我国农作区资源节约农作压力空间分布研究

资源节约型农作制是进行农业资源节约、高效利用的农作制度, 将成为我国农业生产中突破资源短缺这一发展瓶颈的有效手段。为明确我国主要农作区的资源特点和节约压力, 选择农业水、耕地、化肥3 种资源为主要研究对象, 根据目前各农作区3 种资源的数量、消耗率、粮食产量水平等指标, 初步计算了各区节水压力、节地压力与节肥压力, 并据此初步推导出各区资源节约农作制的综合压力指数, 研究了资源节约农作制压力的空间分布。结果显示: 我国绝大多数农作区资源节约型农作制压力处于中度以下, 东部各农作区大于西部各农作区, 南方各农作区大于北方各农作区; 节水重点区主要是北方的东北区、黄淮海区、西北区和北部低中高原区, 节地重点区主要是东南部的长江中下游地区、江南地区和华南区, 节肥重点区主要是四川盆地、华南区和江南区。     

基于WebGIS的农业空间信息管理及辅助决策系统

该研究在总结和提炼区域农业信息管理和评价理论与技术研究成果的基础上，运用知识工程和系统建模方法，建立了种植制度评价、农产品生态区划、农作生产潜力分析和精确农作管理的定量化动态知识模型。并运用软构件技术，基于B/S的分布式网络结构，以WebGIS为空间信息管理平台，建立了网络化、数字化的农业空间信息管理及辅助决策系统。系统实现了基本地图操作、农业空间信息查询与分析、种植制度评价、农产品生态区划、农作生产潜力分析、精确农作管理、可视化输出以及系统维护等功能。以江苏省为案例区，对系统进行了实例应用，结果表明，系统能有效地管理区域性农业空间信息，并在基于空间信息的农业生产管理决策方面具有较好的适应性和指导性。     

高产高效持续农作制度是农业可持续发展的基础

论文回顾了国际农业思潮的演进,介绍了农业可持续发展的新动向,在分析江苏农业生产现状与可持续发展面临主要问题的基础上,提出建立现代型高产高效持续农作制度是江苏农业可持续发展的基础,并相应提出农作制度技术体系设想。     

“精细农业”发展与工程技术创新

综述了目前国外“精细农业”实践的主要目标及其技术思想的内涵。着重围绕其主要支持技术发展,讨论了有关工程技术创新及推动我国开展试验研究的问题。针对目前国外对这一技术体系的研究与实践,主要集中在基于ＧＰＳ和ＧＩＳ技术应用的作物生产系统精细管理方面,提出用“精细农作”的译名来表达。进入２１世纪,基于知识和信息的“精细农作”技术思想,必将扩展到大农业经营的各个领域,推动农业生产的信息化与知识化,逐步形成一个基于农业生物科学、电子信息技术及工程装备为主导的“精细农业”技术体系,为建立优质、高效和可持续发展的农业系统服务。     

水土保持耕作措施与预防控制地下水污染的综合研究初探

水土保持耕作措施(以下简称"保土耕作措施")以保土、保水、保肥为主要目的,是我国普遍采用的水土保持农业措施之一。笔者结合多年实践经验,在考虑保土耕作措施对控制耕地土壤侵蚀的积极作用的同时,对保土耕作措施可能对地下水造成的负面影响进行了综合分析,建议严格控制保土耕作区农作物化肥使用量,提高化肥使用效率,开展区域性水质动态监测,提升保土耕作区地下水环境监管能力,开展宣传教育,科学开展保土耕作等。     

中国农业信息化技术发展现状及存在的问题

围绕农业传感器技术、精细农作技术、农业机器人技术、农业物联网技术和农业信息服务技术五大方面,对农业信息化前沿技术的发展态势进行了分析,同时探讨了中国农业信息化前沿技术发展存在的问题并提出了相应的建议。研究表明,农业传感器技术是农业信息获取与信息化的基础,精细农作技术代表了当今农业装备的先进水平,农业机器人技术是未来农业智能装备的重要方向,农业物联网技术是农业监管与质量监控的有效手段,农业信息服务技术则愈来愈聚焦农业信息服务中的云存储、云计算、云服务和移动互联的关键技术问题。     

