新造雅阳系土壤养分变化的研究

随着城乡建设和经济发展的需要,征用耕地面积不断扩大。通过新造农田复垦在较短的时间内能实现耕地面积总量的动态平衡,但新造农田复垦达到耕地质量标准尚需较长的时间。本文以新造雅阳系3个不同耕作年限耕层土壤养分变化的分析研究,其结果表明,耕作年限在15年后,土壤有机质、速效P、速效K含量才能达到老雅阳系耕层土壤养分水平,即耕地质量标准,而全N含量存在着一定的差异。     

Factors of soil formation in soil classification systems

The development of soil classification systems in Russia has been accompanied by certain changes in the attitude toward the factors of soil formation as criteria for separating soil units at the high taxonomic levels. The works of N.N. Rozov supported the traditional priority of the bioclimatic approach to the separation of soil types and subtypes in the classification systems of 1967 and 1977. In the new classification of Russian soils, the factors of soil formation are taken into account in a “hidden” form, through the diagnostic horizons and features reflecting the facial and zonal changes in the character of the pedogenesis and through the separation of several high-level soil taxa developing under specific combinations of lithological and geomorphic conditions. Ecological matrices illustrating the position of the soil types distinguished on the basis of substantive criteria in the field of soil-forming factors are included in the latest version of the new Russian soil classification system. The idea of these matrices fully corresponds to the logic of the factor-genetic soil classification system developed in the works of N.N. Rozov.     

Myxomycetes in soil

The myxomycetes are a group of protists that form a monophyletic taxon in the phylum Amoebozoa. Evidence of their evolutionary success is the fact that they account for more species (ca. 900 are currently recognized) than the combined total for the rest of the Amoebozoa. Moreover, myxomycetes are present in every terrestrial environment investigated to date and also, as amoebae or flagellated cells, in aquatic environments where they cannot form fruiting bodies. Even if culture-based methods tend to underestimate their occurrence in soil, myxomycetes probably account for ∼50% of soil amoebae. The emergence of molecular-based methods has revolutionized our concepts of biodiversity, but myxomycetes are conspicuously absent from all environmental surveys. Herein we show that this is due to their highly diverging SSU rRNA gene sequences, which contain numerous Group I introns.Further proof comes from a recent study that used a massive sequencing approach without primer bias to amplify RNAs. The results obtained show that the mycetozoans (myxomycetes along with dictyostelids and protostelids) are indeed a dominant group of soil protozoans.     

节水灌溉对盐渍土盐分调控与土壤微生物区系的影响

河套灌区是我国大型自流灌区之一,盐渍化是该区土壤主要障碍因素之一。目前,河套灌区葵花田生育期灌溉量约为1 100～1 200 m3hm-2,灌溉用水量偏大和地下水位偏高已成为制约当地灌溉农业可持续发展的主要障碍:一方面,水资源浪费严重;另一方     

An equivalent soil mass procedure for monitoring soil organic carbon in multiple soil layers

Soil carbon stocks are commonly quantified at fixed depths as the product of soil bulk density, depth and organic carbon (OC) concentration. However, this method systematically overestimates OC stocks in treatments with greater bulk densities such as minimum tillage, exaggerating their benefits. Its use has compromised estimates of OC change where bulk densities differed between treatments or over time periods. We argue that its use should be discontinued and a considerable body of past research re‐evaluated. Accurate OC estimations must be based on quantification in equivalent soil masses (ESMs). The objective of this publication is to encourage accurate quantification of changes in OC stocks and other soil properties using ESM procedures by developing a simple procedure to quantify OC in multiple soil layers. We explain errors inherent in fixed depth procedures and show how these errors are eliminated using ESM methods. We describe a new ESM procedure for calculating OC stocks in multiple soil layers and show that it can be implemented without bulk density sampling, which reduces sampling time and facilitates evaluations at greater depths, where bulk density sampling is difficult. A spreadsheet has been developed to facilitate calculations. A sample adjustment procedure is described to facilitate OC quantification in a single equivalent soil mass layer from the surface, when multiple‐layer quantification is not necessary.     

Hydroxyanthraquinones in soil

(1) Seven hydroxyanthraquinone pigments were separated from Sochiken soil 1 (Kuroboku soil). Chrysotalunin, chrysophanoi, chrysazin, and skyrln were identified by spectroscopy and co-chromatography with authentic compounds. The presence of oxyskyrin was presumed by spectroscopy and color reactions.

