不同施肥模式下红壤性水稻土中磷的分布及其有效性

研究了不同施肥模式下红壤性水稻土中磷的分布及其有效性。结果表明,随团聚体粒径从大到小的变化,红壤性水稻土全磷含量在不同施肥模式下均表现出先上升后下降的趋势,在5～2 mm粒径团聚体中出现一个峰值;有效磷含量表现出先缓慢上升后迅速下降的特征,在5～2 mm粒径团聚体中出现一个大峰值;在施磷处理中,磷的有效率表现出先缓慢上升后迅速下降的特征,分别在5～2 mm和0.5～0.25 mm粒径团聚体中出现一个大峰值和一个小峰值,但在无磷处理中,磷的有效率表现出逐渐下降的趋势,只在0.5～0.25 mm粒径团聚体中出现一个小峰值。研究表明,长期施加磷肥,尤其与有机物还田相结合,会促使土壤全磷富集于>1 mm粒径团聚体,显著提高>2 mm粒径团聚体中有效磷含量与磷的有效性;在磷肥不足的情况下,减少磷肥施入量,结合有机物还田也能取得较好的效果;即使没有磷肥施入,实行秸秆还田也能在一定程度上提高土壤磷的有效性。     

不同灌溉方式对猕猴桃园土壤团聚体结构和养分的影响

为探究不同灌溉方式对猕猴桃园土壤结构和养分的影响,2017—2019年在陕西杨凌猕猴桃种植园布设地面灌溉、微喷灌2种处理,测定0—50 cm土层的土壤团聚体结构和有机质、碱解氮、速效磷和速效钾的含量,分析不同灌溉方式下土壤团聚体结构和养分的差异。结果表明:在0—50 cm土层,地面灌溉处理土壤中粒径分别为5.0,2.0～5.0,1.0～2.0,0.5～1.0,0.25～0.5,0.25 mm的颗粒在不同土层中的分布均匀程度高于微喷灌处理,2种灌溉方式下均以0.25 mm的土壤颗粒分布最为均匀;微喷灌处理土壤中粒径0.25 mm的水稳性大团聚体含量显著高于地面灌溉处理,土壤团聚体的平均质量直径(MWD)、几何平均直径(GMD)高于地面灌溉,而分形维数(D)低于地面灌溉,土壤氮磷钾总含量高于地面灌溉。微喷灌有利于保持猕猴桃园土壤结构的稳定性和土壤肥力,能促进土壤的可持续发展,是成龄猕猴桃园适宜的灌溉方式。     

红壤旱土和水稻土团聚体中磷素的分布特点

为深入探讨红壤磷素有效性的控制机理,研究了典型红壤旱土和水稻土团聚体中磷的组分与分布特点。结果表明:旱土和水稻土以粒径>0.2mm的团聚体为主,且在该级土壤团聚体中磷素含量较高;两种土壤>0.2mm团聚体中吸附态无机磷以Fe-P为主,而<0.02mm团聚体以O-P为主;水稻土>0.2mm和<0.002mm团聚体的各组分有机磷总量亦显著高于旱土对应的团聚体。说明土壤磷的形态分布与团聚体粒级有密切关系,旱土有效磷含量较低可能与其团聚体游离氧化铁含量较高、且有机磷含量较低有关。     

