黄土地区非代换性钾与土壤发育的关系

黄土地区土壤类型和发育程度与土壤非代换性钾有关。本文初步研究了黄土地区主要土壤类型非代换性钾的变化。影响土壤非代换性钾含量和释放累积量的主要因素是土壤质地和有机质。粉砂粒、粘粒和有机质与非代换性钾呈正相关,而砂粒与非代换性钾呈负相关。土壤非代换性钾含量由北向南从66.71-84.62增到117.09-129.95mg/100g土;释放累积量由北向南从147.03-173.00增到251.18-346.08mg/100g土。说明黄土地区土壤非代换性钾的含量和释放累积量均从北向南逐渐增加。砂绵土和黄绵土,砂黑垆土和轻黑垆土的非代换性钾含量和释放累积量其剖面分布较均一;而粘黑垆土和黑(土娄)土的粘化层的非代换性钾含量和释放累积量高于耕作层和母质层,但因地形部位不同又存有一定差异。     

棉花钾素营养与土壤钾素供应水平

大田试验和田间调查分别在杭州浙江农业大学实验农场黄松土(Semihy dromorphic soil)和金华盆地红壤上进行.品种分别为钱江9号和协作2号,这两处土壤有效钾含量均较低,棉花(Gosoypium hirsutum L.)生长不良,普遍早衰.根据土壤中交换性钾的含量与棉花生长情况,一般可分为四类:土壤交换性钾>90ppm,棉花生长正常,70-90ppm,潜在缺钾;<70ppm,明显缺钾;<50ppm,严重缺钾.棉花叶片含钾量与土壤交换性钾含量呈正相关,r=0.928,显著性超过1%水准.大田试验表明,施用钾肥能提高棉花叶片含钾量,增加叶面积和叶绿素含量以及CO₂的同化率;钾还能促进叶片中细胞色素氧化酶和硝酸还原酶的活性,提高气孔导度,降低水分的蒸腾速率.缺钾叶片结构松弛,角质层发育不良;正常叶片结构紧密,角质层发育良好.叶片含钾量无论在苗期、初花期、盛花期、花铃期,均与皮棉产量呈正相关,达到显著水准.     

黄土区土壤钾的形态及其释放

本文研究了黄土区（陕西部分）土壤钾的形态,按毫克/100克土计,有机钾0.36-5.04,水溶性钾0.24-2.37,代换性钾3.61-16.96,有效钾3.85-19.33,非代换性钾64.45-149.77,结构钾1,840.3-2.538.3,全钾为1.920-2.640。有效钾为非代换性钾的11.42%,结构钾的0.53%和全钾的0.51%。水溶性钾和代换性钾分别是有效钾的8.2%和91.8%。通过主成分分析可知,土壤各种形态的钾与有机质呈正相关:水溶性钾、代换性钾、非代换性钾与有机态钾,代换性钾和非代换性钾与粉粒和粘粒也呈正相关,但都与沙粒呈负相关.钾的释放符合于幂回归方程（y=ax^-b）.释放量从北向南是逐渐增加的.幼年土壤和轻黑垆土耕作层释放量高于其他层次,但是粘黑垆土和黑土的粘化层的释放量高于其它层次。     

黄土区土壤腐殖物质的化学性质及其与成土条件的关系

土壤腐殖质是土壤发生、发育的结果,是土壤区别于成土母质的主要标志。特定的生物气候条件(以及其它成土条件)形成特定的土壤类型,也形成具有特定性质的土壤腐殖质。因此,研究土壤中腐殖物质的组成、特性可以在一定程度上估计土壤生物活动的强弱与成土过程的趋向,从而为土壤分类提供重要的依据。     

THE POTASSIUM STATUS OF MALAWI SOILS

Twenty surface soils from four main Soil Groups in Malawi and their sub-soils were divided into three groups based on cation exchange capacity (group I, CEC < 50; group II, 50–100; and group III > 100μeq g^–1). In each soil group the maximum amounts of K removed by successive extraction with 0.005 M CaCl₂ solution were well related to the potassium potential pK–0.5p(Ca + Mg), exchangeable K, ‘step K’, and the quotient ‘step K’/CR.K, where CR.K is ‘constant-rate’potassium. In Group III soils only, ‘step K’/CR.K values were significantly correlated with pH, clay, and CEC, and this suggested that the soils were relatively rich in K⁺ specific binding sites. In 27 soils from an NPK factorial experiment on tea, the rate of depletion of extractable K reserve increased with ammonium sulphate treatment, whereas K fertilizers tended to off-set significantly (P= 0.001) the depletion of K reserve. The values for the change in free energy ΔG =RT In a_K/ (a_(Ca+Mg)) ^½, ranged from –12 to –16 kJ mol^–1, and field observations showed that tea plants growing on soils having ΔG values less than –15 kJ mol^–1 responded to K fertilizers. The investigation has indicated that heavily cropped soils are likely to show crop responses if the intensive cropping system does not include supplementation of K.     