(2) A homologue of 4,9-dihydroxyperylene-3, 10-quinone was also detected.

(3) The amounts of hydroxyanthraqulnones in eight soils of different types were determined by colorimetry using chrysotalunin as a standard pigment. Their amounts varied from 3 to 11 ppm.

(4) The main pigment extracted from most soils was chrysotalunin, though it was not detected in Miyahara, Higashiyama, and Kisokoma soils.     

紫色土坡耕地埂坎土壤抗剪性能对含水率的响应

选取三峡库区典型紫色土坡耕地埂坎进行试验,通过室内三轴试验研究不同含水率(质量分数6%、11%、16%、21%、26%和31%)对埂坎土壤抗剪强度指标的影响,以深化紫色土坡耕地埂坎力学性质研究。结果表明:1)试验含水率范围内,紫色土坡耕地埂坎土壤黏聚力受含水率影响显著(P0.05),且随着含水率增加呈现出先增大后减小的趋势,明显的峰值出现在含水率质量分数11%左右,黏聚力为85.52 k Pa;2)埂坎土壤内摩擦角随含水率增加而减小,呈非线性衰减,符合一阶指数衰减规律。高含水率时,衰减缓慢;3)紫色土坡耕地埂坎抗剪强度受含水率变化影响显著(P0.05),埂坎土壤极限主应力差随含水率和围压的变化明显且具有规律性。相同围压下,埂坎土壤极限主应力差随含水率增大而迅速减小,即土体的抗剪强度降低。相同含水率下,极限主应力差随围压增大而增大,低含水率时增加明显,高含水率时增加缓慢。当含水率质量分数达到26%左右,埂坎土壤抗剪强度趋于低值;4)紫色土埂坎土壤的应力-应变曲线随含水率递增依次呈现应变软化型、硬化型和弱硬化型。研究结果可为三峡库区高标准基本农田等工程的埂坎建设提供依据和技术支撑。     

土壤系统分类在大比较尺土壤制图中的应用—以安徽宣城样区为例

提出了制图的指导思想，拟订了上图单元类型，在此基础上详细地阐述了样区大比例尺土壤制图的过程。     

黑土、栗钙土和潮土胡敏酸分子结构的差异性分析

以北方典型的黑土、栗钙土和潮土提取的胡敏酸为研究对象,通过元素分析、傅里叶红外光谱仪及13C核磁共振仪对三者进行结构分析。不同胡敏酸的各种元素含量略有差别,各种官能团含量也不同。元素分析结果来看H/C原子比潮土最高,栗钙土次之,黑土最少;O/C的原子比三者没有明显的差别;C/N比呈现由高到低的次序分别为黑土、栗钙土、潮土。3种胡敏酸的红外光谱吸收峰相似,但吸收强度有差别,如3 352 cm-1和2 931 cm-1处潮土和栗钙土信号强度相当,黑土较低,而在2 580 cm-1处三者信号差异不明显,1 720,1 620,1 420,1 220 cm-1这4个吸收峰信号强弱均为黑土最强,栗钙土次之,潮土最弱。而从核磁共振图谱可以看出潮土结构中含有更多的多糖和蛋白质类结构单元;黑土有机质含量高,芳香化程度也较高。     

秸秆还田深度对黑土腐殖质和酶活性的影响

在田间条件下对耕地黑土3个土层(0~15、15~30、0~30 cm)进行玉米秸秆还田试验,研究不同秸秆还田深度土壤腐殖质各组分含量、土壤酶活性的变化及其相关性。结果表明:还田深度0~15、15~30、0~30cm土壤总有机碳含量与初始相应层次土壤分别增加9.5%、9.9%、10.7%,与0~15 cm相比,秸秆还田深度为15~30 cm时,有利于土壤有机碳的积累。与初始相应层次土壤比,未秸秆还田的土壤总有机碳含量降低了5.8%。土壤各组分有机碳含量与土壤蔗糖酶活性之间显著(或极显著)相关,土壤胡敏素碳含量与土壤过氧化氢酶活性之间显著相关,土壤富里酸碳含量与土壤脲酶活性之间显著相关。     

