Control of C,N,P distribution in soils of riparian forests

It is now well accepted that riparian forests have an important role in regulating upstream/downstream flow of matter and energy in river ecosystems. Since geomorphic processes determine the structure of channels and floodplains, we have investigated whether different geomorphic features of riparian forests had any effects on the ability of their soils to retain nutrients and organic carbon. Willow riparian forests were chosen within the annual floodplain of the Garonne River, southwest France, to represent two different geomorphic types. Erosional types of riparian forests (E-type) were characterized by sand deposition on their soils because of high current velocity which hampered fine particle deposition. Depositional types of riparian forests (D-type) were characterized by slower overflow velocity; consequently silt and clay were dominant in their soils. Soil samples were taken at the end of the vegetation growth period, coinciding with low water levels prior to annual floods. Erosion and sedimentation processes affected the distribution of total C,N, and P contents in riparian forest soils, since they were significantly correlated with soil grain size. D-type riparian forest soils act as a sink for upstream/downstream nutrients and carbon flows during floods through accumulation of total C,N and P from year to year. In contrast, E-type riparian forests act as potential nutrient sources during high water periods, since they may release from their soils large amounts of easily available C, N and P into the river. These results demonstrate that nutrients and carbon retention ability of riparian forests soils should be analyzed through their geomorphic features rather than by their vegetation composition. Even if they belong to the same vegetation succession, riparian forests should not be considered as a homogeneous buffering system for upstream/downstream flows of nutrients and organic carbon.     

不同施肥方式对苹果钙素吸收及土壤养分的影响

在大田条件下,研究了单施有机肥和有机肥配施化肥(混施)处理对苹果果品钙素吸收及土壤养分的影响。结果表明:单施有机肥土壤剖面硝态氮变化量不大,但可显著增加0~30 cm土层有机质含量,而混施可造成深层土壤硝态氮的累积,累积可达到120 cm土层。单施有机肥显著提高了果品钙素含量,与混施相比单施有机肥处理下SOD酶活性增加了21.82%,果实硝态氮含量降低了77.46%,说明当地有机肥的施用量基本维持了果园生态系统的碳、氮平衡,单施有机肥促进了果品钙素的吸收,对改善果实品质,促进果实硝态氮的转化,调节土壤硝酸盐含量变化有着很好的效果,而混施土壤硝态氮的累积可能在一定程度上抑制了苹果树对钙素的吸收。     

温室生态经济系统的氮、磷、钾营养物质流动

为了研究温室生态经济系统氮、磷、钾营养物质流动规律,以“津优1号”黄瓜和意大利耐抽苔生菜为试材,在江苏大学农业工程研究院实验温室进行了基于配方施肥的“黄瓜-生菜-黄瓜-生菜”一年四茬复种试验.结果表明:作物对氮、磷、钾的吸收比例分别为56.04％、55.48％、42.40％,对氮、磷、钾的损失率分别达到40.38％、31.18％、56.17％.     

不同肥料对菜地土壤有机质和全氮含量的影响

对不同施肥条件下菜地土壤有机质和全氮含量变化进行了较系统的研究。结果表明:与对照相比,尿素、鸡粪、玉米秸秆在Ⅰ施肥水平上,使土壤有机质含量分别增加12.24%、27.43%、26.35%;土壤全氮含量分别增加15.42%、39.85%、33.28%。均显著高于对照。在Ⅱ施肥水平上使土壤有机质含量分别增加了25.34%、49.03%、50.25%;使土壤全氮分别增加20.00%、61.98%、42.29%。在Ⅲ施肥水平上使土壤有机质含量分别增加34.13%、51.55%、71.71%,土壤全氮含量分别增加22.90%、83.36%、70.99%。3种肥料不同施肥水平对土壤有机质含量影响顺序依次是鸡粪、秸秆、尿素(Ⅰ施肥水平)和秸秆、鸡粪、尿素(Ⅱ、Ⅲ施肥水平)。在不同施肥水平上,对土壤全氮含量的影响大小顺序均是鸡粪、玉米秸秆和尿素。     

