Potassium:rubidium ratio in ultramafic rocks: differentiation history of the upper mantle

The increase in K:Rb ratio with decrease in potassium content found in basaltic rocks does not seem to apply to ultramafic rocks. The ratios in a series of alpine ultramafic rocks and ultramafic inclusions in basals and kimberlite pipes are about 200 to 500-significantly lower than those in oceanic tholeiites. This characteristic of ultramafic rocks appears to be consistent with a simplified model in which early differentiation of the primitive mantle led to formation of an upper mantle region enriched in alkali elements and having a low K:Rb ratio. Alpine ultramafic rocks may be residuals from such an upper mantle region.     

喀斯特高原山地区主要人工林土壤生态化学计量特征

[目的]探究喀斯特高原山地区主要人工林土壤碳(C)、氮(N)、磷(P)、钾(K)含量及生态化学计量特征,为揭示喀斯特高原山地区土壤养分限制状况、植被恢复和生态系统重建提供参考.[方法]在贵州省毕节市撒拉溪示范区内选取刺梨林(Rosa roxburghii)、核桃林(Juglans regia)和裸地进行野外定点取样,结合室内分析方法对3种人工林样地不同深度的土壤化学性质进行分析比较.[结果]3种人工林样地的有机C、全N、碱解N、全P和速效P含量总体上随土层深度的增加呈递减趋势,全K和速效K含量在不同深度土层间变化不显著(P>0.05)或略有增减,养分总体上呈表层聚集性.土壤C/N、C/P、C/K、N/P、N/K和P/K均表现出一定的差异性,不同深度土层的C/N均以刺梨林最高,C/P表现为刺梨林>裸地>核桃林,C/K均随土层深度增加呈递减趋势,N/K和P/K均表现为核桃林>裸地>刺梨林.刺梨林、核桃林和裸地土壤生态化学计量特征的变异系数分别为11.14%~31.25%、5.59%~17.14%和6.82%~23.71%.相关性分析结果表明,有机C含量与全N含量、全P含量、C/K、N/K,全N含量与全P含量、C/K、N/K,全P含量与C/K、N/K,全K含量与N/P及C/K与N/K均呈极显著正相关(P<0.01,下同);全N含量与全K含量、C/N,全P含量与全K含量、C/N、N/P,全K含量与C/K、N/K及C/N与N/K均呈极显著负相关.[结论]不同人工林样地的土壤养分分配均受土层深度影响,主要聚集在表层,N和P含量处于亏缺状态;生态化学计量比总体上为表层显著高于底层,土壤养分对其贡献存在差异.     

甘南白龙江2种次生林不同器官C、N、P、K计量特征

为明确甘南白龙江2种次生林各器官C、N、P、K生态化学计量特征,掌握养分元素在不同次生林分配格局及各器官养分受限状况等情况,对该地区红桦和辽东栎2种主要次生林各器官（根、主干、各级枝、叶片）进行取样,分析其含水率、C、N、P和K含量以及各元素之间化学计量特征,结果表明:1）2种次生林叶片含水率最大,红桦各器官含水率在34.09%～59.01%,从大到小依次为叶片＞一级枝＞根＞二级枝＞三级枝,辽东栎各器官含水率在33.98%～52.66%,叶片＞根＞一级枝＞二级枝＞三级枝＞四级枝,叶片含水率均最高,其次为根,枝级越高含水率越小。2）2种次生林叶片的C、N、P、K含量最高。辽东栎C含量在387.19～529.64 g·kg^-1,叶片C含量最高,其他各器官含量相差不大,C属于弱变异。N含量在5.03～19.54 g·kg^-1,从大到小依次是叶片＞三级枝＞四级枝＞根＞二级枝＞一级枝＞主干。叶片P和K含量也是最高,除根的K含量以外,其他器官都表现出2种元素含量从形态学的下端到上端依次增加。N与K含量呈显著性相关,P变异系数较大,属于强变异。红桦C、P和K变化一致,除根以外,从主干到叶片3种元素含量依次增加,P含量从根到叶片依次增加,C变异系数最小属于弱变异,K含量属于强变异。3）2种次生林叶片的C:N、C:P、C:K和P:K最小,N:P最大。红桦叶片的N:K也是最小,C:N与N:K呈显著性负相关,C:P与N:P以及C:K与N:K呈显著性正相关。辽东栎的N:K除叶片,从根到四级枝依次减小,C:P与N:P呈显著性正相关,C:K与N:K和P:K也呈显著性正相关。由此可见,甘南白龙江2种次生林各器官营养元素含量与相应器官的功能结构密切相关。     

Mantle plume helium in submarine basalts from the galapagos platform

Helium-3/helium-4 ratios in submarine basalt glasses from the Galapagos Archipelago range up to 23 times the atmospheric ratio in the west and southwest. These results indicate the presence of a relatively undegassed mantle plume at the Galápagos hot spot and place Galápagos alongside Hawaii, Iceland, and Samoa as the only localities known to have such high helium-3/helium-4 ratios. Lower ratios across the rest of the Galápagos Archipelago reflect systematic variations in the degree of dilution of the plume by entrainment of depleted material from the asthenosphere. These spatial variations reveal the dynamics of the underlying mantle plume and its interaction with the nearby Galápagos Spreading Center.     

