无土盆栽红掌潮汐灌溉技术

为支撑设施无土盆栽潮汐灌溉技术应用,该文以连栋温室固体基质盆栽花卉-红掌为试材,设置营养液深分别为花盆高的1/2(T1)、1/3(T2)、1/4(T3)、1/5(T4)和传统滴灌供水处理(T5),研究了潮汐灌溉和滴灌对基质含水率、灌溉水利用、红掌品质和耗水的影响。结果表明:与滴灌处理相比较,潮汐灌溉处理基质含水率明显偏高,灌水周期增加1～3d,耗水量增加44.2%～69.3%,红掌株高、冠幅分别增加6.6～11.4和7.3～10.6cm,佛焰苞长、宽分别增加0.8～1.5和0.5～1.8cm,花序高增加0.2～1.0cm。潮汐灌溉营养液深不超过盆高的1/4时,对基质含水率、灌水周期和红掌耗水量影响不明显,超过盆高的1/4后,随营养液深增加,基质含水率显著增加,灌水周期延长,耗水量总体随营养液深增加而增大。潮汐灌溉的营养液深是花盆高的1/5时,红掌观赏品质最优,此时营养液深为2.56cm,是供试潮汐灌溉营养液较优控制深度,灌水周期为3～5d。     

Effects of irrigation and nitrogen management on hybrid maize seed production in north-west China

Scientific irrigation and nitrogen management is important for agricultural production in arid areas. To quantify the effect of water and nitrogen management on yield components, biomass partitioning and harvest index (HI) of maize for seed production with plastic film-mulching, field experiments including different irrigation and N treatments were conducted in arid north-west China in 2013 and 2014. The results indicated that kernel number per plant (KN) was significantly affected by irrigation and N treatments. However, 100-kernel weight was relatively stable. Reducing irrigation quantity significantly increased stem partitioning index (PI_stem) and leaf partitioning index (PI_leaf), and decreased ear partitioning index (PI_ear) at harvest, but lowering N rate (from 500 to 100 kg N·hm^-2) did not significantly reduce PI_stem, PI_leaf, and PI_ear at harvest. HI was significantly reduced by reducing irrigation quantity, but not by reducing N rate. Linear relationships were found between KN, PI_stem, PI_leaf, PI_ear at harvest and HI and evapotranspiration (ET).     

An investigation on second phases in the as-cast Mg-3Al-1Zn-(0-0.5)Sr magnesium alloys

In order to systematically investigate the effect of Sr addition on the second phases in the as-cast AZ31 magnesium alloy and provide the theoretical basis for the design of the Mg-Al-Zn series alloys containing Sr element,the type and formation theory of second phases in the AZ31 as-cast magnesium alloys with low Sr contents(mass friction of 0.1,0.3,and 0.5) are investigated and analyzed by using scanning electron microscope(SEM),energy dispersive spectrometer(EDS),differential scanning calorimetry(DSC),and X-ray diffractometer(XRD). The results indicate that for the AZ31 as-cast alloy without Sr addition,besides the Mg17Al12 phase,the extra Mg21(Zn,Al)17 phase with small amount is found to exist in the alloy. In addition,the difference both in the volume fraction and the type for the second phases in the AZ31 as-cast alloys with different Sr contents is very obvious. The alloys with the addition of 0.1 and 0.3 Sr(mass friction) mainly consists of the α-Mg,Mg17Al12,Mg21(Zn,Al)17 and Al4Sr phases. However,only the α-Mg,Mg21(Zn,Al)17 and Al4Sr phases are observed for the alloy with the addition of 0.5 Sr(mass friction). Otherwise,the volume fraction of the Al4Sr phase with lamella-like sharps increases with the Sr contents increasing among the 0.3-0.5(mass friction) range.     

裂解温度及高锰酸钾活化对棉花秸秆生物炭性状的影响

采用不同浓度的高锰酸钾溶液浸渍棉花秸秆在不同裂解温度下制备棉花生物炭,研究了高锰酸钾浓度及裂解温度对棉花生物炭性状的影响。结果表明,不同制备条件下获得的棉花生物炭的产率位于22.22%～47.17%之间,随着裂解温度的升高而降低,而不同生物炭灰分含量（9.99%～28.83%）、pH（9.7～12.1）及比表面积（2.34～167.58 m²·g^-1）随着裂解温度的提高逐渐升高。棉花生物炭中元素以C和O元素为主。高锰酸钾处理会显著提高棉花生物炭pH及比表面积,并使炭表面官能团种类更为丰富。     

富含氨基的聚酰胺-胺树枝状大分子的合成与表征

以乙二胺(EDA)和丙烯酸甲酯(MA)为原料,采用发散法合成了0.5代到3.0代聚酰胺-胺(PAMAM)树枝状大分子。分别考察了反应温度、反应时间对半代及整代PAMAM树枝状大分子合成工艺的影响,并对合成的PAMAM产物进行了傅里叶变换红外光谱(FTIR)、高效液相色谱(HPLC)表征及端基滴定分析。实验结果表明,生成PAMAM半代及整代产物的最适反应温度均为25℃,反应时间为24 h;采用该方法合成的3.0G PAMAM树枝状大分子的纯度为88.22%,表面伯胺数约为16个,与理论值一致。合成的PAMAM树状分子表层富含大量的氨基基团,可以与抗体、核酸适体等功能分子结合而应用于食品安全检测和医药领域。     

