土壤有机质热性质初步研究

本文初步研究了我国4种主要土壤类型有机质的差热分析。这4种土壤在差热曲线上均出现低温放热峰(LEP,约300℃);黑土和黄棕壤同时还出现高温放热峰(HEP,约400℃)。通过分析证明这4种土壤的有机无机复合主要是通过铁等二、三价金属离子(不包括Al)化学吸附形成的,并提出400℃左右的HEP可以作为有机无机复合胶体通过表面物理吸附形成复合体的标志。砖红壤有比黄棕壤更大的化学吸附有机质形成复合体的能力。有机质通过相同机制与不同粒级的土壤矿物复合后,较粗粒级中的有机质有较高的能量水平。     

CHANGES IN THE CHEMICAL NATURE OF SOIL ORGANIC PHOSPHATE DURING PEDOGENESIS

In two chronosequences of soils, total organic phosphate (P₀) accumulated rapidly during the first 50 years of soil development, when organic matter increased and pH decreased. The rate of P₀ accumulation then declined with age of soil until a ‘steady state’ was reached. The amounts of phospholipid, inositol phosphates and humic acid—P₀ followed the same trends as the total P₀. Parent materials and very young soils contained largely citric acid-soluble P₀, but after less than 50 years, surface horizons accumulated sufficient organic matter to complex a considerable proportion of the P₀. An upper limit of 20–5 per cent citric acid-soluble P₀ and 70–80 per cent NaOH-soluble P₀ was attained within 50 years of soil formation in the surface layers, and this slowly extended down the profile so that, after 10000 years, the soil had 20 per cent citric acid soluble-P₀ and 70 per cent NaOH-soluble P₀ to a depth of 1 m.     

作物残体还田对赤红壤有机质状况的影响

闽东南沿海丘陵地上的赤红壤旱地存在着一个普遍的问题,即是农业生态环境较恶劣,土壤有机质的含量相当低,土壤肥力性状很差,这也是生产上急需解决的问题.为了保持和提高土壤库中物质和能量的贮量水平,提高土壤肥力[1-3],首先必须提高土壤有机质含量,这是土壤肥力的稳定指标.因此本试验试图寻找适合在沿海赤红壤上提高土壤有机质含量的几种途径,以便推广应用,从而提高作物产量增加经济效益.     

THE NATURE OF THE NITROGEN COMPOUNDS IN SOIL ORGANIC MATTER EXTRACTED BY ANHYDROUS FORMIC ACID

Organic matter extracted with 9 : 1 formic acid : acetylacetone from twenty-five soils of widely varying organic content and precipitated with excess di-isopropyl ether was hydrolysed with 6N HC1. The relationships between the proportions of acid-soluble N, acid-insoluble N, amino-N, and ammonium-N thus produced, and the properties of the original soil were examined. The distribution of N in acid hydrolysates was similar to that reported in the literature for material isolated by neutral and alkaline extractants. The relatively large proportion of N released as ammonium-N from organic matter obtained from soils of high pH and low C : N ratio may derive from organically fixed ammonia. The low levels of amino-N in organic matter extracted by formic acid from soils of high clay content imply the existence of clay-amino complexes that resist extraction although formation of such complexes during extraction cannot be ruled out.     

THE EFFECT OF SOIL FACTORS ON THE EXTRACTION OF SOIL ORGANIC MATTER BY ANHYDROUS FORMIC ACID

Twenty-five soils, having a wide range of organic matter contents, were extracted with anhydrous formic acid containing 10 per cent acetylacetone, and the extracted material precipitated in two fractions with diisopropyl ether. Precipitates comprised from 5.1 to 51.1 per cent of the original soil organic matter, the proportion extracted tending to be greatest from acid soils of fairly high organic matter content and least from neutral or slightly alkaline soils of low organic matter content. Soil clay content appeared to have no effect on the efficiency of organic matter extraction, but was the most important soil factor governing the proportion of the total soil-N extracted. Amounts of N extracted ranged from 10.2 to 57.8 per cent of the original soil N content, extraction efficiency being greatest with soils of low clay content and low pH. There was evidence to suggest that soil clay afforded some protection to N compounds against extraction. The results indicate that formic acid/acetylacetone is most effective with soils in which much of the organic matter is only partly humified.     

有机肥料对镉污染土壤的改良效应

通过培养与盆栽试验，研究了有机肥料对污染土壤中Ｃｄ的有效性、各形态及其生物活性的影响。结果表明，有机肥料的施用明显降低了土壤中有效性Ｃｄ的含量，其中猪粪效果优于秸秆类；有机肥料的施用促使交换态Ｃｄ向松结合有机态、锰氧化物结合态以转化。相关分析表明，土壤交换态Ｃｄ和松结合有机态Ｃｄ与土壤中有效态Ｃｄ、水稻地下部分含Ｃｄ成显著或极显著正相关。     

OCCURRENCE OF INOSITOL PHOSPHATES AND OTHER ORGANIC PHOSPHATE COMPONENTS IN AN ORGANIC COMPLEX

A calcareous organic soil was extracted by shaking with Na⁺-resin suspended in 0·2M acetyl acetone at pH 8·3. Fractionation of the fulvic acid on Sephadex G 25 gave (a) a high molecular-weight component which contained inositol tetraand hexa-phosphates and a sugar phosphate; (b) low molecular-weight components which included the mono-, di-, and triphosphate esters of inositol and two sugar phosphates, but no free inositol phosphates. Inositol phosphates and sugar phosphates accounted for 30·2 per cent and 16·6 per cent of the soil organic P respectively. Our evidence indicates that these phosphate esters exist in an organic complex.     

