东北地区春玉米临界氮浓度稀释曲线的建立和验证

过量施氮是目前玉米栽培中存在的普遍现象,基于临界氮浓度稀释曲线计算得出的氮营养指数是诊断氮营养丰缺的重要手段。基于东北地区4个生态点的试验数据,构建了东北地区春玉米临界氮稀释曲线,并在此基础上建立了氮营养指数模型和需氮量模型,结果表明,东北地区春玉米地上部临界氮浓度与生物量符合幂函数关系。利用独立试验资料对建立的临界氮浓度稀释曲线进行检验,发现基于临界氮浓度稀释模型计算的氮营养指数可以准确诊断玉米植株的氮营养状况,并计算出实时的氮素需求量。该研究建立的东北地区春玉米临界氮稀释模型可以为该地区春玉米的氮营养诊断和动态调控提供较好的理论和技术指导。     

有机生态栽培基质配比对生菜生长及品质的影响

以传统基质草炭、蛭石及腐熟羊粪和玉米秸秆为原料,配制成12种不同配比的栽培基质,以商品叶菜类栽培基质作为对照,研究不同基质配方对生菜生长的影响,以期获得最适合生菜栽培的基质配比组合。结果表明,不同组合基质配比均能满足生菜的正常生长,所有处理的株高、叶面积、单株鲜重和单株干重都较对照组(CK)有着不同程度提高,其中T11(草炭∶腐熟羊粪∶玉米秸秆∶蛭石=1∶4∶3∶4)条件下各指标表现最好,分别较CK提高了31.80%、47.15%、59.43%和79.53%;从生理生化指标来看,T11处理的Vc含量最高,是CK的2.5倍;T10(草炭∶腐熟羊粪∶玉米秸秆∶蛭石=3∶1∶4∶4)的根系活力是所有处理中最高的,达到CK的2.02倍;T12(草炭∶腐熟羊粪∶玉米秸秆∶蛭石=3∶4∶1∶4)处理的叶绿素含量最高,是CK的1.41倍,硝酸盐含量最低,较CK降幅达到74.59%。通过隶属函数进行综合比较分析,我们认为T11是所有供试处理中最适合生菜栽培的基质配比。     

pH 值与金属离子浓度对多种果蔬植物色素的影响

从植物中提取的天然色素对pH值与金属离子浓度的敏感度不同,所受影响也不同。主要选取黄皮果皮色素、赤豆皮色素、柑桔皮色素、勾儿茶果、红雪茶色素,来测定pH值对它们的影响。选取,黄皮果皮色素、赤豆皮色素、勾儿茶果色素、红雪茶色素来测定金属离子浓度对他们的影响,从而探讨这些色素对pH值与金属离子的稳定性。     

自动施肥系统开发与性能测试

目的 开发一种适应于以固态水溶肥为原料的自动施肥系统,测试分析自动施肥系统性能。方法 主控机采用ARM9电路控制模块可实现对轮灌编组、预搅拌时长、施肥开始与结束时间、施肥持续时长、施肥量等参数的设置;选择以蠕动泵为注肥装置,通过变频器控制注肥泵电机功率的方式控制注肥速率,控制施肥量。对装置核心部件搅拌器额定功率、计量方式、溶肥搅拌参数、排肥速度及固液相比例等主要参数等进行设计与测试。结果 电感脉冲计量方式标准误差最大值1.26%,误差小、性价比好,确定其为本装置采用的计量方式;搅拌器以1.5 Kw额定功率、38 r/min转速搅拌、肥液浓度在1.1~1.3 g/mL、预搅拌时间30 min时,罐内各液位输出肥液浓度值差异不显著(P< 0.05),达到对肥料浓度均匀性的设计要求。结论 将施肥开始前的预搅拌时间设为30 min、搅拌转速设为38 r/min、肥液浓度不高于1.3 g/mL,输出肥液浓度有较好的均匀性,实现精准施肥。     

Soil available potassium affected by rice straw incorporation and potassium fertilizer application under a rice–oilseed rape rotation system

Data from 147 field trials were collected to study the influence of straw incorporation on soil potassium (K) under an intensive rice–oilseed rape rotation system, while pot experiments were conducted to evaluate the effects of rice straw incorporation on soil K availability. A significant correlation was observed between the soil available K and the relative yield (RRY) and the relative K uptake (RKU) of oilseed rape, with R² values ranging from 0.07 to 0.08 and from 0.10 to 0.11, respectively, when data were fitted to a logarithmic equation model. In approximately 30% of trials, RRY reached 90%, while soil test available K values were below the critical limit, indicating that soil K values at the time of sampling (within 1 week of rice harvest) underestimated the actual soil K supply capacity. The pot experiment results showed that soil available K was affected by straw incorporation and soil type in the fallow period. The NH₄OAc‐K and NaBPh₄‐K concentrations of soils increased at first, and then, plateaued after 28 days. Straw incorporation significantly influenced the critical soil K concentration, which is important for making accurate K fertilizer recommendation. These results suggested that straw K should be seriously considered in making K fertilizer recommendations. Extending the sampling time from 1 to 3 weeks after the harvesting of rice to stabilize the effects of straw incorporation may help achieve a more accurate evaluation of soil available K.     

In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.     

