包膜尿素不同用量对黄瓜幼苗生长及氮平衡的影响

为确定合理的包膜尿素用量以指导黄瓜育苗施肥,采用生产中常用的草炭:蛭石(2:1)为育苗基质,研究了包膜尿素不同用量对黄瓜幼苗生长、养分吸收及氮平衡的影响。结果表明:包膜尿素用量在125~375 mg N/株的情况下,可协调黄瓜幼苗地上部和地下部的生长,促进幼苗对磷、钾的吸收;移栽时,基质中的氮素残留总量90.5~250.3 mg N/株,其中,残留的包膜氮素占75.4%~82.3%,可实现带肥移栽;育苗期间可产生31.9~121.5 mg N/钵的氮素表观损失。     

氮素形态对黄瓜幼苗生长及氮代谢酶活性影响

用营养液培养的方法,研究了同一氮素水平不同氮素形态比例对黄瓜幼苗生长及氮代谢关键酶：硝酸还原酶（NR）、谷氨酰胺合成酶（GS）活性的影响。结果表明：单独供给硝态氮（NO3^--N）比单独供给铵态氮（NH4^＋-N）更有利于黄瓜幼苗的生长;当NO3^--N∶NH4^＋-N为75∶25时,主根长度、根总表面积、根总体积、株高、茎粗、地上部干重的值最大。NR活性随NO3^--N比例的增加而增加,GS活性在NH4^＋-N比NO3^--N少时,随NH4^＋-N的比例增加而增大,当NO3^--N∶NH4^＋-N为50∶50时活性最大,当NH4^＋-N大于NO3^--N时活性下降。表明NO3^--N∶NH4^＋-N为75∶25时对黄瓜幼苗最适宜。     

氮肥形态及氮钾施用措施对水稻生长 和养分吸收的影响

为探明不同氮（NH4-N和NO3-N）源下，不同施钾水平及氮钾施用次序对水稻生长和养分吸收的影响，进行了温室盆栽试验。结果表明：在水稻生长早期（20d左右时），以NO3-N作为N源时水稻的生物产量和氮钾养分吸收量均显著高于NH4-N作N源的处理，但随着生长时期的延长，NH4-N源更能促进水稻的生长和养分吸收，因此，从整个营养生长时期来讲，铵态氮肥作为水稻N源更具有优越性。结果同时表明，氮肥施用效果与钾肥的施用水平有很大关系，在一般盆栽试验氮肥用量（纯N用量0.15 g/kg）水平下，施钾（K2O）量达到0.51g/kg时会导致水稻的生长及养分吸收量显著下降。铵钾施用次序对水稻的营养生长及养分吸收均有一定的影响，特别是施钾量较高时，铵钾在土壤中的交互作用会导致水稻因氮素供应不足而影响生长和养分吸收。     

供氮形态和水分胁迫对苗期水稻吸收氮素营养的影响

为探讨不同形态氮素营养对水分胁迫条件下水稻幼苗吸收氮素的影响,采用室内营养液培养及聚乙二醇(PEG6000)模拟水分胁迫处理的方法,在苗期设置3种供氮形态(NH4 -N,NO3--N以及NH4 -N和NO3--N相同浓度下等体积混合)和2种水分条件(非水分胁迫及水分胁迫)的耦合处理进行研究。结果表明,在非水分胁迫条件下,全NO3--N营养水稻比全NH4 -N营养水稻的氮素消耗多。在水分胁迫条件下,全NO3--N营养水稻的氮素消耗略有增加;同时供应NH4 -N和NO3--N显著促进水稻对氮素的消耗;对全NH4 -N营养水稻氮素消耗的影响不明显。在水分胁迫条件下,同时供应NH4 -N和NO3--N增加水稻的氮素积累;对全NH4 -N营养水稻的氮素含量没有明显影响。在非水分胁迫条件下,NH4 -N和NO3--N混合营养水稻的氮素利用率在3种供氮形态处理中最高。水分胁迫后复水,同时供应NH4 -N和NO3--N显著提高水稻的氮素利用率;水分胁迫对全NH4 -N营养水稻的氮素利用率没有明显的影响,但明显降低全NO3--N营养水稻的氮素利用率;无论是非水分胁迫,还是水分胁迫条件下,全NO3--N营养水稻的氮素利用率均为最低。     

