地质学在农业上的拓展应用与展望

地质科学向农业拓展并交融渗透,形成一门新的边缘学科--农业地质学.当前,从国内外对农业地质的研究现状来看,其愈来愈被广大地学和农学科技人员所重视.农业地质学为全球地质科学和农业科学结合并推进其向纵深发展发挥了重大作用.近年我国开展了大区域的农业地质环境调查与评价工作,取得了一定的经济、社会和生态效益.文章简要综述农业地质的发展历史,从农业地质学在我国的应用现状谈起,并列举大量实例,分析、阐明了农业地质研究工作在农业生产及其生态环境中的独特作用、发展趋势,对今后如何开展该项工作提出了建议.     

Sulfur distribution in five Ethiopian Rift Valley soils under humid and semi-arid climate

The Rift Valley has diverse soil types with different fertility potential. The climate of the Rift Valley is also diverse. Five major soil types that lie in the humid, sub-humid, and semi-arid parts of the Rift Valley were studied. Total sulfur (S) in the subsoil of the Solonetz and Andosol approximates total S contents of similar soils in other parts of the world. Organic matter is the major source of total sulfur for the soils in the humid parts (Nitisol, Andosol and Vertisol), whereas gypsum is the major source for the soils in the drier parts (Fluvisol and Solonetz). The Nitisol has the lowest soluble sulfate, which is below the critical level for crop production. All other soils contain soluble sulfate which is adequate for crop production. Land degradation, crop residue removal, clearing and burning of forests and other vegetation, crop uptake, and use of non-S fertilizers are major causes of sulfur deficiency in the Rift Valley. Maintenance of the soil organic matter, utilization of subsurface inorganic S and proper management of soils should maintain the S status of the soils in the future.     

全球重要农业文化遗产：云南红河哈尼梯田研究进展与展望

云南省红河州哈尼梯田已成为世界重要农业文化遗产之一,哈尼梯田作为传统农业具有丰富的农业甚至生态知识和深厚的文化底蕴,很值得关注和研究。从哈尼梯田自然地理特征及形成、生物多样性、生态系统与景观方面、水资源、哈尼梯田文化与旅游5个方面总结了目前关于哈尼梯田的研究。在回顾相关研究的基础上,展望哈尼梯田方面今后的研究,对现有研究表明关于哈尼梯田的研究还有很大的发展空间。哈尼梯田的进一步研究,将对促进哈尼梯田的遗产价值和文化多样性的保护具有重要意义。     

基于NPWP的云南植物保护优先区分析

本研究以国家重点保护野生植物（NPWP-National Protected Wild Plants）为指示物种,基于云南各县（市、区）的NPWP信息统计,应用Dobson 算法系统筛选出云南植物保护优先区,并利用已建自然保护区信息评价所筛选的植物保护优先区及其关联生态（亚）区的保护现状。结果表明：在75%和100%的NPWP保护水平上,分别筛选确定了河口县等7 个和24 个县/市/区为植物保护优先区,其中75%保护水平上的7 个植物保护优先区是云南植物多样性保护最关键地区;在75%和100%保护水平上,分别有4 个和8 个植物保护优先区的自然保护区面积百分比低于5%,亟待加强建设;2 个生态区和7 个生态亚区的自然保护面积百分比都明显低于10%,未达到全球植物保护战略2010 年的基本目标;应将I-25-03、I-25-04、I-28-07 生态亚区纳入云南植物保护地体系优化之中。     

Evaluation of Procedures for Prediction of Unconventional Gas in the Presence of Geologic Trends

This study extends the application of local spatial nonparametric prediction models to the estimation of recoverable gas volumes in continuous-type gas plays to regimes where there is a single geologic trend. A transformation is presented, originally proposed by Tomczak, that offsets the distortions caused by the trend. This article reports on numerical experiments that compare predictive and classification performance of the local nonparametric prediction models based on the transformation with models based on Euclidean distance. The transformation offers improvement in average root mean square error when the trend is not severely misspecified. Because of the local nature of the models, even those based on Euclidean distance in the presence of trends are reasonably robust. The tests based on other model performance metrics such as prediction error associated with the high-grade tracts and the ability of the models to identify sites with the largest gas volumes also demonstrate the robustness of both local modeling approaches.