Alternate partial root-zone irrigation with high irrigation frequency improves root growth and reduces unproductive water loss by apple trees in arid north-west China

Alternate partial root-zone irrigation (APRI) can improve water use efficiency in arid areas. However, the effectiveness and outcomes of different frequencies of APRI on water uptake capacity and physiological water use have not been reported. A two-year field experiment was conducted with two irrigation amounts (400 and 500 mm) and three irrigation methods (conventional irrigation, APRI with high and low frequencies). Root length density, stomatal conductance, photosynthetic rate, transpiration rate, leaf water use efficiency, midday stem and leaf water potentials were measured. The results show that in comparison with conventional irrigation, APRI with high frequency significantly increased root length density and decreased water potentials and stomatal conductance. No differences in the above indicators between the two APRI frequencies were detected. A significantly positive relationship between stomatal conductance and root length density was found under APRI. Overall, alternate partial root-zone irrigation with high frequency has a great potential to promote root growth, expand water uptake capacity and reduce unproductive water loss in the arid apple production area.     

Planting density affected biomass and grain yield of maize for seed production in an arid region of Northwest China

Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency(WUE) of maize for seed production. Five planting densities of 6.75, 8.25, 9.75, 11.25 and 12.75 plants/m~2 were conducted in 2012, and a planting density of 14.25 plants/m~2 was added from 2013 to 2015. Through comparison with the Aqua Crop yield model, a modified model was developed to estimate the biomass accumulation and yield under different planting densities using adjustment coefficient for normalized biomass water productivity and harvest index. It was found that the modified yield model had a better performance and could generate results with higher determination coefficient and lower error. The results indicated that higher planting density increased the leaf area index and biomass accumulation, but decreased the biomass accumulation per plant. The total yield increased rapidly as planting density increased to 11.25 plants/m~2, but only a slight increase was observed when the density was greater than 11.25 plants/m~2. The WUE also reached the maximum when planting density was 11.25 plants/m~2, which was the recommended planting density of maize for seed production in Northwest China.     

调亏灌溉及施肥对玉米干物质积累和相关生理性状的影响

通过盆栽试验,在2种施肥水平下,研究了拔节期和抽雄期4个水分亏缺水平,即重度亏水(SD,40%~50%θf,θf为土壤田间持水量)、中度亏水(MD,50%~60%θf)、轻度亏水(LD,60%~70%θf)和正常灌水(CK,70%~80%θf)对玉米干物质积累、水分利用和相关生理性状的效应。发现施肥有利于玉米干物质积累,拔节期和抽雄期LD均不会明显降低干物质总量或略有增加,而SD明显降低干物质总量,但水分亏缺和施肥水平对冠层水分利用效率的影响不明显。与CK相比,两个生育时期LD对叶片叶绿素(Chl)、可溶性糖(SS)、脯氨酸(Pro)和丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响较小;SD明显降低Chl含量以及SOD、POD和CAT活性,但明显增加SS、Pro和MDA含量。LD复水后各项生理生化指标均能恢复至正常灌水水平,MD复水后能在一定程度上恢复到正常灌水水平,而SD复水后则不能。因此本试验玉米拔节期和抽雄期调亏灌溉以轻度亏水适宜。     

生物有机肥与石灰对土壤肥力和木薯产量质量的影响

通过田间试验,研究在3种石灰水平下,生物有机肥对土壤养分含量、生物活性和木薯产量质量的影响。结果表明：与单施化肥比较,50%生物有机肥处理的土壤有机质、速效K含量和转化酶活性分别提高12.5%、36.7%和26.8%;土壤细菌、真菌和放线菌数量分别增加21.4%、41.8%和48.4%;25%生物有机肥处理鲜薯产量提高18.4%,淀粉产量增加17.9%。这表明施用生物有机肥能提高土壤有机质、速效K含量和微生物数量,增强土壤转化酶活性,并能提高鲜薯产量和淀粉产量。施用石灰能提高土壤细菌和放线菌数量,但降低土壤有机质、速效N和速效K含量。     

烤烟不同生育时期分根区交替灌溉的节水调质效应

为寻找烟田节水调质灌溉方式的理论依据,本文通过盆栽试验研究了两种施肥条件下,不同生育时期分根区交替灌溉（APRI）对烤烟生理特性、水分利用以及主要品质指标的影响。结果表明,APRI能有效地调节气孔开度,降低气孔导度和蒸腾速率,减少其奢侈蒸腾耗水,达到节约灌水量和提高水分利用效率（WUE）的目的。与常规灌溉（CI）相比,不同生育期APRI处理低肥时平均节水10.6%,高肥时平均节水6.1%,低肥时烟叶WUE平均提高2.3%。APRI还可以明显提高烟叶K、还原糖和粗蛋白含量,改善烟叶的内在品质。与CI相比,APRI处理烟叶K和粗蛋白含量,低肥时平均提高19.9%和7.1%;高肥时平均提高29.5%和15.1%,低肥伸根期APRI还原糖含量提高17.6%,烟碱含量降低25.7%。本研究结果表明,低肥时在烤烟伸根期进行分根区交替灌溉是烟叶生产中一种较好的节水调质的烟田灌溉方式。