柳枝浸提液对小麦籽粒发芽的抑制作用研究

研究了柳树枝叶浸提液对小麦籽粒发芽的抑制效应，结果表明：抑制作用的大小随浸提时间和浸提液浓度的不同而异，煎煮时间对小麦种子发芽抑制强度依次为4h〉3h〉2h〉0．5h，浸提液不同浓度的抑制效果为280g／L〉200g／L〉120g／L〉40g／L。     

潮州产13种野菜中硝酸盐和亚硝酸盐的含量

根据潮州产13种野菜中硝酸盐和亚硝酸盐含量的测定结果,参考蔬菜中硝酸盐含量分级评价标准和我国的无公害蔬菜亚硝酸盐含量限量标准(≤4.0mgkg),对13种野菜的品质进行了评价。结果显示,菜、酢浆草、野茼蒿、黄鹌菜和腋花蓼硝酸盐含量低于轻度污染水平,亚硝酸盐含量低于我国制定的无公害蔬菜亚硝酸盐含量的限量标准(≤4.0mgkg),属于一级无公害野菜,可以安全食用;少花龙葵、马齿苋、鳢肠、叶下珠、铁苋菜、小藜和牛繁缕的硝酸盐含量高于432mgkg,而低于785mgkg,亚硝酸盐含量低于限量标准(≤4.0mgkg),属于二级野菜,不宜生食,煮熟和盐渍可安全食用;鼠曲草的硝酸盐含量高于785mgkg,低于1440mgkg,属于三级野菜,不可生食和盐渍,可熟食。     

4种荚蒾属植物种子内源抑制物存在特征初探

通过荚蒾种子浸提液对小白菜种子萌发的抑制作用,分析探讨荚蒾种子内源抑制物主要存在部位及其可溶性化学特征,为荚蒾属植物种子破除休眠提供科学依据。实验结果表明:4种荚蒾种子水和甲醇浸提液对小白菜种子萌发和胚根生长都有抑制作用,种皮水溶性抑制物活性:蒙古荚蒾朝鲜荚蒾暖木条荚蒾鸡树条荚蒾,胚乳水溶性抑制物活性:蒙古荚蒾鸡树条荚蒾暖木条荚蒾朝鲜荚蒾;种皮脂溶性抑制物活性:暖木条荚蒾蒙古荚蒾朝鲜荚蒾鸡树条荚蒾,胚乳脂溶性抑制物活性:鸡树条荚蒾朝鲜荚蒾蒙古荚蒾暖木条荚蒾。鸡树条荚蒾、朝鲜荚蒾、暖木条荚蒾内源抑制物主要是脂溶性物质,前两者较集中分布于胚乳,后者多存在于种皮;蒙古荚蒾以胚乳中水溶性抑制物为主。     

The effect of plastic mulch on the fate of urea-N in rain-fed maize production in a semiarid environment as assessed by 15N-labeling

A better understanding of the fate of fertilizer nitrogen (N) is critical to design appropriate N management strategies in plastic-mulched croplands. We evaluated the effects of plastic mulch on urea-N recovery by crops and loss from soil in furrow-ridge plots, with and without maize (Zea mays L.) cropping, in a semi-arid rain-fed site in China. We applied the same rate of urea-N (281 kg ha⁻¹) to all treatments during the preparation of the furrow-ridges in 2011 and 2012 but ¹⁵N-labeled the urea in 2011 only. We used transparent film to cover all soil surfaces in the mulched treatments and seeded maize in furrows in treatments with crop. In 2011, plastic mulch increased the total N uptake in the aboveground biomass of maize by 53%, whereas it decreased the in-season labeled-N uptake by 19%, compared to non-mulched treatment. At harvest in 2011, in mulched treatments the total labeled-N remaining in the 0−170 cm soil layer was 25% greater whereas unaccounted labeled-N was 69% less, than in non-mulched treatments, regardless of whether maize was cropped. In 2012 the effect of mulch on total maize N uptake was comparable to that in 2011, but the residual soil labeled-N uptake by maize was 63% higher in mulched compared to non-mulched treatment. At harvest in 2012, plastic mulch increased total labeled-N remaining in the 0−170 cm depth in cropped soils and unaccounted labeled-N in non-cropped soils, compared with no mulch. Our results indicate that plastic mulch profoundly changes the fate of urea-N in maize production in cold and dry croplands.     