添加不同氮源对紫铜色松乳菇菌丝生长的影响

研究在PDA培养基中添加不同氮源对紫铜色松乳菇菌丝的生长速度和干重的影响。结果表明:在PDA培养基中添加KNO3和牛肉膏菌丝生长速度最快。添加酵母膏与和牛肉膏菌丝的干重最重,综合分析,牛肉膏不仅使菌丝生长快,而且菌丝生长浓密,干重最重,所以最适宜紫铜色松乳菇的生长,适宜浓度0.1%~0.5%,有机氮源比无机氮源更适宜紫铜色松乳菇的生长。     

不同有机物料对土壤碳氮含量及紫甘蓝产量的影响

设计不施肥(CK)、常规施肥(CM)、施玉米秸秆+鸡粪(SM)、施草炭+鸡粪(PM)、施蘑菇渣(MM)和施高量鸡粪(HM)6个处理的大田试验,探讨不同有机物料对新建蔬菜大棚土壤碳氮含量及紫甘蓝产量的影响。结果表明:各处理碳、氮分解残留率的大小顺序为MMPMCMHMSM。各处理均能提高土壤有机碳、活性有机碳、全氮和铵态氮的含量。其中MM、PM处理土壤有机碳和活性有机碳含量显著高于CK处理和常规施肥处理,有机碳含量比空白处理提高36.64%以上,活性有机碳含量提高31.90%以上;HM、PM、MM处理土壤全氮、铵态氮含量显著高于CK处理,全氮含量比空白处理提高18.89%以上,铵态氮含量提高92.74%以上;土壤硝态氮含量仅HM、PM处理高于CK处理,而CM、SM、MM处理都低于CK处理。施用有机物料也能提高紫甘蓝的产量,其中以HM、MM处理产量最高,增产20%以上。综合考虑紫甘蓝产量及土壤碳、氮等指标以MM处理效果最好,因此注重粪肥与菇渣等有机物料的配合施用能提高新建大棚土壤碳素和氮素含量,改善土壤肥力,有利于紫甘蓝增产。     

大樱桃栽培对土壤养分状况的影响

对"中国大樱桃之乡"烟台市福山区8个乡镇1986年收集的土壤数据和2009年采集的土壤样品,进行了养分含量分析。结果表明:经过长期的种植管理,大樱桃种植区土壤养分含量显著增加,有机质含量增加65.36%,全磷含量增加93.21%,碱解氮含量增加128.40%;大樱桃种植区,有机质与碱解氮的相关系数的下降与氮肥的施用量有密切的联系;随高程升高,大樱桃种植区土壤有机质、碱解氮、全磷呈不同速率减少。     

莲藕干物质积累与氮磷钾吸收分配特征

以山东莲藕地方品种"齐头"为试材,采用田间池栽试验,在莲藕不同生育期动态取样,测定各器官的干物质量和氮、磷、钾养分含量,计算各生育时期养分积累量,明确莲藕干物质积累及氮、磷、钾的吸收规律,以期为黄河中下游地区莲藕合理施肥提供参考依据。结果表明:莲藕干物质积累呈"慢-快-慢"的变化趋势。膨大茎形成期是莲藕干物质积累最快的时期,积累速率为每株29.27 g·d^-1。根状茎膨大之前,干物质主要集中在叶片和叶柄中,膨大之后,叶片和叶柄中的营养物质逐渐向膨大茎中转移,膨大茎中干物质最终积累量占全株的66.68%。不同时期莲藕氮、磷、钾的吸收积累量不同。膨大茎形成期莲藕对氮、磷、钾的积累速率最大,分别为每株0.46、0.18、0.56 g·d^-1,积累量分别占全生育期的49.50%、31.49%、39.56%。整个生育期莲藕氮、磷、钾吸收积累量的比例为1∶0.62∶1.53。根状茎膨大之前,莲藕氮和磷主要集中在叶片中,钾主要集中在叶柄中,之后随着地下根状茎的膨大,叶片和叶柄中的养分逐渐向地下部分转移,成熟期地下膨大茎中氮、磷和钾积累量分别占全株积累总量的...     

