磷动力对油菜生长及产量效益的影响

为磷动力在油菜高产栽培上的推广利用提供理论依据,比较了直播与育苗移栽2种种植方式下施用磷动力1kg/667m^2、2kg/667m^2与45%(15∶15∶15)复合肥25kg/667m^2作底肥时,油菜生长及产量效益的差异。结果表明:施用磷动力1kg/667m^2的油菜苗期株高、最大叶长宽、根湿重、茎叶湿重及开盘直径等指标与施用45%复合肥25kg/667m^2的相当,而施用磷动力2kg/667m^2的多项生长指标均高于复合肥处理;直播和移栽试验各产量性状及产量均以磷动力用量2kg/667m^2时最高,分别比施用复合肥增产20.42%、18.75%,分别比不施用底肥增产49.95%、47.43%,产值分别为917.45元/667m^2、1144.64元/667m^2,利润分别为280.45元/667m^2、458.64元/667m^2,比施用复合肥处理分别增收152.07元/667m^2、177.22元/667m^2,投入产出比亦为最高。因此,在油菜高产栽培中使用磷动力(后期配合钾肥)替代底肥有明显的增产效果,推荐用量为2kg/667m^2。

黑土累积磷的释放动力学特征及主要影响因素

【目的】长期大量施用磷肥致使农田土壤磷快速累积,磷肥增产效率和利用率下降。研究不同施肥措施下土壤累积磷的释放动力学特征及其机制,为累积磷的活化利用和磷肥高效施用提供理论依据。【方法】黑土长期定位试验位于黑龙江省哈尔滨市,在5个不同处理采集土样,分别标记为P1、P2、P3、P4和P5,其Olsen-P含量依次为15.5、20.2、93.2、199和216 mg/kg。采用0.5 mol/L NaHCO3连续浸提法测定5个土壤样品中有效磷的释放量,以5个动力学方程拟合或描述有效磷的释放动力学。采用Hedley法测定了浸提前后土壤活性磷(Resin-P、NaHCO3-Pi、NaHCO3-Po)、中活性磷(NaOH-Pi、Na OH-Po、DilHCl-P)和稳性磷(ConcHCl-Pi、ConcHCl-Po、Residual-P)含量。【结果】连续浸提过程中,供试5个土壤的Olsen-P释放均呈先快后慢的趋势,在浸提1400 min (10次)时基本达到平衡。以米氏方程(Michaelis)、一级方程、Elovich方程、抛物线方程和幂函数方程描述有效磷的释放动力学特征,拟合方程的决定系数(R2)均在0.964及以上(P<0.01),其中又以米氏方程和一级方程为佳,其R2分别为0.9955和0.9922。由米氏方程可知,供试5个土壤的有效磷最大释放量分别为59.8、60.9、332.6、589.7和717.0 mg/kg,随Olsen-P含量的增加而增加,Olsen-P每增加1 mg/kg,磷释放量平均增加3.12 mg/kg;5个土壤有效磷的最大释放量占土壤全磷的比例分别为13.68%、14.86%、45.44%、60.67%和66.45%,也随Olsen-P含量的增加而增加,但土壤浸提残留磷(全磷与可提取有效磷之差)均为373.99 mg/kg左右,说明施磷对土壤残留磷的影响较小,长期施肥累积的磷具有较高的活性。一级方程和Elovich方程表明,黑土有效磷的释放是以扩散为主的动力学过程。连续浸提后,土壤活性磷平均减少了82.9%(67.8%~93.5%),中活性磷平均减少了34.6%(17.2%~52.0%),稳定性磷无显著变化。活性磷中的Resin-P和Na HCO3-Pi显著降低了89.8%(78.5%~96.0%)和84.5%(72.9%~91.3%),这表明Resin-P和Na HCO3-Pi的有效性最高。土壤活性磷库、中稳态磷库、磷释放的动力学方程参数与土壤有机质、Olsen-P、全磷呈显著正相关,与p H呈显著负相关,说明土壤累积磷的释放过程主要受到土壤活性磷、中活性磷、土壤有机质、pH和全磷含量的影响。【结论】黑土固定的残留磷量受施肥的影响较小,施肥累积的磷大部分可以释放,尤其Resin-P和Na HCO3-Pi的有效性最高。黑土中磷的释放符合米氏方程和一级方程,磷释放量随Olsen-P水平的增加而增加。土壤有机质、p H和全磷含量是磷释放过程的主要影响因素。