ACCUMULATION OF ORGANIC MATTER IN A CHRONOSEQUENCE OF SOILS DEVELOPED ON WIND-BLOWN SAND IN NEW ZEALAND

A study was made of the amounts and distribution of C, N, S, and organic P accumulated over a period of 10 000 years of soil development on wind-blown sand. After initial rapid rates of accumulation of C, N, and organic P during the first 1000 years, subsequent rates of gain were slower, but steady states for C, N, and S had still not been reached after 10 000 years. Sulphur declined during the first 50 years of soil development but then increased in a parallel fashion to organic C. During 10 000 years, gains of organic C, total N, total S, and organic P were 204 000, 9800, 1180, and 1170 kg/ha m profile, respectively. Gains in total N and S in the older soils are readily accounted for by returns in precipitation. Pronounced changes in soil organic matter composition during 10 000 years are reflected in the widening of the C/N ratio (8 to 20) and the C/organic P ratio (39 to 159).     

THE ACCUMULATION OF SOIL ORGANIC MATTER AND ITS CARBON ISOTOPE CONTENT IN A CHRONOSEQUENCE OF SOILS DEVELOPED ON AEOLIAN SAND IN NEW ZEALAND

Soil organic matter was extracted by a mixture of O.IM Na₄P₂O: O.IM NaOH from a chronosequence of weakly weathered soils developed on aeolian sand, and fractionated into humin (non-extractable), humic acid, and fulvic acid. The mass of total organic carbon in the profiles, the ¹⁴C content and the ¹³C/12C ratios were also determined. The weight of total carbon increased rapidly at first and then gradually without attaining a steady state. This trend was also shown by the humin and fulvic acid fractions, but the humic acid fraction appeared to have reached a maximum after about 3000 years. The order of total weights of the organic fractions was humin > fulvic acid > humic acid. The evidence suggests that the proportions of the humic fractions formed by decomposition are related to soil differences but not to vegetation. The greater part of the plant material found in the soils appears in the humin and fulvic acid fractions.     

我国南方一些土壤的钾素状况及其含钾矿物

本文研究了我国南方一些土壤的钾素状况及其含钾矿物。结果表明，土壤含钾矿物的含量和种类因成土母质和土壤发育程度而异。花岗岩发育土壤的含钾矿物随粒烃增大而增加（＞５０μ除外），沉积岩发育的土壤情况相反。土壤的非交换性钾与云母类矿物含量呈较好的相关性（ｒ＝０．６６９＾＊），交换性钾与土壤ＣＥＣ呈极显著正相关（ｒ＝０．８０８＾＊＊）。不同粒级对土壤全钾量贡献不一，花岗岩发育土壤的全钾量主要集中于１０－５０     

THE OXIDATION OF IRON SULPHIDES IN SOILS IN RELATION TO THE FORMATION OF ACID SULPHATE SOILS, AND OF OCHRE DEPOSITS IN FIELD DRAINS

Aerating pyritic soils causes acidification and the forrnation of acid sulphate soils, or cat-clay. The Oxidation of pyrite in soils is associated with the deposition in tile drains of a form of ochre quite distinct from that formed by the action of filamentous iron bacteria. Pyrite-derived ochre results from the action of Thiobacillus ferrooxidans, which, below pH 3.5–4.0, catalyses the Oxidation of Fe²⁺ and pyrite. In soils less acid than c. pH 4, pyrite oxidizes relatively slowly by chemical reactions to Fe²⁺ and SO²₄^?. Under these conditions iron enters the drains as Fe²⁺ and is there oxidized by T. ferrooicidans and deposited as hydrated ferric oxide. Once the soil becomes acid enough for T. ferrooxidans to multiply, the rate at which pyrite oxidizes increases several-fold, and at c. pH 3 iron appears in the drainage water in the ferric form. Liming seems to decrease the rate of Oxidation.     

