共查询到18条相似文献,搜索用时 126 毫秒
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通过对深圳市近几年蔬菜设施栽培的基本情况的调查,比较了各种不同设施栽培与露地生产的效果,提出深圳市未来设施栽培可持续发展的对策和措施,为有关职能部门制定菜篮子工程发展规划和更好地搞好深圳市的蔬菜生产提供参考。 相似文献
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苏南地区设施蔬菜经常遭受持续阴雨寡照天气的危害,模拟试验揭示了持续寡照条件下大量元素吸收相对过剩,微量元素吸收相对不足,营养失调导致生育障碍的生理因素。采取高畦栽培膜下滴灌,扩大行距,强制排湿等综合措施,改善栽培环境,抑制病害发生和蔓延,避免农药污染。研究开发了改善土壤环境和提高蔬菜品质的有机营养技术,使产品营养品质和风味品质得到了提高。 相似文献
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大有前景的蔬菜自动嫁接机器人技术 总被引:9,自引:0,他引:9
蔬菜嫁接技术的发展 1997年,我国设施栽培面积达到120万公顷,成为世界上最大的设施栽培国家。特别是以日光温室为代表的具有中国特色的保护地蔬菜栽培和塑料大棚的发展尤为迅速,目前已突破1000万亩。它缓解了蔬菜淡季的供需矛盾,同时也成为我国农民致富的重要途径。但是由于蔬菜的生物特性和生长环境特性,连茬病害和低温障碍也一直是严重影响设施蔬菜生产的主要问题。据调查统计,在新建的大棚内种植的黄瓜,其枯萎病的发病率为12%,若第二年连续种植,则枯萎病的发病率上升为50%以上,我国每年仅由此病而造成的损失… 相似文献
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本文论述了我国设施蔬菜产业可持续发展中应注意的几个问题,目的是为了正确地理解和认识这些问题,使设施蔬菜生产得以健康发展。 相似文献
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根据我国设施蔬菜生产中存在产量低而不稳、病虫害发生较重、蔬菜质量较差和效益不高等问题,从可持续发展的角度论证了我国蔬菜设施生产的发展方向及其应采取的对策。 相似文献
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本文以河北省蔬菜供给现状分析为基础,揭示了自然条件、投入生产要素情况、农田水利设施和技术等因素对河北省蔬菜产业发展的影响,并构建了河北省蔬菜供给函数模型。结果表明蔬菜播种面积、农药使用量、地膜使用量是目前影响河北省蔬菜供给的决定性因素。 相似文献
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蔬菜设施生产技术的应用,在帮助定西地区的群众脱贫致富、奔小康,提高生活水平方面发挥了重大作用。同时,由于定西地区自然条件恶劣,进一步发展蔬菜设施生产仍面临着许多难题,但只要充分认识形势,认真分析面临的问题,采取必要的措施,抓住西部大开发的机遇,因地制宜发展蔬菜设施生产,蔬菜设施生产一定能够成为振兴定西贫困地区经济的支柱产业。 相似文献
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从农业可持续发展的观点,分析了河北省设施蔬菜生产、销售的现状及存在的问题,对今后的发展提出了相应的对策。 相似文献
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《蔬菜保护地栽培学》课程过去只讲有关专业的理论和技术,已不能适应当前市场经济的需要。为此提出必须增加蔬菜保护地生产的经济效益分析内容及具体建议。为讲好这部分内容,教师必须丰富自己的市场经济知识,文中提出了几点经验和做法。 相似文献
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W. Timothy Liu Wenqing Tang Rachel T. Pinker Xiaolei Niu Tong Lee 《International journal of remote sensing》2014,35(14):5411-5419
Surface solar radiation is found to have contributed significantly and positively to the record warming event in the south-central Pacific (SCP) that peaked in December of 2009. The SCP region is within a positive teleconnection pattern between sea surface temperature anomalies in the equatorial Pacific and basin-wide surface solar radiation, as revealed by a 24-year time series; the pattern extends southeast from the western equatorial Pacific toward the SCP region. The results are consistent with the ‘atmospheric bridge postulation’ on El Niño teleconnection with extratropical sea surface temperature anomalies, but with the extension to cloud cover and surface solar radiation over the mid-latitude southern oceans. 相似文献
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Ahmet Koca Hakan F. Oztop Yasin Varol Gonca Ozmen Koca 《Expert systems with applications》2011,38(7):8756-8762
An artificial neural network (ANN) model was used to estimate the solar radiation parameters for seven cities from Mediterranean region of Anatolia in Turkey. As well known that Turkey is a bridge between Asia and Europe and it lies in a sunny belt, between 36° and 42°N latitudes. Indeed, the country has sufficient solar radiation intensities for solar applications. In order to make estimation of solar radiation, the data from the Turkish State and Meteorological Service were used. Data of 2006 were used for testing and data of 2005, 2007, and 2008 were estimated. Effects of number of input parameters were tested on solar radiation that was output layer. With this aim, number of input layer parameters changed from 2 to 6. The obtained results indicated that the method could be used by researchers or scientists to design high efficiency solar devices. It was also found that number of input parameters was the most effective parameter on estimation of future data on solar radiation. 相似文献