中国特色的精细农作的技术支持体系初探

在分析比较近十几年来西方精细农业思想和中国农业生态工程等精耕细作主要思想基础上，肯定了中国农业生态工程研究与实践在中国具有不可取代的独特作用。主张优先研究开发4S一体化的技术支持体系，结合吸纳西方精细农业的思想和技术，发展中国特色的精细农业。提出了4S一体化技术支持体系的基本构架，并且指出我国应以4S一体化技术支持体系为依托，结合各地具体情况逐步组装相关技术，由精细农作、精细养殖向精细农业发展的思路。同时指出精细农业要用数字地球的相关标准来规范自身的发展。     

坡耕地开发利用和保护模式研究

坡耕地严重的水土流失对山区农业的可持续发展构成了极大的威胁。由于坡耕地之间的条件差异不同 ,针对其特点 ,合理地开发利用并采取适宜的保护模式 ,是防治坡耕地水土流失、实现山区农业可持续发展的关键。对于坡度小于 10°的坡耕地 ,只要采取横坡耕作和覆盖耕作相结合的方式 ,就可以防治水土流失 ;对于 10°～ 2 5°的坡耕地 ,采取修梯田的方式可以防治水土流失 ,但从生态环境建设的角度来看 ,等高植物篱农作系统的效果更好一些 ,如果能够把坡改梯和等高植物篱农作系统结合起来 ,效果更为显著 ;对于大于 2 5°的坡耕地 ,可采取垄沟格网式农作和秸秆覆盖的保土措施 ,逐步实施退耕还林。只有根据坡耕地的实际情况 ,研究坡耕地开发利用和保护模式 ,把合理的耕作模式、适宜的种植模式和有效的防护体系有机地结合起来 ,辅之以先进的农业技术措施 ,才能建立高产高效的坡耕地生态农业模式。     

历史时期黄淮海平原农作制度变迁与农业生产环境演变

一定地域内的农业发展与其自然条件、社会经济和技术条件紧密相关, 而农业不同发展阶段对环境的影响深受所采取的农作制度的影响, 这恰恰是传统研究中重视不够的地方。基于文献回顾, 本文以不同农业发展阶段农作制度的变迁及其对农业环境的影响为切入点, 论述了历史时期黄淮海平原农业不同发展阶段农作制度演变的主要特点, 以及农作制度的变迁对农业生产环境的影响。黄淮海平原的农业发展与黄河下游河道的稳定与否密切相关。南宋黄河改道以前, 黄河下游在河北平原长期摆动, 加上战争的破坏, 导致河北平原农业发展大部长期落后于黄淮平原。黄淮平原则在黄河南流的漫长时期内深受河患影响。在现代农业科技光临黄淮海平原以前, 黄淮海平原的农作制度深受自然环境的影响, 只是在对环境适应的前提下的细微改进,其对环境的作用主要体现于平原自然植被被人工植被安全替代后, 因林木需求而导致山地植被的破坏、山地土壤侵蚀加剧, 从而导致下游地区的河道淤塞、湖泊消失、排水不畅和大面积的盐碱地出现, 最终恶化了农业生产环境, 使得农业生产水平长期维持较低水平。     

农作系统研究方法在持续农作系统发展研究中的应用

农作系统方法可划分为农作系统分析和农作系统研究。在发展中国家农作系统方法已被广泛地应用于改善农场技术和提高土地生产率。在西方国家已将这一方法应用于研究和发展持续农作系统。本文将简要介绍农作系统方法以及在研究和发展持续农作系统中的应用，并对研究结果进行综述。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.