出率和净化除杂。     

一步法制备硬脂酸锌的研究

采用一步法工艺制备硬脂酸锌,适宜的工艺条件为:采用乙酸作为催化剂,加入量为硬脂酸质量的1%,控制反应物n(氧化锌):n(硬脂酸)为1.03:2,液固比为6:1,反应温度70℃,反应时间90 min,该工艺制备的硬脂酸锌理化性能达到优级品要求,生产工艺较复分解法在节能环保方面更优。