云南植烟土壤有机碳含量对土壤磷库组成和磷吸附特性的影响

土壤有机碳(SOC)流失和磷素缺乏是限制云南植烟土壤生产力的关键因素,为促进碳磷协同管理,本研究采集云南具有SOC梯度的典型植烟土壤耕作层样品,通过对土壤磷库组成(Hedley法)、磷吸附动力学特性及其与SOC的相关性的分析,探讨碳磷库容的耦合关系。结果显示,SOC主要影响吸附态磷含量,随着SOC的升高,土壤疏松吸附态磷含量下降,紧密吸附态磷和总磷含量升高,但水溶性磷及的稳定态磷与SOC的关系不显著。Elovich模型对所有土壤的磷吸附动力学特性均有良好的描述效果,模型参数α与SOC关系不显著,但β与SOC显著负相关,说明SOC升高对植烟土壤中磷的初始吸附速率影响小,但降低了吸附活化能随土壤颗粒表面覆盖度增加的速率,致使强吸附更易发生。初始吸附速率与吸附态磷含量无显著关系,但随着β的升高,NaHCO3-P降低,NaOH-P和总磷增加。以上结果说明,在植烟土壤中,SOC含量的增加提高了土壤对磷的吸附强度,促进了疏松吸附态磷向紧密吸附态磷的转化,减少了土壤磷流失风险,提高了储备磷库含量,有利于磷肥减施增效。

低分子量有机酸对土壤磷释放动力学的影响

模拟植物在缺磷条件下，根系所分泌的有机酸种类和数量，用流动法研究了柠檬酸、苹果酸、草酸和酒石酸对土壤磷释放（解吸）的影响。结果表明：有机酸能明显促进土壤中磷的释放，不同有机酸对石灰性土壤磷活化能力大小的次序为草酸≥柠檬酸＞苹果酸＞酒石酸；而对酸性土壤磷的释放量与Fe+Al释放量之间呈极显著正相关，有机酸活化土壤磷能力大小的次序为柠檬酸＞草酸＞酒石酸＞苹果酸。抛物线扩散方程能较好的拟合有机酸对土壤磷释放的动力学过程（r＞094）。在两种土壤上，柠檬酸和草酸均可明显地提高磷的相对扩散系数，而酒石酸只对酸性土壤磷的相对扩散系数有明显的提高作用。

低分子量有机酸对石灰性土壤磷吸附动力学的影响

模拟植物在缺磷胁迫下，根系分泌的有机酸种类和数量，用流动法研究了柠檬酸、苹果酸、草酸和酒石酸对石灰性土壤磷吸附动力学的影响。结果表明：有机酸均能明显降低土壤对磷的吸附，不同有机酸降低磷吸附的能力大小的次序为草酸≥柠檬酸＞苹果酸≥酒石酸。pH对有机酸抑制土壤吸附磷的影响十分复杂，如酒石酸对2，3和4号土壤磷吸附的抑制随着pH从6．5升高到8．0而增加，而酒石酸对1号土壤磷吸附的抑制随着pH从6．5升高到8．0而降低。回归分析结果表明，描述有机酸对土壤磷吸附动力学影响的最优方程为一级动力学方程，其次为抛物线扩散方程和双常数方程，最差模型为Elovich方程。可以认为有机酸对土壤磷吸附的影响是一级反应。有机酸主要通过消除石灰性土壤中磷吸附位点（CaCO3），抑制土壤对磷的吸附。

