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21.
对杜仲、农作物、蔬菜（简称“杜农蔬”）立体栽培作了研究,提出了平原农区适宜的立体栽培模式及与此配套的良种壮苗和栽培技术措施,并分析了立体栽培模式对小气候的影响。 相似文献
22.
Arthropod natural enemies (ANEs) play an indispensable role in maintaining the balance for plant communities that also significantly affects the ANE diversities not only by supporting herbivorous prey, but also by providing habitats and floral food resources. Studying the diversity of ANEs is thus vital to develop an understanding of sustainable pest control. Relationships of the vegetation diversity (including richness, coverage, and Shannon–Wiener diversity) with associated arthropod aphidophagous natural enemies (AANEs) and their groups under Pinus tabuliformis of different distances were analyzed by non-metric multidimensional scaling (metaMDS). Our results indicated that the vegetation richness affects AANEs at a small scale, while the vegetation structure affects it at a large scale. The richness and abundance of AANEs and the abundance of green lacewings (GLs) and aphid parasitoids (APs) were positively related to neighboring tree richness. But the richness of AANEs and aphidophagous ladybirds (ALs) were negatively associated with nearby tree coverage, as well as AANE richness with close-up shrub coverage, while the abundance of AANEs, ALs, and GLs possessed a negative and hump-shaped relationship with nearby tree coverage, as well as the abundance of AANEs and GLs with close-up shrub coverage. When tree and shrub layers each had approximately half coverage within a vegetation structure, the richness and abundance of AANEs were highest. Similarly, the richness and abundance of AANEs were positively related to neighboring blooming plant richness. However, the richness of AANEs and ALs, and the abundance of AANEs, AL, GL, and APs had a positive association either with the coverage or with the Shannon–Wiener diversity of close-up blooming plants. Half coverage of the tree and shrub layer combined with higher diversities (richness, coverage, and Shannon–Wiener diversity) of blooming plants resulted in low aphid density. The results provide a basis for effectively improving AANE diversity. 相似文献
23.
Cecile Brugre Jos Aguilar‐Manjarrez Malcolm C. M. Beveridge Doris Soto 《Reviews in Aquaculture》2019,11(3):493-514
Over a decade ago, the ecosystem approach to aquaculture (EAA) emerged from discussions between the Food and Agriculture Organization (FAO) of the United Nations and international aquaculture experts on how to move aquaculture development towards greater sustainability. The purpose of this review is to critically examine the use and mainstreaming of the EAA in aquaculture development to date and consider its possible evolution in the next decade. We systematically searched citations of key EAA publications in the academic and related literature for the period 2007–2016 and analysed all relevant FAO publications and project documents. We assessed the lessons learnt from the past decade of EAA experiences, the opportunities the EAA has created and the links between the EAA and the new development agenda. Our review suggests that mainstreaming the EAA in planning processes has raised awareness of the usefulness of holistic and participatory approaches in aquaculture and helped to steer the sector towards greater sustainability. However, the approach has had varying degrees of resonance and uptake with different user groups. The emphasis on spatial planning that has developed as part of the EAA implementation efforts, and close links between the EAA and initiatives such as ‘blue growth’, constitute significant opportunities for the future of the approach, although its ability to tackle increasingly complex governance issues may be limited. Thus, it is now opportune to reconsider the EAA's raison d’être, taking into account ongoing developments within and outside the aquaculture sector. 相似文献
24.
Jessica Sosa‐Quintero Hctor Godínez‐Alvarez 《Land Degradation u0026amp; Development》2019,30(5):494-503
The impacts of human activities on temperate and subtropical deserts have been evaluated worldwide. However, data about tropical deserts are scarce. In this study, we evaluated the impacts of rainfed agriculture and firewood extraction on vegetation and soil of abandoned croplands (mesquite cropland and goldeneye cropland) and mesquite shrublands (open‐canopy mesquite and closed‐canopy mesquite) in a tropical Mexican desert. We interviewed peasants to understand their management practices and evaluated vegetation traits and soil properties of sites. We also examined the impacts of land management on vegetation and soil with structural equation modeling. Rainfed agriculture consisted of cultivating crops, fertilizing with manure, and introducing goats to croplands after harvest. Goldeneye cropland had higher canopy cover, vegetation structure, and litter cover than mesquite cropland. However, soil in both croplands was highly compacted with low infiltration rate, organic matter, and nutrient content. Firewood extraction only consisted of removing mesquite branches. Open‐canopy mesquite had lower canopy and litter cover and higher biological soil crust cover than closed‐canopy mesquite. The soil in both shrublands was less compacted with relatively high infiltration rate, organic matter, and nutrient content. Rainfed agriculture decreased soil nutrient content due to removal of native vegetation, plowing, and goat introduction to croplands. In contrast, firewood extraction maintained a relatively high soil nutrient content because branch removal enables the establishment of biological soil crusts, which increased the infiltration rate and nutrient availability. Thus, firewood extraction has a lower impact on the structure and function of fluvial terraces than rainfed agriculture in this tropical desert. 相似文献
25.
