杨粮间作行距对小麦生长及产量的影响

对杨粮间作条件下小麦生长结果研究表明，杨树间作行距与土壤水分呈反比关系，即3～15m的行距范围内林木行距每扩大1m，土壤季平均含水量则降低1.0%，证明间作可有效减少土壤水分损失；同时林木行距与小麦叶绿素含量呈反比，说明一定程度的林木遮荫可提高小麦叶绿素含量。试验表明，小麦光合作用速率和蒸腾速率与林木行距呈正比，林木行距每增加1m，小麦的光合速率和蒸腾速率分别提高1.3μmol/m²·s和0.2μmol/m²·s，说明林木行距过小，则影响作物的光合作用，进而影响小麦的生物量和产量。通过计算，在该杨树4年林龄条件下小麦取得最大产量的行距为21～22m。     

黄家二岔小流域能量流的系统分析Ⅱ．种植业子系统能量流分析

计算了小流域小麦、豌豆、马铃薯、胡麻、玉米的有机能、无机能投入和各种作物的籽粒、秸秆、根的能量产出，以此分析了各种作物的能量产投关系、种植业子系统能量流的现状与问题，并作了种植业投能结构和数量的优化分析。     

作物遥感识别中的数据挖掘技术

该文综述了数据挖掘技术应用在图像分类方面的各种方法，介绍了每种方法的优缺点、适用领域及应用情况。介绍了将数据挖掘技术应用于图像分类方面以有效解决当前作物遥感识别中的瓶颈问题。对当前作物遥感识别系统在数据源的使用、识别过程的规范和方法的实用性方面的问题进行了分析，展望了作物遥感识别中的数据挖掘技术研究发展方向。     

紫色土丘陵林农间种模式种间适应及作物种类选择试验

1997~1998年在试验区进行了林农间适应及作物种类选择试验,结果如下;适度的林木郁闭对作物生长有利,郁闭度为0.35时,其生物产量和经济产量均优于0.125;郁闭度为0.67以上,不宜进行间种。适宜于试区土地条件的冬春作物有满园花、油菜;夏季作物有西瓜、甘薯、凉茹、辣椒、大豆、花生、豌豆等,但从防侵蚀角度考虑,甘薯、凉茹等收获地下块根的作物不宜选用。     

广西作物旱情诊断的分析与预测

根据广西各地的水稻，玉米，甘蔗的受旱资料，求出各地各旬各种作物的旱情百分率（受旱面积／播种面积）。然后，建立广西各种作物逐旬旱情趋势（分轻，中、重３个等级）与作物生长发育关系比较密切的８个气象要素，在不同旱情诊断等级下各个因子区间的隶属度矩阵，以此人微言轻 旱性诊断的模糊变换矩阵Ｒ及因子权重Ａ的备选元素，根据各地不同份的气象要素来构造Ｒ及Ａ，用７种算子作出各种作物旱情诊断等级的归属评判。     

哲里木盟主要作物产量波动与气候变化

分析１９８１～１９９５年间哲里木盟主要作物产量波动及其与影响因素的关系表明，粮豆总产和单产均在波动中有较大的提高，总产增幅趋势大于单产，单产年际波动大于总产，各种作物单产的波动受气候因素的影响均大于技术水平，气候因素中以温度影响最大。     

哲里木明主要作物产量波动与气候变化

分析１９８１－１９９５年间哲里木盟主要作物产量波动及其与影响因素的关系表明，粮豆总产和单产均在波动中有较大的提高，总产增幅趋势大于单产，单产年际波动大于总产，各种作物单产的波动受气候因素的影响均大于技术水平，气候因素中以温度影响最大。     

植物组织中速效性氮磷的纸上点滴分析法

研究农业化学的最主要目的,是解决各种作物的合理施肥问题,提高农产品的产量和质量。在作物的生育过程中,通过分析植物的各种养分含量,以确定追肥的种类和数量更有实际意义。     

1995年东北地区粮豆生产与农业气象条件关系分析

１９９５年东北地区粮豆生产与农业气象条件关系分析娄秀荣，沙奕卓（中国气象科学研究院，北京１０００８１）１９９５年东北地区作物生长季（４～９月）光温水时空分布差异较大。春季大部地区热量条件较差，各种作物播种、出苗缓慢，幼苗生育期延迟。初夏热量条件一度转...     