湘南红壤地区土壤肥力现状及其退化原因

调查结果表明：土壤的肥力已经出现了较为明显的退化现象,如果用土壤养分含量的结果来表示,则有５０％以上出现了肥力退化;如以产量为标准来衡量,则有２５％～３０％出现了退化。其主要表现是：部分土壤酸化;有机质、氮、磷、钾等养分的含量下降。退化的主要原因是施肥结构的无机化趋势上升以及氮、磷、钾化肥的施用比例失调,因此,调整目前不合理的施肥结构和施肥比例,是防止该地区土壤肥力进一步退化的当务之急。     

黑土土壤水分反射光谱特征定量分析与预测

选择单一土类黑土作为研究对象, 并准确调配其不同含水量,实验室测定土壤高光谱反射率,利用光谱分析与统计方法,定量描述了不同含水量黑土反射光谱特征,并建立了黑土含水量反射光谱预测模型,结果表明,随土壤含水量的增加,达到一定阈值（300 g kg-1）,反射率存在过饱和现象,但其倒数对数微分可以有效去除饱和问题;土壤反射率倒数对数微分对土壤含水量的响应表现出三个变化阶段,导致1 870 nm波段的倒数对数微分也表现为非线性变化,需要利用分段函数进行土壤含水量的光谱精确速测。     

土壤酶活性对土壤中土霉素的动态响应

采用室内培养试验研究了土霉素（OTC）对土壤过氧化氢酶、磷酸酶、脲酶、蔗糖酶和脱氢酶活性的影响。结果表明,在整个培养期间,土霉素对土壤过氧化氢酶和土壤磷酸酶活性具有明显的抑制作用;对土壤蔗糖酶和脱氢酶活性在培养前期具有轻微的抑制作用,但培养后期（培养第112 d）具有较强的抑制作用;而对土壤脲酶活性的影响则相反,在培养第1 d,OTC 100 mg/kg处理对脲酶具有显著的刺激作用,以后土霉素对脲酶活性影响不明显。土壤过氧化氢酶和磷酸酶对土霉素污染响应比土壤脲酶、蔗糖酶和脱氢酶更敏感,因而可以表征土壤受土霉素的污染程度。     

Effects of soil erosion on long-term soil productivity in the black soil region of northeastern China

China's northeastern Black Soil Region, one of the country's most important crop production areas, has been seriously affected by soil erosion. This study evaluated the effects of soil erosion on the long-term productivity of this region. We used a modified productivity index (MPI) model (MPI is a number between 0 and 1, with 1 indicating highest productivity) to assess the current effects of soil erosion on soil productivity, as well as to predict long-term change in productivity. Samples from 21 black soil profiles yielded varying MPI values, although most MPI values were indicative of moderate productivity. Organic matter content and available water capacity impact MPI values in the region, whereas soil clay content and pH were less important. Overall, organic matter content and available water capacity of soil profiles decreased consistently as depth of erosion increased. Modeling indicated that MPI in the region will decrease by 0.0052 for each centimeter of topsoil eroded; this rate represents 1% of the current average MPI for the study area. The model predicts a 9.6% productivity reduction over 100 years and a 48.3% reduction over 500 years.     

紫色土坡耕地土壤物理性质空间变异对土壤侵蚀的响应

为了研究不同坡度和坡长的耕地上土壤侵蚀对土壤物理性质空间变异的影响,通过地形测量、137 Cs示踪、土壤物理性质分析等方法对川中丘陵紫色土区土壤物理性质对土壤侵蚀的响应进行了研究,结果表明：在中等坡度（16.60%～25.10%）的梯坡地上,耕作侵蚀处于主导地位,是导致耕层土壤物理性黏粒含量和容重在梯坡地上总体差异不大（CV＜6.3%）,且与137Cs含量不相关的主要原因;在已退耕还林的陡梯坡地上（35.60%）,水蚀占据主导地位,导致耕层土壤物理性黏粒含量和容重均与137Cs的含量显著相关。在长坡耕地上(10.10%),具有分选搬运能力的水力侵蚀占据主导地位,致使耕层土壤物理性黏粒含量与137Cs的含量具有显著的相关关系,而容重却与137Cs含量没有显著的相关关系。川中丘陵区坡耕地上,耕作侵蚀和水蚀共同作用于土层深度,使土层深度在坡顶、上坡最浅,在坡脚最深,顺坡向下逐渐增加。因此,在川中丘陵区不同坡长的坡耕地上,占主导地位的土壤侵蚀类型导致坡耕地上土壤物理性质出现相应的变化。     

