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施磷对镉胁迫下黄瓜苗期光合作用及抗氧化酶系统的影响 总被引:1,自引:0,他引:1
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对辽东山地典型冰缘地貌上覆土壤的粒度、常微量化学元素进行测试分析,结果表明:土壤颗粒组成包括黏粒20.79%、粉粒69.54%和砂粒9.67%,平均粒径整体偏细,约为6.45Ф,不同土壤类型、地貌类型及坡向的粒度分布存在一定差异。土壤元素化学组成以SiO2(45.60%),Al2 O3(12.90%),Fe2O3(3.90%),K2O (2.17%)为主,最大比例可达73.36%。元素Ca,Na,P,Sr显著淋溶,而Mn,Ti,Cu,Zn则相对富集,其他元素迁移不甚明显。少数元素还表现出与粒度分布存在显著关联,其中K,Na,Sr,Ba多存在于砂质土壤中,而元素Ti则容易在粒度更细致的黏土颗粒中留存。化学风化指数CIA均值约为65.50,Rb/Sr约为0.70,反映风化程度较低,且长期经历干冷气候,A—CN—K三角模型表明,研究区土壤风化以脱钙钠、富铝为主,风化水平尚处于低等风化阶段中后期。 相似文献
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利用室内培养实验,分析燥红壤和砖红壤中分别施加N0(不添加氮素)、N1(氮添加量为100mg·kg−1)、N2(氮添加量为200mg·kg−1)和N3(氮添加量为300mg.kg−1)4个水平氮后对土壤性质及N2O、CO2排放的影响。结果表明:氮肥添加显著降低了土壤pH和有机碳含量。相较于N0,燥红壤N1、N2和N3处理pH和有机碳降幅分别为8%~18%和4%~12%,砖红壤降幅分别为5%~23%和3%~15%;添加氮肥后各处理土壤全氮含量显著增加,燥红壤和砖红壤分别增加15%~54%和13%~52%。氮施入增加了土壤NH4+−N和NO3−−N含量,各处理土壤铵态氮和硝态氮含量均表现为N3>N2>N1>N0。氮添加促进土壤N2O和CO2排放,相较于N0,燥红壤N2O和CO2累积排放量分别增加1176%~2425%和124%~281%,砖红壤分别增加1054%~1887%和138%~256%。施氮量和土壤类型是影响农田土壤N2O和CO2排放的重要因素。土壤N2O和CO2排放与施氮量呈线性显著相关,减少施肥是降低土壤N2O排放最直接和最有效的措施。与砖红壤相比,燥红壤N2O和CO2排放对氮素添加的响应更敏感。 相似文献
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《土壤通报》2018,(6)
黄土高原第四纪黄土之下,埋藏着更加古老的新近纪红黏土。以黄土高原甘肃西峰剖面和灵台剖面为例,采集了两个剖面第四纪黄土和古土壤与新近纪红黏土典型样品,比较了各自风化强度和磁性特征的差异。结果表明,新近纪红黏土样品的风化强度与第四纪古土壤较为接近,远强于第四纪黄土;但新近纪红黏土磁化率显著减弱,在西峰剖面平均只有古土壤的1/5、黄土的1/2;在灵台剖面平均亦不到古土壤的1/2,并小于黄土。两剖面黄土、古土壤与新近纪红黏土磁化率与有机质和活性铁含量呈显著正相关,说明有机质含量与铁活化程度对磁性矿物的含量有显著影响。因此,新近纪红黏土磁性的减弱,可能由于沉积年代久,有机质含量减少,氧化铁矿物老化,磁赤铁矿转化成赤铁矿;也有可能与地下水活动,导致磁性矿物的溶蚀有关。有关机理仍需作进一步研究。 相似文献
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施用常规磷水平的80%可实现玉米高产、磷素高效利用和土壤磷平衡 总被引:5,自引:2,他引:5
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以洛川坡头和兰州九州台黄土剖面为例,系统地观测和描述了各层黄土与古土壤的形态(包括微形态)特征,选取了10个土壤形态属性以评价古土壤发育状况:红化作用(颜色彩度和色调)、总质地(质地类型、粘结性和可塑性)、黑化作用(颜色亮度)、微结构(类型、结构性发育程度、孔隙类型和总孔度)、细物质(丰度)、原生碳酸盐(丰度)、黑云母(丰度及蚀变程度)、铁氧化物(丰度)、次生碳酸盐(类型及丰度)和淀积粘粒(干涉色、淀积粘粒特征、胶膜丰度、胶膜厚度)。在此基础上,建立了土壤发育指数,并初步讨论了该指数在环境变化研究方面的应用。 相似文献
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[目的]厘清不同前处理方法对土壤颗粒组成(PSD)测定结果的影响,对土壤水分运移、养分迁移、土壤侵蚀和泥沙搬运过程研究有重要意义。[方法]选择典型紫色土人工林地剖面土壤(0—110 cm)为研究对象,采用浸泡、振荡的物理方式,H2O2,HCl处理的化学方式等9种前处理方式,然后用Mastersizer2000激光粒度仪进行颗粒分析。[结果](1)各物理前处理中值粒径较干测(对照)平均减小33.79μm,其中浸泡、振荡2 h、振荡10 h中值粒径依次减小,但其对黏粒的释放作用较弱,不同振荡时间之间黏粒含量无显著差异(p>0.05)。各化学处理中值粒径较对照平均减小32.72μm,其中H2O2处理总体比HCl处理分散作用更强,该处理下黏粒含量为所有处理中最大,平均>4%。(2)各物理前处理方式下,不同土层间颗粒含量总体无显著差异。对不同H2O2用量的敏感性中土层(30—70 cm)>下土层(70—110 cm)>上土层(0—30 cm)... 相似文献
