白浆土形成过程中某些物理、化学性质的研究

白浆土发育在我国温带半湿润条件下,母质为第四纪河湖沉积物,土壤长期处于季节性干湿交替过程,使土壤剖面中铁、锰、铝等矿物元素被还原淋失,粘粒下移,在A及SB层中粘粒显著减少,淀积层中粘粒明显增加。整个剖面中硅铁率、硅铝率和硅铁铝率变化较小。土壤酸度稳定、盐基饱和度在70—90%。没有明显的矿物分解与灰化淀积层,在白浆化过程中,呈现了粘粒非破坏性的机械淋移,或者侧向漂洗作用。     

美国玛洛试验地的种植制度和施肥措施对土壤理化性状和产量的影响

美国伊利诺大学农学系玛洛试验地(Morrow Plots)建于1876年,是美国最早用来研究种植制度和施肥效应的试验地.我们通过养分、土壤结构、土壤水分等测定,结合历年的产量,研究玉米连作、玉米-大豆轮作和玉米-燕麦-三叶草轮作以及土壤施肥处理对土壤性状的影响.玉米连作使土壤有机质和全氮减少一半以上,其他营养元素也相应降低,土壤容重增加,孔隙度减少,结构变坏,土壤蓄水保墒能力减弱.而轮作结合施用有机肥料和化学肥料,有利于改善土壤理化性状和作物生长的环境条件,使作物高产稳产.     

镁对土壤某些理化性质的影响

本文研究了镁离子在土壤中的吸附特性和交换性镁对土壤某些物理性质的影响。试验结果表明:镁盐阴离子对镁离子侵入土壤吸收复合体能力的影响为:CO₃^2->SO₄^2->Cl^-。在低浓度下,Mg²+在Na⁺陪伴下较其单独存在时更易被含MgCO₃的石灰性土壤吸附。在混合盐溶液中,当盐渍度和SAR一定时,Na⁺在Na⁺-Mg²⁺体系中比在Na⁺-Ca²⁺体系中更易被土壤吸附。当ESP一定时,随着土壤吸收复合体中交换性镁百分率(EMP)的增加,分散系数逐渐增加,饱和导水率和毛管水上升高度逐渐降低,当EMP>60%时,不再发生变化。随着ESP的增加,交换性镁的不良影响逐渐变小。     

THE MORPHOLOGICAL, PHYSICAL AND CHEMICAL PROPERTIES OF TWO MOUNDS OF MACROTERMES BELLICOSUS (SMEATHMAN) COMPARED WITH SURROUNDING SOILS IN SIERRA LEONE

The mounds are situated in the Makeni Area, Northern Province, Sierra Leone. Seventy five percent of this area consists of clayey upland soils that belong to the Makeni series (Typic Paleudult), which contain about 80 per cent of gravel-sized hardened plinthite glaebules. The upland is dissected by numerous streams along which gravel-free fine-loamy terrace soils occur that belong to the Masuba series (‘Plin thic’Udoxic Dystropept) occupying about 15 per cent of the area. Mound 1 is a young inhabited mound on a Masuba soil, whilst mound II is an old abandoned mound on a Makeni soil. A trench was dug from the centre of the mounds into the surrounding soils. Profiles were described and samples were analyzed for organic carbon, CEC, exchangeable Ca, Mg, K, Na, and pH, and for particle size analysis with 5 sand fractions. The material used to build the mounds is derived from the subsoil (between 30 and 100 cm depth). Termite channels extended laterally for at least 10 m for mound I, but could not be traced so clearly for mound II. Mound I and the nest of mound II contain a higher percentage of particles less than 250 μm than the surrounding subsoil. Material over 2 mm is not carried by termites. Both mounds show a higher base saturation and higher values of exchangeable Ca, Mg and K, compared to the surrounding subsoil. Increased CEC and pH are noted in mound I and the nest part of mound II, the latter also showing increased values of exchangeable Na. Organic carbon values are equal to those of the surrounding subsoil. Accumulation of mineral elements from organic matter collected as food, including small contributions from the fungus combs and termite bodies, is primarily responsible for the observed differences. In view of the water analyses no contribution is expected from the fluctuating groundwater table.     

土壤砷的化学形态及其含量

砷是自然界普遍存在的重要元素之一.砷的化合物一般具有毒性.土壤中砷是来源于成土母岩.岩石在风化过程中,原生矿物遭到分解,次生矿物不断形成,在这过程中,土壤从中得到砷的补给,并且大部分与Fe、Al、Ca等离子结合成难溶性砷化物.     

