Effect of Organic Manure and Chemical Amendments on Soil Properties and Crop Yield on a Salt Affected Entisol

A field experiment was conducted for two consecutive years in a farmer's field at Haji Mora Village, Dera Ismail Khan (D.I. Khan) in the Northwest Frontier Province (NWPP) of Pakistan to compare various management practices, such as the effect of various organic manures and gypsum in a rice-wheat cropping system on a saline-sodic Entisol (Zindani soil series). The treatments consisted of 1) a control (rice-wheat), 2) gypsum, 3) farmyard manure (FYM), 4) berseem (Trifolium alexzndrinum L.) as green manure (GM), and 5) dhancha (Sesbania sp.) as GM. All treatments increased yields of both rice and wheat significantly (P < 0.01) over the control, with the green manure treatments proving more economical than the others; while they decreased pH, electrical conductivity (EC), and sodium adsorption ratio (SAR) of the soil. Saturation percentage and available water of the soil were raised for all treatments due to an increase in organic matter content of the soil.

陕西三种类型土壤剖面硝酸盐累积、分布与土壤质地的关系

研究了陕北黄绵土,关中(土娄)土与陕南水稻土土壤剖面中硝酸盐的分布与累积,分析了硝酸盐淋移与土壤剖面粘粒含量的关系.结果表明,黄绵土由于粘粒含量少,土壤疏松,氮肥施入土壤后硝化作用速度快,氮素多以硝态氮存在于土壤中,遇到过量的灌溉或降水,容易引起硝酸盐淋失.在米脂的川道地,施肥2个月后,硝酸盐峰值在50 cm 左右,4个多月后,峰值下移至100 cm 左右,6个月后,该峰值下降到130 cm 左右,一年内,硝酸盐的峰值已经消失,分布在130至 350 cm 之间.因此,在黄绵土地区可以灌溉的川道地,氮素损失的主要途径是硝酸盐淋失.关中(土娄)土,粘粒含量相对较高,硝化作用速度快,但由于在80-120 cm有一粘化层,阻碍了水分与硝酸盐的向下淋移,使得大部分硝酸盐累积在0-100 cm 土层,其累积量占到0-400 cm总累积量的64% ～ 74%,而200-400 cm仅占到7% ～ 13%.而且淋移到100 cm 以下的硝酸盐,也通过反硝化损失了.陕南水稻土,由于深层土壤水饱和,硝酸盐难以向下淋移,氮素主要累积在土壤表层.由于下层土壤长期处于厌气条件,即使淋移到下层的硝酸盐也通过反硝化作用而损失掉了.

新疆和田开发区土壤系统分类研究

为了确定新疆和田开发区的土壤系统分类归属,对该区约220 km2待开垦土地进行了调查,分析了不同类型土壤剖面的理化性状,并对其诊断层和诊断特性进行了鉴定。结果表明,该地区棕漠土、风沙土、草甸土、盐土(按土壤发生学分类)在中国土壤系统分类中分别为普通石膏正常干旱土、弱盐干旱砂质新成土、普通简育干旱雏形土和普通干旱正常盐成土,最后对各土类提出了相应的利用措施。

中国砂质新成土的系统分类

以土壤的诊断层和诊断特性为依据 ,以土壤发生学作指导 ,阐述了我国砂质新成土的系统分类。砂质新成土是新成土纲中具有砂质沉积物岩性的土壤 ,相当于我国过去土壤分类中的“风砂土” ,是指风成砂性母质上发育的土壤 ,其形成过程可以划分为 :流沙上的成土阶段、半固定沙上的成土阶段和固定沙上的成土阶段 ;具有细土累积、结皮形成和有机质聚集三个成土特点。砂质新成土的控制层段的深度标准规定为 1～ 2m。砂质新成土亚纲可以划分为 :寒冻砂质新成土、潮湿砂质新成土、干旱砂质新成土、干润砂质新成土和湿润砂质新成土等 5个土类 ,在土类之下 ,又可主要根据是否偏离中心概念、是否具有附加过程的特征和是否具有母质残留的特征 ,进一步划分为永冻寒冻砂质新成土等 2 2个亚类 ,并列有检索系统。最后 ,以砂质新成土的土类为单元 ,论述了其土壤分布、特征及其改造利用方向。