长期施肥对红壤性水稻土团聚体特征的影响

利用干筛法研究了红壤性水稻土连续施肥23年后,各粒径土壤团聚体含量及其特征值变化.结果表明:施用有机肥(NPKM、OM)与CK相比,可提高粒径3～5 mm土壤团聚体含量25.4%～24.6%,并分别降低粒径0.05～0.25 mm、＜0.05mm团聚体含量70.6%～71.1%和113.6%～121.7%,差异达显著水平;单施化肥处理(N、NP、NPK)与CK相比,各粒径土壤团聚体含量无明显差异,表明施肥对红壤性水稻土团聚体的影响主要受有机肥的控制.施用有机肥显著提高红壤性水稻土团聚体的平均重量直径(MWD)、几何平均直径(GMD),而降低团聚体的分形维D值:水稻土团聚体的MWD、GMD与＞3 mm团聚体含量和水稻年产量存在显著的正相关,而团聚体分形维D值则与＞3 mm团聚体含量和水稻年产量存在显著的负相关,因而土壤团聚体的MWD、GMD和分形维D值可较客观地反映土壤肥力的状态.不同施肥处理的水稻年产量与粒径3～5 mm团聚体含量呈显著正相关而与0.05～0.25 mm、＜0.05 mm团聚体含量呈显著负相关,表明红壤性水稻土团聚体干筛分析条件下,粒径3～5 mm、0.05～0.25 mm、＜0.05 mm团聚体含量可作为红壤性水稻土土壤肥力表征的物理性指标.     

不同施肥处理对红壤水稻土团聚体有机碳分布的影响

通过23年的长期田间定位试验观测,研究了施肥对红壤水稻土不同发生层团聚体组成、有机碳含量及有机碳库分布的影响.试验设不施肥（CK）、无机肥（NPK）、有机肥（猪粪＋紫云英）（OM）和无机肥与有机肥配施（NPKM）等4个处理.结果表明,＞3 mm团聚体含量随土层深度呈增加趋势,而其他粒径的团聚体含量则呈下降趋势.施肥处理有利于1～3 mm和0.25～1 mm团聚体含量增加.各处理中,各层同粒径团聚体有机碳含量从高到低的顺序为：A＞P＞W1、W2.不同粒径团聚体中有机碳含量有明显差异,除＜0.05 mm团聚体外,粒径愈细,有机碳含量愈高.1～3 mm和0.25～1 mm团聚体含量与全土有机碳含量呈显著正相关.不同施肥处理有机碳储量表现出NPKM＞OM＞NPK＞CK的趋势.同施肥处理同发生层不同粒径团聚体有机碳储量从高到低的顺序为：＞3 mm、1～3 mm、0.25～1 mm、0.05～0.25 mm和＜0.05 mm,且差异显著.施肥处理增加的新碳主要向1～3 mm、0.25～1 mm团聚体富集.     

有机肥增减施后红壤水稻土团聚体有机碳的变化特征

利用一个长达35 a水稻土长期定位试验,在保证原有定位试验继续正常开展的前提下,将部分原化肥处理增施有机肥,部分原有机肥处理改施化肥或者增施有机肥,研究有机肥增减施后长期不同施肥红壤性水稻土团聚体有机碳变化特征及影响。结果显示:红壤性水稻土以0.25 mm团聚体为主;长期不同施肥下土壤团聚体有机碳含量高低排序均表现为:0.25 mm团聚体0.25～0.053 mm团聚体(0.053 mm)团聚体,长期施用有机肥可提高红壤水稻土各粒级有机碳含量和2mm团聚体有机碳的贡献率。施肥对红壤性水稻土各粒径团聚体有机碳影响的大小排序为:0.053 mm0.25～0.053 mm(2 mm)2～0.25 mm;游离氧化铁和络合态铝对2～0.25 mm粒径团聚体有机碳有着重要影响,游离氧化铁在2 mm团聚体的形成中发挥作用。增加有机肥施用量可提高2 mm各粒级团聚体有机碳含量,减施有机肥则显著降低各粒级团聚体有机碳含量。不管减施还是增施有机肥均导致2mm团聚体有机碳贡献率降低;同时,减施有机肥后2 mm的各级团聚体有机碳贡献率提高,而增施有机肥后2～0.25 mm团聚体有机碳贡献率提高。     

