小麦/玉米垄沟套作条件下施肥部位对土壤水氮分布的影响--测试文章

通过旱棚小车模拟小麦/玉米垄沟套作种植试验,研究了3种不同垄沟部位（垄顶、垄底和沟中）施肥对小麦/玉米生长和产量及土壤水氮分布的影响。结果表明：相同灌水条件下,施肥部位对垄沟套作水分分布影响不显著,但土壤硝态氮的分布差异较大; 垄顶施肥和垄底施肥处理下,由于水肥异区,其垄上小麦生长带的硝态氮主要分布在0～30 cm土层,有效地减少了硝态氮向土壤深层淋溶,而后期沟内玉米生长带的水氮处理相同,因此其硝态氮分布差异较小; 在相同灌水条件下,垄沟套作可以有效降低水分流失,减少氮肥损失,因此较传统平作更有利于作物生长,提高小麦、玉米的产量,且以垄顶施肥和垄底施肥效果最显著,小麦产量较平作分别增加11.47%、10.81%,玉米产量较平作分别增加18.87%、22.70%。     

配方肥在小麦上的应用

通过田间试验探讨了施用不同配比的配方肥对小麦产量、经济效益的影响。结果表明,18-20-7缓控释肥配方肥增产效果明显,经济效益显著,每667 m~2产量及经济效益较普通复合肥处理分别提高12.2%和102.2元。可为配方肥在小麦上合理施用提供依据和技术指导。     

Crop yield, nitrogen uptake and nitrate-nitrogen accumulation in soil as affected by 23 annual applications of fertilizer and manure in the rainfed region of Northwestern China

Application of chemical fertilizers and farmyard manure affects crop productivity and improves nutrient cycling within soil–plant systems, but the magnitude varies with soil-climatic conditions. A long-term (1982–2004) field experiment was conducted to investigate the effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizers and farmyard swine manure (M) on seed and straw yield, protein concentration, and N uptake in the seed and straw of 19-year winter wheat (Triticum aestivum L.) and four-year oilseed (three-year canola, Brassica napus L. in 1987, 2000 and 2003; one-year flax, Linum usitatisimum L. in 1991), accumulation of nitrate-N (NO₃-N) in the soil profile (0–210 cm), and N balance sheet on a Huangmian soil (calcaric cambisols, FAO) near Tianshui, Gansu, China. The two main plot treatments were without and with farmyard swine manure (M); sub-plot treatments were control (Ck), N, NP, and NPK.␣The average seed yield decreased in the order MNPK ≥ MNP > MN ≥ NPK ≥ NP > M > N > Ck. The average effect of manure and fertilizers on seed yield was in the order M > N > P > K. The seed yield increase was 20.5% for M, 17.8% for N, 14.2% for P, and 2.9 % for K treatment. Seed yield response to fertilizers was much greater for N and P than for K, and it was much greater for no manure than for manure treatment. The response of straw yield to fertilization treatments was usually similar to that of seed yield. The N fertilizer and manure significantly increased protein concentration and N uptake plant. From the standpoint of increasing crop yield and seed quality, MNPK was the best fertilization strategy. Annual applications of N fertilizer and manure for 23 successive years had a marked effect on NO₃-N accumulation in the 0–210 cm soil profile. Accumulation of NO₃-N in the deeper soil layers with application of N fertilizer and manure is regarded as a potential danger, because of pollution of the soil environment and of groundwater. Application of N fertilizer in combination with P and/or K fertilizers reduced residual soil NO₃-N significantly compared with N fertilizer alone in both no manure and manure plots. The findings suggest that integrated and balanced application of N, P, and K fertilizers and␣manure at proper rates is important for protecting soil and groundwater from potential NO₃-N pollution and for maintaining high crop productivity in the rainfed region of Northwestern China.     