我国南方水田耕整机械经过了30多年的发展,已基本形成了多功能、多机型的格局.随着科学技术的创新与进步,水田耕整机械正朝高标准、智能化、自动化方向发展;但实现这一目标的任务还很艰巨,政府须给予政策和资金支持,保障科研成果及时转化、推进农机研发"产学研"结合. 相似文献
26.
We assess how tree species richness and ecosystem services vary along a tropical urbanisation gradient in a rapidly expanding mega-city (Bangkok, Thailand). We conduct tree surveys in 150 1 km cells selected by random stratification across an impervious surface cover gradient. In each cell, surveys were conducted at the centre (representing typical conditions) and in the largest patch of trees (assessing woodland retention impacts). We estimated trees’ contributions to i) carbon storage, ii) food production for people, iii) biodiversity support (production of food for frugivorous birds), and iv) economic value (assessed using regulations for using trees as collateral for financial loans). Surveys detected 162 species (99 natives) indicating substantial species loss relative to nearby natural forests. Despite this, and contrasting with typical patterns in temperate cities, tree species richness (including of natives) and ecosystem service provision is relatively stable across the urbanisation gradient. This finding has two important consequences. First, growing cities through high intensity developments that require less space may benefit regional biodiversity without compromising ecosystem services. Second, even the typically very small woodlands present in highly urbanised locations contribute to supporting biodiversity and providing ecosystem services; thus such woodlands require protection. Species richness is not strongly positively associated with most of our focal ecosystem services. Urban planners must therefore pay attention to both biodiversity and ecosystem services as these do not automatically accrue from each other, partly because non-native species contributed substantially to most ecosystem services except biodiversity support. Finally, trees provide substantial value as collateral for financial loans (averages of £643 ha at random locations and £2282 ha in wooded locations). Policies promoting such valuations may reduce tree removal and encourage tree planting, but the list of eligible species warrants revision to include additional species that enhance biodiversity support, ecosystem services, and resilience against future environmental instability. 相似文献
27.
P. Kumar 《Land Degradation u0026amp; Development》2011,22(4):432-443
The understanding of the requirement for PES and necessary capacity of stakeholders to conceive, design and execute PES, are critical to its successful operationalisation. Identification and assessment of capacity needs are also prerequisite for PES especially in a developing country like India where institutional setting and functioning are far from the desirable level. In this background, the paper begins with an introduction of the basic concept and centrality of economic valuation in PES. Next, the paper discusses the status of the land degradation problem in India and how the PES can prove to be an efficient tool to manage the declining ecosystem services due to increasing land degradation in the Country. By identifying the direct and indirect drivers of land degradation, the stage is set for designing of appropriate response options for halting the degradation of land which is not only the base of agrarian economy of India but source of livelihood options for the poor. In the subsequent section, the paper assesses the required capacity to operationalise PES in the states where the problem of land degradation is acute. This has been done on the basis of wider consultation with land users (farmers), conservation agencies, Departments of Land Agriculture and related R&D agencies through a structured questionnaire in group meetings in different parts of the Country during 2006–2007. The necessary capacity on behalf of stakeholders like the Local, State and National level institutions have been mapped out. The result from the survey suggests that while the capacity to understand the ecosystem services is adequate, the capacity to do valuation of incremental change in the ecosystem services is not sufficient and the State still needs to invest significant amount of resources before this tool can be used to manage the land based ecosystem services in India. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
28.
Luying Sun Fengbin Song Shengqun Liu Qingjun Cao Fulai Liu 《Archives of Agronomy and Soil Science》2013,59(14):1932-1943
ABSTRACTSustainable agricultural management practices have attracted increasing attention due to their significant roles in benefiting the functions and sustainability of agro-ecosystems. An integrated agricultural practice (IP) in a maize cropping system was developed by changing row spacing, adopting no-tillage and residue return in the Northeast China. A 12-year field study was carried out to evaluate the effect of IP and conventional practice (CP) on soil physical properties, microbial biomass and enzyme activity during the cropping season. The results showed that soil organic matter under IP was increased by 17.4, 9.88 and 6.69% in June, August and October, respectively, than CP. IP enhanced microbial biomass C (by 31.7, 25.1 and 30.4% in June, August and October) and activities of invertase, urease and phosphatase (by 27.2–38.0, 78.9–182 and 9.8–29.0%) compared to CP, possibly attributing to an increase in the soil microbial community. Furthermore, the soil pH, water content, nitrogen and phosphorus contents, microbial biomass and some specific enzyme activities varied with sampling time. It is concluded that IP improved soil quality and health by increasing organic matter content and microbial biomass and activity in maize field in Northeast China, suggesting that IP is a feasible management technology for sustainable agriculture. 相似文献
29.