引黄灌溉耕作对土壤团聚体有机碳的影响

为研究灌溉耕作影响下土壤团聚体及有机碳的特征情况,以宁夏引黄灌区为研究对象,选取对照土壤与耕作土壤,通过干、湿筛结合的方法,得到大团聚体(2mm)、中间团聚体(2~0.25mm)、微团聚体(0.25~0.053mm)和粉+黏团聚体(0.053mm),并测定团聚体有机碳含量,分析团聚体有机碳与总有机碳之间的关系。结果表明,灌溉耕作对团聚体分布具有极显著影响(P0.01),其中大团聚体和中间团聚体质量分数上升,微团聚体和粉+黏团聚体质量分数下降,灌溉土壤团聚体分布趋势为微团聚体粉+黏团聚体中间团聚体大团聚体。经灌溉耕作后土壤团聚体稳定性大于对照土壤,不同类型的灌溉土壤稳定性基本一致,对照土壤间差异明显。除0.053mm外,团聚体有机碳分布在经过灌溉耕作后有显著性差异(P0.05),团聚体有机碳分布随粒级大小基本呈"V"形分布。团聚体有机碳含量均表现出灌溉土壤高于对照土壤,其中灌溉土壤中灌淤土和潮土团聚体有机碳总量较高。未受人为灌溉耕作影响的自然土壤团聚体有机碳与总有机碳间具有显著的正相关性,土壤总有机碳增加主要依赖0.053mm团聚体有机碳增加。引黄灌溉耕作有利于增加大粒级团聚体的比例,提升团聚体稳定,显著增加有机碳含量。     

农田暴雨径流侵蚀泥沙流失及其对氮磷的富集

利用室内模拟降雨径流试验(降雨强度72mm/h),研究侵蚀泥沙的粒径分布特征及其对氮磷的富集作用。结果表明,侵蚀泥沙的团聚体组成和原来土壤有很大差异,<0.25mm团聚体占侵蚀泥沙重量的81%,而在原土壤中只有16%;>0.25mm的团聚体只有19%,远远低于原土壤中的84%。颗粒态氮磷分别占径流流失氮磷的94%和91%以上,而78%的颗粒态氮和69%的颗粒态磷是通过小于0.25mm团聚体流失的;44%的颗粒态氮和32%的颗粒态磷是通过<0.045mm团聚体流失的。侵蚀泥沙氮磷富集系数随时间而下降,并与侵蚀泥沙累积流失量之间呈显著的对数线性相关。侵蚀泥沙中<0.25mm团聚体,尤其是氮磷含量较高的<0.045mm团聚体的富集是侵蚀泥沙对氮磷富集的原因。     

铁和不同形态氮素对玉米植株吸收矿质元素及其在体内分布的影响——Ⅰ.对氮、磷、钾、钙、镁等营养元素的影响

用营养液培养方法研究了铁和两种形态氮素(NO₃^--N和NH₄⁺-N)对玉米植株吸收氮、磷、钾等大量元素和钙、镁等中量元素及其在体内分布的影响。结果表明:与NO₃^--N相比,供应NH₄⁺-N促进了玉米对氮的吸收,在缺铁条件下,降低了对磷、钾、钙及镁的吸收。铁和NH₄⁺-N都显著提高了玉米植株各器官中氮的含量。与NH₄⁺-N处理相比,NO₃^--N处理的新叶中磷含量显著增加,但铁的供应对植物体内磷的含量无显著影响。使用NO₃^--N显著提高了玉米新叶和老叶中钾的含量,根和茎中钾的含量无明显影响。铁的供应降低了新叶和老叶中钾的含量。供铁时,NH₄⁺-N处理的玉米新叶中钙和镁的含量显著低于NO₃^--N处理,而在缺铁时则无显著差异。     

