Soil-landform relationships at two localities in Papua New Guinea

Two test areas, each of several hectares, in denudational terrain in the lowlands and highlands of Papua New Guinea were intensively studied to establish the association between soil conditions and landforms. Whether soils were allocated either to the great soil groups of a classification based on the 7th Approximation or to FAO soil units, an extremely wide range of soils occurred in each of the land units that could be distinguished on the basis of landform. Defensible statements concerning soil distribution were achieved only by limiting the categories of soil to the level of soil orders and by restricting the number of land units to three or four. Even so, the statistical significance of the relationships was very low.These results indicate that current techniques and sampling densities used in photointerpretative land resource surveys in terrains typical of Papua New Guinea can produce only very generalized information on soil distribution. To obtain reliable predictions of soil information at the level commonly implied in such surveys, further intensive studies on the relationships between attributes of soil, landform and vegetation are required.     

Participatory soil survey: experience in working with a Mesoamerican indigenous community

In traditional rural societies that still represent the majority of small farmers worldwide, the use of conventional soil survey information frequently fails because it does not take into account or underestimates soil knowledge and experience of local people. Innovative approaches have been proposed to utilize the soil knowledge of rural communities through the participation of local farmers. This paper reports experience of participatory soil survey in the Purhépecha community of San Francisco Pichátaro in the volcanic highlands of central Mexico. Ethnographic and ethnopedologic techniques were applied to acquire soil and land data. Local soil knowledge was incorporated through plenary workshops designed to produce a participatory soil map based on a Purhépecha soil classification. This soil map reflects farmers’ soil–landscape understanding and correlates fairly well with a scientific soil map of the same area because in both approaches terrain plays a key role in the delineation of soil units. Participatory soil mapping promoted cooperation between local and external participants and formed the basis for an agreed land‐use plan.     

Live fences – a hidden resource of soil fertility in West Kenya

In the highlands of Western Kenya, intensified land use combined with low use of mineral fertilizers at farm level is driving soil nutrient depletion and declining yield levels. All farms and individual field crop plots are surrounded by life fences and the area under such hedge structure is estimated to cover 3–5% of the total farmland area. The land below the hedges is not tilled and may receive nutrient and carbon inputs by the occasional addition of field crop residues and litter fall. We hypothesized that the areas covered by live fences represent not only an important land resource, but are also largely untapped sites characterized by high soil fertility in an otherwise largely degraded environment. We characterized physico‐chemical attributes of top soils collected on farmland and from adjacent live fences composed of five different fencing species in representative environments of Kakamega district (sandy Acrisol and bimodal rainfall distribution vs. clay Ferralsol and monomodal rainfall distribution). In addition, the maize production potential of these soils was assessed in a supplementary pot experiment. Concentrations and total amounts of soil C, N, N supplying capacity, exchangeable K, as well as aggregate stability tended to be higher in hedge structures than in field crop soil. The amount of labile (permanganate‐oxidizable) carbon and the carbon management index in fence lines on Acrisol were similar to those of the adjacent Kakamega rain forest reserve, while they were reduced by > 50% in crop fields. These trends were reflected in the biomass and N and K uptake by maize in potted soil. Effects were generally larger in Acrisol than in Ferralsol and were most pronounced with Tithonia diversifolia. We conclude that live fences are soil fertility hotspots that may be valorised in the future by replacing the generally unproductive fencing species with economical perennial crops.     

天山中部北麓丘陵地带土壤发生特性与系统分类

通过样地调查与土壤理化性质分析相结合对天山中部北麓丘陵地带的土壤特性进行研究,确定各剖面的诊断层和诊断特性及其在系统分类中的位置。结果表明天山中部北麓丘陵地带在系统分类中可划归为3个土纲4个土类;系统分类中土壤的分类位置与发生分类位置并不具有简单的一一对应的关系。     

Soil mapping for land‐use planning in a karst area of N Thailand with due consideration of local knowledge

For the development of sustainable land‐management systems in the highlands of N Thailand, detailed knowledge about soil distribution and soil properties is a prerequisite. Yet to date, there are hardly any detailed soil maps available on a watershed scale. In this study, soil maps on watershed level were evaluated with regard to their suitability for agricultural land‐use planning. In addition to common scientific methods (as underlying the WRB classification), participatory methods were used to exploit local knowledge about soils and to document it in a “Local Soil Map”. Where the WRB classification identified eight soil units, the farmers distinguished only five on the basis of soil color and “hardness”. The “Local Soil Map” shows little resemblance with the detailed, patchy pattern of the WRB‐based soil map. On the contrary, the “Local Soil Map” is fairly similar to the petrographic map suggesting that soil color is directly related to parent material. The farmers' perception about soil fertility and soil suitability for cropping could be confirmed by analytical data. We conclude that integrating local soil knowledge, petrographic information, and knowledge of local cropping practices allows for a rapid compilation of information for land‐evaluation purposes at watershed level. It is the most efficient way to build a base for regional land‐use planning.     