Dynamic change of mineral nutrient content in different plant organs during the grain filling stage in maize grown under contrasting nitrogen supply

The introduction of new hybrids and integrated crop-soil management has been causing maize grain yield to increase. However, less attention has been paid on the nutrient concentration of the grain; this aspect is of great importance to supplying calories and nutrients in the diets of both humans and animals worldwide. Increasing the retranslocation of nutrients from vegetative organs to grain can effectively increase the nutrient concentration of grain and general nutrient use efficiency. The present study involved monitoring the dynamic change of macro- and micronutrients in different organs of maize during the grain filling stage. In addition, the mobility of different elements and their contribution to grain nutrient content were evaluated in a 2-year experiment under low (LN, no N supplied) and high N (HN, 180 kg N ha⁻¹) supply. Under HN supply, the net remobilization efficiency (RE) of the vegetative organs as a whole (calculated as nutrient remobilization amount divided by nutrient content at silking) of N, P, K, Mn, and Zn were 44%, 60%, 13%, 15%, and 25%, respectively. The other nutrients (Mg, Ca, Fe, Cu, and B) showed a net accumulation in the vegetative organs as a whole during the grain filling stage. Among the different organs, N, P, and Zn were remobilized more from the leaves (RE of 44%, 51% and 43%, respectively) and the stalks (including leaf sheaths and tassels) (RE of 48%, 71% and 43%, respectively). K was mainly remobilized from the leaves with RE of 51%. Mg, Ca, Fe, Mn, and Cu were mostly remobilized from the stalks with the RE of 23%, 9%, 10%, 42%, and 28%, respectively. However, most of the remobilized Mg, Ca, Fe, Mn, Cu, and Zn were translocated to the husk and cob, which seemingly served as the buffer sink for these nutrients. The REs of all the nutrients except for P, K, and Zn were vulnerable to variations in conditions annually and were reduced when the grain yield and harvest index were lower in 2014 compared with 2013. Under LN stress, the RE was reduced in P and Zn in 2013, increased in Cu and unchanged in other nutrients. The concentration of these nutrients in the grain was either unchanged (P, K, Ca, Zn, and B) or decreased (N, Mg, Fe, Mn, and Cu). It is concluded that grain N, P, K, Mn, and Zn, but not Mg, Ca, Fe, Cu, and B concentration, can be improved by increasing their remobilization from vegetative organs. However, enhancing the senescence of maize plant via LN stress seems unable to increase grain mineral nutrient concentration. Genetic improvement aiming to increase nutrient remobilization should take into account the organ-specific remobilization pattern of the target nutrient.     

重庆南温泉洗浴废水用作植物灌溉水的可行性研究

重庆市温泉资源丰富,温泉洗浴废水运用于绿地灌溉可以节约成本,缓解城市的水危机。温泉洗浴废水对植物生长有正负两方面的影响,与植物的种类,温泉洗浴废水的水质等因素有关。实验以重庆市常见的两种绿地植物——冷水花木春菊为研究对象,对温泉洗浴废水中影响植物生长的pH、固体悬浮物、高锰酸钾,总溶解性固体4个常见指标进行了浓度值对比实验。运用对相对电导率拟合Logistic方程求半致死浓度值的方法,确定绿地植物所能耐受的上限阀值。以此为基础对温泉废水进行相关处理,使温泉废水既可以达到灌溉绿地的水质标准,又能最大限度地降低废水处理成本,从而充分利用水资源。     

基于田间空气中病菌孢子浓度的小麦白粉病病情估计模型研究

2014和2015两年度利用Burkard定容式孢子捕捉器监测了高感小麦白粉病品种京双16种植区和中感品种众麦2号种植区田间空气中的病菌孢子浓度变化动态,同时利用小型气象站监测了田间的气象因子,通过分析京双16和众麦2号种植区空气中孢子浓度与空气温度、湿度、降雨、风速和太阳辐射率的相关性,发现空气中的孢子浓度主要与空气温度呈显著的正相关性(r0.348 3,P0.05)。在此基础上,分别分析了田间病情与调查日期前累积孢子浓度、一周前累积孢子浓度、前一周累积孢子浓度和当周累积孢子浓度的关系,结果表明,中感品种众麦2号田间病情与累积孢子浓度的关系均呈指数关系,其中田间病情与调查日期前累积孢子浓度或一周前累积孢子浓度的拟合效果最好,而感病品种京双16的田间病情与累积孢子浓度多呈对数关系,其中病情指数与一周前累积孢子浓度的拟合效果最好。     

Effect of the Substrates on the Production of Engrafted Vine Cuttings in Heated Greenhouses

This article highlights the results of a long-term research project on the production of grape stalks engrafted by the desk method. The integrated impact of rootstock varieties, modes of stratification, and different substrates on vegetating vine cuttings, raised in heated greenhouses, and the capacity of their acclimatization after planting was studied. The results of the research show that rootstock variety and modes of stratification influence the output of engrafted vegetating cuttings of vines grown in pots using various substrates. In particular, the engrafted cuttings of variety Rkatsiteli produced on two rootstocks, 5 BB and 101-14, passed stratification (a) in sawdust with local electroheating, (b) on the water with its periodic change, and (c) in the layer of perlite. After preplanting preparations they were planted in pots with six different substrates: (1) soil (control); (2) perlite; (3) sawdust; (4) rice husk + soil + sand (1:1:1); (5) peat + soil + sand (1:1:1); and (6) mold + soil + sand (1:1:1). The cuttings were grown with a covered root system in a heated greenhouse for 35–40 days. Forty-day-old vegetating cuttings, after hardening, were planted into the open ground. Specialties were established during the root and shoot formation on vegetating nursery plant grafts during the rooting period. Optimal substrates for growing engrafted cuttings with a covered root system in heated greenhouses for each rootstock and stratification mode were determined.