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1.
Large-scale, energy-intensive, specialized production systems have dominated agricultural production in the United States for the past half-century. Although highly productive and economically successful, there is increasing concern with unintended negative environmental impacts of current agricultural systems. Production systems integrating crops and livestock have potential for providing additional ecosystem services from agriculture by capturing positive ecological interactions and avoiding negative environmental outcomes, while sustaining profitability. A diversity of ecologically sound integrated crop-livestock systems have been and can be employed in different ecoregions: sod-based crop rotations, grazing cover crops in cash-crop rotations, crop residue grazing, sod intercropping, dual-purpose cereal crops, and agroforestry/silvopasture. Improved technologies in conservation tillage, weed control, fertilization, fencing, and planting, as well as improved plant genetics offer opportunities to facilitate successful adoption of integrated systems. This paper explores the use and potential of integrated crop-livestock systems in achieving environmental stewardship and maintaining profitability under a diversity of ecological conditions in the United States. 相似文献
2.
Sesbania sesban and S. grandiflora were studied for their physiological characters under different light intensities (100, 75, 50 and 25 %) in a natural environment for 4 months. Rate of photosynthesis (PN) and stomatal conductance (CS) significantly decreased with decreasing light intensities and with intensity reduced to half the full sun light under high shading i.e. at 25 % light intensity, whereas the intercellular CO2 concentration increased with decreasing light intensities in both the species. The reduction in PN was more in S. grandiflora than S. sesban. S. sesban maintained higher carboxylation efficiency under shade condition as compared to S. grandiflora. Rate of transpiration and water use efficiency (PN/TR) decreased while leaf diffusion resistance increased significantly with decreasing light intensities. Total chlorophyll content was maximal under 50 % light intensity in both plant species. Accumulation of chl b increased but chl a decreases under low light intensities. The higher accumulation of chl b in S. sesban under shade predicted its shade adaptability. The total protein content and NRA reduced under low light intensities. The overall rate of photosynthesis, stomatal conductance, carboxylation efficiency and water-use efficiency were higher in S. sesban as compared to S. grandiflora , indicating its better adaptability under shade condition and that it may be suitable to grow under stress in agroforestry systems in semi-arid tropics. 相似文献
3.
In every agroforestry system, the tree canopy reduces the incident radiation for the crop. However, cereal varieties were selected, and most crop growth models were designed for unshaded conditions, so both may be unsuited to agroforestry conditions and performance. In southern France, durum wheat productivity was monitored over 2 years in an agroforestry system including walnut trees and under artificial shade conditions. Yield components were measured in both full and reduced light conditions. The cereal yield was always decreased by shade; by almost 50% for the heaviest shade conditions (31% of light reduction). The main effect of the shade was the reduction in the number of grains per spike (35% at the most) and in the weight of grains (16% at the most). The mean grain weight was moderately affected, while the protein content was increased in shaded conditions (by up to 38% for artificial shade). Consequently, the protein yield per hectare was less reduced by the shade than the dry matter grain yield. A crop model (STICS) was also used to simulate the crop productivity in full light and shaded conditions, but the crop LAI and the yield components were not correctly simulated in the shade. The simulations emphasized the sensitivity of the wheat grain filling to shade during the critical period, 30 days before flowering, for yield elaboration. Further experimental and modelling studies should take into account the heterogeneity of shade intensity due to the shape of the tree crown, the width of the crop alley and the orientation of the tree rows and the modification of carbon allocation inside the plant. 相似文献
4.
生态系统服务是人类赖以生存和发展的资源与环境基础,有关研究已成为地理学、生态学、环境科学和经济学等诸多学科的研究热点,国内外已有大量的研究成果面世。本研究借鉴引文分析方法作为论据支撑,评述近20年来生态系统服务研究的核心问题的研究进展,结果发现各时段生态系统服务研究的热点与前沿集中在社会与文化、权衡与管理、评估与模型、生态付费、景观格局、可持续发展6个方面。分析生态系统服务研究中的关键问题,从生态系统服务的基本问题、形成机制、生态系统服务功能多样性、生态系统服务时空异质性和尺度特性、生态系统服务与人类社会福祉之间的耦合关系5个方面进行分别阐述。总结了生态系统服务研究发展趋势及并分析了未来发展的重点领域,指出生态系统服务研究需要多学科乃至跨学科的研究范式的原因,最后对中国生态系统服务研究存在的问题进行评价。 相似文献
5.