黄土性土壤在连续液流条件下吸附、解吸磷酸根的动力学研究

采用连续液流法研究了黄土性土壤吸附、解吸磷酸根的动力学性质。结果表明：（１）供试土壤对磷酸根的吸附、解吸按速率可分为快、中、慢三种反应类型；（２）描述吸附、解吸反应的最优模型均为Ｅｌｏｖｉｃｈ方程，最差模型分别为一级反应方程及双常数方程，拟合差的模型对反应速率变化“敏感”，可用于反应类型划分和机理研究；（３）粘粒含量及代换量对吸附速率有显著影响，游离铁对吸附速率、ＣａＣＯ＿３对较低温度下的吸附及较高温度下的解吸速率也有明显影响，速效磷含量是控制解吸速率的重要因子；（４）升高温度吸附加速，但对解吸速率无明显影响；（５）不同土类及同一剖面不同层次的吸附、解吸速率，反应时间及吸附、解吸量不同。

有机肥对不同母质菜田土壤磷解吸动力学模拟

通过室内恒温培养试验研究了华南3种典型母质发育的菜田土壤(玄武岩母质发育、花岗岩母质发育、河流冲积物母质发育)在经过两种有机肥(鸡粪堆肥和商品有机肥)预培养30 d和60 d后其土壤有效磷含量及磷解吸动力学过程的影响。结果表明,添加鸡粪堆肥和商品有机肥后,3种母质发育菜田土壤其有效磷含量均显著增加,且添加鸡粪堆肥处理的土壤其有效磷含量的增加量大于添加商品有机肥处理;3种母质发育土壤在添加两种有机肥处理后其磷解吸动力曲线均是先快速解吸然后缓慢达到平衡的过程;磷解吸量不仅与各处理的土壤初始有效磷含量密切有关,而且与土壤成土母质类型、施入有机肥种类相关;3种母质发育的菜田土壤在经过两种有机肥处理后其磷解吸动力曲线用5种动力学方程进行拟合,发现Elovich方程、抛物线方程和幂函数方程能够取得较好的拟合效果。

黄腐酸对黄土性土壤磷吸附解吸动力学性质的影响

采用连续液流法研究了黄腐酸处理对５种黄土性土壤Ｈ＿２ＰＯ＿４￣（－１）吸附、解吸动力学性质及有效性的影响。结果表明：①黄腐酸处理对Ｈ＿２ＰＯ＿４￣（－１）吸附、解吸动力学模型的拟合性无影响，但能使Ｈ＿２ＰＯ＿４￣（－１）的吸附速度及吸附量分别降低１６．７％～６６．７％及１５．３％～６５．４％，解吸速度及解吸量分别增加１４．３％～９４．４％及１０．８％～８１．４％；②黄腐酸处理能使磷的有效系数降低３８．３％～７２．０％，Ｈ＿２ＰＯ＿４￣（－１）的有效性大幅度提高。黄腐酸对黄土性土壤Ｈ＿２ＰＯ＿４￣（－１）有明显的活化作用。

低分子有机酸对淹水土壤磷释放动力学的影响

采用室内模拟淹水方法研究了不同浓度的草酸、柠檬酸、酒石酸对三峡库区典型土壤?紫色潮土磷释放动力学的影响。研究结果表明:3种有机酸能明显促进土壤磷的释放,不同有机酸活化土壤磷的能力大小为草酸>柠檬酸>酒石酸;土壤磷释放与有机酸浓度的关系,可用一次线性方程来描述,根据所建立的模型可对不同浓度、不同种类有机酸影响消落区土壤水污染风险进行定量评估。淹水过程中有机酸对土壤磷的释放量与土壤铁的释放量之间呈显著正相关,不同有机酸在浓度为10 mmol/L时对Fe的释放能力的大小为柠檬酸>草酸>酒石酸。有机酸影响土壤磷的释放是酸溶解作用和与金属离子络合反应共同作用的结果。淹水可使上覆水pH值逐渐上升。加入有机酸能显著降低土壤pH,原因是其质子的离解。微酸性或微碱性都有利于磷释放,中性条件下,土壤磷的吸附能力增强,释放能力减弱。

