The effect of various nitrogen fertilization and foliar nutrition regimes on the concentrations of nitrates,ammonium ions,dry matter and N-total in carrot (Daucus carota L.) roots

Two field experiments (Experiment I in 2003–2005 and Experiment II in 2004–2005) with carrot c.v. ‘Kazan F₁’ were conducted at Trzciana village (50°06′N, 21°85′E). The experiments were arranged in a split-plot design with four replications. Two sub-blocks were identified in both experiments: I, without foliar nutrition; II, receiving plant foliar nutrition. The plants were sprayed three times alternately with: 2% urea solution, 1% solution of multi-component ‘Supervit R’ fertilizer (produced by Intermag, Poland) and again with 2% urea solution. Combinations with diversified nitrogen fertilization were distinguished within both sub-blocks. Experiment I comprised of: (1) Control, (2) Ca(NO₃)₂ 70, (3) Ca(NO₃)₂ 70 + 70, (4) (NH₄)₂SO₄ 70 and (5) (NH₄)₂SO₄ 70 + 70. Experiment II included: (1) Control, (2) ENTEC-26 35 + 35, (3) ENTEC-26 70 + 70, (4) ENTEC 26 105 + 105, (5) NH₄NO₃ 35 + 35, (6) NH₄NO₃ 70 + 70, (7) NH₄NO₃ 105 + 105. Where 70 kg N ha⁻¹ was used before sowing, whereas 35 + 35, 70 + 70 and 105 + 105 kg N ha⁻¹ were applied before sowing and as top dressing. Solid nitrogen fertilizer was added to the soil (produced by): Ca(NO₃)₂, Yara International ASA (Hydro); (NH₄)₂SO₄, Zak?ady Azotowe in Tarnów, Poland; NH₄NO₃, Zak?ady Azotowe in Pu?awy, Poland; and ENTEC-26, COMPO GmbH & Co. KG, Germany. The research aimed at determining the effect of diversified nitrogen fertilization and foliar nutrition on NO₃⁻, NH₄⁺, N-total and dry matter (d.m.) concentrations in carrot, and N uptake by storage roots. In Experiment I, nitrogen fertilization did not affect NO₃⁻ concentration, whereas in Experiment II, the applied N treatment increased NO₃⁻ concentration in carrot in relation to the control, except for the storage roots of plants fertilized with ENTEC-26 35 + 35. Nitrogen fertilization applied in both experiments caused a significant increase in N-total concentration in carrot and N uptake by storage roots in comparison with the control plants. In both experiments, nitrogen fertilization had a different effect on the concentrations of NH₄⁺ and d.m. in carrot. What is more, foliar nutrition treatments in both experiments had a different effect on the concentrations on NO₃⁻, N-total, d.m. in carrot and N uptake by carrot storage roots.     

杉木新造幼林施肥方案优选的初步研究

杉木新造幼林不同施肥方案的试验结果表明,施肥对杉木新造幼树生长具有明显的促进作用。经多目标决策分析确定,造林前施基肥钙镁磷600 kg.hm-2、造林当年追肥施复合肥180 kg.hm-2为最佳施肥方案,其次为施基肥钙镁磷600 kg.hm-2、追肥施尿素180 kg.hm-2。生产上可根据实际情况选择应用。     

施肥量对水稻准两优527产量和营养动态的影响

贵州省黔南苗族布依族自治州属于中国西部丘原山地，平均海拔1100m，岩溶地貌发育典型，土壤贫瘠且宜耕作性较差，耕作粗放，作物的产量一直不高。农民为了提高作物的产量，大量施用无机肥料，肥料利用效率逐步降低，而且肥料的大量施用已经引起了严重的环境问题，因此合理运筹肥料是提高肥料利用率、减少污染的重要措施。     

大面积用材林代化栽培模式技术

林业生产要达到当今经济技术条件下最大限度的速生、丰产、优质、高效稳定和持续，不仅要有良种壮苗，还要做好造林地调查与规划，做到适地适树、适时适法，这是实现林业优化栽培模式的前提与保证；同时，造林树种选择、造林时间、密度确定、种植点配置、栽培方法、林木施肥、营造混交林以及森林保护、造林地设保护带、造林地留栽补植苗，这一系列均是用材林优化栽培模式的重要技术措施。     