Schutzwürdige Böden in Nordrhein-Westfalen — Bodenkundliche Kriterien für eine flächendeckende Karte zum Bodenschutz

Valuable soils in Northrhine-Westphalia — soil scientific criteria for generating a complete map for soil protection At the Geological Survey of Northrhine-Westphalia a map was developed: Soils to be protected in Northrhine-Westphalia at a scale of 1:50.000. It is based on the Soil map of Northrhine-Westphalia at a scale of 1:50.000. This map indicates areas where such land uses should get high priority which need, save and develop the identified main soil functions. There are three groups of land use with main soil functions:

• natural habitat with high potential of biotope evolution
• agricultural production on soils with (regionally) high fertility
• regional specifica, including soils as archives of natural and cultural history.

Land uses disregarding or lowering these soil functions have to be placed otherwhere or have to be compensated by areas with comparable functions. The criteria generating this map are given and discussed. The evaluation of information coming from the digital soil map runs soil protection under the aim of securing the kind and state of soil substrate and characteristics, giving the functionality of soils in favor of other media of the environment.     

Geo‐Pedogenese mariner Rohmarschen Spiekeroogs

Geo‐pedogenesis of Salic Fluvisols on the North Sea island of Spiekeroog Although the mainland's Salic Fluvisols of the southern North Sea coast are rich in carbonate, those of the adjacent island Spiekeroog are not. Thus, the aim of this study was to investigate the Salic Fluvisols of Spiekeroog in comparison to those of the mainland and to find out the reasons for the lack of carbonate, which was supposed to be an interaction between sedimentation and sulfur dynamics. The vegetation, many physical and chemical properties (e.g. pH, C_org, salinity, Fe_od, exchangeable cations, CEC) of the Spiekeroog Fluvisols are similar to those of the mainland. However, the Spiekeroog soil profiles extended over the marsh sediments, and the sand sediments below and they contained more silt and less clay and carbonate (0.3 – 34.5 g kg^–1) than the soils of the mainland. A survey proved carbonate‐free areas. The relatively moderate S dynamics showed a spatial and temporal stabile SO₄‐S‐fraction (0.3 – 0.6 mg g^–1), a fairly stabile HNO₃‐HCl‐S fraction (1.5 – 2.9 mg g^–1), but a variable HCl‐S fraction. The vertical Cs‐137 distribution showed peaks at 3 – 4 and 7 – 8 cm soil depth, indicating sedimentation rates of 0.2 – 0.5 cm a^–1. The results showed that moderate S dynamics lead to carbonate losses which are not compensated because of low sedimentation rates. Consequently, the Spiekeroog Salic Fluvisols will enter the terrestrial phase of soil development without carbonate. Thus, besides the usual pedogenesis of Eutric Fluvisols via Salic and Calcaric Fluvisols, the investigation proved a direct development from Salic to Eutric Fluvisols.     

广西岩溶地区水稻土发生特性及其在中国土壤系统分类中的归属

为明确广西岩溶地区水稻土在中国土壤系统分类中的归属，以该区域不同母质发育的水稻土为研究对象，挖掘20个典型剖面，通过野外观测、分层取样与分析，依据《中国土壤系统分类检索（第三版）》进行分类检索。结果表明，大多剖面出现明显的复钙现象。供试剖面的系统分类高级单元归属为人为土土纲，水耕人为土亚纲，潜育、铁聚和简育水耕人为土3个土类，复钙、铁聚和普通潜育水耕人为土、复钙和普通铁聚水耕人为土、复钙和普通简育.水耕人为土7个亚类，在系统分类基层单元归属上，可划归出17个土族和续分为20个土系。考虑广西地区水耕人为土耕作层Ap1碳酸钙相当物含量往往低于犁底层Ap2的现象，而现行水耕人为土复钙亚类的检索中“表层土壤”的“表层”不尽明确而可能导致的亚类误判，建议将其修改为“水耕表层（耕作层或犁底层）土壤”；另外，由于实际调查发现广西地区的一些铁聚水耕人为土也具有复钙特征，建议在检索中增设复钙铁聚水耕人为土亚类。     

中国水稻土磷储量及其空间分异

Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China’s farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 M digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m-3, respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.1 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.     