1995年夏季(6～8月)气候对我国农业生产的影响

１９９５年夏季，全国大部地区平均气温基本与常年同期接近，主要求区降雨分布比较调匀，日照较常年同期略偏少，长江中下游沿江至江南北部和在北地区东南部先后遭受暴雨洪涝，农业生产受到较大损失。华北地区中乐部多阴雨寡照天气，作物生育受到一定影响。西北地区东部、华北地区西部和川北、鄂西北春夏连旱，东北地区西北部持续伏旱，各种作物生长发育受到较大影响。东北地区中北部、西北地区西部、西南地区大部、江淮和华南大部农业气象条件较为适宜，各种作物长势较好。江南晚稻插秧后，光温较为充足，禾苗长势良好。华南早稻获得丰产丰收，季末晚稻生长遭受台风和热带风暴的影响。     

黄土丘陵区水土保持措施配置与土壤水分的关系

土壤水分与水土保持措施配置间存在密切关系,从空间结构看,地形起伏引起降水再分配,而工程措施可使降水形成有益的再分配,由此产生土壤水分的微域分异。这种分异制约影响着生物措施的空间配置;从时间过程看,为防止某些植物过度的水分消耗而致土壤干燥化,需采取循环轮作配置。在黄土丘陵区要求林草与农作物地在轮作周期内的总耗水量与有效雨量（降雨量与径流深之差）持平。     

我国盐渍化土壤的营养与施肥效应研究进展

阐述了盐渍化土壤的营养障碍因素及其对作物、蔬菜、林木等的危害程度、盐渍化土壤中N、P、K以及微量元素的养分状况与土壤盐分效应、施肥效应和施肥技术等；重点探讨了磷石膏作为化学改良剂应用于盐渍化土壤的前景及存在的问题；简介了北方盐渍化土壤的K素发展趋势及K肥效应，并展望了今后研究的方向。     

Ozone measurements in Europe

Ozone measurements have been apart of EMEP since its third phase in 1984–1986 and since 1988 data have been collected systematically. By 1992 data for 76 sites were being collected by the Chemical Co-ordinating Centre in NILU. The mean ozone concentration increases from 20–25ppb in the western and northern fringes to 30–35 in central areas of Europe. There is also evidence from the last decade of an upward trend of up to 0.5ppb y^?1 at rural sites in the UK. The data have been analysed to estimate the spatial patterns in AOT 40 for ozone effects on crops and forests. The data show that the critical level for cereal crops of 5300 ppb.h above a threshold of 40 ppb is exceeded over almost all of continental Europe south of 65°N and over most of S.Britain. A similar exercise for the AOT 40 for the forest again shows exceedances of the critical load of 10⁴ ppb.h across all the mapped area of Continental Europe south of 65°N including S.Britian. As land use for forestry and ozone dose both increase with altitude, and these effects have not so far been incorporated in the AOT 40 assessment for forests, the degree of exceedence for forests may have been significantly under-estimated.     

Forest management and carbon storage: An analysis of 12 key forest nations

Forests of the world sequester and conserve more C than all other terrestrial ecosystems and account for 90% of the annual C flux between the atmosphere and the Earth's land surface. Preliminary estimates indicate that forest and agroforest management practices throughout the world can enhance the capability of forests to sequester C and reduce accumulation of greenhouse gases in the atmosphere. Yet of the 3600 × 10⁶ ha of forests in the world today, only about 10% (350×10⁶ ha) are actively managed. The impetus to expand lands managed for forestry or agroforestry purposes lies primarily with nations having forest resources. In late 1990, an assessment was initiated to evaluate the biological potential and initial site costs of managed forest and agroforest systems to sequester C. Within the assessment, 12 key forested nations were the focus of a special analysis: Argentina, Australia, Brazil, Canada, China, Germany, India, Malaysia, Mexico, South Africa, former USSR, and USA. These nations contain 59% of the world's natural forests and are representative of the world's boreal, temperate, and tropical forest biomes. Assessment results indicate that though the world's forests are contained in 138 nations, a subset of key nations, such as the 12 selected for this analysis, can significantly contribute to the global capability to sequester C through managed tree crops. Collectively, the 12 nations are estimated to have the potential to store 25.7 Pg C, once expanded levels of practices such as reforestation, afforestation, natural regeneration and agroforestry are implemented and maintained. Initial site costs based upon establishment costs for management practices are less than US$33/Mg C.     

The Micro-behavioral Framework for Estimating Total Damage of Global Warming on Natural Resource Enterprises with Full Adaptations

This paper presents a novel methodology in which an individual’s optimization decisions are statistically decomposed into choices of systems, system-specific outcomes, and the overall outcome in an integrative framework. The methodology is applied to individuals’ decisions on natural resource enterprises given climatic changes. This paper finds that when the Goddard Institute scenario comes to pass by the middle of this century, adoption of a crops-only enterprise will fall, so will adoption of a crops–forests enterprise. Instead, people will increase adoption of a livestock-only as well as a crops–livestock–forests enterprise. The impacts of climate change on the six enterprises are varied, which are calculated from the estimated models by altering climate variables. The crops-only enterprise will lose the value of land by 8.3 %. However, the livestock-only enterprise will gain by 8.9 %. The crops–livestock–forests enterprise also will gain largely by 7.8 %. The impacts on the other enterprises are muted, e.g., 1 % gain for the crops–livestock enterprise. The total damage under the scenario is expected to be a loss of 1.9 % of land value. Under a severer UK Met Office scenario, the damage is predicted to increase to 6.2 %.     