豫东平原土壤养分时空变异特征研究

通过土壤耕层养分特征分析，论述了不同农田利用和管理措施下不同土壤类型的土壤养分时空变异特征及硝态氮的累积特性。由于“重氮磷，轻有机肥，忽视钾素补给”，土壤养分变化以退化趋势为主，钾素耗竭性明显。硝态氮累积表现为从上向下递减、由上至下递增和相对积累于土体某一深度3种变化趋势。提出了土壤持续利用途径。

黄土─土壤结构剖面构型的形成及其重要意义

该文主要从黄土地区特殊的环境条件入手，反复论证了黄土—土壤结构剖面的形成是在黄尘沉积、成壤和成岩三种过程同时同地进行而形成的现象，并详细论述了这三种过程的实质及其演变规律后认为：黄土土壤结构剖面主要来自：①在干冷时期成壤过程中形成的团粒和团块状结构，这类结构是在原先黄尘堆积时形成的黄土点棱接触支架式多孔结构的基础上多少受植物根系的固结缠绕和有机物的掺加而形成的。②在温湿时期成壤过程中形成的团粒、海绵状结构，更由于生物粘化作用的强烈进行，在腐殖质大部矿化后新形成粘粒的包裹作用下形成棱块和棱柱状等结构。③富含钙质的水在下伏缓渗层的上部滞留，并将ＣａＣＯ＿３淀积下来形成沙礓或钙板，那时孔隙全被封闭而成托水层。由此不难理解黄土土壤结构剖面构型的深入研究将对全球变化，尤其周期的气候变化及其波动，黄土高原的开发和生态环境的改善，以及成壤过程的实质等方面的研究都具有非常重大的意义。

Geochemistry of cryoconite and soils in the Central Caucasus region and its environmental implications

Climate change and deglaciation are active processes in current changing environments.In the Central Caucasus region rapid degradation of glaciers is caused often by the formation of superficial blackcolored sediments-cryoconite.Cryoconite plays a crucial role in changing ecosystems and may contribute to the formation of primary soils after glacier retreat.Over the past 20 years,the frequency of mudflows and other dangerous mountain events have increased in the Central Caucasus,which is associated with the glacial retreats.Intensification of tourism results in increasing of traffic,recreational activity and environment contamination.Determination of the cryoconites geochemical properties in comparison with other types of sediments and local soils is crucial for investigation of geochemistry and contamination state of superficial glacial sediments.This environmental aspect is important in terms of the Central Caucasus settlements safety under conditions of deglaciation and anthropogenic influence.The sediments studied(cryoconite,mudflow,moraine)were sampled at Garabashi and Skhelda glaciers as well as some local soils at the Baksan gorge.Sampled materials were investigated in terms of physicochemical and agrochemical parameters.The concentrations of trace elements(Cu,Pb,Zn,Ni,Cd)were also determined and contamination indices(geoaccumulation index-Igeo,contamination factor-CF and degree of contamination-Cdegree)were used to evaluate the pollution status of studied material.Data obtained shows much higher content of organic carbon in soils(up to 7.82%)in comparison with cryoconite(max.1.63%)due to presence of vegetation,however,the basal respiration values in some cases were similar betweenсryoconite and soils,indicating high rates of microbial activity in a cryoconite holes.It was found that almost all materials studied have sandy structure.Cryoconite sediments on both of the glaciers are enriched with phosphorus,high values of K_(2)O(max.298 mg·kg^(-1))and N-NH4(max.247 mg·kg^(-1))are identified at Garabashi glacier which could be influenced by long-distant transfer but mostly a result of local anthropogenic activity.In case of trace elements,the highest content is identified for Zn(62 mg·kg^(-1) for cryoconite and 60.5 mg·kg^(-1) for soils)and the most contaminated materials are cryoconite from Garabashi glacier and Entisols,up to moderate level,which is mostly associated with local anthropogenic activity.