B. Bertrand E. Alpizar L. Lara R. SantaCreo M. Hidalgo J. M. Quijano C. Montagnon F. Georget H. Etienne 《Euphytica》2011,181(2):147-158
Coffea arabica F1 hybrids derived from crosses between wild Sudan-Ethiopian and American cultivars and propagated by somatic embryogenesis
have been obtained in Central America. These new hybrids considerably enhanced the genetic diversity of coffee in the region.
We conducted 15 trials to assess whether using hybrids represents substantial genetic progress in terms of productivity in
agroforestry and full-sun cropping systems. The new germplasm was grown in the same conditions as the best American cultivar
(homozygous pure lines). The results showed that yields of hybrids were earlier and superior to those of American cultivars.
The hybrids were also more stable than the American cultivars in all environments. In the agroforestry system, the mean yield
of hybrids was 58% higher than that of the American cultivars, while the mean yield of hybrids in the full-sun system was
34% higher. Coffee-based agroforestry systems (AS) are considered effective in protecting the environment in the volcanic
cordilleras of Central America. We found that introducing hybrids in coffee-based AS can considerably increase productivity.
This finding could be a convincing argument to encourage coffee growers who have adopted the full-sun cropping system to return
to agroforestry cropping systems. Finally, the conditions for large-scale dissemination of those new hybrids—which represent
a major innovation for C. arabica cropping—was analysed. 相似文献
6.
Weeds are harmful for crop production but important for biodiversity. In order to design cropping systems that reconcile crop production and biodiversity, we need tools and methods to help farmers to deal with this issue. Here, we developed a novel method for multi-objective cropping system design aimed at scientists and technical institutes, combining a cropping system database, decision trees, the “virtual field” model FlorSys and indicators translating simulated weed floras into scores in terms of weed harmfulness (e.g. crop yield loss, weed-borne parasite risk, field infestation), weed-mediated biodiversity (e.g. food offer for bees) and herbicide use intensity. 255 existing cropping systems were simulated with FlorSys, individual indicator values were aggregated into a multi-performance score, and decision trees were built to identify combinations of management practices and probabilities for reaching performance goals. These trees are used to identify the characteristics of existing cropping systems that must be changed to achieve the chosen performance goals, depending on the user's risk strategy. Alternative systems are built and simulated with FlorSys to evaluate their multi-criteria performance. The method was applied to an existing oilseed rape/wheat/barley rotation with yearly mouldboard ploughing from Burgundy which was improved to reconcile weed harmfulness control, reduced herbicide use and biodiversity promotion, based on a risk-minimizing strategy. The best alternative replaced a herbicide entering plants via shoot tips (during emergence) and roots after barley sowing by a spring herbicide entering via leaves, introduced crop residue shredding before cereals and rolled the soil at sowing, which reduced the risk of unacceptable performance from 90% to 40%. When attempting to reconcile harmfulness control and reduced herbicide use, the best alternative changed the rotation to oilseed rape/wheat/spring pea/wheat, replaced one herbicide in oilseed rape by mechanical weeding, delayed tillage before rape and applied the PRE herbicide before oilseed rape closer to sowing. This option reduced the risk of unacceptable performance to 30%. None of the initial or alternative cropping systems succeeded in optimal performance, indicating that more diverse cropping systems with innovative management techniques and innovative combinations of techniques are needed to build the decision trees. This approach can be used in workshops with extension services and farmers in order to design cropping systems. Compared to expert-based design, it has the advantage to go beyond well-known options (e.g. plough before risky crops) to identify unconventional options, with a particular focus on interactions between cultural techniques. 相似文献
7.
M. Guadalupe Arenas‐Corraliza M. Lourdes Lpez‐Díaz Víctor Rolo Gerardo Moreno 《Journal of Agronomy and Crop Science》2021,207(1):100-119
Agroforestry systems are reported as climate‐resilient productive systems, but it is yet unclear how tree shade affects crops performance. The aim of this work was to assess how the phenology, plant traits and grain yield of wheat and barley were affected by shade. In an open greenhouse experiment, we cultivated in pots nine cultivars differing in precocity for each species and imposed three artificial shading levels (S0 ~ 0%, S1 ~ 25%, S2 ~ 50%) at the start of cereal booting. Our results showed that shade speeded up first growth stages in both species, until the starting of milk development. Barley showed consistent phenological responses to the three irradiance levels among cultivars, but not wheat that showed larger phenological differences among cultivars at moderate shade. Deep shade prolonged the time needed for wheat grain ripening. Both species increased grain yield by 15%–20% with shade, driven by shade‐acclimations of plant traits that differed among species. For wheat, grain yield was determined by the assemblage of traits that contribute to yield, such as grain weight, precocity and non‐photochemical quenching, while, for barley, SPAD value, precocity to reach phenological stages, grains per spike and plant height had the strongest influence. These traits varied widely among cultivars and seem of interest to identify best suited cultivars for shading conditions of Mediterranean agroforestry systems. 相似文献
8.