Methane (CH4) is a potent greenhouse gas and the huge CH4 fluxes emitted from paddy fields can prejudice the eco-compatibility of rice cultivation. CH4 production in submerged rice crops is known to be highly influenced by water temperature. Hence, lowering ponding water temperature (LPWT) could be an option to mitigate CH4 emissions from paddy environments when it is possible either to irrigate with slightly colder water or to increase ponding water depth. However, paddy soil is a complex environment in which many processes are simultaneously influenced by temperature, leading to a difficult prediction of LPWT effects. For this reason, LPWT efficiency is here theoretically investigated with a one-dimensional process-based model that simulates the vertical and temporal dynamics of water temperature in soil and the fate of chemical compounds that influence CH4 emissions. The model is validated with literature measured data of CH4 emissions from a paddy field under time-variable temperature regime. Based on modeling results, LPWT appears promising since the simulated reduction of CH4 emissions reaches about −12% and −49% for an LPWT equal to −5 °C during the ripening stage only (last 30 days of growing season, when rice is less sensitive to temperature variations) and −2 °C over the whole growing season, respectively. LPWT affects CH4 emissions either directly (decreasing methanogenic activity), indirectly (decreasing activity of bacteria using alternative electron acceptors), or both. The encouraging results provide the theoretical ground for further laboratory and field studies aimed to investigate the LPWT feasibility in paddy environments. 相似文献
30.
Aiping Zhang Ji Gao Ruliang Liu Zhe Chen Shiqi Yang Zhengli Yang Hongbo Shao Qingwen Zhang Nagai Yoshikazu 《Land Degradation u0026amp; Development》2016,27(4):1255-1265
High N fertilizer and flooding irrigation applied to rice in anthropogenic‐alluvial soil often result in N leaching and low use efficiency of applied fertilizer N from the rice field in Ningxia irrigation region in the upper reaches of the Yellow River. Sound N management practices need to be established to improve N use efficiency while sustaining high grain yield levels and minimize fertilizer N loss to the environment. We investigated the effects of Nursery Box Total Fertilization technology (NBTF) on N leaching at different rice growing stages, N use efficiency and rice yield in 2010 and 2011. The four fertilizer N treatments were 300 kg N ha−1 (CU, Conventional treatment of urea at 300 kg N ha−1), 120 kg N ha−1 (NBTF120, NBTF treatment of controlled‐release N fertilizer at 120 kg N ha−1), 80 kgN ha−1 (NBTF80, NBTF treatment of controlled‐release N fertilizer at 80 kg N ha−1) and no N fertilizer application treatment (CK). The results showed that the NBTF120 treatment increased N use efficiency, maintained crop yields and substantially reduced N losses to the environment. Under the CU treatment, the rice yield was 9634 and 7098 kg ha−1, the N use efficiency was 31·6% and 34·8% and the leaching losses of TN were 44·51 and 39·89 kg ha−1; NH4+‐N was 5·26 and 5·49 kg ha−1, and NO3−‐N was 27·94 and 26·22 kg ha−1 during the rice whole growing period in 2010 and 2011, respectively. Compared with CU, NBTF120 significantly increased the N use efficiency and decreased the N losses from the paddy field. Under NBTF120, the N use efficiency was 56·3% and 51·4%, which was 24·7% and 16·6% higher than that of CU, and the conventional fertilizer application rate could be reduced by 60% without lowering the rice yield while decreasing the leaching losses of TN by 16·27 and 14·36 kg ha−1, NH4+‐N by 0·90 and 1·84 kg ha−1, NO3−‐N by 110·6 and 10·14 kg ha−1 in 2010 and 2011, respectively. Our results indicate that the CU treatment resulted in relatively high N leaching losses, and that alternative practice of NBTF which synchronized fertilizer application with crop demand substantially reduced these losses. We therefore suggest the NBTF120 be a fertilizer application alternative which leads to high food production but low environmental impact. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献