长期定位施肥对潮土团聚体结构及其磷组分的影响

以国家潮土肥力与肥料效益监测基地的长期施肥试验为基础,从土壤团聚体微域环境的角度研究潮土不同团聚体中磷的形态及含量对单施化肥和化肥配施有机肥的响应.结果表明:(1)潮土土壤团聚体主要分布在0.25～5 mm范围,占土壤总重量的60.72%～77.99%;其次为>5 mm团聚体;<0.25 mm团聚体占的比例最低,仅为7.09%～13.68%.化肥处理0.25～5 mm团聚体重量比例(60.72%)显著低于其余处理的重量比例(71.5%～77.99%),而>5 mm团聚体重量比例(25.82%)显著高于其余地块的重量比例(11.90%～19.98%);在长期施用有机肥的处理(MNPK和1.5MNPK)中,<0.25 mm的团聚体重量比例(7.09%)相比不施肥的(13.68%)降低了6.37%,0.25～5 mm团聚体比例却增高5.95%.(2)不同粒径团聚体,施肥可显著提高有效磷、有机磷和无机磷的含量,增加幅度从大到小均依次为1.5MNPK,MNPK,NPK;全磷中无机磷所占比例(88.25%～92.67%)要远远高于有机磷所占比例(7.33%～11.75%).(3)潮土有机磷组分,MLOP含量最高,所占比重也最大(65.97%～70.29%),MSOP居中,LOP和HSOP含量和比重最小.而作为主要形态的MLOP在各施肥处理中的含量由低到高依次为CK,NPK,MNPK,1.5MNPK;潮土中的无机磷组分里,Ca10-P含量最高,所占比重也最大(42.6%～66.8%),然后依次是Ca8-P,A1-P,O-P,Ca2-P和Fe-P.     

Levels and Distribution of Petroleum Hydrocarbons in the Coastal Waters and Sediments of the United Arab Emirates in the Arabian Gulf and the Gulf of Oman

The levels and distributions of petroleum hydrocarbons incoastal waters and sediments of the United Arab Emirates (U. A. E.) along theArabian Gulf and the Gulf of Oman were investigated. Oil concentrations in the waters ofthe U. A. E. were below the 15 μg L^-1 and ranged from 1.6 to 13 μg L^-1.Petroleum hydrocarbons showed different pattern of distribution in the Arabian Gulf and the Gulf of Oman withmore or less similar values. Horizontal distribution of petroleum hydrocarbons atthe Arabian Gulf showed significant differences between most sites. At the Gulf ofOman, similar oil concentrations were measured at different sites. Meanwhile,vertical distributions of petroleum hydrocarbons indicated higher concentrations atsurface layers of the Arabian Gulf compared to bottom layers. Whereas, more or less similarconcentrations were measured at the Gulf of Oman. The concentration of petroleum hydrocarbons in marinesediments varied from 2.5 to 8.2 μg g^-1 (dry sediment weight), with higher concentrations at theArabian Gulf compared to the Gulf of Oman. The pattern of distribution for petroleumhydrocarbons in marine sediments resembled to some extent the distribution of organiccarbon in marine sediments. The study revealed that the concentrations ofpetroleum hydrocarbons in waters and sediments of the investigated area are not highcompared to other areas of the world.     

Diversity and dominance of crop plantations in the agroecosystems of the Kujawy and Pomorze region in Poland

Abstract

The Kujawy and Pomorze Province with 127 rural and municipal-and-rural communes in 19 districts is a typical agricultural region, with the highest plant farming intensity in Poland. The diversity and dominance of crop plantations in the agroecosystems in communes were calculated based on percentage share of 21 kinds of crops in the cropland structure. The algorithms applied in ecological research of biodiversity were used: the Shannon–Weaver diversity index (H’) and Simpson's dominance index (λ). The diversity (H’) of crops in arable land in the Kujawy and Pomorze Province ranges from 1.68 to 2.54. The diversity of crop plantations in the region was bigger in the communes in which there are: better soil, a higher share of arable land in the agricultural acreage and cropland in the arable land as well as with a higher share of barley, corn for grain and sugar beet in the cropland structure. The highest dominance index (λ) for crops in the whole province is 0.291. The index of dominance of agricultural crops in this region increases with an increase in the share of: woodland in the total area, meadows and pasture in the agricultural acreage and rye in the cropland structure.     