太阳能消毒时不同处理方式对土壤温度的影响

研究了覆膜与添加有机物(鸡粪、麦糠)在太阳能消毒中对土壤温度的影响。结果表明:鸡粪加覆膜处理可显著提高土壤日平均温度和日最高温度,可使10、15、20及30cm土壤日平均温度分别达到40.5、38.5、35.8和33.3℃,较不覆膜分别提高7.5、6.5、5.4和4.7℃,较覆膜但不添加有机物分别提高3.4、3.2、3.0和3.0℃;可使其土壤日最高温度分别达到46.4、43.5、40.3和36.4℃,较不覆膜处理分别提高10.1、9.2、7.9和5.8℃,较覆膜但不添加有机物处理分别提高了4.9、6.3、5.8、4.2℃。同时,覆膜、添加有机物增大了土壤日温差。故利用太阳能消毒时添加有机物与覆膜结合可显著提升0～20cm深度内土壤温度。     

Effect of exogenous H2S and ATP-sensitive potassium channels on colonic hypermotility in a rat model of chronic stress

AIM: To investigate the potential role of exogenous hydrogen sulfide (H₂S) and ATP-sensitive potassium (K_ATP) channels in chronic stress-induced colonic hypermotility.METHODS: Male Wistar rats were divided into water avoidance stress (WAS) group and sham WAS (SWAS) group. Organ bath recordings were used to test the contractile activity of colonic strips. The effects of H₂S donor NaHS and pretreatment with glibenclamide on the contractions of colonic smooth muscle were studied and the IC₅₀ of NaHS was calculated. The localization and expression of the subunits of K_ATP channels were determined by the methods of immunohistochemistry and Western blotting.RESULTS: WAS increased contractile activity of colonic strips. NaHS concentration-dependently inhibited the spontaneous contractions of strips from the SWAS and WAS rats. The IC₅₀ of NaHS for longitudinal muscle (LM) and circular muscle (CM) of the WAS rats was 0.2033 mmol/L and 0.1438 mmol/L, significantly lower than those of the SWAS rats. Glibenclamide significantly increased the IC₅₀ of NaHS for LM and CM from the SWAS and WAS rats. In both SWAS and WAS rat colon, Kir6.1, Kir6.2 and SUR2B were expressed on the plasma membrane of the smooth muscle cells. WAS treatment resulted in up-regulation of the expression of Kir6.1 and SUR2B in the colon devoid of mucosa and submucosa.CONCLUSION: The increased expression of Kir 6.1 and SUR2B in colonic smooth muscle cells may be a defensive response to chronic WAS. H₂S donors may have potential clinical effect on treating chronic stress-induced colonic hypermotility.     

七种植物秸秆对连作番茄苗生长及土壤酶活性的影响

以7种不同科属的作物秸秆为试验材料,采用随机区组设计,在连作10年的番茄土中添加不同的秸秆,以不添加秸秆的番茄连作土壤为对照,共8个处理。研究不同秸秆对番茄生长及土壤酶、根结线虫的影响,以期为番茄根结线虫的生态防控及克服连作障碍提供参考依据。结果表明:不同作物秸秆对番茄生长产生不同影响,其中玉米和分蘖毛葱秸秆处理番茄生长势最好。添加不同作物秸秆均可增加土壤pH,同时降低了土壤EC值,有利于改善土壤环境。添加万寿菊秸秆可增加土壤有机质含量,50 d显著高于对照。在各取样时期不同作物秸秆对土壤酶活性产生不同程度的影响,30 d,万寿菊和菊芋秸秆处理的脲酶和转化酶的活性显著高于对照。40 d,玉米和万寿菊秸秆处理的转化酶和中性磷酸酶活性显著高于对照。50 d,分蘖毛葱和大蒜秸秆处理的转化酶和中性磷酸酶活性低于对照。60 d,玉米和小麦秸秆处理中性磷酸酶活性显著高于对照。70 d,番茄、玉米和小麦秸秆土壤转化酶活性与对照差异显著,各处理的中性磷酸酶活性差异不显著。土壤酶和有机质、pH和EC值的简单相关关系分析表明,脲酶和中性磷酸酶活性与pH呈极显著负相关,与EC值呈显著正相关,同时脲酶活性和有机质含量呈极显著正相关。分蘖毛葱秸秆对番茄根结数量有显著的抑制作用。综上,将一定量分蘖毛葱秸秆添加入番茄连作土中,能显著促进番茄生长,改善土壤环境,对根结线虫有一定的防治效果。     

Role of ATP-sensitive potassium channels in inhibitory effect of hydrogen sulfide on high glucose-induced injury in H9c2 cardiac cells

