共查询到20条相似文献,搜索用时 31 毫秒
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耕层养分状况是决定土壤肥力水平的重要因子,定期检测耕层养分变化及其发地趋势,是人们制定合理施肥方案及改良措施的重要依据。 相似文献
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淮北平原砂姜黑土区砂姜的空间分布及其驱动因素 总被引:1,自引:0,他引:1
砂姜黑土的典型特征就是土体内含有“砂姜”。基于经典统计学及地统计学方法,研究了淮北平原砂姜黑土区东西(河南上蔡到安徽泗县)及南北(河南鹿邑到安徽怀远)两条典型样带0~100 cm土层内砂姜含量分布及0~20 cm土壤性质、地形因子和气候特征。结果表明:(1)东西样带内从西向东、南北样带内从北向南,砂姜含量逐渐增多,埋深也逐渐变浅;(2)两条样带砂姜含量随土层的加深呈增加的趋势,而极大值出现在20~60cm土层,砂姜以2~5mm粒级的占比最大(40%~44%);(3)相关分析表明砂姜含量与蒙脱石组成比例(r=0.321,P <0.01)、年均降水量(r=0.416,P <0.01)、年均温度(r=0.369,P <0.01)呈正相关,而与土壤全钙(r=–0.279,P <0.05)、高程(r=–0.387,P <0.01)、年均蒸发量(r=–0.392,P<0.01)呈负相关。可见,淮北平原砂姜含量受地形、气候条件和土壤性质等因素的共同作用,形成了“西低东高,北低南高”空间分布格局。 相似文献
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长期秸秆还田对砂姜黑土矿质复合态有机质稳定性的影响 总被引:7,自引:2,他引:5
依托10 a定位试验研究了秸秆还田对典型砂姜黑土有机矿质复合体中有机质稳定性的影响机制。田间试验设置5个处理:氮磷钾配施下的小麦和玉米秸秆双季还田(WMS+F)、小麦秸秆还田(WS+F)、玉米秸秆还田(MS+F)、非秸秆还田(F)处理,以不施肥模式下的非秸秆还田为对照(CK)。结果显示,铁铝键合态和紧密结合态有机质含量累计占土壤总有机质的88.70%,且三者变化趋势一致,均呈现WS+F≈WMS+F≈MS+FFCK,并与土壤短程有序、有机结合态铁铝氧化物呈显著正相关,但与非晶型铁铝氧化物呈负相关性。秸秆还田显著促进了土壤有机质累积,并受到土壤铁铝键合态有机质的影响,但由于非晶型铁铝氧化物生成速度较慢,限制了土壤有机质的进一步累积。土壤紧密结合态有机质对其全量的贡献明显高于铁铝键合态有机质,相关机制值得进一步研究。 相似文献
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土壤有机-无机复合体是土壤肥力的物质基础之一,不仅依随成土过程而发生变化,人类耕作利用也可产生影响。 相似文献
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本文通过实验对砂姜黑土的水分特性及其与土壤易旱的关系进行了分析研究。结果表明:砂姜黑土持水性能较差,有效水分不仅含量较低,而且低吸力段所占比重较小;比水容量随吸力增大而急剧减少,在10—30kPa时即已减小到10-7数量级(ml/g·Pa)。土壤导水性能弱,土壤吸力>30kPa后水分移动极其缓慢。说明土壤的供水容量和供水强度均较小,不利于对作物的及时供水。土壤毛管水上升速度缓慢,上升高度小,不利于作物对地下水的利用。土壤上部土层蒸发强度大,不利于保水;下部土层毛管性能微弱,水分运行缓慢,虽有利于保水,但不能及时补充根层所需的作物供水。这些特性综合反映了砂姜黑土的抗旱性较弱,是土壤易旱的主要原因。 相似文献
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EFFECTS OF solUTION: SOIL RATIO AND VIGOUR OF SHAKING ON THE RATE OF PHOSPHATE ADSORPTION BY SOIL 总被引:2,自引:0,他引:2
The effects were measured of varying the solution: soil ratio, and the vigour of shaking on the rate of adsorption of phosphate. One soil appeared to break down with vigorous shaking, prior to adding phosphate, especially at low solution: soil ratio. As a result, subsequent phosphate adsorption was faster. With gentle shaking, there was no effect of solution: soil ratio with the soil. Another soil was more stable and there were only small differences due to vigour of shaking and no effect of solution: soil ratio with any method of shaking. The change in phosphate concentration was not proportional to the reciprocal of time as reported by Ryden and Syers (1975) and Hope and Syers (1976). Hence the validity of extrapolating from short sections of reciprocal-time graphs in order to estimate equilibrium is questioned. 相似文献
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THE ADSORPTION OF COPPER BY SOIL MATERIALS AT LOW EQUILIBRIUM SOLUTION CONCENTRATIONS 总被引:1,自引:0,他引:1
The adsorption of copper by individual soil components (organic matter fractions, oxides and clay minerals) was examined at equilibrium solution concentrations of copper within the range found in natural soils, the distribution of copper between solution and solid phases being measured by means of labelling with radioactive 64Cu. At these low solution concentrations it was found that the copper adsorption isotherms were essentially linear. The oxides and organic materials adsorbed the greatest amounts of copper. The concentration of copper in natural soil solutions will be controlled by these materials to a far greater extent than by the clay minerals, the influence of which may be negligible in some soils. Solution concentrations of copper are relatively unaffected by both the background concentration of major cations and by changes in pH within the ionic strength and pH range found in normal agricultural soils. Copper adsorption studies with humic and fulvic acids showed that total solution copper concentrations could be greatly enhanced above the equilibrium levels for ionic copper by the presence of soluble organic complexes. The importance of taking into account the presence of such copper complexes in soil copper studies is emphasised. 相似文献
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The density of hydrophobic sites on the surface of some soil minerals has been determined by adsorption of aliphatic alcohols from aqueous solution. The amount of alcohol adsorbed was evaluated by measurements of the surface tension of the solution. 相似文献
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采用平衡批处理法,研究了模拟根系分泌物——酒石酸溶液的浓度(0~80 mmol L-1)、pH(2.5~7.0)对酸性磷酸酶在针铁矿、高岭石及黄棕壤和砖红壤胶体(<2μm)上的吸附及比活性影响。结果表明,当酒石酸浓度由0 mmol L-1(作为对照)升高至80 mmol L-1时,酸性磷酸酶在供试土壤胶体和矿物表面的吸附量先急剧降低(0~5mmol L-1之间),后逐渐达到平衡;以羟基化表面为主的针铁矿对酸性磷酸酶的吸附百分率受酒石酸浓度的影响最大,吸附百分率从对照的96.2%降至80 mmolL-1酒石酸浓度时的33.7%,其他以层状铝硅酸盐矿物为主的供试土壤胶体和高岭石则受影响较小,吸附百分率从对照的76.3%~60.6%降至80 mmol L-1酒石酸浓度时的56.2%~41.6%。酸性磷酸酶在酒石酸体系中的最大吸附pH点均在该酶的等电点酸侧,这可能与酒石酸对矿物表面的电荷性质改变有关;酒石酸体系中,针铁矿上酸性磷酸酶的比活性远高于其它供试土壤胶体,该酶的最适比活性点随胶体类型的不同而无变化或有所高移。 相似文献