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Solar radiation data are important parameters of crop model,hydrological model and climate change model,however,the distribution of solar radiation sites is scarce and uneven throughout the country,and it is difficult to obtain spatial continuous solar radiation by using only rare radia.Therefore,the lack of solar radiation data restricts the development of the relevant model,and the neural network on the solar radiation has a good predictability,many Artificial Neural Network ensemble models were developed to estimate solar radiation using routinely measured meteorolological variables,but it did not consider cloud,aerosol,and precipitable water vapor influence on solar radiation.In this paper,we used cloud,aerosols,atmospheric precipitable water vapor from MODIS atmosphere remote sensing products and conventional meteorological data including air pressure,temperature,sunshine duration and latitude and elevation,based on the LM-BP neural network model to simulate the 90 conventional weather stations in Eastern China from 2001 to 2014.The results show that the model has a good fit of 0.95,and the root mean square error is controlled within 2 MJ·m-2.The average deviation error is between -1 MJ·m-2 and 1 MJ·m-2.Finally,using the simulated values of the model and the measured values of 13 radiation sites,the spatial distribution of the annual solar radiation in the East China region from 2001 to 2014 is obtained by spatial interpolation and the spatial variation trend is analyzed. 相似文献
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A 10‐year solar radiation climatology is developed for the Great Barrier Reef region using data from the Geostationary Meteorological Satellite (GMS). The method uses a look‐up table based on the STREAMER radiative transfer model for a tropical atmosphere. One outstanding feature appears in the summer and autumn climatologies which exhibit distinct maxima in the southern end of the study area, between latitudes 18° S and 26° S. There is a small but statistically significant increase in solar radiation over the 10‐year study period, with maximum values of just under 1% per decade. The radiation climatology was used to examine previous coral bleaching episodes, and in particular the largest mass bleaching episode that occurred in 2002. Results show that the area of maximum bleaching corresponded closely to the area of maximum solar insolation. Sea surface temperature and solar radiation were used in a variance analysis to discriminate bleached from unbleached reefs. Solar radiation is a better discriminator for inshore areas, but temperature is better at discriminating offshore reefs. Possible reasons for this difference are discussed. 相似文献
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Emine Bay Tom Kovacs M. Patrick Mccormick 《International journal of remote sensing》2013,34(19):5505-5525
This study investigated the performance of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5) in calculating the aerosol forcing on cloud cover, incoming surface solar radiation, and near-surface air temperature via the implementation of aerosol optical depth in the shortwave radiation parameterization. MM5 simulations with and without aerosol data are performed in the periods of 6–7 August 2003 and 19–21 September 2003 during which strong aerosol forcing was observed with Moderate Resolution Imaging Spectroradiometer (MODIS) data in the mid-Atlantic region. Both periods clearly showed that aerosols had a direct negative effect on surface solar radiation through aerosol scattering. For example, every 0.1 change in MODIS aerosol optical thickness (AOT) results in 44 and 59?W?m?2 decreases in surface solar radiation for the first and second periods, respectively. A magnitude of 0.1 increment in MODIS AOT reduces air temperature 0.36 and 0.56?K for the first and second periods, respectively. Comparisons with satellite-derived surface solar radiation retrievals showed that aerosol implementation in MM5 consistently showed better incoming surface solar radiation than that of the non-aerosol case. This helps to reduce uncertainties related to the radiation–cloud–aerosol interaction in numerical weather modelling systems. 相似文献
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针对太阳辐射加热导致的误差显著限制了温度测量的准确度的问题,提出了基于流体动力学的太阳辐射误差的修正方法--数值分析法.建立从地面到32 km高空不同气压条件下珠状热敏电阻器探空温度传感器的误差热分析模型,通过计算流体动力学对其进行太阳辐射误差数值模拟分析.着重研究了太阳辐射方向、传感器表面涂层反射率、传感器尺寸等物理参数对太阳辐射误差的影响.研究结果表明:太阳辐射引起的温度测量误差随海拔高度的上升呈现非线性单调递增的变化趋势.当太阳辐射方向垂直于传感器正面时误差最大,增大传感器表面涂层反射率、减小传感器尺寸都能有效降低太阳辐射误差. 相似文献