旱地春谷子不同生育期吸收氮、磷、钾养分的特点

试验研究了在施肥与不施肥处理情况下,半湿润偏旱区春谷子不同生育期氮、磷、钾养分的吸收特点。结果表明,在供试土壤条件下,施肥可明显提高春谷子产量、干物质累积量、体内氮、磷、钾含量及其累积量。施肥或不施肥,春谷子地上部干物质的累积量随生育期呈典型“S型”曲线增长,其中抽穗灌浆期为累积高峰期,占总累积量的50%左右。植株氮含量随生育期呈曲线下降趋势;整个生育期植株含磷量呈 “W型”变化;植株含钾量呈单峰曲线变化,峰值出现在拔节期。植株氮、磷、钾累积吸收量随生育期的延长和施肥水平的提高而增加,但各生育期相对累积吸收比例,施肥与否差异不大。苗期氮、磷、钾的吸收量约占总吸收量的1%~3%,拔节期约占总吸收量的30%、20%、37%,是钾素吸收的高峰期,孕穗期约占22%、21%、34%,抽穗灌浆期约占43%、53%、23%,是氮、磷吸收的高峰期,籽粒形成期约占3%~5%。不论施肥与否,地上部氮、磷、钾累积吸收量与干物质累积量之间均呈极显著正相关,而与植株氮、钾含量之间呈极显著负相关。     

不同种植制度和施肥措施对烟田土壤养分及微生物的影响

分析了烤烟连作与轮作对土壤养分含量和微生物区系的影响以及底肥中硝态氮(NO3--N)、铵态氮(NH4 -N)不同配施比例对烤烟生育期土壤N03--N的影响.结果表明,烟田连作3年、6年与轮作相比,土壤有机质均下降,速效氮、磷和钾含量增加,pH值上升;连作6年与3年相比,土壤pH值、速效磷和速效钾又有所升高,碱解氮持平,有机质降低4.3%.土壤细菌和放线菌数茸随连作年限增加而呈减少趋势.真菌以连作3年最低;连作使细菌和真菌有益菌群数量降低,而腐霉等有害菌群数量增加.烤烟生育前期.随着底肥中NO3--N施用比例增加.耕层土壤N03--N含最增加,而生育中后期没有显著差异;随着烤烟生育期推进,土壤NO3--N主要累积在40～60 cm土层.从烤烟整个生育期土壤NO3--N变化和累积看,底肥氮以NO3--N占30%-50%的配比,对烟株吸收NO3--N较为有利.     

不同氮浓度和形态对高羊茅叶片活性铁及叶绿素合成的影响

以2年生高羊茅（Festuca arundinacea Shreb．）为供试材料,采用移植盆栽方法,不同浓度硝酸盐（NO3^- -N）和氨盐（NH4^＋-N）溶液供给为处理,研究不同形态氮素对高羊茅叶片活性铁含量,叶绿素合成及叶片氮、磷、钾含量的影响,为进一步优化草坪施肥方案和改善观赏品质提供理论依据。研究表明：（1）NH4^＋-N有利于植物叶片对Fe的吸收,叶片内活性铁含量高;NO3^--N不利于叶片对Fe的吸收．活性铁含量偏低。（2）不同形态氮浓度从1-8mmol／L范围内,随着氮浓度的增加叶绿素含量提高,在12mmol／L浓度时叶绿素含量均下降。（3）随两种形态氮素浓度增加,叶片氮、磷的含量随之增加,施用NH4^＋-N叶片内钾的吸收和分配受到抑制。NH4^-N有利于植株对活性铁的吸收和叶绿体的合成;NO3-N有利于植株对营养元素的吸收。     

不同氮形态及配比对甘草生长及品质的影响

为了探究氮素形态对甘草生长、产量及品质的影响,并为甘草的优质高产栽培提供氮肥施用依据,本试验采用营养液培养的方法,在不同氮素形态及硝铵配比处理后,比较了甘草生长量、药用成分以及游离氨基酸、可溶性蛋白质等物质含量变化。结果表明：适量的硝铵配比能提高甘草的产量和品质。不同硝铵配比中,NO3--N/NH4+-N为50/50时,根的产量、整株合成的药用成分以及可溶性糖、可溶性蛋白质等含量最高。硝态氮、铵态氮及尿素三种不同氮素形态中,铵态氮最不适宜甘草生长;根的产量上,硝态氮和尿素处理之间没有显著差异;但尿素处理的整株植株合成药用成分的量最大。     

不同形态氮素对燕麦营养生长和磷素利用的影响

本试验采用溶液培养和砂基培养的方法,研究了NO3ˉ-N和NH4+-N两种不同形态氮素对燕麦营养生长、氮代谢、根际pH及磷素利用的影响。结果表明, 在NO3ˉ-N和 NH4+-N同时存在的条件下,燕麦生长明显优于单一NH4+-N或NO3ˉ-N处理,且植株生长量特别是根系生长量随着NO3ˉ-N在氮源中比例的提高而增加。燕麦吸收NO3ˉ-N 和NH4+-N对     

