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51.
提出上海都市农业作为与都市经济发展和人民生活息息相关的基础产业,应当优先实施可持续发展战略。上海都市农业的可持续发展,一定要走农业产业化的道路。具体来讲,就是要建设以下两大类型6种产业形态的都市农业:(1)产品型都市农业,包括生态农业、设施农业、创汇农业等;(2)服务型都市农业,包括绿化农业、旅游农业、休闲农业等。 相似文献
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Plot trenching and root decomposition experiments were conducted in a warm-temperate oak chronosequence (40-year-old, 48-year-old, 80-year-old, and 143-year-old) in China. We partitioned total soil surface CO2 efflux (RS) into heterotrophic (RH) and rhizospheric (RR) components across the growing season of 2009. We found that the temporal variation of RR and RH can be well explained by soil temperature (T5) at 5 cm depth using exponential equations for all forests. However, RR of 40-year-old and 48-year-old forests peaked in September, while their T5 peaks occurred in August. RR of 80-year-old and 143-year-old forests showed a similar pattern to T5. The contribution of RR to RS (RC) of 40-year-old and 48-year-old forests presented a second peak in September. Seasonal variation of RR may be accounted for by the different successional stages. Cumulative RH and RR during the growing season varied with forest age. The estimated RH values for 40-year-old, 48-year-old, 80-year-old and 143-year-old forests averaged 431.72, 452.02, 484.62 and 678.93 g C m−2, respectively, while the corresponding values of RR averaged 191.94, 206.51, 321.13 and 153.03 g C m−2. The estimated RC increased from 30.78% in the 40-year-old forest to 39.85% in the 80-year-old forest and then declined to 18.39% in the 143-year-old forest. We found soil organic carbon (SOC), especially the light fraction organic carbon (LFOC), stock at 0-10 cm soil depth correlated well with RH. There was no significant relationship between RR and fine root biomass regardless of stand age. Measured apparent temperature sensitivity (Q10) of RH (3.93 ± 0.27) was significantly higher than that of RR (2.78 ± 0.73). Capillary porosity decreased as stand age increased and it was negatively correlated to cumulative RS. Our results emphasize the importance of partitioning soil respiration in evaluating the stand age effect on soil respiration and its significance to future model construction. 相似文献
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Goutailler G Guillard C Faure R Païssé O 《Journal of agricultural and food chemistry》2002,50(18):5115-5120
The solar photolytic behavior of the pesticide 4,6-diamino-2-cyclopropyl-pyrimidine-5-carbonitrile, currently known as dicyclanil, has been mimicked in a photoreactor operating with an artificial light flux. The rate and pathway of degradation were performed. An additional study, using TiO(2) photocatalysis, has been achieved in order to determine the efficiency of photocatalysis to degrade the molecule. The catalyst was titania Degussa P-25. The aim of this article was the identification of the intermediate products formed during the irradiation, to establish the degradation pathway of dicyclanil. The kinetics of the reactions were followed by liquid chromatography with a diode array detector (LC-DAD). Most of the organic compounds occurring during the photodegradation have been identified by means of liquid chromatography and mass spectrometry coupled techniques (HPLC-MS). Additional analyses were carried out to evaluate the mineralization rates into nitrate and ammonium ions. 相似文献
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通过突变黑粒种质的纯化、筛选,采用回交转育法将黑粒种质导入到白糯玉米育种材料中再选系或转育成黑粒同型系,组配黑糯玉米杂交种.根据育种目标,经籽粒色泽、品质、抗逆性鉴定和产量配合力的测交试验,决选出适合作母本和父本的品系组成“黑糯941”杂交种.经初步生产检验和示范已获较好效果. 相似文献
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通过对水泵性能差异引起的水泵出水量的变化分析,提出了调节级间流量差的小机组流量的确定方法,解决了多级提水泵站空流段的级间流量配合问题。 相似文献
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红花刺槐茎段组织培养研究 总被引:5,自引:0,他引:5
红花刺槐为刺槐的变型,其组织培养至今尚未见报道。为提高红花刺槐的繁殖系数,进行了红花刺槐茎段外植体诱导成活、初代培养基和继代培养基以及生根培养基的筛选试验,并对愈伤组织成苗进行了探索。结果表明当年生枝条茎段组织培养春天比秋天成活率高,绿色致密的愈伤组织能够成苗。初代培养以SH为基本培养基为好,继代培养以B5为基本培养基为好,生根培养以1/2MS为基本培养基为好,繁殖系数达每芽30天4.7株,生根率为84.4%。表7参22。 相似文献