Phosphorus and Potassium Release Pattern from Leucaena Leaves in Three Environments of Haiti

In tropical ecosystems trees have the potential to supply nutrients essential to crops. Leucaena [Leucaena leucocephala (Lam) De Wit] leaf decomposition experiments were established at three sites in Haiti representing diverse soil types to assess the potential of leucaena leaves to supply P and K to crops and to determine their pattern of release. Mesh bags containing 17.4 g of air-dried leucaena leaves were placed in plots receiving 100 kg ha⁻¹ of N as ammonium sulfate and leucaena prunings as mulch with and without 60 kg ha⁻¹ of P and 40 kg ha⁻¹ of K fertilizers for each crop. One bag from each plot was retrieved periodically over a period of 32 weeks for ash free dry matter, P and K determination. In the three locations applications of P–K inorganic fertilizer had no significant effects on leucaena leaf ash free dry matter remaining, P and K concentration nor content of leaves. Cumulative leucaena leaf P content release after 32 weeks of decay for the three sites averaged 4.9 kg ha⁻¹. Cumulative leucaena leaf K content release for the three sites was about 35.4 kg ha⁻¹. The rate of K release was higher in very humid climate than in semi-humid climate. The pattern of leucaena leaf ash free dry matter remaining, residual P and K content followed a double exponential model of decomposition for the three locations. Leucaena leaves applied at the three sites showed potential to supply P and K to crops. Plant material quality, time of decomposition and tree age should be investigated in future studies.     

磷石膏的复合矿化作用及其对硅酸盐水泥生料煅烧的影响

通过易烧性、正交实验和XRD分析,研究了磷石膏的复合矿化作用及其对硅酸盐水泥生料煅烧的影响,并对KH、复合矿化剂与熔剂组分配比和煅烧温度与硅酸盐水泥生料易烧性及SO2挥发量的关系进行了探索.结果表明：磷石膏具有复合矿化作用,可改善硅酸盐水泥生料煅烧,促进固相反应;磷石膏2.0%和矿渣2.0%作复合矿化剂,不仅可促进水泥生料的煅烧,而且减少SO2挥发,既有利于工业固体废物的资源化利用,又有利于生态环境的保护.     

不同施肥处理土壤及不同C/N比有机物料中有机N的矿化进程

采用室内恒温控湿好气培养试验研究长期不同施肥制度培育的土壤有机N库的供氮能力及不同C/N比有机物料掺混土壤后有机N的矿化特征与进程。结果表明:长期不同施肥制度培育的土壤有机N库的供氮能力各不相同,与不施肥处理相比,长期施用化肥或有机肥均能提高土壤的供氮能力,二者相结合可明显提高土壤供氮力;不同C/N比有机物料掺混土壤后有机N的矿化特征与物料的C/N比密切相关,有机N的矿化进程可区分为前期的快速分解和后期的缓慢分解。     

The comparison of nitrogen use and leaching in sole cropped versus intercropped pea and barley

The effect of sole and intercropping of field pea (Pisumsativum L.) and spring barley (Hordeum vulgareL.) and of crop residue management on crop yield,NO₃ ^– leaching and N balance in the cropping systemwas tested in a 2-year lysimeter experiment on a temperate sandy loam soil. Thecrop rotation was pea and barley sole and intercrops followed by winter-rye anda fallow period. The Land Equivalent Ratio (LER), which is defined as therelative land area under sole crops that is required to produce the yieldsachieved in intercropping, was used to compare intercropping performancerelative to sole cropping. Crops received no fertilizer in the experimentalperiod. Natural ¹⁵N abundance techniques were used to determine peaN₂ fixation. The pea–barley intercrop yielded 4.0 Mg grainha^–1, which was about 0.5 Mg lowerthan theyields of sole cropped pea but about 1.5 Mg greater than harvestedin sole cropped barley. Calculation of the LER showed thatplant growth resources were used from 17 to 31% more efficiently by theintercrop than by the sole crops. Pea increased the N derived fromN₂fixation from 70% when sole cropped to 99% of the total aboveground Naccumulation when intercropped. However, based upon aboveground N accumulationthe pea–barley intercrop yielded about 85 kg Nha^–1, which was about 65 kg lower thansolecropped pea but about three times greater than harvested in sole croppedbarley.Despite different preceding crops and removal or incorporation of straw, therewas no significant difference between the subsequent non-fertilized winter-ryegrain yields averaging 2.8 Mg ha^–1, indicating anequalization of the quality of incorporated residue by theNO₃ ^– leaching pattern.NO₃ ^– leaching throughout the experimental periodwas61 to 76 kg N ha^–1. Leaching dynamics indicateddifferences in the temporal N mineralization comparing lysimeters previouslycropped with pea or with barley. The major part of this N was leached duringautumn and winter. Leaching tended to be smaller in the lysimeters originallycropped with the pea–barley intercrops, although not significantly differentfromthe sole cropped pea and barley lysimeters. Soil N balances indicated depletionof N in the soil–plant system during the experimental period, independent ofcropping system and residue management. N complementarity in the croppingsystemand the synchrony between residual N availability and crop N uptake isdiscussed.     