DISTRIBUTION OF SOME CHEMICAL ELEMENTS IN THE SOILS OF NORTH WEST PEMBROKESHIRE

Total amounts of Mn, Fe, Ni, Cu, Zn, As, Bt, Rb, Si, Y, Zr and Pb were determined in soil samples from approximately 250 profiles. Examples of automatically plotted maps show the distribution of some of these elements in topsoils and subsoils. Element distribution in the soils is related to land units based on underlying rock-type and air photograph interpretation; these units distinguish soils of different lithological and drainage status and many are dominated by a single soil subgroup. Agricultural and pollution aspects of the work are discussed. The survey indicates the present levels of the elements, and may be used as a comparison in future pollution studies.     

CHEMICAL AND MINERALOGICAL PROPERTIES OF BROWN PODZOLIC SOILS IN COMPARISON WITH SOILS OF OTHER GROUPS

Chemical and mineralogical properties of brown podzolic soils, brown earths, a podzol, and an Andept have been studied with particular reference to the kinds and distribution of amorphous materials. In addition to pyrophosphate extractable (Fe + Al)/per cent clay, brown podzolic soils can be distinguished from brown earths by Fe-oxalate/Fe-dithionite and Fe-pyrophosphate/Fe-dithionite ratios, fluoride reactivity, and the presence of intergrade 2:1-2:2 and smectite-like clay minerals in surface horizons. Significant amounts of amorphous alumino-silicates resembling allophane were found in the Bs horizons of the brown podzolic soils, particularly those on igneous rocks. These amounts are sufficiently large to suggest the recognition of an Andic sub-group of brown podzolic soils in England and Wales.     

磁场对土壤理化和机械物理性状影响的研究

对土壤磁效应的研究表明,磁场可引起土壤理化性质,机械物理性质变化,在适宜的外加磁场作用下,土壤电位,土壤比表面,土水势,膨胀量,剪切力下降;土壤胶体电荷密度升高,土壤微团聚化作用增强,土壤结构状况有所改善。     

CHANGES IN THE PHYSICAL AND CHEMICAL PROPERTIES OF A MINERAL TOPSOIL UNDER THE INFLUENCE OF PEAT DEBRIS

Changes are reported of particle size distribution, organic carbon and nitrogen values, cation exchange capacity and exchangeable cation populations, and in iron and aluminium patterns as a result of adding varying rates of acid peat debris to a mineral topsoil. Up to 3 cm of peat had beneficial effects on soil chemical and physical properties but 5 to 8 cm was sufficient to cause considerable acidification, release of Fe and other ions from primary minerals and the development of an iron seam (or pan) which contains up to 7 per cent free iron. Greater thickness of peat (up to 30 cm) caused soil reaction to drop to pH 4 or less and produced so much humic acids as to inhibit iron precipitation and to facilitate its removal from the profiles. The effects of soil moisture on the pattern of peat humification in the deeper additions (20–30 cm) are also outlined.     

周秦两汉时代华北平原与渭河平原盐碱土的分布及利用改良

近年来有关华北盐碱土的特点、分布、发生和演变规律及利用改造等方面的研究,不仅丰富了盐碱土的科学理论,同时对华北地区的农业生产也有很大的意义。为了进一步掌握华北盐碱土的发生和演变规律,不仅要加强现代盐碱土的研究;还应探究历史时期的分布情况、演变规律以及利用改良的经验与教训等。为此,我们将文献中有关周秦两汉时代华北平原与渭河平原盐碱土的分布及利用改良的资料,初步整理,以供参考,并希批抨指正。     

INFLUENCE OF ORGANIC MATTER ON THE PHYSICAL PROPERTIES OF SOME EAST ANGLIAN SOILS OF HIGH SILT CONTENT

A comparison was made of the physical properties of pairs of silt soils differing only in organic matter content. Within the textural group studied, the member of the pair with more organic matter had better physical properties relating to both plant growth and soil management. Increased organic matter give higher water holding capacities and porosities, and decreased compaction, breaking strength and bulk densities. Organic matter content alone was not sufficient to explain differences in aggregate stability to water.     

长期秸秆覆盖免耕对土壤某些理化性质及玉米产量的影响

免耕农作是一项重要的农业生态管理系统,长期秸秆覆盖免耕条件下土壤性质的变化及作物产量可以反映这一系统的可持续性,研究表明,长期（１９７０年－１９９４年）免耕与犁耕相比土壤容重并未增加,而表层（０－５ｃｍ）土壤有机Ｃ和有机Ｎ显著增加,并有随Ｎ肥施用量增加而增加的趋势,土壤ｐＨ随ＮＨ４ＮＯ３化肥施用量的增加而明业降低,免耕表层土壤的交换性Ｃａ,Ｍｇ,Ｋ和可提取Ｐ与犁耕比较明显的表聚现象,交换性Ｃａ,Ｍ     