Biodiversity conservation in tropical forest landscapes of Oceania

The fragmented island realm of Oceania includes a relatively small proportion of the world’s tropical forests, but those forests support unusual richness of narrowly endemic species. In common with tropical forests across most of the world, tropical forests in Oceania are declining due to factors associated with increasing human population size, economic drivers and more intensive exploitation. In parts of Oceania, forests are being cleared at unsustainable rates, and replaced with far simpler ecosystems of timber or food crops. To a small degree, the present-day biodiversity of tropical forests in some parts of Oceania may be predisposed to such disturbance, given a history of natural disturbance (particularly through cyclones), and of smaller-scale slash-and-burn agriculture or landscape-scale burning. But, in most places, the current intensity, scale and/or rate of modification far surpass their precedents, and biodiversity is consequently diminishing. Tropical forests in Australia may be an exception to this trend, with now reasonably effective protection. However, more so than for tropical forests in most other continents, the major biodiversity conservation challenges for tropical forests in Oceania are extrinsic. Introduced plants, animals and diseases have collapsed ecological communities through much of Oceania, homogenising the biota from a series of highly distinctive and localised species assemblages to a more impoverished set of ubiquitous disturbance-tolerant exotic species. In many islands, this simplification has occurred regardless of the extent of native forest remaining, such that retention and reservation of primary forest is an insufficient conservation action. The fate of biodiversity in Oceania is also likely to be much affected by climate change, an unbalanced consequence given the region’s relatively small contribution to greenhouse gas emissions. Future hope for biodiversity conservation in tropical forests of Oceania lies in the renewed application of some traditional management constraints, the appropriate delivery of international support (such as may be available through carbon markets), improved quarantine processes, and through some protection naturally offered by the remote scattering of the islands that comprise Oceania.     

Nitrogen balances in forest ecosystems of the Pacific Northwest

In order to understand the role of nitrogen in the forests of the Pacific Northwest, especially Douglas-fir, a great number of studies have been initiated to evaluate both static and dynamic aspects of the nitrogen balance. This paper presents a summary of many of these past results covering 20 yr research with the specific intent of defining the nitrogen economy of these systems and the long- and short-term changes that are occurring. Variations of nitrogen in both soils and vegetation are discussed with some sampling techniques applicable to coniferous forests given. It appears that the soil total nitrogen, in different soils, varies several fold more than the nitrogen in the forest crops of these soils. The dynamics of nitrogen transfer within the ecosystem, together with gains and losses from the system, are presented.     

Agroforestry developments and potential in the Brazilian Amazon

Much attention in the media and scientific literature has focused on the destruction of tropical forests in Amazonia since the early 1970s, especially in the Brazilian states of Rondǒnia, Acre, Paré and Mato Grosso. Concern is mounting that the peeling back of the forests is wiping out biodiversity, destroying soil resources, possibly exacerbating global warming, and provoking land conflicts, among other socioeconomic and ecological problems. Yet little regard has been paid to some of the promising agricultural developments in the region that are helping to counteract pressures on the remaining forest while recuperating debilitated areas. In particular, a pronounced trend towards planting a mix of tree crops on small farms throughout the basin augers well for the future of the rainforest and more sustainable agriculture. Agroforestry developments in Amazonia underscore the linkages between conserving biodiversity and more productive and resilient agricultural systems.     

西双版纳热带雨林次生林的生物养分循环

本文获得了西双版纳热带雨林，砍伐后２块处于恢复演替阶段不同年代的次生林的生物量、生长量、年凋浇物量及它们的主要营养元素含量、对土壤养分状况的影响、以及土壤微生物状况和土壤生化活性等一系列资料。阐明了次生林生物物质和养分吸收、积累和归还的特点及对土壤养发状况的影响，研究了土壤微生物对凋落物的分解作用，从而对热带雨林次生林的生物养分循环作了一初步的探讨，为热带森林生态系统研究奠定了基础。研究表明：１．     

IBQS: A synthetic index of soil quality based on soil macro-invertebrate communities

We developed a synthetic index of biological soil quality (IBQS) based on soil macro-invertebrate community patterns to assess soil quality. In 22 sites representing the diversity of agroecosystems encountered in France, invertebrate communities co-varied significantly with a set of 14 parameters describing the physical and chemical properties of soil (co-inertia, p < 0.001; RV = 0.70). Using hierarchical classification, sites could be separated into four homogeneous groups and, using the ‘indicator value’ method, 46 indicator taxa characteristic of one or another of these groups were identified. We then used a formula that takes into account the abundance of indicator species and their respective indicator values to score soils from 1 to 20. IBQS was able to detect the effects of management practices on soil quality. Soil quality varied from 6 to 20 in forests, 7 to 9 in pastures and 2 to 9 in crops respectively. This suggests that well-managed crops and pastures may have better soil quality than some forests. Our results confirm that soil macro-invertebrates provide an integrative measure of soil quality and that the proposed index can be used either in short- or long-term monitoring, provided that it is calibrated and validated with respect to the regional context of the study.