OPPORTUNITIES AND APPROACHES FOR MANIPULATING SOIL-PLANT MICROBIOMES FOR EFFECTIVE CROP NITROGEN USE IN AGROECOSYSTEMS

● Matching nitrification inhibitors with soil properties and nitrifiers is vital to achieve a higher NUE. ● Enhancing BNF, DNRA and microbial N immobilization processes via soil amendments can greatly contribute to less chemical N fertilizer input. ● Plant-associated microbiomes are critical for plant nutrient uptake, growth and fitness. ● Coevolutionary trophic relationships among soil biota need to be considered for improving crop NUE. Soil microbiomes drive the biogeochemical cycling of nitrogen and regulate soil N supply and loss, thus, pivotal nitrogen use efficiency (NUE). Meanwhile, there is an increasing awareness that plant associated microbiomes and soil food web interactions is vital for modulating crop productivity and N uptake. The rapid advances in modern omics-based techniques and biotechnologies make it possible to manipulate soil-plant microbiomes for improving NUE and reducing N environmental impacts. This paper summarizes current progress in research on regulating soil microbial N cycle processes for NUE improvement, plant-microbe interactions benefiting plant N uptake, and the importance of soil microbiomes in promoting soil health and crop productivity. We also proposes a potential holistic (rhizosphere-root-phyllosphere) microbe-based approach to improve NUE and reduce dependence on mineral N fertilizer in agroecosystems, toward nature-based solution for nutrient management in intensive cropping systems.     

SUSTAINABLE NITROGEN MANAGEMENT IN AUSTRALIAN AGROECOSYSTEMS: CHALLENGES AND OPPORTUNITIES

● There is huge potential for improvement of nitrogen management in Australia. ● N management should incorporate environmental, social and economic sustainability. ● Agronomic, ecological and socioeconomic approaches and efforts are needed. Nitrogen is an essential nutrient that supports life, but excess N in the human-environment system causes multiple adverse effects from the local to the global scale. Sustainable N management in agroecosystems, therefore, has become more and more critical to address the increasing concern over food security, environmental quality and climate change. Australia is facing a serious challenge for sustainable N management due to its emission-intensive lifestyle (high level of animal-source foods and fossil fuels consumption) and its diversity of agricultural production systems, from extensive rainfed grain systems with mining of soil N to intensive crop and animal production systems with excessive use of N. This paper reviews the major challenges and future opportunities for making Australian agrifood systems more sustainable, less polluting and more profitable.     

四川盆地旱坡地生态农业的建设重点与途径

四川盆地的紫色土区,生态环境甚为脆弱,季节干旱频繁,森林覆盖率低,土壤侵蚀严重,坡薄土面积土,土质干瘦。因此,生态农业建设的重点应是雨养农业,采取全面改善生态条件,合理布局农林牧业及应用高产配套技术等途径,以保证农业全面持续发展。     

INTERCROPPING: FEED MORE PEOPLE AND BUILD MORE SUSTAINABLE AGROECOSYSTEMS

• Intercropping is a useful practice when agricultural sustainability is emphasized.• We integrate biodiversity-ecosystem functioning and intercropping.• Intercropping optimizes ecosystem services such as stabilizing yield and reducing use of chemicals.• Intercropping benefits are attributed partly to complementarity and selection effects.• Application of ecological principles is key to sustainable agricultural development.Intercropping is a traditional farming system that increases crop diversity to strengthen agroecosystem functions while decreasing chemical inputs and minimizing negative environmental effects of crop production. Intercropping is currently considerable interest because of its importance in sustainable agriculture. Here, we synthesize the factors that make intercropping a sustainable means of food production by integrating biodiversity of natural ecosystems and crop diversity. In addition to well-known yield increases, intercropping can also increase yield stability over the long term and increase systemic resistance to plant diseases, pests and other unfavorable factors (e.g. nutrient deficiencies). The efficient use of resources can save mineral fertilizer inputs, reduce environmental pollution risks and greenhouse gas emissions caused by agriculture, thus mitigating global climate change. Intercropping potentially increases above- and below-ground biodiversity of various taxa at field scale, consequently it enhances ecosystem services. Complementarity and selection effects allow a better understanding the mechanisms behind enhanced ecosystem functioning. The development of mechanization is essential for large-scale application of intercropping. Agroecosystem multifunctionality and soil health should be priority topics in future research on intercropping.     