基于CVM 的吉林省湿地生物多样性 总被引：1，自引：1，他引：1
湿地生态系统作为全球生态系统的重要类型之一,在维持生物多样性方面发挥着举足轻重的作用。为了更好地保护湿地,笔者基于条件价值法(CVM)这一当前国际上比较成熟的生态系统价值评价方法,对吉林省湿地的生物多样性维持服务价值进行定量评价。研究采用实地调研和网络发放结合的方式进行支付意愿问卷调查,共发放支付卡式问卷500份,回收有效问卷491份。结果表明,吉林省湿地2012年人均支付意愿值为120.7元/a,根据全国和吉林省人口总数计算的吉林省湿地生物多样性维持服务价值分别为1005.1亿元和20.8亿元。受访者受教育的程度、收入水平和对湿地生物多样性的关心程度对支付意愿具有显著影响,与平均支付意愿值呈显著的正相关关系(P<0.05),而性别和年龄对受访者支付意愿没有显著影响。调查方式和距离远近也会对支付值有显著影响(P<0.0001)。为了保护好吉林省的湿地生物多样性,政府应该加大宣传力度,提高公众的环保意识。研究结果将使湿地保护和开发的价值对比成为可能,对于制定合理的区域生态保护和经济开发决策、保护和恢复湿地生态系统具有重要意义,为政府相关政策的制定提供理论基础。 相似文献
9.
农业生态系统是一个半自然半人工的复合生态系统,受人类的活动影响较大。在我国的农业生产活动中,渠道化农田水利建设的推广和应用,引起了一系列的农业生态环境问题。本文采用现场调查、野外实验和实验室检测分析的方法,通过：(1)渠道对其不同距离(远、中、近)土壤速效养分的影响;(2)不同类别渠道对其内水样养分含量的影响;(3)不同类别渠道对其所在生境生物多样性的影响;三个方面进行研究。主要研究结果如下：(1)渠道所在区域土壤铵态氮及硝态氮呈现一致的季节性变化特征,即夏高冬低,而有效磷呈无规律性;渠道周边土壤铵态氮含量：中>远≈近;硝态氮为：近<中<远(2) 渠道的形态结构对生物多样性有显著的影响,各渠道动植物种类均呈现特征为：土渠>水泥渠。土渠对生境的影响较小,并且还有较好的“生物廊道”作用,有利于保持农业生态系统的物质及能量流动。(3)土渠对农业污染物净化能力明显高于水泥渠,通过对渠道内污染物含量的监测分析,土渠的截留净化效果优于水泥渠。 相似文献
10.
Improving the land-use efficiency (LUE) of farming systems could satisfy increasing global food, feed, biomass and bioenergy demand in a sustainable manner. This study presents a new method for calculating LUE, beginning with an overview of different approaches to assessing agricultural LUE. This new method takes into account the quality and function of agricultural products and the relationship between the yield of the assessed farm and the average yield of the reference region with comparable soils, climate and socio-economic conditions.The new approach was tested using data from long-term experiments at the Scheyern Research Farm in southern Germany, which include different farming systems (organic mixed farming, arable farming, and agroforestry; conventional arable farming and agroforestry). In our case studies, the LUE of conventional systems (arable farming: 1.00; improved arable farming: 1.06; agroforestry: 0.98) was higher than those of the organic systems (mixed farming: 0.69; arable farming: 0.33; agroforestry: 0.43) due to different crop rotations, dry matter yields, and biomass usage (harvest ratio). The conversion of high-input arable farming systems (conventional farming) to agroforestry systems is an extensification with negative effects on the dry matter yield and land-use efficiency. Nevertheless, the conversion to agroforestry systems can increase dry matter yield and land-use efficiency in low-input arable farming systems (organic farming). LUE should be used in combination with agri-environmental indicators, in order to ensure both efficient and sustainable land use. 相似文献
11.