渭干河上游流域近60年的入库水沙变化特征及趋势分析

研究干旱半干旱地区多沙河流的水沙特性及趋势，对流域内水沙调控、水沙预测具有重要意义。基于宏观(微观)的角度来详细研究干旱半干旱地区多沙河流的水沙特性及趋势，以期为流域内水沙调控、水沙预测提供理论帮助。应用累积距平法、ITA法和ITA-CB法计算克孜尔水库入库流量、入库输沙率，并分别从年内、年际、年代际3个尺度系统地分析流量、输沙率的变化特征与趋势。结果表明：(1)年内水沙分布特征高度相似，二者的最高值均分布在7月，其最低值分别分布在3月和1月，年际尺度上波动性强且差异明显；(2)年度入库流量呈现上升趋势且有增加倾向，夏季表现为上升趋势且存在减弱倾向，其中高值区升高趋势减弱，需要注意干旱的极端气候；(3)年度输沙率呈上升趋势，季度尺度下的趋势特征均表现为下降趋势，其中夏秋两季下降趋势有减弱倾向，冬季出现增强倾向。与传统分析方法相比，ITA与ITA-CB方法能够有效识别出序列内部间存在的微观趋势，有助于详细分析区域水沙的变化特征。     

Comparative Analysis of the Number and Structure of the Complexes of Microscopic Fungi in Tundra and Taiga Soils in the North of the Kola Peninsula

The number, biomass, length of fungal mycelium, and species diversity of microscopic fungi have been studied in soils of the tundra and taiga zones in the northern part of the Kola Peninsula: Al-Fe-humus podzols (Albic Podzols), podburs (Entic Podzols), dry peaty soils (Folic Histosols), low-moor peat soils (Sapric Histosols), and soils of frost bare spots (Cryosols). The number of cultivated microscopic fungi in tundra soils varied from 8 to 328 thousand CFU/g, their biomass averaged 1.81 ± 0.19 mg/g, and the length of fungal mycelium averaged 245 ± 25 m/g. The number of micromycetes in taiga soils varied from 80 to 350 thousand CFU/g, the number of fungal propagules in some years reached 600 thousand CFU/g; the fungal biomass varied from 0.23 to 6.2 mg/g, and the length of fungal mycelium varied from 32 to 3900 m/g. Overall, 36 species of fungi belonging to 16 genera, 13 families, and 8 orders were isolated from tundra soils. The species diversity of microscopic fungi in taiga soils was significantly higher: 87 species belonging to 31 genera, 21 families, and 11 orders. Fungi from the Penicillium genus predominated in both natural zones and constituted 38–50% of the total number of isolated species. The soils of tundra and taiga zones were characterized by their own complexes of micromycetes; the similarity of their species composition was about 40%. In soils of the tundra zone, Mortierella longicollis, Penicillium melinii, P. raistrickii, and P. simplicissimum predominated; dominant fungal species in soils of the taiga zone were represented by M. longicollis, P. decumbens, P. implicatum, and Umbelopsis isabellina.     

Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.     

Nutrient disturbances in forest trees and the nature of the forest decline in Quebec and Germany

The serious decline of forest trees in Quebec and adjacent areas of the U.S. parallel those observed in Germany. In certain locations, in both cases, K deficiency is now occurring on glacial tills and outwash soils and is associated with a low concentration of exchangeable K⁺ and a high molar ratio of exchangeable Ca⁺ ions to K⁺ ions in the soil. This deficiency results from the so-called Ca-K antagonism in which an increased concentration of Ca²⁺ ions blocks the entry of a reduced concentration of K. Mg deficiency is occurring on granitic soils and results from a low concentration of exchangeable Mg²⁺ and a high molar ratio of A1³⁺ ions to Mg²⁺ ions. The role of the parent rock, weathering reactions and atmospheric inputs are discussed in relation to the changes that have resulted from the cumulative effect of acid deposition. The changes in storage, transfer and losses of cationic nutrients in soil and trees can explain the development of these imbalances, which are still increasing, and are resulting in these forest declines.     