辽河平原土壤背景值与主要成土条件关系

土壤中许多重金属元素含量超过某一限定指标后,常对生物和人体构成潜在毒性,故世界各国都非常重视土壤环境背景值和重金属元素控制指标的研究^[1,7,8]。本文对辽河平原土壤中铅、锌、铜、锡、镍、铬、汞、砷等8种金属元素含量与土壤成土条件的关系做了粗 浅的分析讨论。     

THE COVARIANCE OF PHOSPHATE SORPTION WITH OTHER SOIL PROPERTIES IN SOME BRITISH AND TROPICAL SOILS

Phosphate sorption capacity estimated by Piper's (1942) ‘anion exchange capacity’ and Bache and Williams's (1971) phosphate sorption index were correlated with soil pH, clay, organic matter, ‘free iron oxides’ and ‘extractable aluminium’ (McLean et al., 1958) for topsoil and subsoil samples from twenty tropical and twenty British acidic soil profiles. These two groups of soils did not differ significantly in phosphate sorption. Extractable aluminium and free iron oxide were well correlated with phosphate sorption, free iron oxide being superior to aluminium in freely drained British soils but not in poorly drained ones. Organic matter content correlated well with phosphate sorption for the poorly drained British soils, and for the tropical soils when sorption capacitywas measured using a high phosphate concentration.     

玉溪市设施栽培与露地栽培的土壤化学性状对比分析

针对玉溪市设施栽培中存在的土壤盐分富集及养分不平衡问题,采用对比分析方法,将设施栽培土壤与露地栽培土壤配对,采集剖面土样和耕作层混合土样进行化学性状测试分析研究。结果表明,玉溪市设施栽培土壤pH值显著降低,盐分浓度、有机质、有效态N、P、K、S、Cu、Zn、Fe及交换态Mg显著提高,而交换Ca和有效Mn提高不明显;设施栽培土壤养分富集主要在0~10cm土层,且集中在0~2cm的表土层,其中以EC值、有效S、有效K及有效Mn在0~2cm表土层的相对富集量最多。     

江苏南部几种水稻土的有机-矿貭复合体性貭的初步研究

近几年来的研究表明,丰产水稻土不但具有供給水稻生长的良好的土壤环境,而且还具有便于調节肥力因素的土壤特性^[2,3]。同时,在羣众經驗总結中,也发现我国农民对土壤的評价不仅有“肥瘦”之分,而且还有“好坏”之別。而判別“好坏”的标准看来也就是土壤是否易于調节其肥力因素以滿足不同作物或同一作物在不同生育时期生活的需要。     

冲积平原上区域土壤质地层次的某些分布特征

本文根据冲积平原区上一个１５平方公里区域内格网化布点的大量土壤剖面质地层次的观测数据,采用地统计学方法研究区域粘土层一些指标值的空间变异结构,通过概率统计研究了区域内几种地质类型层次厚度的概率分布特征。研究结果表明,第一粘土层厚度,第一粘土层出现深度,１米内粘土层总厚度和２米内粘土层总厚度的最大相关距离均在１５００米－２０００米之间,各种类型质地层厚度的概率分布均具有对数正态分布的特点。     

东北松嫩平原盐渍土的盐分累积

松嫩平原是我国东北平原的一部分,东北西三面分别为东满山地、小兴安岭和大兴安岭所围绕,南抵松辽分水岭,并与辽河平原相连接。该平原面积辽阔,南北宽达500余公里,东西长及300公里,气候温和,土壤肥沃,适合发展农业,一向为我国主要产粮地区。但在本区中部及西部分布有大面积盐渍化土壤,限制了农业的发展。     

太湖地区水稻土的物理特性与少免耕法的关系

本文从土壤物理特性和作物生长的关系探讨了耕作的要求.土壤水分能量特性可被机械扰动改变,这是导致土壤粘闭的重要原因.水稻土的含水量和有效水均以表土高,而下层低,含水量和容重成线性负相关(n=62,r=-0.909^**).土壤扰动可提高持水量,长年免耕在干旱年份可能会出现水分不足问题.土壤含水量、气容量和机械强度三者的变化相互联系.由三个因素决定的小麦生长最佳范围是在水分吸力0.02-0.5巴内,而田间持水量大于塑性限,所以秋季耕作必然导致土壤粘闭.免耕土壤的容重一般在1-1.25g/cm₃之间,是稻麦生长的较佳环境,所以水稻土本身存在适合稻麦免耕生产的条件.根据水稻和三麦分别52和23组次对比试验,水稻免耕增产19斤/亩,三麦49斤/亩,均达到极显著水平(p=0.01).平田地区连续三年免耕土壤不恶化,囊水型土壤第二年开始有变差趋势,但产量不减低.免耕有保护土壤结构的作用,但不利于结构发展.