Potassium uptake and requirement in organic grassland farming

Use of mineral fertilizers is restricted in organic farming. The aim of the present paper was therefore to study whether potassium (K) limits yields in Norwegian organic grasslands. The K status in soil and herbage on 26 organic farms was investigated, and the response to K application in six fertilization experiments was explored. Further, the relationship between soil K analyses and K release from soil was examined. K application to grassland on the investigated farms was generally low, giving negative field K balances on 23 of the farms. The soils were classified as low or intermediate in readily available K (K_AL) on 23 of the farms. The mean K concentration for herbage samples from the first cut on these farms was 18.0 g K kg⁻¹ dry matter. In fertilization experiments, K application increased the K concentration in herbage. However, there was no significant effect on yield, even when K concentration in herbage on plots without K application was low. The lack of significant yield response to K application can be explained by low amounts of crop-available nitrogen (N). There was a tendency for increased plant uptake from reserve K with increasing values of acid soluble K (K–HNO₃) in soil. Separate K analyses of timothy (Phleum pratense) and red clover (Trifolium pratense) revealed that red clover showed better competitiveness for K than timothy in leys where N supply was limited.     

Guano as a nitrogen source for fertigation in organic farming

Guano is a natural organic fertilizer used in organic farming management when supplementary nitrogen is needed. In modern irrigated agriculture N top dressing is often applied through the irrigation water. The objective of this research was to evaluate the potential of guano as a source of available N when applied through water, compared with application to soil. The release of mineral and total soluble N from guano to water was monitored, as a function of time, under laboratory conditions, and compared with mineralization of guano in soils. The effect of guano:water ratio, aeration of the mixtures, addition of rock-phosphate or clay minerals, and temperature on the composition of the solutions was determined. Guano released more than 90% of its N content into solution during 10 d at a guano:water ratio of 1:10 at 27°C. The release of soluble N, of which 85% was NH₄-N, was linked with an increase of pH from 7.0 to 8.5 or more. None of the treatments increased the rate or the total N release beyond that. Suboptimal temperatures, 13.6 ± 4.7°C or 50°C, greatly reduced the rate of guano-N release to solution. The mineralization of guano in soil was more rapid than in water, but the total N release was the same, leading to the conclusion that the application of guano through the irrigation water may be as efficient as directly to soil, provided sufficient time for fermentation is allowed.Contribution from the ARO, The Volcani Center, Bet Dagan 50250, Israel, no. 3290-E, 1991 series.     

双极性材料在有机太阳能电池领域的应用

双极性材料以其低能隙、宽吸收、高电子传导率和较高稳定性的优势成为增强有机太阳能电池性能的优良材料。研究显示,双极性材料不但能够作为有机光伏器件中的给体材料和受体材料,还能作为辅助添加剂来增加电池的能量转化效率。     

Active nonwoven carbon-based material in the analysis of organic water pollutants

The use of active nonwoven carbon-based material in the analysis of organic water pollutants is considered. The initial (commercial) carbon material requires careful preliminary removal of microimpurities (aliphatic compounds and phthalates).     

Phosphorus budget and phosphorus availability in soils under organic and conventional farming

The aim of this work was to assess to which extent organic farming practices would affect the accumulation of total and available phosphorus (P) in a cropped soil in comparison to conventional practices. In order to achieve this, soil samples were taken from a long-term field trial comparing a non-fertilised control (NON), two conventionally cultivated treatments (MIN, CON), and two organically cultivated treatments (ORG, DYN). Soil samples were taken from each treatment at two depths (0-20 and 30-50 cm) before starting the field trial (1977) and at the end of every three crop rotations (1984, 1991 and 1998). They were then analysed for total P (P_t), total inorganic P (P_i), total organic P (P_o) and isotopically exchangeable P_i. After 21 years, the average P input-output budget reached -20.9 kg P ha^–1 a^–1 for NON, -7.8 for DYN, -5.7 for ORG, -5.0 for MIN and +3.8 for CON. Total P, P_i as well as the amount of P_i isotopically exchangeable within 1 minute (E₁) were positively correlated to the P budget. Comparison between P budget and P_t in the top- and subsoils of the fertilised treatments suggested a net transfer of P from the 0–20 to the 30–50 cm layers between 13 and 26 kg P ha^–1 a^–1during the first rotation and between 3 and 12 kg P ha^–1 a^–1during the second rotation. During the third rotation a net upward movement of P from the subsurface to the topsoil ranging between 3.7 and 10.5 kg P ha^–1 a^–1was estimated. In the topsoil, E₁decreased from an initial value of 12 mg P kg^–1 to 11 in CON, 8 in MIN, 6 in ORG, 5 in DYN and 2 in NON after 21 years. In the subsoil, E₁ increased from an initial value of 2 mg P kg^–1 to 4 in MIN, ORG, DYN and NON and to 6 in CON. These results show that, with the exception of NON, all treatments had still an adequate level of available P after 21 years of trial and that, in this low to moderately P sorbing soil, an equilibrated input-output budget allows to maintain P availability at a constant level. In the organic systems, yields have so far partly been attained at the expense of soil reserves or residual P from earlier fertiliser applications.     