AIM: To investigate the roles of ATP-sensitive potassium (K_ATP) channels in high glucose-induced cardiac injury and the inhibitory effect of hydrogen sulfide (H₂S) on the cardiomyocyte injury. METHODS: The expression level of K_ATP channel protein was tested by Western blot. The cell viability was measured by CCK-8 assay. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining. Mitochondrial membrane potential (MMP) was examined by JC-1 staining. RESULTS: After the H9c2 cells were treated with 35 mmol/L glucose (high glucose, HG) for 1~24 h, the protein level of K_ATP channel was significantly reduced at 6 h, 9 h, 12 h and 24 h, reaching the minimum level at 12 h and 24 h. Pretreatment of the cells with 400 μmol/L NaHS (a donor of H₂S) prior to exposure to HG for 12 h considerably blocked the down-regulation of K_ATP channels induced by HG. Pretreatment of the cells with 100 μmol/L mitochondrial K_ATP channel opener diazoxide, 50 μmol/L non-selective K_ATP channel opener pinacidil or NaHS obviously inhibited HG-induced injuries, leading to an increase in the cell viability, and decreases in the number of apoptotic cells and the MMP loss. Pretreatment with 100 μmol/L mitochondrial K_ATP channel antagonist 5-hydroxydecanoic acid or 1 mmol/L non-selective K_ATP channel antagonist glibenclamide attenuated the above cardioprotective effects of NaHS. CONCLUSION: K_ATP channels mediate the inhibitory effect of H₂S on HG-induced cardiac injury.     

土壤有机质对"红富士"苹果产量和品质的影响

测定了"红富士"苹果园0~40 cm土层的有机质含量,分析了相应果园苹果的产量和果实品质,为果园科学施肥提供依据。结果表明:土壤有机质含量在2%以上的果园苹果产量高、果实品质好,几乎不发生苦痘病;土壤有机质含量在2%以下的果园苹果产量低、果实品质差,苦痘病发生严重。     

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km² Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km² of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y¹. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y¹ in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y¹. The potential retention by wetlands was estimated to 57,000–145,000 ton y¹ when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y¹. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.     

Changes to the landscape pattern of coastal North Carolina wetlands under the Clean Water Act, 1984–1992

Wetland management in the United States is organized through a permit process that requires a permit be filed with the U.S. Army Corps of Engineers prior to wetland alteration. A collection of these permits from 1984 through 1992 was analyzed in conjunction with classified Landsat Thematic Mapper data from 1984 and 1992 in order to quantify changes to wetland habitat in the study area in coastal North Carolina. The wetland management process in the U.S. focuses on a site-by-site review, possibly overlooking important changes to wetlands at the landscape-scale. These the two datasets were used to determine if wetland habitat loss was occurring at permit sites, but also to determine if landscape-scale wetland fragmentation and reorganization were occurring in the area surrounding each permit site under the wetland management process. The use of these two datasets attempted to span two scales: the site-specific scale often used in the management of wetlands, and the landscape-scale where effects of such management are evident. Important conclusions from the research include the following. First, while several sources imply that coastal wetlands are disproportionately protected as a result of the widespread recognition of their habitat value, estuarine wetlands were altered much more frequently in the study area than their inland counterparts. Second, despite federal level efforts that require compensatory mitigation when wetland habitat is lost, such mitigation was required in only three percent of permits, ensuring wetland loss. Third, correlation between estimates of wetland loss from the Permit Record and from the remotely sensed record was minimal, highlighting the problems inherent to wetland delineation and implying alterations to habitat not evidenced in the permit record. Finally, landscape-scale changes of loss, fragmentation and habitat reorganization have occurred in estuarine emergent wetland habitat in areas adjacent to several permit sites, implying unanticipated additional impacts to permitted actions. Wetland loss at the permit site occurred with additional fragmentation in 80 percent of the sites examined. The results highlight the lack of agreement between management and landscape-scale wetland structure, function and change, and imply the importance of examining the spatial context of permit sites in the permit review and evaluation procedure.     

