耕作与施肥模式对渭北旱塬春玉米田蓄水保墒与玉米产量的影响

为揭示渭北旱塬春玉米田休闲期不同保护性耕作模式的蓄水保墒与增产增收效应,寻找适合渭北旱塬春玉米田水肥高效利用的耕作方式和施肥水平,于2013—2014年度在陕西省合阳县甘井镇春玉米田分别设置传统农户模式(翻耕+低肥,S1)、现有高效模式(免耕+高肥,S2)、创新高效模式(深松+平衡施肥,S3)等模式处理,研究各类耕作与施肥相结合保护性耕作模式下春玉米水分利用率、产量和经济效益差异。结果表明,创新模式S3和现有模式S2较农户模式S1播前增加了土壤贮水量;创新模式S3和现有模式S2处理在玉米主要生育期0~200 cm土层平均土壤贮水量分别比农户模式S1增加23.3 mm和18.1 mm,水分利用效率分别提高12.3%和10%,产量增加11.1%、9.2%。创新模式和现有模式均较农户模式能够增加土壤贮水量,提高水分利用效率,增加产量和经济效益,但创新模式蓄水保墒,增产增收优势明显,是适合渭北旱塬地区春玉米生产的水肥管理模式。     

荒漠草地物种多样性的水分特征研究

通过在伊犁河谷山前倾斜平原荒漠草地开展的不同灌溉量草地恢复试验,对测试的试验地内草地植物物种多样性指数和灌溉水量之间的关系进行了初步的研究。结果显示:在荒漠草地,水分是影响草地植物长势的重要限制因子,随着水分条件的转好,植被盖度和蒿类的分盖度均有显著的提高,草地植物的生物量和群丛高度均显著增加;随着灌溉量的增加,S im pson指数、Shannon-W iener指数、P ie lou指数和M arga lef指数均出现递增的趋势,其中每增加1 kg/d水量,S im pson指数将增加0.021,表明在温性荒漠草原生物多样性指数对水量变化的灵敏度较高。     

应用间接荧光抗体技术研究水中嗜水气单胞菌的数量与鱼类出血性败血病的关系

应用间接荧光抗体技术（ＩＦＡＴ），并结合嗜水气单胞菌（Ａｈ）地区优势血清型，对鱼类出血性败血病的致病菌Ａｈ进行水中数量的测定。ＭＭ感染试验和对生产鱼塘调查的结果表明，水中Ａｈ菌量与疾病呈正相关，致病浓度又随鱼体健康低下、水中氨氮偏高、溶氧偏低等多种因子的影响而下降。本试验方法快速简便，检测对象为水体，非常适用于预测疾病的发展趋势。     

灌溉方法对温室栽培番茄产量及水分利用效率的影响

用温室小区栽培试验的方法,研究滴灌、渗灌、沟灌三种灌溉方法对番茄养分吸收、产量及水分利用效率的影响;结果表明,温室番茄栽培采用渗灌灌溉,在其它条件相同的情况下,1 m3灌溉用水生产出的番茄数量是沟灌的1.9倍、滴灌的1.2倍,滴灌则是沟灌的1.6倍;在番茄生长的整个生育期内,滴灌土壤水吸力平均值最大为24.20 k Pa,渗灌次之为23.11 k Pa,沟灌最小为22.01 k Pa;土壤温度表现出一定差异,但差异相对较小。沟灌处理番茄果实氮素含量高于滴灌和渗灌,而滴灌能够促进番茄的营养器官对氮素的吸收。渗灌和滴灌能有效地调控耕层土壤水分,有利于土壤养分供应,具有明显的节水、增产效果,是理想的设施番茄栽培灌溉模式。     

不同去雄方法诱导草地早熟禾雄性不育的研究

试验分别用温汤去雄杂交和两种化学去雄剂化学去雄诱导草地早熟禾雄性不育,结果表明,在两种化学去 雄剂作用下去雄效果比较理想,温汤去雄雄性不育率达100％。     

人类活动对珠江三角洲酸性硫酸盐土壤发育的影响

In the Pearl River Delta with more than 1000 years of intensive land reclamation history,the development of acid sulphate soils has been generally limited in terms of their acid potential (pyrite content)and spatial extent.This is attributed to the rapid delta progradation,partially resulted from increasing sediment yield caused by deforestation within the catchment and the empolderment in the estuarine embayment.The empolderment practice accompanied by the clearance of mangroves stopped the upward growth of the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic estuarine sediments on the other.In such a case,the pyritic layer in the area is frequently thin and of shallow occurrence.Under forced leaching-recharge conditions for the paddy rice cultivation ,the leaching of acid sulphate materials prevails over its production and this leads to a net loss in pyrite oxidation products.Land excavation for fishpond farming accelerates pyrite oxidation due to the direct exposure of the pyrtic sediments to air on the pond bunds.Severe acidification can intensity the environmental degradation of estuarine ecosystems.     

Effects of nitrogen and water stress on the rehydration,endogenous hormonal regulation and yield of maize

Water scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi-arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought-tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth-leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha⁻¹) and N3 (N300 kg N ha⁻¹) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole-3-acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi-arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100-grain weight, hormone content, ear characteristics and grain yield of maize.     

红薯光合特征对土壤透气性的响应

通过盆栽试验研究了不同土壤质地和水分条件下红薯光合特性对土壤透气性的响应。结果表明:土壤透气性显著影响红薯叶片蒸腾速率和水分利用效率,随土壤透气性的增加,蒸腾速率显著降低,水分利用效率显著增加,红薯的光合作用不受土壤透气性的影响;透气性对红薯蒸腾和水分利用效率的影响与土壤质地有关,在沙土质地下,红薯的光合速率、蒸腾速率和水分利用效率均不受透气性影响,而在壤土质地下,红薯的蒸腾速率随透气性的增加显著降低,而水分利用效率显著增加;透气性对红薯光合特性的影响与生育期有关,不同生育期内,红薯光合特征对土壤透气性的响应也不同。研究表明,在分析作物对土壤透气性的响应时,需要考虑土壤质地、水分条件和生育期的影响。     

外源甜菜碱对作物的抗旱作用效果研究

通过小麦浸种、水培、大面积喷施和茄子盆栽试验,研究了不同浓度外源甜菜碱对作物的抗旱作用效果。结果表明:外源甜菜碱浓度为25～50mg/L时可促进小麦种子发芽,光合作用强度[达7.07～7.57μmol/(s·m~2)]及生物学产量增加;在外源甜菜碱浓度100 mg/L时小麦幼苗叶片硝酸还原酶活性最高,达到35.23μg/(g·h),同时小麦抗旱性增强。数学模式寻优结果表明:在外源甜菜碱浓度26.4～68.9mg/L,土壤水分含量12.6％～20.7％时,可获得最佳的茄子生物总量。     

FAAS法测定原生态硒米中的微量元素铁和镍

[目的]测定黔东南苗族侗族自治州原生态丹寨精硒米中微量元素铁和镍的含量。[方法]采用正交试验优化仪器最佳工作条件,湿法消解硒米样品,火焰原子吸收光谱法（FAAS）测定微量元素铁和镍。[结果]原生态丹寨精硒米中微量元素铁和镍的含量分别为8.00和0.50 mg/kg。[结论]该研究方法操作简便,灵敏度高,检出限低。