吉首—凤凰锰矿带成矿模式探讨

湘黔川鄂边境早震旦世的锰矿称为民乐式锰矿。锰矿床（点）的分布大部分受扬子准地台东南边缘之武陵台陷的控制,锰矿主要生成于滨海相的半局限海湾含锰页岩亚相中,应属于暖温带—亚热带气侯,化石藻类发育的地段,菱锰矿颗粒密集,锰品位增高。分析此类矿床的成矿物质来源、锰质搬运方式、锰质沉积作用,探讨此类矿床成因及成矿模式,对缺锰地区寻找类似锰矿床具有重要意义。     

辽宁省成矿区带划分及特征

辽宁省成矿区带划分,是“辽宁省矿产资源潜力评价”项目的阶段性成果。I—III级成矿区带主要参考“全国矿产资源潜力评价项目”和《中国成矿区带划分方案》。1V级成矿区带是以m级大地构造单元为基础,结合沉积、变质、岩浆及构造成矿作用、控矿因素、找矿标志及各矿种综合预测成果进行圈定的：本文对Ⅳ成矿区带的划分原则和方案进行了阐述,最终划分Ⅳ成矿区带13并对每个成矿区带特征进行了系统的分析。     

Chemical leaching mechanism of chalcopyrite with difference mineralization

This paper presents the effect of mineralization on chalcopyrite chemical leaching in very simple H2SO4 solution systems at pH 1.0, with 5 % chalcopyrite concentrate at 65℃. The copper extractions after 12 days leaching of marine volcanic and porphyry chalcopyrite were 85.7 and 66.6 %, respectively. It was found that sulphur element formed on the surface of two samples as a result of XRD and SEM-EDAX, which was very porous that did not inhibit chemical leaching reaction. Meanwhile, (Cu, Fe)12As4S13 formed on the surface of porphyry type chalcopyrite, which may cause low leaching ratio of porphyry type chalcopyrite as passivation. (Cu, Fe)12As4S13 may be one kind of the polysulphide compounds.     

甘肃寨上金矿床南矿带断层泥的形成与成矿作用浅析

寨上金矿床勘查过程中,在南矿带中发现了一定规模的断层泥,其本身也含矿,个别工程品位达到2.78×10-6。从这一典型的地质现象入手,结合地震学研究的进展,探索断层泥与成矿的内在联系。文章简述了断层泥的地质特征,指出断层泥是在浅构造层次条件下发生脆性变形的产物,经历了褶皱—断裂—断层泥的演化过程。分析了断层泥的发育与成矿的关系,认为断层泥的形成贯穿于成矿的全过程,是构造作用—热液叠加成矿作用的重要组成部分,断层泥对于热液成矿有封闭隔挡和促进含矿热液与围岩充分交代沉淀的作用。     

Vascular calcification: Inducers and inhibitors

Unlike the traditional beliefs, there are mounting evidences suggesting that ectopic mineral depositions, including vascular calcification are mostly active processes, many times resembling that of the bone mineralization. Numbers of agents are involved in the differentiation of certain subpopulation of smooth muscle cells (SMCs) into the osteoblast-like entity, and the activation and initiation of extracellular matrix ossification process. On the other hand, there are factors as well, that prevent such differentiation and ectopic calcium phosphate formation. In normal physiological environments, activities of such procalcific and anticalcific regulatory factors are in harmony, prohibiting abnormal calcification from occurring. However, in certain pathophysiological conditions, such as atherosclerosis, chronic kidney disease (CKD), and diabetes, such balances are altered, resulting in abnormal ectopic mineral deposition. Understanding the factors that regulate the formation and inhibition of ectopic mineral formation would be beneficial in the development of tissue engineering strategies for prevention and/or treatment of such soft-tissue calcification. Current review focuses on the factors that seem to be clinically relevant and/or could be useful in developing future tissue regeneration strategies. Clinical utilities and implications of such factors are also discussed.