Nitrogen limitation in arid-subhumid ecosystems: A meta-analysis of fertilization studies

Evidence supporting water limitation in arid-semiarid ecosystems includes strong correlations between aboveground net primary production (ANPP) and annual precipitation as well as results from experimental water additions. Similarly, there is evidence of N limitation on ANPP in low precipitation ecosystems, but is this a widespread phenomenon? Are all arid-semiarid ecosystems equally limited by nitrogen? Is the response of N fertilization modulated by water availability?We conducted a meta-analysis of ANPP responses to N fertilization across arid to subhumid ecosystems to quantify N limitation, using the effect-size index R which is the ratio of ANPP in fertilized to control plots. Nitrogen addition increased ANPP across all studies by an average of 50%, and nitrogen effects increased significantly (P = 0.03) along the 50-650 mm yr⁻¹ precipitation gradient. The response ratio decreased with mean annual temperature in arid and semiarid ecosystems but was insensitive in subhumid systems. Sown pastures showed significant (P = 0.007) higher responses than natural ecosystems. Neither plant-life form nor chemical form of the applied fertilizer showed significant effects on the primary production response to N addition. Our results showed that nitrogen limitation is a widespread phenomenon in low-precipitation ecosystems and that its importance increases with annual precipitation from arid to subhumid regions. Both water and N availability limit primary production, probably at different times during the year; with frequency of N limitation increasing and frequency of water limitation decreasing as annual precipitation increases. Expected increase N deposition, which could be significant even in arid ecosystems, would increase aboveground net primary production in water-limited ecosystems that account for 40% of the terrestrial surface.     

1951—2010年中国土壤温度时空变化特征及其影响因素

土壤温度状况对于研究气候变迁、地球物质能量循环以及土壤性质演变具有重要意义,但目前对国家尺度上土壤温度状况的长期序列和空间变化缺少研究。因此,本文基于土壤温度内插法和地理加权回归（GWR）模型,使用1951—2010年中国880个气象站点的观测数据,研究了中国土壤温度状况时空变化特征及其影响因素。结果表明：① 中国60年来土壤温度变化整体趋势为东北地区升温,西南地区少部分地区降温;② 中国土壤温度状况可划分为冷性土壤温度状况（东北地区、青藏高原地区和内蒙古东部）、温性土壤温度状况（新疆南部、内蒙古和山西南部以及山东）和热性土壤温度状况（华中、华东、华南以及西南的云南、贵州和四川）;③ 经纬度和气温与土壤温度具有良好的响应关系,其中气温是最重要的影响因素;④ 中国60年来整体呈现温性土壤向北迁移（约46.5 km）、冷性土壤向南迁移（约43.4 km）的趋势。研究结果可为地理学、土壤学等相关领域深入研究提供一定参考,并为土壤系统分类研究提供理论依据。     

DESERTIFICATION IN CHINA: STATUS, TRENDS, AND STRATEGIES

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Ecological status assessment in the lower Eo estuary (Spain). The challenge of habitat heterogeneity integration: a benthic perspective

The implementation of the European Water Framework Directive (WFD) requires evaluation of the ecological status (ES) of benthic communities in coastal and transitional water systems, and the intercalibration of assessment methodologies therefore becomes a research challenge. Our aim was to test the suitability of applying the M-AMBI index to assess the status of the Eo estuary (northern coast of Spain). Our results showed that M-AMBI was influenced by the natural variability of benthic communities, and presented an apparent dependence on habitat characteristics. Consequently, the definition of homogeneous areas in transitional water systems should be based on the salinity gradient combined with other factors. To achieve an accurate ES assessment, habitat-specific reference conditions should then be defined prior to the application of M-AMBI; this necessitates dividing an estuary into several sections, which may be classified as different ESs. From this perspective, a novel approach to integrate habitat heterogeneity in a global ES assessment was tested.     

Differences in tree species diversity and soil nutrient status in a tropical sacred forest ecosystem on Niyamgiri hill range, Eastern Ghats, India

We have quantitatively analyzed the tree species diversity with respect to soil nutrient status in three sites of a sacred forest ecosystem of Niyamgiri hill range,Eastern Ghats,India.Extensive field surveys and sampling were conducted in 3 sites of the hill range:Site 1 Pterocarpus dominated forest(PTF)(19°40’02.2" N and 83°21’23.1" E),Site 2 Mangifera dominated forest(MAF)(19°40’02.8" N and 83°21’40.8" E) and Site 3 Mixed forest(MIF)(19°36’47.1" N and 83°21’02.7" E).A total of 28 families,42 genera,46 tree species,and 286 individual trees were recorded on an area of 0.6 ha.Tree density varied between 470 and 490 individuals ha-1 and average basal area between 3.16 and 10.04 m2 ha-1.Shannon Index(H’) ranged from 2.34 to 4.53,Simpson’s Index ranged from 0.07 to 0.09,and equitability Index ranged from 0.7 to 1.34.The number of individuals was highest in the girth at breast height(GBH) class of 50-70 cm.The soil nutrient status of the three forest types was related to tree species diversity.The soil pH value of the three sites reflected the slightly acidic nature of the area.Species diversity was positively correlated with organic carbon and phosphorus and negatively with nitrogen,EC and pH.The results of the current study may be helpful to further develop a conservation planfor tree species in tropical sacred forest ecosystems.