A soil core sampler for paddy soils and some physical properties of the soils under waterlogged condition

Introduction

Recent investigations in soil science have shown that physical properties of paddy soils are of great importance to rice-production. There is extensive literature on the chemical property of paddy soils, but little information on the physical property of paddy soils, especially under waterlogged condition. For studying the physical property of flooded paddy soils, it is necessary to collect the soil cores under an undisturbed condition.     

方正县土壤全硒空间变异研究

为了明确富硒水稻主产县方正县土壤中全硒的含量、分布等特征,以方正县农业土壤为研究对象,运用地统计学和Arc GIS相结合的方法研究土壤全硒含量的空间异质性和分布格局,并探讨硒浓度变异与土壤理化性质之间的关系。结果表明,土壤全硒含量变异函数符合指数模型,空间异质性指数Q=0.125,说明全硒含量的变异主要由结构性因素引起,空间自相关性较强。用普通克里格法(OK法)绘制全县的土壤全硒分布图,发现研究区绝大多数土壤(69.3%)属于足硒土壤,硒含量高值区出现在研究区中部及西南部,而低值区主要分布在研究区东北部。不同土壤类型中,泥炭土全硒含量最高(0.267 mg·kg-1),而沼泽土全硒含量最低(0.153 mg·kg-1);不同土地利用方式下,稻田土全硒含量(0.230 mg·kg-1)略高于旱地土(0.217 mg·kg-1)。影响土壤全硒含量的主要因素为土壤有机碳、粘粒及粉粒含量。     

湘北地区典型水稻土的发生特性及其在中国土壤系统分类中的归属

选取湘北地区7个发育于2种母质的水稻土剖面样点,通过对其成土环境、剖面形态特征以及土壤理化性质进行野外观测和室内分析,按中国土壤系统分类方案,检索出诊断层和诊断特性,确定其在中国土壤系统分类中的归属,并评述土系的生产性能。结果表明:供试水稻土归属于水耕人为土亚纲下的简育和铁聚水耕人为土2个土类,底潜简育水耕人为土、普通简育水耕人为土、普通铁聚水耕人为土、漂白铁聚水耕人为土4个亚类;进一步按照土族和土系划分标准,划分出7个土族和7个土系。在相同成土环境下,同种母质发育的水耕人为土,土壤系统分类比土壤发生分类具有更强的划分能力。其划分的基层土壤单元(土族和土系),对农业生产、土地资源利用更具有指导意义。     

漳州市农业土壤重金属现状、分析及防治

调查漳州市农业土壤重金属Hg、As、Cr、Cd、Pb背景值及污染现状,调查结果,漳州市农业土壤重金属背景值相对较低。其现状为,Hg、As、Cd、Pb含量高于背景值1~4倍(Cr除外),特别是Hg和As为高污染元素。按土壤类型划分,水稻土土类重金属含量高于赤红壤土类(Hg除外);按土地利用方式划分,水田>菜地>果园;按流域划分,九龙江流域农业土壤重金属含量高于非九龙江流域(Cr除外)。污染源以农业污染为主,工业污染相对较轻。     

Effect of humic acid amendment on cadmium bioavailability and accumulation by pak choi (Brassica rapa ssp. chinensis L.) to alleviate dietary toxicity risk

Cadmium (Cd) contamination in soil and its movement into food chain through vegetable dietary poses a risk to human health. A pot experiment was conducted to investigate the effect of humic acid (HA) and two cultivars of Brassica rapa ssp. chinensis L. (pak choi) with differing Cd accumulation abilities on Cd accumulation in different Cd contaminated Ferralsol, Histosol and Luvisol soils. The results showed that HA significantly increased soil pH and cation exchange capacity in Ferralsol (acidic) and Histosol (neutral) soils. HA was more effective in Ferralsol and Histosol soil in reducing bioavailable Cd and its accumulation in both cultivars. Low and high Cd accumulating cultivars combined with HA effectively reduced shoot Cd concentration by 7–34% and 19–35% in Histosol soil, whereas 22–34% and 11–26% in Ferralsol soil, respectively. However, no such reduction was observed for Cd accumulation and bioavailability in Cd-contaminated Luvisol (alkaline) soil. Application of HA enhanced shoot dry biomass in both cultivars grown in Histosol and Ferralsol soils. Therefore, the HA amendment combination with low Cd accumulating cultivars of pak choi could be an effective method for phytostabilization and reduce health risks associated with consuming this vegetable grown in Cd-contaminated acidic and neutral pH soils.     