土壤中磷解吸动力学特征及过渡态理论的应用

在２℃、１２ ℃、２２ ℃、３２ ℃和４２℃５ 个温度条件下，应用动力学和过渡态理论研究了陕西省具代表性的４ 种土壤对所吸附磷的解吸反应特征。结果表明，土壤磷解吸的一级反应速度常数随温度升高而明显增大，其磷解吸活化能（Ｅｄ） 与磷解吸活化焓（ △Ｈ＋ ＋ｄ ） 为黄褐土＞ 黄绵土＞ 黑垆土＞ 土娄土，而磷解吸自由能（ △Ｇ＋ ＋ｄ ） 和活化熵（ △Ｓ＋ ＋ｄ ） 则刚好相反。所以，土壤中磷解吸是吸热反应，４ 种土壤中的磷解吸难易程度，即其克服反应势垒需要的热能为黄褐土＞ 黄绵土＞ 黑垆土＞ 土娄土，而反应满足条件后进行速度顺序为黄褐土＞ 土娄土＞ 黑垆土＞ 黄绵土。

陕西省几种土壤吸附H_2FO_4^(-1)的动力学研究

采用连续液流法研究了陕西省7种土壤吸附H_2PO_4^(-1)的动力学性质。结果表明:①供试土壤的吸磷过程存在快、中、慢3个反应阶段,所需时间分别为20～30、20～55及40～100 min,吸磷量分别占吸磷总量的50％～80％、8％～62％及5％～40％;②Elovich方程对H_2PO_4^(-1)吸附过程拟合最优,拟合最差的一级反应方程对吸附过程中的速率变化比较“敏感”,可用于快、中、慢反应阶段划分和吸附机理深入研究;③温度和粘粒含量、CEC等土壤性质对H_2PO_4^(-1)吸附速度和吸附量有显著影响;④H_2PO_4^(-1)吸附速度可作为土壤吸磷能力评价的动力学指标。

陕西几种土壤磷吸附动力学特征及过渡态理论应用的研究

对陕西几种土壤磷吸附动力学研究表明：在反应开始约３０ｍｉｎ内，溶液中磷浓度迅速降低，之后逐渐趋于稳定。因而，土壤磷吸附动力学可以用两个同时进行的反应来描述，第一个反应是二级反应（快速反应），是土壤对磷的表面吸附；第二个反应是一级反应（慢速反应），与磷酸根进入土壤颗粒内部点位的排列有关；利用吸附反应速率常数计算吸附活化能并进而求得活化焓（△Ｈ）、活化熵（△Ｓ）以及活化自由能（△Ｇ）等假热力学参数，通过讨论得出：过渡态理论应用于土壤磷吸附研究是有益的。

Dynamic Effects of PAEs on Soil Urease and Phosphatase

[Object] The study aimed to supply a reference for evaluating ecotoxicology of soil contaminated with phthalate acid esters(PAEs).[Method] The dynamic effects of DBP and DEHP on activities and kinetics parameters of urease and phosphatase in agro-soil contaminated artificially with DBP and DEHP were studied.[Result] The activities of urease and phosphatase were both inhibited significantly by higher contents of DBP and DEHP in soils compared with CK.The inhabitations increased with increasing DBP and DEHP c...

Kinetics of Thermal Decomposition of Lithium Hexafluorophosphate

With on-line coupled thermo-gravimetric technique, the thermal decomposition of analyzer-Fourier transform infrared spectrometer lithium hexafluorophosphate （LiPF6） and its gas evolution at inert environment （H2O〈10 ppm） were studied under both non-isothermal and isothermal conditions. The results showed that the LiPF6 decomposition is a single-stage reaction with LiF as final residue and PF5 as gas product. In addition, its decomposi- tion kinetics was determined as 2D phase boundary movement （cylindrical symmetry） under both non-isothermal and isothermal conditions. Furthermore, the activation energy of LiPF6 decomposition was calculated as 104 and 92 kJ/mol for non-isothermal and isothermal con- ditions, respectively.