不同土壤pH 下氮素形态对平邑甜茶生长

目前土壤酸化严重制约了果园生产与发展,而科学配施不同形态氮肥可有效缓解土壤酸化。本试验以平邑甜茶(Malus hupehensis Rehd.)实生苗为试材,应用15N示踪技术研究土壤pH梯度下3 种形态氮素对苹果砧木生长及15N吸收利用特性的影响。结果表明：不同土壤pH下,酸化土壤3 种形态氮素处理植株生物量从高到低为酰胺态氮(CO(NH2)2-N)＞铵态氮(NH4+-N)＞硝态氮(NO3--N),与pH呈显著正相关,而碱性土壤植株生物量则表现为酰胺态氮＜铵态氮＜硝态氮;植株各器官Ndff 值和15N分配率在不同形态氮素处理下随土壤pH变化差异显著;NH4+-N和NO3--N处理植株总吸氮量在pH 6.5 时达到最大值0.47 g 和0.33 g,不同土壤pH下的植株15N利用率受氮素形态影响差异显著。可见,不同土壤pH下3种形态氮素对15N的吸收征调、分配及利用差异显著,是限制植株生长的关键因素。     

Time Course of Nitrogen in Soil Solution and Nitrogen Uptake in Maize Plants as affected by Form and Application Time of Fertilizer Nitrogen

Field experiments with silage maize were conducted in 1987 and 1988 on a loess-derived Luvisol in southwest Germany. Four nitrogen fertilizer treatments were compared: application of preplanting NH₄ N (plus a nitrification inhibitor, dicyandiamide as Didin) and preplanting NO₃-N, split application of NO₃-N (preplanting and side dressed 45 days after planting) and a control without nitrogen fertilizer in 1987 and with 64 kg N ha^?1 as calcium ammonium nitrate in 1988. The total amounts of soil mineral nitrogen (N_min+ fertilizer N) were 200 kg N ha^?1 in 1987 and 240 kg N ha^?1 in 1988. Suction cups and tensiometer were installed at five depths and samples were taken in regular intervals. Nitrate concentrations in the suction solution steeply increased at 15 cm and 45 cm soil depth 3-4 weeks after fertilizer application (1987 up to 160mgNl^?1; 1988 up to 170mgN l^?1) and steeply decreased up to 75 cm depth with the onset of intensive N uptake at shooting. Ammonium concentrations in the suction solution were very low (0-0.16 mg N l^?1). Compared to preplanting NCyN application, preplanting NH₄-N and split NO₃-N application decreased nitrate concentrations in the suction solution in spring 1987. In 1988, however, nitrate concentrations in the suction solution of preplanting NH₄-N and split NO₃-N application plots did not fall below 50mgNl^?1 at 15 cm depth during the growing season. Nitrate concentrations of split NO₃-N application increased again in autumn 1988 and hence doubled the calculated N losses by leaching during the winter months compared to preplanting N applications. At shooting, plants of the preplanting NH₄-N treatment had lower nitrate concentrations in leaf sheaths compared to plants of preplanting NO₃-N application. Total N uptake of maize between shooting and early grain filling of preplanting NH₄-N and split NO₃ -N application tended to be higher compared to preplanting NO₃-N application, reflecting the higher N availability in the soil later in the season. However, final dry matter yields and N uptake were not significantly affected by N form or time of N application. Since N losses by nitrate leaching between N application and onset of N uptake by plants were negligible on the experimental site, preplanting NH₄-N application and split NO₃-N application showed no agronomic advantages. High amounts of side dressed NO₃-N may increase nitrate leaching during the winter months, especially in years with delayed rainfall after application.     

氮素形态及供应时期对马铃薯生长发育与产量的影响

选用马铃薯克新1号和费乌瑞它2个品种,于2013-2014年在沙培条件下,研究了氮素形态及供应时间对马铃薯植株生长、块茎形成及发育的影响。结果表明,在块茎形成前供应NO₃-N与NH₄-N两种条件下,马铃薯植株高度、叶面积、叶片SPAD值、整株干物质积累量以及块茎重量无显著差异,而块茎形成后供应NH₄-N的马铃薯叶片SPAD值、植株生长速度及块茎产量均显著高于NO₃-N处理;块茎形成前供应NO₃-N的植株结薯数显著高于NH₄-N处理,但是氮素形态对干物质在马铃薯块茎中的分配比例无显著影响。因此,马铃薯的氮素养分管理应根据商品薯和种薯生产的不同目标,在块茎形成前后分别供应适宜形态的氮素。     

