Using shallow saline groundwater for irrigation and regulating for soil salt-water regime

Drought and fresh water shortage are the main limiting factorsfor sustainable development of agriculture in North China Plain.Using saline water for irrigation plays important role forovercoming the constraints and increasing crops yields. Theexploitation and utilization of shallow saline groundwaterenables to regulate the groundwater depth and to promote thetransform of precipitation into available water resources.Thispaper reviews the research and practice on the utilization ofshallow saline groundwater in the part east of South GreatCanal in Haihe River Plain. Findings are presented on the useof saline water, cycling and blending of saline and fresh waterfor irrigation, indexing of crops salt tolerances, regulating forsoil salt-water regime, saline-alkali land reclamation andgroundwater quality freshening. These approaches help therational regulation and utilization of the local water resourcesfor comprehensive control of drought, waterlogging and salinity.     

棉花膜下滴灌灌溉制度试验研究

以田间试验为基础对棉花膜下滴灌的灌溉制度及其各因素的特点进行了分析研究。膜下滴灌技术采用局部灌水，男间地面蒸发量很小，另外，该技术为浅灌且可控性强，使灌水深度与棉花根系吸水深度相一致，避免深层渗漏，极大地提高了田间水分利用率。     

河南省中低产田地区水资源生产潜

论述了河南省中低产田地区水资源生产潜力的开发途径。主要包括：实行节水灌溉及节水技术；建立合理的灌溉制度，以便改善农田水分状况，按农作物的需水规律进行灌溉；合理规划作物种植，提高农田整体水分利用效率；合理施肥，提高土壤肥力，以降低作物对水分的无效吸收等。     

积雪覆盖下土壤热状况及其对气象因素的响应研究

为研究季节性冻土区在积雪覆盖条件下,土壤温度变化趋势及气象因素对土壤热状况的影响,以野外实测试验数据(2013年11月8日—2014年4月28日)为基础,分析裸地、自然降雪、积雪压实和积雪加厚覆盖条件下5、10、20、40、60、100、140 cm深度土壤温度变化特征,采用灰色关联度分析的方法筛选出影响土壤热状况的主要气象因素,进而统计土壤温度与气象因素之间的相关关系。结果表明:积雪的存在阻碍了环境与土壤之间的能量交换,引起土壤温度和土壤冻融过程的差异;随着积雪覆盖深度的增加,土壤的冻融日期会出现延迟现象,土壤温度相对稳定在较高水平,并且地、气之间温差增大;冻融过程中土壤温度变化的主要影响因素为环境温度,积雪覆盖使得气象因素与土壤温度的关联度减弱。     

Sitka spruce site index in response to varying soil moisture and nutrients in three different climate regions in Ireland

We examined the relationships between Sitka spruce (Picea sitchensis (Bong.) Carr.) site index, windspeed, former land use, soil moisture and soil nutrients with a view to identifying factors limiting the growth potential of the species in three climate regions in Ireland. We selected plantations covering three climate regions (delineated on the basis of ‘growing season’ balance of precipitation and potential evapotranspiration; representing dry, moist and wet climate regions) located on sites representing the range of soil moisture regimes (SMR), soil nutrient regimes (SNR), and land use types found throughout Ireland. Site index of Sitka spruce varied among climate region, with significantly lower site index associated with the wet climate region mainly due to the deterioration in edaphic conditions and adverse climatic conditions. The effect of edaphic variables (SMR, SNR) on site index was consistent across climate regions, site index increasing with increasing SNR, and decreasing with excess moisture or moisture deficit. Site index reached a maximum on fresh/very rich sites in the dry and moist climate regions and on moist/rich sites in the wet climate region. In the dry climate region, water supply (SMR) was the most important variable regulating growth, in wetter windier climates nutrient supply (SNR) was the most important factor, accounting for 69% of the variation in site index. The study has allowed region-specific recommendations to be made for successful plantation establishment in Ireland and for countries with similar climatic regions.     

Growth and carbon sequestration by ectomycorrhizal fungi in intensively fertilized Norway spruce forests

A substantial portion of the carbon (C) fixed by the trees is allocated belowground to ectomycorrhizal (EM) symbionts, but this fraction usually declines after fertilization. The aim of the present study was to estimate the effect of optimal fertilization (including all the necessary nutrients) on the growth of EM fungi in young Norway spruce forests over a three year period. In addition, the amount of carbon sequestered by EM mycelia was estimated using a method based on the difference in δ¹³C between C₃ and C₄ plants. Sand-filled ingrowth mesh bags were used to estimate EM growth, and similar bags amended with compost made from maize leaves (a C₄ plant) were used to estimate C sequestration. Fertilizers had been applied either every year or every second year since 2002 and the estimates of EM growth started in 2007. The application of fertilizer reduced EM growth to between 0% and 40% of the growth in the control plots at one site (Ebbegärde), while no significant effect was found at the other three sites studied. The effect of the fertilizer was similar in sand-filled and maize-compost-amended mesh bags, but the total production of EM fungi was 3-4 times higher in maize-compost-amended mesh bags. The fertilizer tended to reduce EM growth more when applied every year than when applied every second year. The amount of C sequestered in maize-compost-amended mesh bags collected from unfertilized treatments was estimated to be between 0.2 and 0.7 mg C g sand⁻¹ at Ebbegärde and between 0.2 and 0.5 mg C g sand⁻¹ at Grängshammar. This corresponds to between 300 and 1100 kg C per ha, assuming a similar production in the soil as in the mesh bags. Fertilization at the Ebbegärde site reduced carbon sequestration, which confirmed the results based on estimates of fungal growth (ergosterol levels). A correlation was found between fungal biomass and δ¹³C in mesh bags amended with maize compost. Based on this, it was estimated that a fungal production of 1 μg ergosterol corresponded to 0.33 mg of sequestered carbon. In conclusion, the effect of the fertilizer on EM growth seemed to be dependent on the effect of the fertilizer on tree growth. Thus, at Ebbegärde, were tree growth was less stimulated by the fertilizer, EM growth was reduced upon fertilization. At other sites, where tree growth was more stimulated, the fertilizer did not influence EM growth. The large amounts of carbon sequestered during the experiment may be a result of fungal residues remaining in the soil after the death of the hyphae.     