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[目的]揭示污泥堆肥施用后土壤单位有机碳矿化及温度敏感性(Q10)对于市政污泥资源化利用和土壤碳库稳定性的主控因素,并进而为市政污泥处理及土壤有机碳固持提供理论支撑。[方法]以黄土丘陵区退化草地土壤为研究对象,测定了不同污泥堆肥添加比例(0,2.0%,5.0%,10.0%,15.0%,20.0%)和培养温度(15℃,25℃和35℃)下土壤有机碳矿化速率,探讨了污泥堆肥添加对土壤有机碳矿化特征和Q10的影响。[结果](1)与CK相比,不同污泥堆肥添加在培养初期土壤单位有机碳矿化速率显著增加(p<0.01),之后迅速下降直至趋于稳定;而施用污泥处理组的土壤单位累积矿化量是CK的1.6~4.2倍,在施用比例达到10.0%~20.0%时其有机碳矿化速率与累积矿化量均差异不显著。(2)运用一级动力学方程,拟合不同温度不同污泥添加土壤单位有机碳矿化动态均达到较好效果(R2>0.95),潜在矿化势(C0)值在6.92~39.60 mg C/g差异显著(p<0.05),土壤有机碳矿化速率常数(k)... 相似文献
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G.K. Asamoa 《Geoderma》1973,10(4):285-297
The distribution of particle size and Na-dithionite-extractable (di-Fe2 O3) and NH4-oxalate-extractable (ox-Fe2O3) iron oxides were investigated in twelve soil profiles representing latosols and groundwater laterites. Soil profiles studied were selected from the major ecological zones of Ghana. The pattern of distribution of free Fe2O3 was closely related to that of clay (< 2μ) in soil profiles of the humid forest zones where clay content was more than 40% in the B horizons. In soil profiles of the relatively dry savannah zones with less than 40% clay in the B horizon, the pattern of distribution of free Fe2O3 was closely related to that of silt (2–20 μ). The amount of free Fe2O3 in the soils appeared to be related to kind of parent rock or parent material and to climatic factors operating in the various ecological zones. Using the amount of di-Fe2O3 in the B horizon as a basis for assessing the relative degrees of pedogenesis in soil profiles developed from the same kind of parent material, it was concluded that soil profile development had progressed most in the rain forest zone. Free Fe2O3 was considered as having reached an advanced stage of crystallinity or aging in most of the soils because of the low ox-Fe2O3/di-Fe2O3 ratios in the solums of most of the soil profiles. Soils studied were placed in the ferrallitic and ferruginous soil classes of D'Hoore. The great soil groups could not be characterized by depth function curves of free Fe2O3. However, it was proposed that the relative amounts of di-Fe2O3 in the B horizons of the soil profiles could be used as a basis for classifying these soils at the family level. 相似文献
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以甘肃武都地区、云南小江流域发育的泥石流体为研究对象,采用地球化学元素分析方法,分析不同地区,不同时代泥石流体中化学元素的分布、分配、迁移和富集的规律,并对泥石流沉积物中的硅铝系数(SiO2/Al2O3)、CaCO3含量、pH值、有机质含量所反映的气候变化特点进行了探讨.结果表明:第四纪泥石流的地球化学特征有别于其它类型的第四纪沉积物;青藏高原东缘第四纪泥石流体中SiO2、CaCO3、有机质含量表现为时代越老含量越高,而Al2O3、K2O含量则表现为时代越老含量越低;硅铝系数表现为时代越老越高,显示了第四纪时期该地区气候波动的总体趋势是干燥程度逐渐增加.研究结果对分析青藏高原的阶段性隆升具有一定的借鉴意义. 相似文献