Soil Phosphorus Dynamics as Influenced by Land Use Changes in Humid Tropical, Southwest China

Land use changes can greatly influence soil phosphorus (P) dynamics, especially when converting native forests to agricultural land. Soils in Xishuangbanna, which is one of southwest China s tropical areas that maintain fragments of primary forests, were studied to a) evaluate the effect of two common land use changes, conversion of forests to agricultural land or rubber tree plantation, on the dynamics of available P and total P in bulk soils as well as total P in particle size fractions; b) assess the rel…

Effects of Ag-carrying Zirconium Phosphate on the Kinetics of Growth of the Roots of Culture Artemisia annua

在植物组织和细胞培养过程中 ,尤其是在生物反应器培养中的染菌问题 ,一直是制约植物细胞培养工业化的难题。通过比较各种防腐剂的抑菌效果 ,确定银型磷酸锆盐抗菌粉为青蒿根培养的最佳防腐剂。银型磷酸锆盐抗菌粉在浓度为 30mg/L时 ,既能降低培养液的染菌几率 ,又不明显抑制青蒿根的生长及青蒿素的生物合成。在添加 30mg/L抗菌粉的培养液中进行的青蒿根生长、pH值变化以及残糖、铵离子和硝酸根离子消耗的动力学研究表明 ,在 4 0d内青蒿根在培养液中生长良好 ,营养成分的消耗和对照呈相似的趋势。

Dynamics of Microbial Biomass in a Rainfed Soil Under Wheat Cultivation

A pot experiment was conducted to determine the dynamics of soil microbial biomass in a rainfed soil under wheat cultivation at the University of Arid Agriculture, Rawalpindi, Pakistan. The treatments applied were: 1) a control (CK), 2) NPK (0.44-0.26-0.18 g pot-1), 3) farmyard manure (FYM, 110 g pot-1), 4)poultry manure (PM, 110 g pot-1), 5) FYM (110 g pot-1) + NPK (0.44-0.26-0.18 g pot-1), 6) poultry manure (PM, 110 g pot-1) + NPK (0.44-0.26-0.18 g pot-1), 7) FYM (110 g pot-1) + NPK(S) (0.44-0.26-0.18 g pot-1, one half of the NPK at sowing and the other half one month after sowing), and 8) PM (110 g pot-1) + NPK(S) (0.44-0.26-0.18 g pot-1, one half of the NPK applied at sowing and the other half one month after sowing). The experiment was laid out using a completely randomized design with three replications. Microbial biomass C, N and P contents increased continuously from the beginning of the experiment up to the three-leaf stage. A slight decline was observed at the tillering stage in all treatments except with the organic manures + NPK(S) treatments. After tillering there was an increase in all treatments to the recorded maximum point at the full heading stage in all treatments except with the organic manures + NPK(S) treatments. In the FYM + NPK(S) and PM + NPK(S) treatments; however, there was a continuous increase in microbial biomass up to the heading stage. At the harvesting stage a sharp decline was noted in all treatments. The C:N ratio of microbial biomass in tested soil ranged from 7.8 to 11.3, while C:P ratio of microbial biomass in the tested soil ranged from 22.6 to 35.1 throughout all growth stages of the wheat crop.

Dynamics of Micelle Formation from Mixed Lipid Droplets

Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.

Leaching kinetics of calcium molybdate with hydrochloric acid in presence of phosphoric acid

Calcium molybdate(CaMoO4)is the main component of powellite and is a predominant intermediate in the pyrometallurgical and hydrometallurgical process of molybdenum.The extraction of Mo from CaMoO4 by a combination of phosphoric acid and hydrochloric acid was investigated.For further understanding of the leaching mechanism,the effects of five key factors were studied to describe the leaching kinetics.The results indicated that the dissolution rate of CaMoO4 was independent of the stirring speed.Mo extraction significantly increased with increasing HCl concentration and temperature,but decreased with increasing particle size.A shrinking core model with surface chemical reaction was found to withstand the dissolution of CaMoO4.The apparent activation energy was calculated to be 70.879 kJ/mol,and a semi-empirical equation was derived for the rate of reaction.

Effect of Heavy Metals on Phosphorus Retention by Typic Udic Ferrisols: Equilibrium and Kinetics

A study was conducted to examine the effect of heavy metals (Cu,Pb, Zn and Cd in combination or alone) on the equilibrium andkinetics of phosphorus (P) retention in typic udic ferrisols by usingboth equilibrium and flow techniques. Fourteen soil samples withvarying artificial contamination of Cu, Pb, Zn and Cd were prepared.Heavy metal pollution led to increases in retention capacity andmaximum buffering capacity (MBC) of soil P. The rate of P retentionwas also increased and the time to reach equilibrium was advanced byheavy metals addition.