AM真菌Glomus versiforme对连作土壤上黄瓜生长及养分吸收的影响

为明确AM真菌Glomus versiforme在缓解连作障碍中的潜力,以黄瓜为试验材料,于黄瓜播种同时接种G.versiforme,并设立相应对照,苗龄40天时,将幼苗分别移栽至自然连作土与灭菌连作土上,研究2种土壤条件下G.versiforme对黄瓜幼苗的生长,氮磷养分吸收及根际微生物群落组成的影响。结果表明:G.versiforme对幼苗地上部与根系生长的影响因土壤条件而异。出苗第55天时,连作土上接种G.versiforme的幼苗地上部生物量是其相应对照的1.81倍,且该处理与灭菌土上菌根化处理间差异不显著。同时,灭菌土上接种G.versiforme的幼苗根系生物量是连作土上菌根化处理的1.22倍,是连作土上非菌根化处理的2.11倍。连作土上菌根化幼苗地上部生物量的显著积累与G.versiforme对幼苗叶片中氮营养的改善有关,与此同时,灭菌土上G.versiforme可促进根系对磷的吸收。此外,接种G.versiforme可在一定程度上改善土壤环境,使连作土中的细菌数量增加,真菌数量降低。土壤灭菌处理或将菌根化幼苗移栽于连作土壤上均可有效缓解设施黄瓜连作障碍。     

Turnover and fate of 15N-labelled cattle slurry ammonium-N applied in the autumn to winter wheat

The fate of ¹⁵NH₄-N labelled cattle slurry applied before sowing in September of a winter wheat crop was studied on a loamy sand soil. The aim was to quantify immobilization of slurry NH₄-N into microbial biomass, the speed at which nitrate derived from the slurry NH₄-N was transported down the soil profile, and the utilization of slurry NH₄-N by the winter wheat crop. Cattle slurry was applied at a rate corresponding to 75 kg NH₄-N ha⁻¹ , with very little loss by volatilization (<4%) due to rapid incorporation by ploughing. The slurry amendment resulted in a doubling of soil surface CO₂ flux, an index of microbial activity, over non-amended soil within the first c. 2 weeks, but ceased again after c. 4 weeks, due to depletion of the easily degradable substances, e.g. volatile fatty acids, in the slurry. Nitrification of the applied NH₄-N was fast and complete by 3 weeks from application, and at this time, the maximum immobilization of slurry NH₄-N into the microbial biomass (23% of applied ¹⁵NH₄-N) was also observed, although no significant increase in total microbial biomass was observed. Rapid turnover of the microbial biomass quickly diluted the assimilated ¹⁵N, with only 6% of applied ¹⁵NH₄-N remaining in the microbial biomass by next spring. Downwards transport of nitrate was rapid in spite of lower than normal precipitation, and slurry-derived ¹⁵NO₃-N appeared in ceramic suction cups installed at 60 cm depth already 2 months after slurry application. Due to the unusually low winter precipitation in the experimental year, wheat yields were high, and the recovery of N in above-ground plant biomass derived from slurry NH₄-N at harvest reached 32%. An additional 45% of the applied slurry NH₄-N could be found in the soil to a depth of 100 cm (mostly in organic form in the plough layer), indicating that 23% had been lost by leaching or in gaseous form. It was concluded that although significant immobilization of slurry NH₄-N did occur, this was not sufficient to prevent leaching of slurry-derived N over the winter and that the relatively high recovery of slurry-derived N in the wheat crop was due partly to lower than normal winter percolation and partly to a relatively high rooting depth on this particular site.     

Einfluß des Zeitpunktes der K-Düngung auf die Dynamik des nach der Gülledüngung spezifisch gebundenen NH4-N der Tonminerale*

Influence of the time of K fertilization on the dynamics of NH₄-N fixed by clay minerals after slurry application In a pot experiment with topsoil and subsoil of a luvisol derived from loess the influence of the time of K fertilization on the fixation of NH₄-N supplied with slurry as well as on the leaching and the availability of NH₄-N fixed by clay minerals after slurry application was investigated. The following results were obtained: In both soils K fertilization before slurry application resulted in a reduced fixation of the added NH₄⁺.In the topsoil 8 % of the NH₄⁺ supplied with the slurry could be detected in spring as nonexchangeable NH₄⁺ when slurry was added in October and 13 % when slurry was added in January in the treatment K after slurry, when in the treatment K. before slurry the NH₄⁺ fixed after slurry application had been mobilized totally. In the subsoil 45 % of the NH₄⁺ fixed after slurry application in October were mobilized until spring in the treatment K before slurry and only 20 % in the treatment K after slurry. When slurry was applied in January 30 % and 12 %, respectively, were mobilized. In spite of the reduced nitrogen leaching in the treatments K after slurry yield and N uptake of grass were lower as compared to the treatments K before slurry.     