增施钾肥对油葵产量的影响

通过田间试验在宁夏灵武农场研究了增施钾肥对油葵产量的影响,以期为指导当地农户的合理施肥提供依据。结果表明:与对照比较,N、P处理和N、P、K处理均降低了油葵的空粃率,提高了油葵的千粒重,显著提高油葵的产量。N、P处理和N、P、K处理的产量分别比对照提高了37.2%和73.0%。同常规只施用N、P处理比较,增施钾肥(N、P、K处理)油葵产量提高了26.1%,差异达到显著水平。在当地土壤肥力条件下要进一步提高油葵的产量,增加经济效益,必须改变农民的传统施肥习惯,增施钾肥,平衡施肥。     

生物有机肥对茶园土壤肥力、养分及土壤环境的影响

采用大田试验,以不施肥为对照,研究不同用量的生物有机肥对茶园土壤有机质含量、全氮含量、碱解氮含量以及pH值、微生物种群数量和土壤脲酶活性的影响.为生物有机肥的推广提供理论依据.结果表明:施用TS-1型生物有机肥能显著提高茶园土壤中有机质含量、全氮含量和碱解氮含量,且提高了微生物种群数量、多样性指数和土壤脲酶活性.从而显著提高茶园土壤肥力,改善土壤环境,具有良好的推广价值.     

不同土壤条件对越橘生长发育及果实品质的影响

以吉林省蛟河市、靖宇县2个地区现有越橘种植土壤条件为研究对象,将土壤条件分为草炭地、改良地和园土地3种,研究了2个地区不同土壤条件下越橘品种“北陆”的生长特性,探究了土壤养分与果实品质的相关性,为提高果实品质的土壤改良技术提供参考依据。结果表明:2个地区3种土壤条件有机质含量存在显著差异,均表现出草炭地>改良地>园土地的现象,且均大于4%;各土壤条件下果实可溶性糖含量差异不显著,靖宇园土地有机酸含量最高,蛟河草炭地果实维生素C含量最高,靖宇改良地果实花色苷含量最高。相关性分析表明,土壤养分含量与果实品质相关性较强,土壤有机质含量与可溶性固形物及维生素C含量呈极显著正相关,与花色苷含量呈显著负相关。因此,调节土壤有机质含量是2个地区种植越橘的首要问题。     

有机氮对平菇原基分化期胞外酶的影响

以平菇为试材,采用不同有机氮浓度的培养料培养,在平菇原基形成的扭结期、桑椹期、珊瑚期分别测定漆酶、愈创木酚氧化酶、邻苯二酚氧化酶、淀粉酶、羧甲基纤维素酶的活性。结果表明:配方5(棉籽壳97.70%,尿素0.30%,过磷酸钙1%,糖1%)是最好的配方,胞外酶活性最大,平菇子实体分化速度快;适宜的有机氮含量有助于增加平菇原基分化过程中各酶活性,加快原基分化进程。     

番茄根系分泌物、木质部和韧皮部汁液组分对矿质氮、有机氮营养的响应

 采用营养液培探讨了番茄幼苗根系参数、根系分泌物、木质部和韧皮部汁液组分对矿质氮（NH₄⁺-N、NO₃^--N）和有机氮（Glycine）的不同响应。结果表明,不同氮素处理8 d后,'申粉918'、'沪樱932'番茄根系干质量、根系体积表现为NO₃^--N > Gly-N > 对照 > NH₄⁺-N处理;而根系活力则表现为以供Gly-N 或NO₃^--N为最高,其次为供NH₄⁺-N的处理,以对照处理为最低。不同氮素形态显著影响不同番茄品种根系分泌物、木质部和韧皮部各组分含量。 NO₃^--N处理的番茄根系分泌物、木质部和韧皮部汁液中的NO₃^--N和P含量最高,供Gly-N、NH₄⁺-N其次,对照最低;而供Gly-N、NH₄⁺-N时铵态氮、游离氨基酸、可溶性糖含量一般均高于处理NO₃^--N和对照。番茄根际吸收不同氮素对根际pH亦产生不同的影响,吸收NO₃^--N和Gly-N后,根际pH显著升高,而吸收NH₄⁺-N后则降低。根系分泌物可溶性蛋白含量的变化表现为NO₃^--N > Gly-N > NH₄⁺-N> 对照,而木质部、韧皮部可溶性蛋白含量的变化则表现为Gly-N > NO₃^--N> NH₄⁺-N > 对照。番茄幼苗不同品种间的差异性表现,与氮素形态有关,以根系活力为指标的基因型差异在供应NO₃^--N、NH₄⁺-N和Gly-N及对照时,'沪樱932' 的根系活力均显著（P<0.05）大于 '申粉918'。