新疆干旱荒漠生态条件下实现小麦高产优质的途径

新疆干旱荒漠区光热资源丰富,有利于小麦生长,是新疆小麦主要产区之一。但由于冻害,干热风,土壤次生盐渍化,耕地沙化等问题,影响小麦产量。因此,在干旱荒漠生态条件下,实现小麦高产优质必须重视:一、注意环境保护,防止耕地沙化和土壤次生盐渍化。二、合理调整冬、春小麦比例。三、增加物质与技术投入,培养地力,改善生产条件。四、抓好栽培技术的主要环节。     

限制性内切酶片段长度多态性（RFLP）及其在植物育种中的应用

 本文是一篇有关遗传标记的综述论文，探讨了限制性内切酶片段长度多态性（RFLP）及其在植物育种中的作用。首先简述了RFLP技术的理论基础，它可作为遗传标记加以利用，在理论上可运用RFLP进行遗传作图，而在植物育种中潜在的应用价值有：1.鉴别品种及品种专利；2.遗传资源多样性的识别；3.在数量性状研究中的应用；4.外源染色体的鉴别。最后还比较了RFLP、同工酶及RAPD等遗传标记的异同和优、缺点。     

DESIGNING DIVERSIFIED CROPPING SYSTEMS IN CHINA: THEORY,APPROACHES AND IMPLEMENTATION

•Agricultural green transformation of China requires restructuring of cropping systems.•Ecosystem services enhanced by crop diversification is key to sustainable agriculture.•Crop diversification improve ecosystem services at field, farm and landscape scales.•Cropping system design should meet regional characteristics and socio-economic demand.Intensive agriculture in China over recent decades has successfully realized food security but at the expense of negative environmental impacts. Achieving green transformation of agriculture in China requires fundamental restructuring of cropping systems. This paper presents a theoretical framework of theory, approaches and implementation of crop diversification schemes in China. Initially, crop diversification schemes require identifying multiple objectives by simultaneously considering natural resources, limiting factors/constraints, and social and economic demands of different stakeholders. Then, it is necessary to optimize existing and/or design novel cropping systems based upon farming practices and ecological principles, and to strengthen targeted ecosystem services to achieve the identified objectives. Next, the resulting diversified cropping systems need to be evaluated and examined by employing experimental and modeling approaches. Finally, a strategic plan, as presented in this paper, is needed for implementing an optimized crop diversification in China based upon regional characteristics with the concurrent objectives of safe, nutritious food production and environmental protection. The North China Plain is used as an example to illustrate the strategic plan to optimize and design diversified cropping systems. The implementation of crop diversification in China will set an example for other countries undergoing agricultural transition, and contribute to global sustainable development.     

智能网络化水资源的实时预测分析

在水资源严重短缺地区，对水资源较准确可靠的实时预测预报是充分利用当地有限的水资源、实施地表地下水资源的联合调度和最优配置极为重要的前提和条件。本文利用BP神经网络的纠错性、智能性，对复杂的水资源产汇流黑箱模型进行预测计算，并应用于太子河流域枯季的水资源实时监测监控系统，较传统的统计回归计算方法，其计算速度与拟合优度都有较大的提高与改进。     

分子标记及其在植物育种中的应用

本文介绍了限制性片断长度多态性（ＲＦＬＰ）、随机扩增多态性ＤＮＡ（ＲＡＰＤ）、扩增片断长度多态性（ＡＦＬＰ）、简单重复序列（ＳＳＲ）、染色体原位杂交（ＩＳＨ）分子标记的基本原理、特点及其在植物育种中的应用。在植物育种中分子标记可用于绘制品种、品系的ＤＮＡ指纹图谱、种质资源遗传多样性的研究、种质资源的创新与鉴定、分子标记辅助选择。     

我国竹材加工利用现状与探讨

本文扼要介绍国内目前竹材加工利用现状。着重阐述开发高附加值的"以竹胜木"产品的意义及今后竹材加工利用的方向。     

荒漠绿洲额济纳生态空间占有与生态恢复空间研究

以2000年、2001年和2002年额济纳旗统计年鉴资料为研究对象,对额济纳绿洲进行生态空间占有和生态恢复空间分析,结果表明:生态空间占有需求从2000年-2002年是下降的,分别为1 089.526 2hm2、835.767 9hm2和831.006hm2,生态空间占有供给是增加的,分别为366.296hm2、412.966hm2和414.546hm2,但生态空间占有呈亏损状态,不过亏损随年度呈下降趋势,分别亏损为,-723.2302hm2、-422.801 9hm2和-416.46hm2.额济纳虽有11.4万km2的土地面积,但真正可以供人类居住的实有额济纳绿洲中的3.16万km2,只占总面积的27.57‰,在绿洲居住的人口已远超过生态承载力,其实际生态恢复空间是负值.按目前额济纳旗人均需生态空间45hm2,则绿洲的生态恢复空间在现有人口状况下,没有可恢复空间,所以在额济纳绿洲应该进行生态移民,以减少对绿洲的压力.     

基于支持向量机和人工免疫的新结合算法

为了减少大规模数据的支持向量机的样本训练时间，提出了人工免疫（aiNet）和支持向量机（SVM）相结合的算法（ai—SVM）。aiNet能在进行样本压缩的同时抽取原始数据的相关信息并保持原始数据的样本分布。压缩后的样本组成了抗体网络，并在此抗体网络上构建了支持向量机模型。最后结合实际数据样本对ai—SVM算法进行了验证。结果表明，ai-SVM算法可大大减小训练样本集和训练代价，且不降低精度。     