氮钾配施对芝麻菜产量形成的影响

为了指导芝麻菜合理施肥,从而生产高产优质的芝麻菜,以芝麻菜为试验材料,采用基质栽培方法,通过测定叶绿素含量、根系活力、单株地上部和地下部鲜重,研究了不同氮钾配施对芝麻菜产量形成的影响。结果表明：氮素和钾素施用量都较高的处理,即N3K、N3K4、N4K3与N4K4（N3：7．5mmol·L-1、N：10mmol·L-1;K3：4．5mmol·L-1、K4：6mmol·L-1）,叶绿素含量较高,根系活力较强,植株地上部与地下部鲜重积累较多,单株产量较高,确定其为最适合的氮钾配施比例。     

不同基质对盆栽海南三七生长和光合作用的影响

以不同比例红壤、腐叶土和进口泥炭混合作为海南三七的盆栽基质进行盆栽试验,研究不同基质条件下,基质的氮磷钾养分特征及其对不同大小根茎海南三七生长和光合作用的影响。结果表明,红壤、腐叶土和进口泥炭(体积比1︰1︰1)混合基质的p H、EC值、氮磷钾养分含量适中,明显促进大、中、小根茎海南三七的生长和光合作用;而红壤、进口泥炭、红壤与腐叶土、红壤与进口泥炭混合基质对大、中、小根茎海南三七的生长和光合作用不全是促进。本研究筛选大、中、小根茎海南三七的盆栽基质,为海南三七根茎的盆栽生产提供科学依据和参考。     

Genetic relations of oceanic basalts as indicated by lead isotopes

The isotopic compositions of lead and the concentrations lead, uranium, and thorium in samples of oceanic tholeiite and alkali suites are determined, and the genetic relations of the oceanic basalts are discussed. Lead of the oceanic tholeiites has a varying lead-206: lead-204 ratio between 17.8 and 18.8, while leads of the alkali basalt suites from Easter Island and Guadalupe Island are very radiogenic with lead-206: lead-204 ratios between 19.3 and 20.4 It is concluded that (i) the isotopic composition of lead in oceanic tholeiite suggests that the upper mantle source region of the tholeiite was differentiated from and original mantle material more than 1 billion years ago and that the upper mantle is not homogeneous at the present time, (ii) less than 20 million years was required for the crystal differentiation within the alkali suite from Easter Island, (iii) no crustal contamination was involved in the course of differentiation of rocks from Easter Island; however, some crustal contamination may have affected Guadalupe Island rocks, and (iv) alkali basalt may be produced from the tholeiite in the oceanic region by crystal differentiation. Alternatively the difference in the isotopic composition of lead in oceanic basalts may be produced by partial melting at different depths of a differentiated upper mantle.     

Seismic imaging of transition zone discontinuities suggests hot mantle west of Hawaii

The Hawaiian hotspot is often attributed to hot material rising from depth in the mantle, but efforts to detect a thermal plume seismically have been inconclusive. To investigate pertinent thermal anomalies, we imaged with inverse scattering of SS waves the depths to seismic discontinuities below the Central Pacific, which we explain with olivine and garnet transitions in a pyrolitic mantle. The presence of an 800- to 2000-kilometer-wide thermal anomaly (ΔT(max) ~300 to 400 kelvin) deep in the transition zone west of Hawaii suggests that hot material does not rise from the lower mantle through a narrow vertical plume but accumulates near the base of the transition zone before being entrained in flow toward Hawaii and, perhaps, other islands. This implies that geochemical trends in Hawaiian lavas cannot constrain lower mantle domains directly.     

蔬菜废弃物、稻草与猪牛粪不同配比厌氧堆肥研究

将蔬菜废弃物、稻草以不同配比分别与牛粪和猪粪进行厌氧堆肥研究.试验对牛粪、猪粪分别设置了4种不同的配比,依次增加蔬菜废弃物的含量;采用厌氧发酵的方法进行堆肥,为提高发酵效果,在堆肥开始前接种了微生物发酵剂.分析了堆肥结束后的pH、EC、有机质、C/N比值、总氮、速效磷钾含量等指标.试验结果表明,猪粪处理的效果在氮含量、...     