有机／无机纳米复合材料的制备方法

综述了近年来国内外有机/无机纳米复合材料的制备方法及其最新进展情况。     

Application of reactive phosphate rock and sulphur fertilisers to enhance the availability of soil phosphate in organic farming

Plant available soil phosphate is frequently deficient for crop and pasture production on organic farms in southern Australia. Improved P management, including developing a fertiliser product conforming to organic farming regulations, is required to sustain and increase production on these farms. Reactive phosphate rock (RPR) and elemental sulphur (S) are natural products. Field and pot experiments were established to measure the impact of ground RPR, and co-treatment of RPR with finely ground S, on available soil phosphate (Olsen P), plant dry matter, and the P concentration (%) and content (kg P ha⁻¹) of the dry matter. Under dry-land field conditions characteristic of cropping regions in southern Australia ( < 600 mm rainfall, organic carbon < 3%), co-treatment of RPR with S was necessary to increase Olsen P, and higher values of Olsen P were generally associated with increased plant dry matter, together with P concentration or P content of the dry matter. The required amount of S was less the more acidic the soil, but greater than reported as being effective in situations of higher rainfall ( > 1,000 mm) and soil organic carbon concentration (OC 11%). It was deduced that the S is probably required to overcome the constraint on dissolution of RPR resulting from frequent periods of low soil moisture. It was concluded that for the south-eastern Australian cropping zone, co-treatment of ground reactive phosphate rock with finely ground elemental S, at ratios (RPR:S) of at least 2:1, depending on soil pH, is required for effective use␣of RPR, even in strongly acidic soil (pH_Ca < 4.5). It was recommended that ‘organic’ farmers may recover soil P fertility by applying RPR + S fertiliser to the most acidic fields, postponing soil liming, and managing the fields to conserve soil moisture.     

Hole injection improvement by doping of organic material in copper phthalocyanine

Hole injection properties of copper phthalocyanine (CuPc) layer doped with hexaazatriphenylene–hexacarbonitrile (HAT) were studied by changing the doping concentration of HAT. Hole injection efficiency of CuPc layer was improved by doping of HAT as a p-dopant and a maximum current density was obtained at a HAT doping concentration of 10%. The use of HAT doped CuPc layer as a hole injection layer improved the current efficiency of green phosphorescent organic light-emitting diodes.     

Some aspects of the role of organic matter in sustainable intensified arable farming systems in the West-African semi-arid-tropics (SAT)

In this paper the role of organic manure in intensified farming systems in the SAT of West-Africa is discussed. Different aspects are treated: its function as a source of plant nutrients, its effects on soil physical and on soil chemical properties. It is concluded that often the major effect is through increased nutrient supply, but that in combination with chemical fertilizer — particularly nitrogen — it serves to counteract the negative effects of these fertilizers, particularly acidification and the increased removal of nutrients other than the one applied in the fertilizer.Insufficient organic material appears to be available to realize the required production increase and prevent the negative effects of nitrogen fertilizers. However, application of chemical fertilizer alone can lead to sustainable production systems provided export and losses of all nutrient elements are sufficiently compensated and acidification is avoided by using the correct type of nitrogen fertilizer, possibly in combination with liming.     

某些有机氯产品转换原料路线势在必行

回顾了有机化工原料路线的转变过程,比较了某些有机氯产品国内生产工艺及规模与发达国家先进工艺间的差距,指出国内企业转换这些有机氯产品的原料路线势在必行。     

Long-term soil accumulation of potentially toxic elements and selected organic pollutants through application of recycled phosphorus fertilizers for organic farming conditions