根区温度对黄瓜幼苗生长和光合特性的影响

试验对日光温室黄瓜幼苗进行了不同根区温度处理。结果表明,与适温处理(ck)相比,亚适温和低温处理降低了黄瓜幼苗的株高、茎粗、叶面积、地上部干重和全株干重,而增加了地下部干重和根冠比,降低了黄瓜幼苗叶片叶绿素含量、光合速率、蒸腾速率、气孔导度和胞间CO2浓度。     

浮床栽培鱼腥草对吉富罗非鱼养殖池塘水质的影响

为研究浮床栽培鱼腥草(0、5%、10%和15%种植面积)对吉富罗非鱼养殖池塘的水质净化作用,测定了NH_4+~-N、NO_3~--N、NO_2~--N、TN、TP、CODMn等主要水质指标。结果表明,在同样的试验条件下,7—8月份鱼腥草处理组NO_3~--N下降,与此同时带来了NH_4~+-N(除5%处理组)和NO_2~--N的上升。9月份浮床栽培鱼腥草对5种水质指标的平均去除率在3%~38%之间。5%鱼腥草种植面积适合进行中试。通过鱼腥草的采收,5%鱼腥草处理组叶、根茎的产量分别可达112.4、1619.2 kg/hm~2,且可从养殖水体带走0.38 g/m~2的总氮,0.06 g/m~2的磷元素;同时收获鱼总重和所测生物学指标(除体重)显著高于对照和其他处理组,且对成活率和饵料系数无多大影响。     

Ein Beitrag zur Stickstoffwirkung nach unterschiedlichen Verfahren stabilisierter Klärschlämme*

A distribution to the availability of the nitrogen in sewage sludges stabilized with different processes In two pot experiments the availability of the nitrogen in sewage sludges stabilized with different processes was investigated. Further it was examined whether the Quantofix-N-Volumeter (method for rapid determination of ammonia in slurries) is able to determine the plant available nitrogen in sewage sludge. The following results were obtained: In the experiment where same amounts of total N were applied as sewage sludge a highly significant correlation existed between the amount of NH₄-N applied and the N uptake of the plants. When equal amounts of NH₄-N were applied the N uptake was lowest with the sewage sludges with a high relative part of NH₄-N of the total N (thermophile-aerob; mesophile-anaerob). However the reason for this result was not only the lower application rate of total N with these sewage sludges but also the lower efficiency of the organically bound nitrogen. A very highly significant correlation existed between the application rate of organically bound nitrogen and the N uptake. The values of nitrogen in sewage sludges measured by the rapid method gave information about the plant available nitrogen in the year of application. A close quantitative agreement existed between the available nitrogen determined with the rapid method and the values calculated with the formula of Furrer and Bolliger (1978).     

施氮量对晋南旱地冬小麦光合特性、产量及氮素利用的影响

在自然降水条件下,通过2年大田试验研究了施氮量对晋南旱地冬小麦光合特性、产量、氮素利用效率以及0~200 cm土层NO₃-N残留的影响。结果表明,在0~270 kg hm^-2施氮量范围内,随施氮量的增加,旗叶的净光合速率和叶绿素含量增加,气孔导度增大,胞间二氧化碳浓度降低,旗叶蒸腾速率显著提高; 但施氮量超过180 kg hm^-2时,除蒸腾速率外其他光合指标均无显著变化。N180处理的氮素当季回收率及氮素农学效率均最高,且显著高于N90处理。生物产量以N270处理最高,且与其他处理差异显著; 但施氮量超过180 kg hm^-2时,氮素营养对籽粒产量不再有显著贡献。从产量构成因素来看,提高穗数和穗粒数是增加当地旱作小麦籽粒产量的关键。施氮量90~270 kg hm^-2会造成土壤NO₃-N的残留,残留量占施氮量的35%左右,其中20~40 cm和40~60 cm土层出现NO₃-N积累峰值,NO₃-N残留会导致氮素淋失风险增加及产量对氮肥反应不明显。综合考虑光合特性、产量、氮素利用率和NO₃-N残留量,当地旱作冬小麦施氮量以180 kg hm^-2左右为宜。