低产水稻土改良与管理研究策略

我国耕地后备资源极端缺乏,改良低产田是提高粮食产量的重要途径。低产水稻土作为低产田的重要组成部分,相关肥力特征及其改良技术研究比较零散,缺乏系统科学的调控管理策略。本文从低产水稻土类型、新的改良研究方法角度,探索可能的技术突破。基于农业部统计数据,因环境条件不良或土壤自身存在障碍因素,全国约有7.67×106hm2低产水稻土。按其主导成因,低产水稻土可分为冷潜型、粘结型、沉板型、毒质型四类。土壤质量评价是低产水稻土研究的重要方面,其评价方法主要包括土壤质量动力学法、土壤质量综合评分法、多变量指标克立格法、土壤相对质量评价法,现已发展了基于GIS的区域尺度水稻土质量评价方法,以及基于土壤生物学性状的质量评价方法。低产水稻土改良研究更多关注新技术和新方法,稳定性同位素探针技术、傅里叶变换红外光谱法(FTIR)和固相交叉极化魔角自旋13C核磁共振(CPMS13C-NMR)波谱技术的应用,将土壤有机碳的微团聚体分布、腐殖质的转化及其与土壤矿物结合机制深入到微观水平;同时高通量测序、土壤宏基因组学、宏转录组学等方法将相关研究推向分子水平。低产水稻土改良与管理的技术主要涉及到冷潜型、粘结型、沉板型、毒质型四大类低产水稻土的改良技术,基于产量反应和农学效率的推荐施肥方法是水稻土养分管理方法的重要发展方向。1)在低产水稻土质量评价方面,未来要结合不同低产类型的障碍因素开展个性化的土壤质量评价,如白土的质地和耕层厚度,加强引入土壤生物学指标进行土壤质量评价研究。2)在低产水稻土改良方面,要研究稻田障碍层次的形成机理与调控途径;研究其他低产类型如新垦水稻土、盐渍化水稻土、石灰化水稻土和污染水稻土的改良技术;研究长期改良措施对不同粒级团聚体腐殖质结构、酶类、微生物多样性和功能基因的影响。3)在低产水稻土管理方面,着重研究秸秆还田技术、推荐施肥技术、抗逆品种技术、群体控制技术。     

太湖流域水稻土的磁化率剖面

土壤磁学是一门新兴的土壤学分支学科。它以研究土壤磁性为中心内容,把现代磁学理论以及磁测、磁查和磁诊断等研究手段和方法应用到土壤学中来^[2]。土壤磁性的强弱,可用磁化率作为指标。土壤磁化率的大小,主要决定于含铁矿物的种类和数量,特别是强磁性矿物(亚铁磁性的磁铁矿Fe₂O₃·FeO和磁赤铁矿γ-Fe₂O₃)的数量。     

福建耕地土壤磷素富集空间差异及其影响因素

利用1∶250 000福建省耕地土壤类型空间数据库以及1982年1 676个和2008年200 322个耕地土壤调查样点数据资料,借助GIS技术与灰色关联分析模型,探讨了26年间研究区耕地耕层土壤有效磷富集程度空间差异及其影响因素。结果表明:26年来福建省耕地土壤有效磷呈明显富集趋势,全省92.81%的耕地有效磷处于不同程度富集状态,有效磷平均富集量和年均富集率分别高达24.38 mg?kg-1和10.01%,并呈较明显的空间差异。地处南亚热带的厦门市耕地有效磷富集程度最大,中亚热带的南平市富集程度最小;有效磷富集程度较高的土类为紫色土、潮土、水稻土和赤红壤,较小的土类为滨海盐土和石灰土;富集程度较大的亚类包括淹育水稻土、灰潮土和漂洗水稻土,较小的亚类包括棕色石灰土和滨海盐土。研究区耕地土壤磷素富集及其空间差异主要受年均磷肥施用量、p H、年均气温和土壤黏粒含量显著影响,灰色关联系数0.722。根据研究区耕地土壤磷素富集程度及其空间差异制定磷肥优化管理措施是十分必要的。     