氮磷钾肥配施对玉米产量的影响

以玉米品种吉单27为试材,针对目前农田施肥增产能力降低问题,进行了氮磷钾肥不同用量配比施用试验,旨在探索玉米氮、磷、钾养分施用最佳用量,为指导大田生产提供科学依据。结果表明：氮磷钾肥不同配比施用对玉米的产量和肥效有明显的影响。最佳施肥量为N 135kg.hm-2、P 75kg.hm-2、K 90kg.hm-2,N∶P2O5∶K2O=1.00∶0.56∶0.67。试验亦得出氮肥是决定玉米产量的主要因素,而钾肥、磷肥也是不可缺少的。所以科学施肥,合理搭配N、P、K肥不仅可以提高化肥利用率,同时也是玉米增产增收的保证。     

Peanut yield,nutrient uptake and nutrient requirements in different regions of China

Nutrient balance is essential for attaining high yield and improving profits in agricultural farming systems, and crop nutrient uptake ratio and stoichiometry can indicate crop nutrient limitations in the field. We collected a large amount of field data to study the variations in yield, nutrient uptake and nutrient stoichiometry of peanut(Arachis hypogaea L.) in Southeast China(SEC), North-central China(NCC), and Northeast China(NEC), during 1993 to 2018. Peanut pod yield gradually increased from 1993 to 2018, with average yields of 4 148, 5 138, and 4 635 kg ha–1 in SEC, NCC, and NEC, respectively. The nitrogen(N) internal efficiency(NIE, yield to N uptake ratio) was similar among the three regions, but phosphorus(P) IE(PIE, yield to P uptake ratio) changed from low to high among regions: NCCSECNEC, while potassium(K) IE(KIE, yield to K uptake ratio) portrayed a different pattern of SECNCCNEC. Based on the nutrient IE, to produce 1 Mg of pod yield, the average N, P, and K requirements of the above-ground parts of peanut were roughly 47.2, 5.1, and 25.5 kg in SEC, 44.8, 5.7, and 20.6 kg in NCC, and 44.6, 4.4, and 14.7 kg in NEC, respectively. The N/P ratio changed in the sequence NCCSECNEC, and the N/K ratio was similar in NEC and NCC, but lower in SEC. The N harvest index(HI) and KHI declined with increasing nutrient uptake across all regions under high nutrient uptake. The low PIE and N/P ratios in NCC could be explained by the high P accumulation in stover, and high KIE and N/K ratios in NEC may be attributed to the low soil K supply. The frontier analysis approach provides a practical framework and allows documentation of a decline in nutrient HI as nutrient uptake increases. Lastly, this study reveals the limitation and surplus of nutrients of peanut in different regions of China.     

40K-(40)Ar constraints on recycling continental crust into the mantle

Extraction of potassium into magmas and outgassing of argon during melting constrain the relative amounts of potassium in the crust with respect to those of argon in the atmosphere. No more than 30% of the modern mass of the continents was subducted back into the mantle during Earth's history. It is estimated that 50 to 70% of the subducted sediments are reincorporated into the deep continental crust. A consequence of the limited exchange between the continental crust and the upper mantle is that the chemistry of the upper mantle is driven by exchange of material with the deep mantle.     

Rogue mantle helium and neon

The canonical model of helium isotope geochemistry describes the lower mantle as undegassed, but this view conflicts with evidence of recycled material in the source of ocean island basalts. Because mantle helium is efficiently extracted by magmatic activity, it cannot remain in fertile mantle rocks for long periods of time. Here, I suggest that helium with high 3He/4He ratios, as well as neon rich in the solar component, diffused early in Earth's history from low-melting-point primordial material into residual refractory "reservoir" rocks, such as dunites. The difference in 3He/4He ratios of ocean-island and mid-ocean ridge basalts and the preservation of solar neon are ascribed to the reservoir rocks being stretched and tapped to different extents during melting.     

Primitive boron isotope composition of the mantle

Boron isotope ratios are homogeneous in volcanic glasses of oceanic island basalts [-9.9 +/- 1.3 per mil, relative to standard NBS 951 (defined by the National Bureau of Standards)], whereas mid-oceanic ridge basalts (MORBs) and back-arc basin basalts (BABBs) show generally higher and more variable ratios. Melts that have assimilated even small amounts of altered basaltic crust show significant variations in the boron isotope ratios. Assimilation may thus account for the higher boron ratios of MORBs and BABBs. A budget of boron between mantle and crust implies that the primitive mantle had a boron isotope ratio of -10 +/- 2 per mil and that this ratio was not fractionated significantly during the differentiation of the mantle.     

