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941.
适当化肥配施有机肥减少稻田氮磷损失及提高产量 总被引:9,自引:2,他引:7
为了减少稻田氮磷损失量,并有效利用畜禽固废物,该研究在广东省东江上游典型农业集水区,开展田间不同施肥方式(不施肥、常规施肥、配方施肥1~3)氮磷损失监测及不施肥处理的室内土柱模拟试验。不施肥、常规施肥、配方施肥1~3的肥料施用量分别为:碳铵0、750.0、510.0、472.5、510.0 kg/hm2;磷肥0、375.0、255.0、255.0、236.25 kg/hm2;尿素 0、225.0、172.5、156.0、172.5 kg/hm2;有机肥:0、0、1162.5、1162.5、1162.5 kg/hm2。通过室内土柱试验,获取不施肥小区氮磷地表径流及淋溶流失量,并结合不施肥小区的田间监测数据(土样、水样、植株样等),测算出水稻生长季固氮量为31.54 kg/hm2。采用元素守恒的方法,综合考虑氮磷淋溶、流失、氨氮挥发、氮素干湿沉降以及水稻固氮等多方面的影响,构建稻田系统氮、磷损失模型,分别计算出5种不同施肥方式的氮磷损失量。研究表明,配方施肥1、2、3较常规施肥,氮、磷损失量减幅分别为7.7%~30.0%、61.2%~70.8%;氮、磷农学利用率增幅分别为24.6%~84.4%、12.8%~78.9%;实现节支增收分别为2 716元/hm2、-2 169元/hm2、-1 646元/hm2。配方施肥方案可有效减少农田氮磷损失量,其中配方施肥1经济效益、环境效益俱佳,可作为常规施肥的替代方案。该研究综合考虑了整个稻田系统中氮、磷的输入与输出,定量评估不同施肥方式的氮磷损失量、农学利用率及其经济环境效益,可为稻田氮磷损失综合防控提供参考。 相似文献
942.
高压CO2处理保持非还原桃汁的品质 总被引:1,自引:0,他引:1
采用高压CO2(high pressure carbon dioxide,HPCD)处理非还原(not from concentrate,NFC)桃汁,分析HPCD处理后NFC桃汁pH值、可溶性固形物、色泽、酚类和抗氧化活性等品质特性的变化,讨论HPCD对NFC桃汁品质的影响。NFC桃汁的pH值和可溶性固形物含量分别为3.82和10.3°Brix,HPCD处理后没有显著变化;HPCD处理后NFC桃汁颜色变暗,色泽参数L、a、b值显著降低,对应的褐变度提高;NFC桃汁中的主要酚类物质有儿茶素、绿原酸、新绿原酸和阿魏酸,HPCD处理后酚类物质含量没有显著变化;采用FRAP和1,1-二苯基苦基苯肼(1,1-diphenyl-picrylhydrazyl,DPPH)清除率2种方法测定NFC桃汁的抗氧化活性,2种方法的测定结果都表明 HPCD 处理后 NFC 桃汁的抗氧化活性提高,并且随着处理时间的延长而逐渐提高。以上结果表明HPCD能较好的保持NFC桃汁的品质,为非热加工技术应用于果蔬加工提供理论基础。 相似文献
943.
Jingzhen Cui Duanwei Zhu Shuijiao Liao Guanglong Liu Liying Ren Wenbing Zhou 《Journal of plant nutrition》2013,36(13):1923-1936
Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth. 相似文献
944.
Fengchang Wu Libin Xu Haiqing Liao Fei Guo Xiaoli Zhao John P. Giesy 《Journal of Soils and Sediments》2013,13(6):1084-1092
Purpose
Factors such as organic matter can significantly influence the distribution of mercury (Hg) in aquatic environments. Recent studies in Arctic and sub-Arctic lakes in Canada have investigated whether scavenging of Hg by phytoplankton significantly affects distributions of Hg in sediments. This study examined the relationships between Hg and organic components in two contrasting lakes (Lakes Qinghai and Chenghai) in low and middle latitudes of China.Materials and methods
Sediment cores from the less-polluted, oligotrophic Lake Qinghai (QH) and from the polluted, eutrophic Lake Chenghai (CH) were collected by a gravity corer. The cores were sectioned and transported on ice to the laboratory where they were stored at ?20 °C. Subsamples were dried in a vacuum freeze dryer and grounded with a mortar and pestle prior to analyses. Total concentrations of Hg were quantified using cold vapor atomic absorption spectrometry. Total organic carbon (TOC) was quantified using an elemental analyzer after removal of carbonate. The Rock-Eval 6 pyrolysis technique (Vinci Technologies, Rueil-Malmaison, France) was used to deconvolute TOC in sediments into S1, S2, and RC components; S2 was further separated into S2a and S2b.Results and discussion
Different relationships between Hg and TOC were found in the two lakes, which suggest that different types of organic compounds might play completely different roles in the distribution of Hg in lakes. S1 (the soluble organic matter (SOM)) was found to significantly control distributions of Hg in sediments of both lakes, while S2 and S2a were not. Combining the synchronous fluctuations of Hg and the oxygen index in the QH sediment core and in recent sections of CH suggested that allochthonous SOM derived from the terrestrial environment had an important influence on the distribution of Hg in both lakes and a large portion of Hg that originated from the lake catchment.Conclusions
This study provides further evidence that organic matter is one of the most important factors that influences distributions of Hg in lake sediments and that SOM was the primary form of carbon associated with sedimentation of Hg. The results also suggest that Hg in lake sediments might not accurately represent its pollution history as it could also be influenced by land use, such as agriculture or other human activities in the catchment. 相似文献945.
深圳市生态修复裸露边坡的植物群落特征研究 总被引:2,自引:0,他引:2
以广东省深圳市14个裸露边坡治理工程为研究对象,分析比较了受损生态系统修复后各边坡的植物群落物种多样性特征。调查结果显示:边坡植物群落中共有120种植物,其中,频度相对较高、适应性相对较强的物种有马缨丹、银合欢、类芦、叶子花、大红花等11种;从群落组成结构看,边坡植物群落主要形成了乔灌草群落结构,飘板植槽的植被覆盖率和物种多样性指数均较高,物种分布较均匀,说明飘板植槽边坡群落结构相对稳定均衡;根据重要值结果可知,乔木层主要物种有台湾相思、银合欢、秋枫、木菠萝、小叶榕等,灌木层主要物种有簕仔树、山毛豆、马缨丹、猪屎豆,而草本层以类芦、异叶地锦为主。 相似文献
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