外源人绒毛膜促性腺激素诱导黑边石斑鱼排卵的研究

【目的】了解外源人绒毛膜促性腺激素(human chorionic gonadotropin,HCG)诱导黑边石斑鱼(Epinephelus fasciatus)排卵的影响。【方法】以成熟的黑边石斑鱼为研究对象,测量其体长、体质量和肥满度后,在2018年7—8月,使用HCG激素(剂量为200 IU/kg或500 IU/kg)注射分别对6尾雌鱼进行成熟诱导。【结果】在200 IU/kg HCG处理中,注射24 h前有5尾雌鱼的卵母细胞处于第三次卵黄球前期阶段;注射48 h后2尾雌鱼出现核移动卵母细胞,1尾雌鱼的卵母细胞为第三次卵黄球后期阶段;注射60 h后1尾雌鱼出现排卵现象,其余5尾雌鱼均为第三次卵黄球后期阶段。在200 IU/kg HCG处理的排卵个体中,注射时其卵母细胞直径为477.0 μm,注射后60 h卵母细胞的直径增加至624.4 μm。此外,经催产、排卵、受精和孵化后共获得总卵数16 906粒,受精率为68.7%,孵化率为43.0%。而500 IU/kg HCG处理的黑边石斑鱼排卵失败。【结论】使用剂量为200 IU/kg的外源HCG激素可诱导黑边石斑鱼成熟且排卵,但为了提高排卵率、受精率和孵化率,其注射剂量和效应时间还需要进一步调节。     

高寒半干旱区油菜与豆科牧草混播草地施肥效应

油菜与豆科牧草混播草地施肥效应表明，氮磷合理配施促进土壤水分消耗，干草、植物量和施肥产投比显著提高。坡梁地最高植物产量施肥量Ｎ为７８．０６ｋｇ／ｈｍ２，Ｐ２Ｏ５为６１．１５ｋｇ／ｈｍ２，最高干草产量施肥量Ｎ为７６．６５ｋｇ／ｈｍ２，Ｐ２Ｏ５为５７．２９ｋｇ／ｈｍ２，增产效果Ｎ＞Ｐ２Ｏ５；旱滩地最高植物产量施肥量Ｎ为５８．３３ｋｇ／ｈｍ２，Ｐ２Ｏ５为５５．６８ｋｇ／ｈｍ２，最高干草产量施肥量Ｎ为５３．６０ｋｇ／ｈｍ２，Ｐ２Ｏ５为５９．１１ｋｇ／ｈｍ２，增产效果Ｐ２Ｏ５＞Ｎ；且氮磷具有明显的正交互效应。氮磷合理配施还显著提高了水分利用效率，坡梁地和旱滩地分别提高３．０５和２．６７ｋｇ／（ｍｍ．ｈｍ２）。     

云南陇川农场甘蔗测土配方施肥效应

试验测定分析162份蔗区土壤样品的氮、磷、钾，有机质，pH值和其中16份样品中的铁、铜、锌、锰4种微量元素。结果表明：碱解氮49.85-307.41mg／kg，有效磷0.9-48.35mg／kg，有效钾26.09-625.78mg／kg。有机质0.84-10.48％，pH值4.32-6.15。有效铁23.64-118.36mg／kg，有效铜0.03-1.17mg／kg，有效锌0.18-1.85mg／kg，有效锰0.11-25.59mg／kg。结合蔗区土壤养分分析，连续两个榨季应用配方施肥，甘蔗增产12.75-15.75t／hm^2，蔗糖分提高0.23％-0.48％，出糖率提高0.14％-0.47％。     

施肥对苜蓿土壤水分、养分和产量的影响:基于定位试验数据的Meta分析

为探究提高苜蓿(Medicago sativa)产量和改善土壤肥力性质的施肥措施,本研究以中国为研究区域,以不施肥苜蓿为对照,通过检索文献整合已发表的相关田间试验数据,采用整合分析方法(Meta-analysis),系统探究施肥措施对苜蓿地土壤水分、养分、产量和水分利用效率的影响.结果表明,施肥可有效增加苜蓿土壤养分含量并提高苜蓿产量,但增加的地上生物量也影响了苜蓿对土壤水分的消耗,其中土壤有机质和全氮含量分别增加了3.1％～33.3％和4.5％～30.9％,土壤速效磷和速效钾含量分别提高了3.6％～144.4％和4.4％～24.8％,土壤水分下降了4.4％～11.8％.与不施肥相比,施肥措施下苜蓿增产率达到15.4％～198.2％,水分利用效率提高了5.9％～169.6％.进一步相关分析表明,苜蓿产量与0-200 cm土壤水分、有机质和速效磷含量均呈极显著正相关关系(P<0.01),苜蓿水分利用效率与土壤速效磷含量呈极显著正相关关系(P<0.01).综上,施肥可有效增加土壤养分含量并提高苜蓿产量,其中化肥和有机肥配施表现出的增产作用最为突出,化肥配施对苜蓿水分利用效率的提升效应最佳.该研究可为苜蓿种植过程中适宜施肥措施的选择提供理论依据.     

时滞recurrent神经网络模型的全局渐近稳定性

讨论了时滞recurrent神经网络模型的全局渐近稳定性,通过构造适当的Lyapuov函数,利用线性矩阵不等式,给出了一类常时滞recurrent神经网络的新的充分条件,所获的稳定性条件是时滞相关的,稳定性判别条件更宽松.最后通过一个实例说明方法的可行性.