播期密度及氮肥运筹方式对冬小麦籽粒产量的影响

通过不同播期、播种密度和氮肥运筹方式对不同冬小麦品种籽粒产量及构成因子影响的研究，探讨了通过调控播期、密度及氮肥运筹方式实现不同品种丰产高效的可能性。试验结果表明，播期、播种密度和氮肥运筹方式均显著影响小麦产量及产量构成因子，播期以10/15~10/22最为适宜，播种密度以120万/km2~240万/km2为宜，氮肥运筹方式以N210(3:5:2)最好，其次为N210(5:5)。保证供试小麦品种实现9000kg/hm2产量的高产途径为主茎和分蘖并重，适宜的产量结构为：4:4:4，即亩有效穗数39.4~44.4万，穗粒数35.3~40.0，千粒重40.2~45.8g。     

表皮生长因子的作用机理及对体外受精的影响

表皮生长因子(EGF)是一种重要的多肽类生长因子,它对卵母细胞的体外成熟和早期胚胎的发育具有明显的促进作用。大量研究表明:EGF能够以旁分泌(Paracrine)或自分泌(Autocrine)的形式作用于胚胎组织中的EGFR,刺激内细胞团(ICM)和滋养外胚层的增殖,从而调节早期胚胎的发育。     

大豆高产优质施肥研究与应用

本文概述了大豆营养特性与施肥的研究结果，提出了高产施肥的关键技术。大豆营养特性：一是对主要营养元素的吸收量较稻、麦作物高（等量籽粒产量），生产100kg大豆约吸收6.5~8.5kg N，1.8~2.8kg P2O5，2.7~3.7kg K2O，3.5~4.8kg CaO，1.8~2.9kg MgO，4.5~9.5g Zn。二是对主要营养元素的吸收积累高峰在花荚期，N、P、K的60~70%在在此期吸收，而不同于稻麦等作物。三是总氮源的40~60%来源共生固氮，而共生固氮又受土壤N、P、K、Ca、Mo、Zn等及土壤PH值影响。四是大豆成熟阶段营养器官的养分向籽粒转移率高，Ｎ、Ｐ、Ｋ分别达58~77%，60~75%，45~75%。大豆施用N、P、K、Zn、Mo、B肥均显著提提高产量，合理配合施用可达到180~300kg/亩。N、P提高籽粒蛋白质含量，K与Zn提高脂肪含量，P、K、Zn、Mo及少量N肥可提高结瘤固氮率。N、P、K和多种微肥可减轻东北连作大豆的不利因子危害，大幅度增加产量。大豆高产施肥，一是根据土壤、植株养分含量确定施肥数量，二是有机肥与N、P、K肥及多种微肥配合施用，三是注重前茬作物施肥，增肥土壤，四是根据土壤条件、耕作制度、大豆品种特性确定施肥数量、方法、时期。中等肥力高产施肥一般应施用N 8，P2O5 4，K2O 4，ZnSo4 1.5(kg/亩)，钼酸铵20~30g/亩，P、K、Zn用作底或种肥，N肥钼肥种肥花期追肥各半，另于花荚期喷施P、N、Mo肥二次     

回归最优设计法在水培白菜肥料效应中的应用

利用“416-A”回归最优设计研究Ca(NO3)2?4H2O、KNO3、NH4H2PO4、MgSO4?7H2O对水培白菜的产量效应。数学模拟建立了四种肥料与白菜产量的回归方程：y=97.808-4.337x1+3.445x2-2.690x3+8.299x4-6.894x1x2+17.331x1x3-7.389x1x4-3.191x2x3+6.364x2x4+0.063x3x4-9.629x12-17.150x22-17.915x32-24.066x42。经检验回归关系显著，并对回归系数进行了检验。从回归方程可得：MgSO4?7H2O对产量以直接作用为主，其次为Ca(NO3)2?4H2O、KNO3和NH4H2PO4。Ca(NO3)2?4H2O与其它三种肥料均有交互作用，其中与NH4H2PO4交互作用达极显著水平。从产量效应回归关系优选出配方浓度为：Ca(NO3)2?4H2O：971mg/L；KNO3：931mg/L；NH4H2PO4：204mg/L；MgSO4?7H2O：581mg/L。采用回归最优设计结合水培研究肥料效应精确可行。