复合改良物料对滨海盐土的改土降盐效果与综合评价

为实现泥质滨海盐土低成本快速脱盐后种植经济作物,本研究以磷石膏、牛粪、腐殖酸和玉米秸秆为复合改良物料的原料,利用了"深翻耕、浅改良、高垄作、少滴灌"农艺措施和耐盐植物梯次种植的生物措施,采取L16(45)正交设计开展试验研究,系统分析了不同复合改良物料对泥质滨海重盐土的改土降盐和对经济作物黄蜀葵的增产效果;应用模糊数学评判原理与方法,综合评价了各复合改良物料的改土降盐与增产效应,确定出适合滨海泥质盐土应用的优选复合改良物料。结果表明:在"翻耕40cm,改良30cm,起垄15cm,滴灌土壤基质势控制在?10kPa,前茬种植田菁"的综合农艺措施条件下,本研究中物料成本在2.55～6.01元?m?2的各复合改良物料对泥质滨海盐土均有显著的改土降盐效果,0～10cm土层土壤盐分含量均由10.86g·kg?1下降到2.0 g·kg?1以下, 10～20 cm土层土壤盐分含量下降到2.5 g·kg?1以下; 0～10 cm土层土壤有机质增加到12 g·kg?1以上,土壤碱解氮和有效磷含量提升明显,土壤大团聚体含量增加2.41～7.62倍。以土壤盐分含量、pH、有机质、碱解氮、有效磷、速效钾、微团聚体为评价指标,结合物料成本,筛选出适宜于滨海泥质重盐渍土的最优复合改良物料:22 500 kg·hm?2磷石膏+105 m3·hm?2有机肥+3 750 kg·hm?2腐殖酸+45 m3·hm?2玉米秸秆,该最优复合物料应用两年后,土壤有机质、碱解氮含量最高,与对照相比分别增加181.87%和130.52%,物料施用成本仅4.05元?m?2。     

工业副产品对红壤酸度改良的研究

选择4种工业副产品(粉煤灰、碱渣、赤泥和磷石青),通过室内培养实验研究了它们对酸性红壤的改良效果.结果表明碱渣和赤泥能降低土壤溶液中的毒性形态的Al、可溶性Al以及交换性Al,增加土壤pH、交换性盐基和ECEC,可成为石灰的替代品作为酸性土壤的改良剂,且长期施用不会像石灰那样加剧土壤Mg、K的缺乏.粉煤灰的改良效果不太理想,而磷石青虽然能增加土壤交换性盐基和ECEC,降低土壤的交换性Al,但增加土壤溶液中的毒性形态的Al和可溶性Al,因此不利于表层土壤酸化的改良.加入质子消耗量与土壤交换性酸量等当量的碱渣和赤泥时,红壤pH升高到5.81～6.26,土壤Al的饱和度降低到15%以下,即可消除Al的毒害.根据碱渣和赤泥的质子消耗容量和红壤的交换性酸量来确定改良剂的施入量是估算改良剂用量的可行方法.     

红壤丘陵区农田土壤酸化的时空变化研究

通过GPS技术,采集38个农田土壤样品,研究了红壤丘陵区农田土壤pH的时空间变化特征。结果表明:20年来,江西省兴国县农田土壤pH平均下降0.94个单位。pH下降的面积为645.9 km2,降幅在1.0～2.0个单位,主要分布在千枚岩、花岗岩和红砂岩发育的土壤地区,面积分别为296.1 km2、136.2 km2和42.2km2;pH增加的面积有24.1 km2,主要分布在紫色页岩发育的土壤地区,面积为11.3 km2。从土壤类型看,pH值下降的土壤主要为潴育型水稻土;从海拔上看,pH增加的土壤主要分布在海拔300 m以下的地区,pH降幅最大的土壤主要分布在海拔300 m以下及300～500 m的地区。相关分析显示土壤pH变化量与初始pH呈负相关关系,与海拔、有机质含量、黏粒含量呈正相关关系,通过线性回归模型可以预测pH的变化量。     

洁霉素在黏土和有机质土中的吸附特性研究

抗生素一般是指由细菌、霉菌或其他微生物在繁殖过程中产生的,能够杀灭或抑制其他微生物的一类物质及其衍生物。目前,抗生素被广泛应用于人们的日常生活与水产及畜牧等产业。美国每年应用于水产养殖的抗生素达9.25×104～19.6×104 kg[1],应用于动物养殖中的抗生素每年约8.5×106～11.2×106 kg[2]。