Effect of Foliar Copper Fertilizer on Pineapple cv. N36 Planted on BRIS Soil at East Coast of Peninsular Malaysia

The physical and chemical properties of BRIS soil are unsuitable for agricultural purposes. A proper fertilizer and crop management practices are required. An attempt was made to convert this land into a sustainable production land for pineapple. Therefore, the objective of the study was to determine the effect of foliar copper fertilizer on the growth and fruit quality of pineapple cv. N36, for fresh consumption planted in Entisol type BRIS soil at the east coast of Peninsular Malaysia. The complete randomized design （CRD） method with three replications was used at 0 to 6.6 kg.ha^-1 of copper sulfate. Results demonstrated that the unpleasant effect of BRIS soil on brix value was restored with copper fertilizer. The most suitable quantity of foliar copper fertilizer for pineapple cv. N36 planted in Entisol type BRIS are between 1.6 to 3.3 kg.ha^-1 of copper sulfate.

Genesis and Classification of Some Soils of the River Nile Terraces: A Case Study of Khartoum North, Sudan

Soils developed in the alluvium terraces of the River Nile at Khartoum North, Sudan was analyzed in an attempt to classify it as well as to refer them to their origin. Three river terraces comprising nine profiles were selected to cover the physiographic positions. Lack of B horizon and carbonate accumulation were main pedogenic processes in subsurface horizons, whereas orhric epipedon was developed on top soil surface. The microscopic inspection of heavy sand mineralogy indicated that the origin of the sand was the Ethiopian plateau. The most abundant clay mineral was smectite, followed by illite, kaolinite and chlorite. The presences of micas (illite) and chlorite in all studied soil samples might emphasize that these soils were young from the pedological viewpoint and less weathered. The soils of the River Nile terraces at Khartoum North were classified into: Typic Torrifluvents (1st terrace), Entic Haplocambids (2nd terrace) and Typic Haplocambids (3rd terrace). Mineralogy analysis indicated that the Entisols and Aridisols of the River Nile terraces in the study area had the same origin that of the igneous and metamorphic rocks from Ethiopian plateau.

生物结皮发育对风沙土盐基离子释放和矿物风化的影响

为探明生物结皮发育对风沙土盐基离子释放和矿物风化的影响,以进一步明确生物结皮的风化成土作用。以典型风沙土上发育的生物结皮为对象,通过模拟淋溶试验比较不同类型生物结皮(藻结皮、藻—藓混生结皮和藓结皮)覆盖土壤的盐基离子释放规律,探究盐基离子释放量随淋溶液pH的变化趋势,以及量化生物结皮覆盖土壤的矿物风化速率。结果表明:矿物风化反应阶段不同种类盐基离子的淋出量均较为平缓,生物结皮覆盖土壤的各盐基离子总淋出量表现为Ca^(2+)>K^(+)>Mg^(2+)>Na^(+),其中藻结皮覆盖土壤的盐基离子总淋出量最高,比无结皮、混生结皮和藓结皮分别增加了112.0%,31.2%,27.1%。淋溶液pH显著影响盐基离子的淋溶释放,且其作用程度因离子种类和结皮类型而异。生物结皮覆盖提升了土壤的易风化矿物含量、风化程度和速率,藻结皮、混生结皮和藓结皮覆盖土壤的风化速率相比无结皮分别提升了61.2%,27.1%,152.6%,并且风化速率随淋溶液pH降低而提升。综上,生物结皮能显著促进风沙土矿物风化,其对风沙土改良和修复具有积极意义。

河南开封土壤养分变化特征及其持续利用途径研究

通过 1 984～ 1 998年河南开封不同土壤耕层有机质与氮磷钾养分分析 ,论述了不同农业利用方式和农田管理措施下不同土壤耕层养分的时空变化特征和硝态氮累积特性 .由于“重氮磷 ,轻有机肥 ,忽视钾素补给” ,土壤养分变化的总趋势以下降 ,钾素耗竭性明显 .土壤养分空间变化较为复杂 ,但不同土壤间耕层养分为普通淡色潮湿雏形土 >底锈干润雏形土 >石灰淡色潮湿雏形土 >灌淤旱耕人为土 >简育干润雏形土 >干润砂质新成土 .硝态氮累积表现为由上至下递减或由上至下递增和相对积累于土体某一深度 .最后研究提出了土壤持续利用的有效技术途径 .

塔里木盆地潮湿冲积新成土形成特点

干旱内陆地区的潮湿冲积新成土主要位于大河两岸的河滩地 ,它的地下水位高 ,土壤水分为潮湿状态。受到洪水的影响 ,虽然盐分已具有表聚 ,但缺乏盐结皮层。由于不断有新的泥沙沉积物加入 ,土壤无明显发育 。