真空碳热还原酸浸含钛高炉渣制备TiC分析

含钛高炉渣中含有20%~30%的TiO 2,是一种附加值较高的二次资源,但在综合利用过程中存在氧化物还原难度大,硅钛难分离,二次污染严重等问题。基于热力学理论基础,采用真空碳热还原联合酸浸工艺处理含钛高炉渣制备TiC。结果表明：真空有助于钛氧化物彻底还原,可实现渣中硅钛彻底分离,减少酸耗量,降低二次污染。真空碳热还原联合酸浸工艺处理含钛高炉渣(TiO 2含量23%左右)制备TiC的最佳条件为：炉渣粒度200目,还原温度1 673 K,渣碳质量比100∶38。     

Screening techniques and improved biological nitrogen fixation in cool season food legumes

Dinitrogen fixation and legume productivity are greatly influenced through the interactions of legume host, Rhizobium, and the above- and below-ground environment. The benefits of improving legume N₂ fixation include reduced reliance on soil N, leading to more sustainable agricultural systems and reduced requirements for fertilizer N, enhanced residual benefits to subsequent crops, and increased legume crop yields. Most of the gains in N₂ fixation to date have been derived from management of legume cropping systems and through inoculation of legume seed with competitive and symbiotically effective rhizobia. Further gains are possible by developing plant cultivars with tolerance to soil abiotic factors, increased plant yield, and a broader and more effective matching of plant host and rhizobia. Techniques for screening material for superior N₂ fixation and examples of programs to increase fixed N, with attention to the major abiotic stresses, are discussed.     

某硫矿重金属分级及土柱淋溶

Fractions of various heavy metals in a sulfidic minespoil were investigated.Column leachine experiment was also conducted to simulate “acid mine drainage“(AMD) from the minespoil.The results show that leaching of heavy metals from the minespoil was extremely significant during the initial water flushing.The amounts of heavy metals leached out dramatically reduced after leaching twice.It is worthwhile to note that in this study,Zn,Mn,Fe,As and Ni in the first leachate exceeded the total amount of each corresponding water-extractable(1:5,soil:water)metal contained in the minespoil sample.This appears to suggest that 1:5 water extraction did not allow accurate estimation of water-leachable concentrations of the above heavy metals.This work has implications for the management of sulfidic minespolis.Acid drainage of great environmental concerns is likely to occur only during heavy rainfall events after substantial soluble and readily exchangeable acid and metals are accumulated in the minespoils.The slow-reacting fractions other than water-soulble and readily exchangeable fractions may pose little environmental hazards.This is particularly true for Pb,As and Ni.     

水分调节剂DY-ET100对番茄产量、品质及水氮在土壤中扩散的影响

为解决水分在土壤中横向扩散范围小和硝态氮淋溶等问题,以水分调节剂DY-ET100为供试材料,以清水、渴以友为对照,研究和对比了水分调节剂DY-ET100的添加对水分在不同土壤中的扩散情况及对硝态氮淋溶和番茄产量及品质的影响。结果表明,在掺沙和未掺沙黏土中添加水分调节剂DY-ET100较清水处理番茄果实中VC含量分别显著提高12.50%和20.51%;添加DY-ET100的处理使距滴头0～30 cm范围内的水分在土壤中分布更加均匀,滴灌时水分扩散半径较清水和渴以友分别增加22.53%和12.33%;在掺沙和未掺沙黏土中较清水处理硝态氮累积量增加41.21%和18.83%;同时减少硝态氮的淋溶损失量,在掺沙和未掺沙黏土较清水处理硝态氮淋溶损失降低7.53%和8.07%。研究为水分调节剂的使用推广提供了数据支撑。     

厩肥对粉煤灰微量元素释放规律影响的研究

该文对粉煤灰在降雨淋洗条件下微量元素的释放规律进行了室内模拟试验。试验处理分别为粉煤灰、粉煤灰+石灰、粉煤灰+石灰+厩肥及其混合物的堆肥腐熟4种情况。实验结果显示淋出液中B、Sr、Ba和Li的最大浓度大于1 mg/L，而其它元素均小于此值。石灰的应用增大了淋出液中B和Ba的浓度而降低了Li、Mo和Cr的浓度；厩肥的应用及其堆肥腐熟处理增大了B、Mo、Zn、V以及Cu、Ni、Cd、As、Mn、Ti、Co、Sn和Se的浓度，而降低了Sr、Ba、Li和Cr的浓度。除V外，淋出液中所有微量元素的浓度随淋出液体积的增加而减小。Cr、Zn以及Cd、Cu和As可能是粉煤灰对环境产生潜在危害的主要元素。     

Yield and nitrogen use efficiency of bell pepper grown in SLAB fertigated with different nitrogen rates

Abstract

Adequate plant nutrition is important to reduce costs and increase the crop yield. This study tried to verify the influence of Nitrogen (N) on plant biomass production and the yield of bell pepper grown in SLAB; quantify the N use efficiency (NUE), and to quantify the residual N concentration in the substrate after the end of the crop cycle. The experiment was carried out in a protected environment. Pepper seedlings were transplanted to SLAB bags containing 40?dm³ of substrate. The treatments consisted of six N rates (0, 1.5, 3.0, 4.5, 6.0, and 7.5?g plant^?1) split into 10 fortnightly applications, in a randomized block design with four replications. The fruit yield was evaluated throughout the experiment and after the final harvest, the dry mass of leaves, stem, and root of the plant, the N content and accumulated, the residual nitrate and ammonium in the substrate, and the NUE were evaluated. The rate of 5.51?g plant^?1 of N, corresponding to 355.5?kg ha^?1, provided the maximum yield of commercial fruits of 1.57?kg plant^?1 or 101.2 t ha^?1. With increasing N rate, the residual nitrate concentration in the substrate increased and the NUE decreased.