酸性水稻土有机磷分组法的探讨

本文研究了Ｂｏｗｍａｎ－Ｃｏｌｅ土壤有机磷有效性分组法应用于酸性水稻土所存在的若干问题。并在该法的基础上提出了一种改进法。结果表明：改进法比Ｂｏｗｍａｎ－Ｃｏｌｅ法能更好地将易矿化的（如ＲＮＡ，磷脂等），中度易矿化的（如植酸钙）和难矿化的（如植酸铁）有机磷化合物区分开来。改进法所测的结果比Ｂｏｗｍａｎ－Ｃｏｌｅ法提高了活性有机磷的数量和中度活性有机磷的质量，增加了稳定性有机磷应有的数量，改善了ＨＡ     

我国土壤有机质和有机肥料研究现状

本文简要的回顾了四十年来我国在土壤有机质的组成、性质、转化，有机肥对植物生长的直接作用和间接作用等方面的一些研究工作，讨论了有机质的组成、性质与成土因子的关系，指出了我国应坚持有机肥与无机肥配合的这一施肥制度。     

土壤中有机酸比色法测定的研究

对Montgomery(1962)比色法测定有机酸总量的方法作了若干改进。根据化学反应的平衡关系,将欲测试的土壤提取液水浴蒸干脱水,大大提高了有机酸的酯化程度,也就提高了测定的准确度。由于提取液浓缩至干,故测定一般可不受吸取的提取液体积和其中有机酸浓度高低的影响。结合温度、时间、pH等条件试验得到了测定的最佳条件。乙酸和丁酸的回收率分别可达99%和102%。几种有机肥料淹水培育10天用气相色谱测定的乙酸含量为本文提出的比色法测定总量的86%。采用这一方法测定土壤有机酸的量,可以在一定程度上反映有机物在土壤中腐解时产生有机酸的实际情况。     

DETERMINATION OF ORGANIC CARBON IN SOIL

The organic carbon contents of a range of soils and of various organic materials (mostly of plant origin) were determined by the titrimetric methods of Tinsley and Walkley and Black, and the results compared with those obtained by Shaw's wet combustion method. Tinsley's method gave more reliable results with soils than Walkley and Black's method, but neither is satisfactory for precise work. Both give high results with organic materials less oxidized than elemental carbon and low results with organic materials more oxidized, although this effect is masked with materials which do not react completely under Walkley and Black conditions. Quantitative results were obtained on a range of whole plant materials with both Tinsley's and Walkley and Black's methods. The latter thus provides a very rapid method for the determination of carbon in plants. The carbon contents, determined by Tinsley's method, of a range of pure organic compounds agreed with the predicted values. Tinsley's method does not give quantitative results with certain soils, partly because of the oxidation level of the organic matter in these soils and partly because oxidation is incomplete.     

水稻土的物理机械性质与机械化耕作的关系

土壤机械化耕作措施应当密切考虑土壤物理机械性质,这些性厦是随着土壤合水量而变化,从而影响耕作的难易。因此,从探求土壤适耕性出发,开展土壤物理机械性厦的研究是十分必要的。     

THE REMOVAL OF ORGANIC MATTER FROM SOIL EXTRACTS BY BROMINE OXIDATION

Brown-coloured extracts are frequently obtained when chemical dissolution techniques are applied to soils. The colour, arising from the presence of organic material, interferes in subsequent spectrophotometric determinations of extractable inorganic components. A bromine oxidation method for the complete removal of interfering organic matter has been devised. This involves the oxidation of the organic matter with alkaline bromine solution and the subsequent removal of excess bromine by acid and heat treatment. To test the effectiveness of the method extracts from chemical dissolution procedures, containing organic matter, were examined before and after bromine treatment by ultra-violet and infra-red adsorption and mass spectrometric techniques.     

APPLICATIONS OF NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY TO THE STUDY OF THE STRUCTURE OF SOIL ORGANIC MATTER

Recent developments in the application of nuclear magnetic resonance (n.m.r.) spectroscopy to soil science are reviewed. Progress in ¹H, ¹³C and CP-¹³C n.m.r. spectroscopy of humic substances is reported. Methods of determining the fraction of aromatic carbon in soil organic matter extracts are discussed, and methods by which structural group analysis can be carried out on in situ organic matter of whole soils are reviewed.     

有机肥料对土壤锌、锰有效性的影响

本文研究了厩肥、猪、牛、羊、鸡、鸭、兔、蚕粪等8种有机肥料的锌、锰总量及不同形态的含量,同时还研究了有机肥料及土壤中酶的活性,试验证明有机肥料是提供作物锌、锰营养的良好肥源,施用有机肥料可提高土壤锌、锰的有效性,但对土壤中锌、锰的有效化的影响和作用不同,有机肥供锰速度慢,强度小,伹在土壤中的残效长;而供锌强度大,速度快.有机肥与无机化肥配合施用,种植麦、稻两季作物后,在第三季的晚稻土壤中锌出现严重的亏缺.