水稻土的氧化还原过程及其与水稻生长的关系

水稻土的主要特点是在一年之中有季节性的淹水和落干,而各种水稻土的干湿程度和时间都有不同,因而影响土壤性质发生复杂的变化。在这些性质中,氧化还原状况是变化最剧烈而指示最明显的性质,并且直接或间接影响水稻的生长。为此,作者等从1954年起,开始了这方面的研究工作,下面是关于几个主要简题的筒单概括。     

不同降雨强度对营养盐垂向迁移过程和淋失量的影响

云南抚仙湖流域农田面源污染日益严重,土壤污染物主要随地表径流进入湖泊,使湖泊受到污染。但目前的现场观测表明,农田区浅层地下水也已受到污染,地下水已成为污染物输移的路径之一。通过四组不同降雨强度作用下的室内土柱试验模拟土壤污染物向地下水的淋失迁移量,对降雨入渗过程中总氮、总磷、铵态氮和硝态氮的垂向迁移过程进行了分析,通过分时段处理来对各组实验中营养盐累积淋失量进行了计算。结果表明,硝态氮的垂向迁移能力和出流浓度均大于铵态氮,总氮和总磷的累积淋失量与累积降雨量呈自然对数关系;降雨强度对总氮的淋失作用明显,对总磷淋失量的影响则相对较弱。实验结果有助于揭示抚仙湖流域降雨作用下农田土壤中污染物的垂向迁移过程及其对农田浅层地下水的污染机制,并为污染物垂向迁移的数学模拟提供数据基础。     

江苏省的地质地貌与林业土壤的关系

在大范围内地质地貌对生物、气候、土壤的影响,例如高山地区的垂直分布规律,已有许多文献论述过.在小范围內地质地貌对山区林业土壤的直接影响,也在一些著作中有所反映(佐伯秀章,1959;Wilde,1958).本文只是试图就江苏省的一些具体事例,来讨论地质地貌对低山丘陵地区土壤类型、性状、分布规律及林木生长的影响.江苏省的低山丘陵,主要分布在东北部和西南部,占全省面积不到15%.     

三种黑土中有机碳、氮、磷的形态分布与肥力的关系

土壤腐殖质是土壤的重要组分。土壤的许多属性都直接或间接地与腐殖质的性质有关。我们曾指出^[2]黑土的腐殖物质及其组分与土壤的物理、化学及生物化学有显著的相关性,这表明它们对氮、磷等营养物质的转化、供应及贮存起着重要的作用。     

LOESS IN THE SOILS OF NORTH NORFOLK

Thin silty deposits cover large areas of north-east Norfolk, occurring mainly on gently sloping and flat plateau sites and on the floors of valleys cut in the glacial deposits. Particle size and geographic distribution of the deposits suggest that the silt is windblown. The mineralogical composition of the silt fraction resembles that of the silt of Hunstanton Till, suggesting that most of the deposit was derived as loess from outwash of the Weichselian glacier. However, at some localities the sand and clay components of the deposits were derived, at least partly, from subjacent glacial sediments of pre-Weichselian age. The distribution of the silty deposits strongly affects the pattern of soil types and sometimes the growth of crops.     

黄土高原土壤入渗速率的研究

根据黄土高原土壤入渗速率的明显地域差异,绘制了黄土高原土壤入渗速率分区图;文中对比了用双圈法测得的土壤稳定入渗速率与用水文资料推出的小流域土壤稳定入渗速率.     

黄土高原水土流失的时间分布规律

本文根据黄土高原地区11个小流域和6个坡面小区的多年水土保持资料,对本地区3种不同时间尺度(年际、季节、频次)的水土流失分布特征进行了分析研究,求得了有关分布特性参数、数学方程式及分布变化曲线。     

土壤中植物有效硫的评价

本文综述了土壤硫素形态及有效性、土壤有效硫的测定方法以及不同方法测定的土壤有效硫与植物生长的相关性。土壤有效硫的测定主要考虑表层土壤可溶性和部分吸附态硫酸盐,但土壤有机质含量、有机硫含量和组成、土壤机械组成、pH值以及下层土壤硫素状况也是不可忽略的重要因素。目前还没有一种行之有效的统一方法能够合理评价土壤有效硫状况。今后应进一步研究不同土壤的供硫特性,并对不同有效硫评价方法进行筛选,找出适合我国土壤和气候条件下的土壤有效硫评价方法和指标,以期为合理施用含硫肥料提供依据。