The pollutant input and the risk of contamination by long-term application of recycled P fertilizers (RPFs) in European agricultural soils were estimated by a mass balance approach. Calculations based on literature data were carried out for the potentially toxic elements (PTEs) Cd, Cr, Cu, Ni, Pb, Zn and for the persistent organic pollutants (POPs) PCBs, PAHs and polychlorinated dibenzo-dioxins and -furans. The PTE accumulation estimation during 200 years of fertilizer application, equivalent to 11 kg P ha^?1 year^?1, the mean P export via harvested products on European stockless organic farms, regarded soil background concentrations and proposed threshold concentrations. For PTEs, inputs were fertilizer application, atmospheric deposition and liming, output processes were leaching and crop harvest. The effect of varying site conditions was assessed by considering two precipitation excess (F) values and two soil pH values. For POPs, fertilizer application and the half-life time were considered. The PTE accumulation risk was low for most RPFs. For the analysed POPs no accumulation was found. The highest accumulation was found for all PTEs at pH 7 and F = 0.1 m year^?1, the lowest at pH 5 and F = 0.3 m year^?1. A high P concentration in fertilizers resulted in a low PTE flow per unit of P. Composts had the highest PTE accumulation risk due to lowest P contents. Struvite, meat and bone meal, digestate of catering waste, ash and biosolids would be better suited as P fertilizers. The use of fertilizers should be regulated based on their pollutant-to-nutrient ratio.     

绿色有机电致发光材料C545T合成工艺研究

研究了绿色有机电致发光材料C545T的合成工艺。以价格较便宜的1-溴-3-甲基-2-丁烯代替1-氯-3-甲基-2-丁烯,降低了原料价格,提高了产品收率;其次,中间体2-苯并噻唑乙酸乙酯的合成采用微波法代替传统的加热反应法,缩短了反应时间,提高了产品收率;另外,最后一步的Knovenagel反应采用有机碱哌啶作催化剂,也缩短了反应时间,提高了产品收率。该合成工艺生产周期短,反应条件温和,纯化过程简单,合成成本低,六步合成总收率达8.2%,产品纯度达99.9%。     

有机厂氨氮废水处理技术达标与回收物料的研究及应用

介绍了水合肼生产氨氮废水处理达标技术,研究了BH型高效填料在有机厂氨氮废水处理老系统改建中的应用。结果表明:利用物理方法通过气提方式,可以在提馏段将NH3从废水中气提出来,在精馏段通过精馏将有机物料浓缩,使塔顶NH3含量达到4%～8%,达到回收利用的目的;塔底废水中NH3含量降至20～50 mg/L,达到并超过排放要求,此水达到纯净程度,可以回收利用。     

Bioethanol production by inherent enzymes from rye and wheat with addition of organic farming cheese whey

In organic farming, there is a strong effort to minimize the share of non-renewable resources (e.g. fossil fuels) and use only (preferably on-farm produced) bio-based energy and renewable raw materials, with the aim of achieving sustainable production systems and to become self-sufficient in energy.Throughout our studies, wheat and rye grain was used as raw material in bioethanol production with the purpose of producing in situ enzymes (during germination) for the hydrolysis of starch in the grains and compared with commercial amylase enzyme preparations. Whey permeate was incorporated into the grain in Simultaneous Saccharification and Fermentation (SSF) process to use a cheap nutrient and water source. The ethanol fermentations were completed by 190 h. The fermentation efficiency of germinated and un-germinated grains (without commercial enzymes) was compared with that of commercial enzymes in SSF and furthermore Autoamylolytical Quotient (AAQ) was calculated. On rye 72% yield of the theoretical was achieved by applying commercial enzymes, which decreased only by 10%, when in situ enzymes produced during germination were used alone. The obtained ethanol yields and high (90%) AAQ values showed that rye is a suitable substrate for autoamylolytical processes. According to the low yields (<56%) and AAQs values for all examined wheat samples the results implied that the tested sorts of wheat grains were no efficient for use in autoamylolytical processes.     

一种可逆热致变色材料的制备及微胶囊化研究

以隐色染料结晶紫内酯、溶剂十六醇、显色剂对羟基苯甲酸苄酯为原料制备有机类可逆热致变色材料,并确定了隐色染料、显色剂和溶剂的最佳配比为1：3：30。在可逆热致变色材料中,溶剂主要决定可逆热致变色材料的变色温度,显色剂主要决定可逆热致变色材料颜色的深浅,隐色染料本身决定了可逆热致变色材料的颜色及隐定性等性能。微胶囊化结果表明,微胶囊产品能增强可逆热致变色材料的热稳定性,可增加材料的抗溶剂性,且材料不易流失。     

可逆热致变色材料的微胶囊包封及性能研究

用环氧树脂E-12作壁材,低分子聚酰胺200为固化剂,采用原位聚合法,对可逆热致变色有机复配物进行微胶囊包封,用SEM和TGA测定了微胶囊的形态结构和热行为。研究包封条件对微胶囊结构和性能的影响,结果表明,最合适的反应条件是:壁材与变色芯材质量比为0.2~0.6,乳化温度50℃,固化反应分5段升温。此条件下可以制得结构致密完整、具有良好透明性、耐热性和耐溶剂性的变色微胶囊,能满足纺织品涂料印花的要求,微胶囊粒径在5μm以下。