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在宁夏灌区淡灰钙土上,通过田间试验的方法,研究了喷灌和漫灌条件下不同氮磷钾施用量对春玉米产量和土壤水盐运移动态的影响。结果表明:不同施肥处理的平均产量为6.9~13.2 t/hm2,变异系数为2.7%~13.6%。相对于对照处理,不同氮磷钾配比都能显著提高产量(不施氮肥处理除外,P < 0.05),增产率为12.7%~92.5%。氮磷钾施用量与春玉米产量都服从二次曲线关系,增产效应为氮肥 > 钾肥 > 磷肥。在玉米生育期内,喷灌更有利于0—20 cm和20—50 cm土层土壤水分分布的均匀性,而漫灌造成土壤水分向深层50—80 cm运移。在喷灌条件下,土壤盐分通常表聚在0—20 cm土层,其最高含量可达2.11 g/kg,而漫灌使盐分向深层土壤运移,50—80 cm土层盐分含量达0.53~1.07 g/kg。因此,在淡灰钙土春玉米种植条件下,喷灌配合氮磷钾施肥可显著增产,但其对耕层土壤的洗盐效果不及漫灌施肥。 相似文献
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我国苹果园施肥现状、土壤剖面氮磷分布特征及减肥增效技术 总被引:2,自引:1,他引:1
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冬小麦?夏玉米体系磷效率对塿土磷素肥力的响应 总被引:2,自引:2,他引:0
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Chemical characteristics and potential source of fulvic acids leached from the plow layer of paddy soil 总被引:2,自引:0,他引:2
To understand better the chemical characteristics and source of dissolved organic matter (DOM) leached from the plow layer of rice paddies, a lysimeter study was conducted, which simulated submerged paddy topsoil during rice growth. The fulvic acid (FA) fraction in the percolation water from the lysimeter was collected by adsorption onto insoluble polyvinylpyrrolidone (PVP), and the temporal variations in its elemental composition, molecular size distribution, IR spectra, 13C CPMAS NMR spectra, and δ13C values were investigated. The proportion of the FA fraction to bulk DOM varied greatly, but the chemical characteristics of the FA fraction did not change appreciably during the experimental period. Thus, it is considered that the changes in the DOM composition in percolation water were mainly due to the differing contributions of the FA fraction. Further, to investigate the source of the FA fraction in the leachate, the chemical characteristics of the FA fraction in the leachate were compared with those extracted from the plow layer soil. A sequential extraction of the FA fraction was conducted using a sequence of water, 0.25 M Na2SO4, 0.1 M Na4P2O7 (pH 7.0), 0.1 M Na4P2O7 (pH 10.5), and NaBH4+0.1 M Na4P2O7 (pH 10.5). It was found that the water- and 0.25 M Na2SO4-extractable fractions, which were most mobile, were not the only source of the FA fraction in the leachate. The small molecular size sub-fraction of the NaBH4+0.1 M Na4P2O7 (pH 10.5)-extractable FAs, most of which are probably bound mainly to iron oxides, are considered to be another source of the FA fraction leached from the plow layer of paddy fields. 相似文献