1982-2012年来杭州市郊水稻田有机质变化特征及其调控措施

[目的]了解杭州市郊水稻田土壤有机质的长期演变,为杭州市正在推进的精品化、高度集约化农业生产提供土壤肥力的精确管理依据。[方法]利用历史资料和近期土壤质量调查数据探讨了近30 a 来杭州市郊水稻田土壤有机质的变化特征。[结果]从1982—2012年,杭州市郊水稻田土壤有机质含量总体呈下降趋势,平均降幅为2．95％,但各土种有机质变化有所差异。其中,培泥砂田、小粉田、黄斑田、泥砂田和粉泥田的土壤有机质呈现增加趋势,特别是培泥砂田,土壤有机质含量增幅高达22．86％;而青紫泥田、青粉泥田和黄松田的土壤有机质呈现下降趋势,且青紫泥田土壤有机质含量降幅高达22．59％。[结论]近30 a 来,杭州市郊水稻田土壤有机质发生了较大变化,但其变化程度和变化方向因土壤种类而异。施肥结构、耕作方式及耕作制度是引起土壤有机质变化的主要原因。     

基于GIS/RS和USLE鄱阳湖流域土壤侵蚀变化

将空间信息技术（RS和GIS）和通用土壤流失方程（USLE）相结合对鄱阳湖流域土壤侵蚀量进行计算。分别利用1990年和2000年TM/ETM+影像分类得到两期土地利用/覆盖类型图,结合鄱阳湖流域数字高程模型（DEM）、土壤类型分布图和流域降雨资料分别获取USLE模型中各因子值的空间分布,最后计算流域2个年份的土壤侵蚀空间分布图。研究表明：鄱阳湖流域土壤侵蚀区域主要分布在赣江上游,信江上游,抚河上中游和修水上游地区;鄱阳湖流域1990年和2000年大范围土地经受着Ⅰ级微度与Ⅱ级轻度侵蚀,其侵蚀面积之和分别占流域面积的97.38%和97.30%;而流域产沙主要来源于Ⅱ级轻度侵蚀和Ⅲ级中度侵蚀,所占土壤侵蚀总量分别为58.16%和51.20%,其中中度以上等级的侵蚀对产沙量的贡献是不可忽视的;从1990年到2000年土壤侵蚀等级变化呈现了由中等级侵蚀（Ⅱ级轻度侵蚀和Ⅲ级中度侵蚀）向低等级（Ⅰ级微度侵蚀）和高等级侵蚀（Ⅴ级极强度和Ⅵ级剧烈侵蚀）的2个极端演化的趋势。鄱阳湖流域土壤侵蚀量从1990年到2000年增长幅度达6.3%;土壤平均侵蚀模数都约为1 100 t/(km2·a),属于Ⅱ级轻度侵蚀。分析2个年份的土地利用/覆盖变化,发现鄱阳湖流域湿地和农田面积减少,建筑用地增加均是造成土壤侵蚀量增加的因素,而降雨侵蚀力因子空间格局也对土壤侵蚀空间分布具有重要影响,最后提出了鄱阳湖流域水土保持规划措施。     

利用方式和土壤肥力对土壤团聚体和养分的影响

The size distribution of water-stable aggregates and the variability of organic C, N and P contents over aggregate size fractions were studied for orchard, upland, paddy, and grassland soils with high, medium, and low fertility levels. The results showed that > 5 mm aggregates in the cultivated upland and paddy soils were 44.0% and 32.0%, respectively, less than those in the un-tilled orchard soil. Organic C and soil N in different size aggregate fractions in orchard soil with high fertility were significantly higher than those of other land uses. However, the contents of soil P in different size aggregates were significantly greater in the paddy soil as compared to the other land uses. Soil organic C, N and P contents were higher in larger aggregates than those in smaller ones. The amount of water-stable aggregates was positively correlated to their contribution to soil organic C, N and P. For orchard and grassland soils, the > 5 mm aggregates made the greatest contribution to soil nutrients, while for upland soil, the 0.25-0.053 mm aggregates contributed the most to soil nutrients. Therefore, the land use with minimum disturbance was beneficial for the formation of a better soil structure. The dominant soil aggregates in different land use types determined the distribution of soil nutrients. Utilization efficiency of soil P could be improved by converting other land uses to the paddy soil.