不同钾钠比的查氏培养基对大丽轮枝菌生物学性状及致病力的影响

研究了大丽轮枝菌(Verticillium dahliae)在不同钾钠比(K~+/Na~+)的查氏培养基中生长的生物学特性及致病力的变化。结果表明,菌株在0K~+/Na~+≤5.248的固体培养基上生长呈近M型,在K~+/Na~+5.248的固体培养基上生长呈近W型。与常规查氏培养基(CK,K~+/Na~+为1.312)相比,菌株在0K~+/Na~+5.248区间的固体培养基上,生长速率明显上升;在K~+/Na~+5.248的固体培养基上,生长速率无显著性差异;在K~+/Na~+为5.248的固体培养基上,菌核型菌株的微菌核产量最大;但在无K~+条件下同样有微菌核的产生,说明K~+对微菌核的产生有一定影响,在适中情况下会增加菌株微菌核的产量,但非必要产生因素。K~+浓度会影响到菌株的致病力,当K~+/Na~+≤2.624时,随着K~+浓度的上升,菌株的致病力有所增强,当K~+浓度过高,K~+/Na~+达到26.24时,菌株的致病力反而减弱。在K~+浓度不变时,Na~+浓度与病原菌的致病力初步呈正相关,Na~+浓度升高,钾钠比下降,病原菌的致病力增强;反之亦然。     

氮钾肥配施对水稻产量和养分平衡的效应

水稻对氮钾两元素的需要要相近。为保持土壤养分平衡,氮钾肥配施比例似以1:1为宜;但为了提高当季作物施钾的增产效应,氮钾配比可乐用1:0.4～0.5。水稻地上部和地下部的协调生长受到氮钾肥配比的影响:N>K,有利于地上部生长;K>N,则有利于地下部生长。过量施氮对根系生长不利。氮钾供应状况影响稻株中的养分平衡,提高氮钾施用水平,稻株中氮钾的浓度随之提高,但钙镁的浓度下降,钾镁的拮抗作用尤为明显。     

不同轮作方式与施肥处理对东北烤烟化学成分和经济性状的影响

分析比较了不同轮作方式与施肥处理对东北植烟区烤烟化学成分和经济性状的影响。综合2004年和2005年试验,结果表明:不同茬口各处理烟叶的钾氯比为5.2~43.0,燃烧性好,且大豆茬口下适当增施磷(P)、钾(K)和硼肥(B)可提高烟叶的钾氯比。不同茬口及不同施肥处理烟叶的糖碱比和氮碱比差别均不显著。2005年,小麦、大豆2个茬口下增加适量硼肥均可使烟叶的施木克值得到改善,从而提高了烤烟内在品质。2005年与2004年相比烟叶经济性状均有显著提高,且小麦茬口各处理的产值显著高于大豆茬口。     

断根结合生长素和钾肥施用对烤烟生长及糖碱比、有机钾指数的影响

河南济源烟区存在着烟叶糖碱比高、有机钾指数较低的生产现状,通过田间试验研究了打顶时断根(C)、打顶时断根结合喷施IAA(C+I)、打顶时断根结合追施钾肥(C+K)、打顶时断根结合喷施IAA并追施钾肥(C+K+I)和对照(CK)5种处理对烤烟生物量及糖碱比、有机钾指数的影响。结果表明:不同调控措施在烟株成熟期较对照均能增加根部、叶片的干重,减少烟碱、总糖在中上部烟叶的累积。断根结合喷施IAA能降低各部位烟叶的糖碱比,且以C+K+I处理的降幅最大,在下、中、上叶位中较对照分别降低了19.12%、15.33%和8.15%。与对照相比,各处理均能提高不同部位烟叶K⁺含量,降低Cl^-和SO₄^2-含量。C+K+I处理能极显著提高各部位烟叶的有机钾指数,且在中上部烟叶中增幅最大,较对照分别提高了125.00%和209.43%。总的看来,打顶时断根结合喷施IAA并追施钾肥能促进烟叶中的干物质积累、降低糖碱比、提高有机钾指数,进而提高烟叶的内在品质。     

氮磷钾配方施肥对南疆扁桃产量的影响

以莎车县扁桃品种纸皮为试验材料,通过果园田间肥料试验,研究了不同氮、磷、钾肥配比对扁桃产量的影响。结果表明:合理施用氮、磷、钾肥有利于提高扁桃坚果的产量,与不施肥(对照)处理相比,各施肥处理扁桃的产量均显著增加(P<0.05),但是各处理之间的扁桃产量有所差异,以处理12(施肥配方氮磷钾比例为1:2.0:0.9)的扁桃产量和经济效益最高。每年施尿素102 g/株,磷酸二铵922 g/株和硫酸钾477 g/株,比不施肥处理增产160 kg/667 m2,增收2 702元/667 m2。综合扁桃产量、经济效益和肥料产投比分析,扁桃较合理氮磷钾比例为处理12,在此条件下,扁桃平均产量可达到258.9 kg/667 m2。