《Journal of Landscape Research》2017,(3)
The forest ecological system fulfills many important ecological functions. Researches on the analysis and valuation on forest ecosystem services are at the cutting edge of current ecology and ecological economics. Based on the calculation method of service value of forest ecosystem, 7 forest ecosystem services of Nanling National Nature Reserve were valued, totaling 703.48 million yuan/year. In terms of the contribution size of the service value of forest ecosystem, carbon fixation and oxygen release came as the greatest one, followed by conservation of soil, purification of the air, biodiversity conservation, conservation of water, accumulation of nutrients, and forest recreation. With its value of 208.46 million yuan, carbon fixation and oxygen release ranked first, accounting for 29.63% of the total value; conservation of soil of 24.67% service value took the second place; purification of the air came in third in the value rankings, representing 22.55% of the total value; the fourth one was biodiversity conservation, whose service value came up to 14.51%. Those 4 services made up 91.36% of the total value while other 3 services ranging from conservation of water, accumulation of nutrients to forest recreation were merely a small proportion. This is because the Nanling National Nature Reserve is essentially a large oxygen bar. The above-mentioned ecosystem valuation method contributes to the understanding of the overall value of the forest ecosystem as well as the implementation and advancement in the regional sustainable development strategy. 相似文献
12.
Partnership discourse is making advances in development dialogue as a means to improve the livelihoods of the agrarian populace. In Papua New Guinea, productive partnerships flourished during the early growth of the coffee industry. After the demise of plantations and rural mills in the lead up to political independence, the support services that plantations used to provide to smallholders, including centralised processing, have ceased as have price incentives for quality. Consequently, smallholders began to produce coffee of inconsistent quality and their productivity has also declined. However, coffee value chain partnerships have the potential to reverse the present decline of coffee production and increase the productivity of coffee farmers and address the inconsistency and the supply of low‐grade coffee. Using two case studies of farmer cooperatives, we investigate collective action and also assess partnerships among present value chain actors. The case studies were supported with interviews of value chain actors to gain further insights into partnerships with farmer groups. This paper illustrates that through collective action and partnerships, coffee farmers can improve coffee production and quality, enhance governance systems in grower groups, attract community development services and diversify into other entrepreneurial activities. 相似文献
13.
For many years, we have seen an increasing specialization of agricultural systems and territories, with a clear separation between territories with very high animal densities and those devoted to the growing of annual crops. This development is explained by market and sector economic logic and has been reinforced by the availability of low-cost inputs and animal housing systems based on direct grazing not requiring straw. It has, however, also involved negative environmental impacts and, in some cases, the impoverishment of soil fertility, a loss of biodiversity, and excesses of N and P, leading to eutrophication and hot spots of ammonia emission in livestock-breeding territories. Having recapped the mechanisms behind the specialization of systems and territories, we examined the extent to which the development of innovative mixed-farming systems that reconnect livestock and crop production on various territorial scales (farm, district, region) can reduce the negative impacts of agriculture on the environment, produce valuable ecosystem services and achieve acceptable economic efficiency for farming enterprises. Examples from temperate regions will be used to show that mixed-farming systems increase the possibilities of better recycling of nutrients within systems, limiting recourse to the purchase of increasingly expensive inputs and safeguarding the biodiversity of agricultural ecosystems. 相似文献
14.
农业景观中林地的生物多样性保育及生态服务提升 总被引：1，自引：1，他引：0
笔者首先简述农业景观中林地的现状、问题及面临的挑战,论述农业景观中林地在生物多样性保育和多功能应用方面的重要作用,在此基础上,探讨在地块和景观尺度上如何对决定功能的结构进行优化配置,通过农业景观中林地的改造和提升,来促进生物多样性保护和生态系统服务功能提升。研究显示,林地类型、面积、形状、配置结构和树种组成以及在地块和景观尺度上实践的驱动力是决定农业景观中林地功能的重要影响因素。最后,针对农业景观中林地在设计和管护方面,如何实现多功能目标进行了讨论,以期推动农业景观多功能林地的发展,避免把农业景观中林地建成“绿色沙漠”。 相似文献
15.
16.
《Journal of Landscape Research》2013,(5)
Huadianba in the Cangshan Mountain, a region where key ecosystem types and species under prior protection are concentrated, is the first choice for the comprehensive protection and development of biodiversity. In this study, natural conditions, location and current protection and development of Huadianba were introduced, major problems emerging in the protection and management were summarized, and pertinent measures were proposed as a reference for the scientific development and protection of Huadianba. 相似文献
17.