Mobility and breakdown of asulam in the soil and the possible impact on the environment

Asulam reaching the soil either directly as spray drift or as rain washings from bracken fronds would, due to its rapid mobility in soil, be expected to leach down the soil profile into the drainage water and thereby contaminate streams and water catchments. The mobility of asulam in soil is influenced by pH, where undissociated asulam will leach less rapidly than the associated form (asulam pK_a 4·82). This is particularly relevant in the case of bracken as it can grow satisfactorily over a wide range of pH values (3·6 – 7·6). Adsorption coefficients expressed as Kd values [(μg asulam/g soil)/(μg asulam/ml solution)] were 2·54, 1·94 and 0·96 at pH readings of 4·0, 4·3 and 4·9 respectively. Another factor involved, the breakdown of asulam, was shown to be temperature dependent, 30·95, 7·65 and 2·50% remaining after 28 days at 5, 18 and 25°C respectively, thus underlining the influence of geographical regions and climatic conditions on asulam behaviour.     

Transformation of the Bryansk Paleosol in Microdepressions in the Center of the East European Forest-Steppe during the Maximum of Valdai Glaciation and in the Holocene

Eurasian Soil Science - Recent and Late Pleistocene soils of the central forest-steppe in the East European Plain have been studied. The main objective of the work is to reveal changes in the...     

Reconstruction of the paleotemperature and precipitation in the Pleistocene according to the isotope composition of humus and carbonates in loess on the Russian Plain

The isotope composition of carbon and oxygen in humus and carbonates has been studied in the Pleistocene loess and soil of the Russian Plain in order to reconstruct the paleoclimatic parameters during the time of their formation. It is established that most of the buried soils were formed upon the mean annual temperature exceeding the modern temperature by 1–2°C. The climate aridity (the portion of C4 plants in the ecosystem) varied from 0 to 25%. It is shown that the isotope composition of carbon and oxygen in the humus and carbonates may be a reliable indicator of the paleoclimate (i.e., the paleotemperature, paleoprecipitation, and aridity dynamics). An isotope procedure of culling soil samples unsuitable for paleoclimatic reconstruction is proposed.     

Total carbon and nitrogen in the soils of the world

The soil is important in sequestering atmospheric CO₂ and in emitting trace gases (e.g. CO₂, CH₄ and N₂O) that are radiatively active and enhance the ‘greenhouse’ effect. Land use changes and predicted global warming, through their effects on net primary productivity, the plant community and soil conditions, may have important effects on the size of the organic matter pool in the soil and directly affect the atmospheric concentration of these trace gases. A discrepancy of approximately 350 × 10¹⁵ g (or Pg) of C in two recent estimates of soil carbon reserves worldwide is evaluated using the geo-referenced database developed for the World Inventory of Soil Emission Potentials (WISE) project. This database holds 4353 soil profiles distributed globally which are considered to represent the soil units shown on a ¹/₂° latitude by ¹/₂° longitude version of the corrected and digitized 1:5 M FAO–UNESCO Soil Map of the World. Total soil carbon pools for the entire land area of the world, excluding carbon held in the litter layer and charcoal, amounts to 2157–2293 Pg of C in the upper 100 cm. Soil organic carbon is estimated to be 684–724 Pg of C in the upper 30 cm, 1462–1548 Pg of C in the upper 100 cm, and 2376–2456 Pg of C in the upper 200 cm. Although deforestation, changes in land use and predicted climate change can alter the amount of organic carbon held in the superficial soil layers rapidly, this is less so for the soil carbonate carbon. An estimated 695–748 Pg of carbonate-C is held in the upper 100 cm of the world's soils. Mean C: N ratios of soil organic matter range from 9.9 for arid Yermosols to 25.8 for Histosols. Global amounts of soil nitrogen are estimated to be 133–140 Pg of N for the upper 100 cm. Possible changes in soil organic carbon and nitrogen dynamics caused by increased concentrations of atmospheric CO₂ and the predicted associated rise in temperature are discussed.