生态平衡施肥：Ⅱ．施肥参数指标体系

介绍如何确定通用施肥模型的特征参数.研究表明,任何有效的田间肥料试验结果和测土结果都可以作为确定通用施肥模型特征参数的原始数据,在没有上述数据情况下,也可以采取专家经验、访问和调查数据的方法确定施肥特征参数.在此基础上,进一步评述了常见几种施肥模型的优缺点及通用施肥模型与其关系.     

平衡施肥理论与肥料高效利用

结合施肥实践阐述了平衡施肥原理中静态的横向平衡和动态的纵向平衡概念,并提出具有纵向平衡特点的速度复合型控释肥,其养分释放速度能与作物的养分需求基本一致,可显著提高肥料利用率和作物产量。     

刨煤机刨链回转接头的可靠性

刨煤机在工作过程中断链事故经常发生,是影响其生产率的主要因素之一。刨煤机主要通过回转接头来抵消刨链产生的扭矩以防止扭链现象发生,为刨链的易损部件。以虚拟样机技术为基础,解决了载荷提取、材料模型建立、合理添加接触、网格细化等关键技术。在动力学仿真软件ADAMS中对刨煤机进行建模及仿真,得到作用在刨链回转接头上载荷的极值和均值;基于Workbench构建刨链回转接头的仿真模型,并基于两组载荷对模型进行仿真研究。研究发现:在最大载荷作用下,衬套、右挂环可靠性不高;右挂环啮合螺栓段及退刀槽处可能在受到瞬时恶劣载荷冲击时发生断裂,垫环内外圈易发生磨损;在均值载荷作用下,各零件主应力都在许用应力范围内,强度满足设计要求;对刨头运行前方刨链拉力曲线进行频域分析,得知刨头运行前方刨链拉力曲线为一个宽平稳随机信号,其特性主要由煤层各向异性导致的随机刨削力决定。刨链回转接头前两阶模态的固有频率较小,与牵引电机的最大输出频率接近,为易激发模态。研究结果与刨煤机井下试运行的结果基本一致,可见该方法具有较高的准确性,能满足工程实践的要求。     

水肥模式对温室小型西瓜水分利用及光合特性的影响研究

通过田间试验，研究不同灌溉模式与施肥方式对设施栽培条件下小型西瓜水分利用、光合特性以及产量品质的影响。研究结果表明，节水灌溉处理W3可在实现节水50％的基础上获得较高的产量，并且糖分测定结果显示，减少灌水对提高西瓜品质也有益处。根据光合特性分析结果，适当范围内控制土壤水分可促进西瓜的光合速率、气孔导度和蒸腾速率，并提高计算水分利用率。不同施肥处理研究结果显示，适当减少氮肥可明显提高西瓜品质，而磷肥处理与西瓜产量品质的关系不明显，需进一步研究。     

Partial Sperm beta1 Integrin Subunit Deletion Proves Its Involvement in Mouse Gamete Adhesion/Fusion

We have previously shown, using antibodies, that the sperm alpha6beta1 integrin is involved in mouse gamete fusion in vitro. Here we report the conditional knockdown of the sperm Itgb1 gene. It induced a drastic failure of sperm fusogenic ability with sperm accumulation in the perivitelline space of in vitro inseminated oocytes deleted or not for the Itgb1 gene. These data demonstrate that sperm, but not oocyte, beta1 integrin subunit is involved in gamete adhesion/fusion. Curiously, knockdown males were fertile in vivo probably because of the incomplete Cre-mediated deletion of the sperm Itgb1 floxed gene. Indeed, this was shown by Western blot analysis and confirmed by both the viability and litter size of pups obtained by mating partially sperm Itgb1 deleted males with females producing completely deleted Itgb1 oocytes. Because of the total peri-implantation lethality of Itgb1 deletion in mice, we assume that sperm that escaped the Itgb1 excision seemed to be preferentially used to fertilize in vivo. Here, we showed for the first time that the deletion, even partial, of the sperm Itgb1 gene makes the sperm unable to normally fertilize oocytes. However, to elucidate the question of the essentiality of its role during fertilization, further investigations using a mouse expressing a recombinase more effective in male germ cells are necessary.