通过调查亚热带森林生态系统中各类属性土壤碳在2种不同类型土壤剖面中的分布规律,分析和探讨原生土和淤积土在森林土壤碳循环过程中发挥的重要作用。本研究地点位于云南省哀牢山亚热带中山湿性常绿阔叶原生林生态系统,以海拔高度较高的上游森林原生土和海拔高度较低的下游灌草淤积土为采样点,沿着土壤剖面分层取样,重点研究土壤剖面根层(0~45 cm)土壤中全碳、活性有机碳、微生物量碳、可溶性碳和水溶性碳的垂直分布规律。研究结果表明：本研究过程中所调查的5类不同属性土壤碳在两种不同类型土壤剖面中均呈衰减指数式分布。土壤全碳、活性有机碳和水溶性碳在淤积土中的平均含量均显著高于原生土;土壤微生物量碳在2种类型土壤剖面中的平均含量差异不显著;而土壤可溶性碳在淤积土中的含量显著低于原生土,说明在哀牢山亚热带中山湿性常绿阔叶原生林生态系统中原生土和淤积土在储存不同属性土壤碳和碳循环方面发挥着不同作用。本研究结果充分证明不同属性土壤碳在同一亚热带森林生态系统不同类型土壤剖面中虽然垂直分布规律一致,但是平均储量存在着明显的空间异质性,这为全球热带和亚热带森林生态系统中土壤碳库不同属性土壤碳的估算和不同类型土壤碳循环的研究提供新的理论依据和研究方向。 相似文献
18.
农田边界植物多样性与生态服务功能研究进展 总被引：1，自引：0，他引：1
农业集约化和城市化导致农业景观重要生境发生巨大变化,农田野生动植物数量下降。农田边界作为农业景观中重要的组成部分,其丰富的物种组成,不仅具有重要的生态功能,也具有重要的景观价值。本研究对农业生态系统农田边界植物多样性进行阐述,论述了影响农田边界植物多样性的影响因素和生态服务功能。综述研究显示,农田边界具有类型多样性、物种多样性、植物功能类型多样性及时空结构多样性特征;其影响因素主要包括4个方面：农田边界结构、农田边界管理、周边土地利用影响以及景观结构特征的影响;农田边界生态功能包括：生产、环境保护、野生动植物保护和景观美学功能等;最后总结了不同类型农田边界生态植被营建模式与优化途径,对中国农田边界植被管护提出了一些建议。 相似文献
19.
以采煤沉陷区为研究对象,分析采煤沉陷区土地利用和损毁情况,并通过生态系统服务价值(ESV)指标对土地整治效果进行评价。结果显示,通过土地整治工程,耕地面积由220.24 hm2增至311.08 hm2;采煤沉陷区总生态服务价值属于正向变化,由整治前的348.03×104元/年,增加至到整治后的356.67×104元/年;采煤沉陷区各单项生态服务价值有正向的,也有负向的。其中,属于正向影响的有气候调节、水源涵养、废物处理、食物生产和原材料;属于负向影响的有气温调节、土壤形成与保护、生物多样性保护和娱乐文化。土地整治改善农业基础设施条件和修复并重构生态环境,进而增加社会经济效益和生态效益。 相似文献
20.
为了提高人们对国有林生态系统价值的认识,合理开发和利用森林资源,制定国有林生态补偿标准,应用生态学和生态经济学原理及方法,对建阳国有林生态系统服务价值进行了定量评价,并从生态系统服务功能的角度分析了建阳国有林生态系统对区域生态安全的影响。结果表明：建阳国有林生态系统8项服务价值总量为14.7924×108元/a。建阳国有林生态系统服务功能的直接经济价值和间接经济价值分别为2.6936×108元/a和12.0988×108元/a,间接经济价值是直接经济价值的4.49倍。在国有林生态系统各项服务功能价值的贡献之中,其大小顺序依次为：保护生物多样性＞净化空气＞固碳释氧＞水土保持＞林产品＞涵养水源＞森林游憩＞就业价值;国有林生态系统有着巨大的生态经济效益,在维护区域经济社会稳定和生态安全等方面具有不可替代的作用,但没有充分发挥自身所应具有的生态服务功能。 相似文献