西双版纳竹类资源开发利用的探讨

云南是世界竹类植物的起源中心和现代分布中心之一，被称为“竹类的故乡”，其中西双版纳竹类资源格外丰富，这与优越的水热条件密切相关。那里不仅具有大面积的大型丛生天然竹林和栽培竹林，而且当地各民族广泛利用竹类于生产、生活及宗教等活动中，竹类与当地各民族有着千丝万缕的联系。怎样合理开发和利用西双版纳丰富的竹类资源，达到资源的永续利用，是一个重要的研究课题。作者基于民族植物学、生态经济学的观念和理论，对西双版纳竹类资源的开发、利用的现状及有利条件进行了分析、探讨，并对发展决策提出了自己的观点和看法。     

氟喹诺酮类药物的研究及其在兽医临床上的应用

第三代喹诺酮类药物,即氟喹诺酮类药物,具有抗菌谱广、抗菌作用强、作用迅速、副作用少等优点。因而是近十几年来研究最多、发展最快的一类药物。本文着重阐述了本类药物的构效关系、抗菌活性、药动学、兽医临床应用及不良反应。     

马尔可夫链及其在林业预测中的应用

马尔可夫链是一种随机模型。它可以用来预测、分析具有多种状态的随机系统。本文介绍了马尔可夫链的基本概念和方法,并就在林业预测中的两个问题——林木病害预测和森林资源变化预测进行了讨论和分析。     

乌梁素海生态恢复规划设计

通过对乌梁素海基本情况的分析，确定了乌梁素海生态规划与设计的指导思想和目标，在景观生态分析、综合以及评价的基础上，进行生态规划与建设分区，规划和建立区域景观优化利用的空间结构和功能，完成了乌梁素海生态系统功能规划与结构设计，并提出相应的方案和对策。     

振兴黑龙江林业,实现经济建设与生态建设的同步发展

黑龙江省是我国最主要的木材生产基地,又是重要的商品粮基地和畜牧业基地。长期的重取轻予,使黑龙江省林业面临困境。文中侧重对森林资源濒临枯竭及生态环境的恶化趋势通过实例给予阐明;指出当务之急是转变观念,将“以大木头为中心”的单一开发经营体系转变为多层次、多渠道的综合开发经营体系;并按照 多样性(生态上的适应与抗干扰力的增强 市场经济中的弹性与竞争能力增强)稳定性这个在生态学及经济学上均具有重要意义的基本原理,对黑龙江省当前林业工作中存在的某些主要问题进行了分析并提出合理、可行的决策建议和具体的技术措施,以争取黑龙江省林业实现经济建设与生态建设的同步发展。     

CONCENTRATIONS AND FLUXES OF DISSOLVED NUTRIENTS IN THE YANGTZE RIVER: LONG-TERM TRENDS AND ECOLOGICAL IMPACTS

• Historic trends in nutrient loading and flux in the Yangtze River were analyzed• Decreasing trends in the concentrations and fluxes of DSi were found• Significant increasing trends in DIN and DIP concentrations were observed• The frequency of and area covered by red tide outbreaks substantially increased• Atmospheric deposition become a vital factor influencing DIN loadings and fluxesIntensifying human activity in the Yangtze River basin has substantially increased nutrient concentrations in the Yangtze River Estuary, leading to degradation of the coastal environment. Analysis of nutrient determinations published over the past 50 years reveals a gradual decreasing trend in the concentrations and fluxes of dissolved silicate (DSi). However, both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphate (DIP) concentrations have increased significantly since the 1970s. The frequency of and area covered by red tide outbreaks have increased greatly during this period, mainly due to changes in nutrient supply ratios [i.e., N/P (DIN/DIP), N/Si (DIN/DSi), P/Si (DIP/DSi)]. A strong correlation was found between the riverine DIN fluxes and the estimated DIN inputs from the major N sources, particularly fertilizers and atmospheric deposition. The data provide a comprehensive assessment of nutrients in the Yangtze River basin and their ecological impacts and indicate a potentially significant influence of atmospheric deposition on DIN loadings and fluxes.     

基于距离和角度信息的无线传感器网络定位算法

提出一种基于距离和信号到达角信息的无线传感器网络节点自身定位算法.在所有节点的坐标轴方向都是未知的假定下,用信号到达角信息来计算信号到达角度差,然后将定位问题转化为一个凸集优化问题,节点间的几何关系也相应地转化成为线性或二次约束条件.当距离和角度测量值足够精确时,该算法是一个线性规划问题.考虑测量误差时,通过引入辅助变量,该算法可以转化为二次规划问题.通过仿真分析证明了该定位算法的有效性,并对距离和角度误差量对定位精度的影响进行了定量分析.仿真结果表明,在距离和角度误差为5%的时候,该定位算法可以满足定位精度要求.     

瘤胃降解蛋白和瘤胃非降解蛋白在反刍家畜日粮中的应用

限制反刍家畜实现对饲料高效利用和畜产品最大产出的主要因素是必需氨基酸,这些氨基酸必须由瘤胃降解蛋白为原料合成的菌体蛋白和瘤胃非降解蛋白从小肠供给。家畜才能实现肉奶皮毛等畜产品的最大产出。应用瘤胃降解蛋白和瘤胃非降解蛋白这一体系评价反刍家畜的蛋白质营养需要和饲料的蛋白质质量比粗蛋白更准确,更经济、更能满足家畜高产的需求。