实验室条件下o-烯丙基苯酚和p/o-丁酰基苯酚在土壤中的降解动力学研究

实验室条件下,在东北黑土、北京褐土、江西红土中添加o-烯丙基苯酚、p/o-丁酰基苯酚后对其降解进行了研究。结果发现,微生物对这2种农药在3种土壤中的降解起主要作用,它们在未灭菌土中的降解速度很快,符合一级动力学方程,T0.5在10.26h￣2.51d之间。两者均在有机质含量较高、pH偏碱性的东北土壤中降解最快;土壤含水量增加,降解速度减慢;外加碳源的存在,并没有加快它们的降解速度。     

施钾条件下杂交水稻氮磷养分吸收利用特点

对浙江省金华市郊区石门农场灌溉稻区进行连续4年定位钾肥试验,结果表明,钾素促进氮磷养分向水稻穗部的输入,故在增产的基础上,同不施钾处理比较,施钾后杂交稻氮的总吸收量增加7.1～9.3kg/hm2,利用效率提高3.7～7.1%;磷的总吸收量增加1.0～2.0kg/hm2,利用效率提高2.0～7.7%。同常规稻比较,每季杂交稻氮和磷的平均总吸收量分别高出7.6kg/hm2和1.2kg/hm2;氮和磷的利用效率平均高出3.1kg/kg和34.7kg/kg;在养分的吸收、积累以及利用效率方面表现出明显的生理优势[1]。因此,在杂交水稻的生产实践中,应相对增加钾肥的施入量,从而提高氮肥和磷肥的利用效率。     

熏蒸条件下有机肥部分替代化肥对西瓜生长及养分利用的影响

基于田间大棚试验,采用等量养分原则,分析生物有机肥、蚯蚓粪、鸡粪等不同有机肥部分替代化肥对西瓜生长、产量、品质以及养分利用的影响。结果表明,与单施化肥相比,有机肥部分替代化肥均不同程度提高了西瓜叶绿素含量、光合性能、产量及品质,其中以蚯蚓粪与化肥配施效果最佳,其光合性能显著高于单施化肥,产量提高了33.63%,可溶性糖、可溶性蛋白及维生素C含量分别增加了14.07%,14.47%和17.52%。有机肥部分替代化肥施肥处理的肥料利用率高于单施化肥,土壤养分元素依存率低于单施化肥,以蚯蚓粪配施化肥作用效果最为显著,氮、磷、钾肥利用率分别为26.02%,5.67%和29.89%,土壤氮、磷、钾素依存率分别为20.96%,20.32%和31.55%。熏蒸处理的西瓜枯萎病发病率整体低于未熏蒸处理,其中熏蒸条件下蚯蚓粪部分替代化肥施肥处理西瓜发病率最低,仅为4.76%。     

润滑油分离机内部流场数值模拟与分离效率分析

用数值方法研究碟式分离机内部流场是优化其设计的重要手段。针对润滑油碟式分离机,采用VOF多相流模型并结合RNG k-ε湍流模型和离散相模型对其内部油水固分离过程和分离效率进行了数值模拟。模拟结果表明,碟片间隙中流场基本为层流,在中性孔和碟片外缘为湍流区;入口速度对油水分离结果影响不大,而对固体颗粒的分离会产生较大的影响;固体颗粒计算分离效率和实测分离效率最大相对误差为1.5%,额定处理量为700 L/h时,入口速度为2.5 m/s,此时分离效率为97.2%,满足设计要求。研究结果表明,该文提出的三相流分析方法是可行的,对碟式分离机的结构优化设计具有重要的指导意义,同时也减少了所需的试验时间和费用。     

松林生态系统退化评价及其与马尾松毛虫灾害关系的研究

通过对长沙县丘陵区马尾松林生态系统进行调查研究,选取生物途径、生境途径以及生态系统功能途径3个诊断途径,采取多途径综合诊断的方法对丘陵区马尾松林生态系统退化程度进行诊断,确认其退化程度,在此基础上分析松林生态系统退化程度与马尾松毛虫灾害的关系。结果表明马尾松毛虫灾害发生程度与生态系统退化程度关系密切。生态系统退化越严重的地区,马尾松毛虫灾害越严重,退化较轻的地区,马尾松毛虫灾害较轻或不发生。     

氮肥运筹对农大108产量、氮肥利用率及土壤氮素平衡的影响

以农大108为试材,通过田间试验研究不同氮肥运筹方式对春玉米干物质积累、子粒产量、氮肥利用率及土壤氮素平衡的影响。结果表明,氮肥不同运筹方式增产效果差异显著,其中,1/3氮肥底施、2/3氮肥两次追肥(N3)处理增产效果最好,其次是1/4氮肥底施、3/4氮肥3次追肥(N4)处理,氮肥全部作底肥(N1)处理增产效果最小。分次施肥有利于子粒粗蛋白含量、子粒蛋白质产量以及氮肥利用率的提高;随着施肥次数的增加,子粒粗蛋白含量、子粒蛋白质产量以及氮肥利用率均呈上升趋势,以N4处理最佳,其次是N3处理。氮肥不同运筹方式氮素表观损失量差异显著,N1处理其表观损失量最高,N3处理最低。因此,N3处理有效促进了植株对氮素的吸收利用,显著增加了产量和子粒蛋白质产量,降低了氮素表观损失量,是最佳氮肥运筹方式。     

不同灌溉模式下小麦荧光特征及品种抗旱性研究

为探讨低平原区节水灌溉模式和筛选高产节水品种,在2014-2015和2015-2016两个小麦生长季,采用裂区试验,以5个灌溉模式(春季灌溉0、1、2、3和4水,分别用W_0～W_4表示)作为主处理,以3个当地主推冬小麦品种(衡观35、石4185和衡4399)作为副处理,研究了不同灌溉模式对小麦产量、叶绿素荧光特征参数、水分利用效率等的影响及荧光特征与品种抗旱性的关系。结果表明,随灌溉量和灌溉次数的增加,小麦产量非线性增加,但不同年份表现有所不同,2014-2015年以W_2处理产量最高,2015-2016年以W_4处理产量最高;灌溉提高了PSⅡ的潜在活性F_v/F_o和原初光能转化效率F_v/F_m,但F_o却降低。不同品种对灌水的反应特性不同,且存在年际间差异,两年平均产量以衡4399最高,石4185最低;随灌溉量的增加,衡4399和衡观35产量变化幅度较小,而石4185的产量变化幅度相对较大。从荧光特征参数看,石4185受水分胁迫的影响大,在灌浆后期,其不灌溉处理(W_0)的荧光参数F_o相对于灌溉处理的增加幅度高于衡4399和衡观35,但F_m、F_v/F_m和F_v/F_o在不灌溉情况下的降低幅度也相对较大,说明石4185的抗旱性差。从水分利用效率看,以W_2处理较好。因此在本试验条件下,衡4399和衡观35的增产潜力大,抗旱性好,春季灌2水可达到节水高产和水分利用效率提高的目的。     

Genotypic differences of maize in grain yield response to deficit irrigation

This study was undertaken to investigate genotypic differences of five maize cultivars in grain yield response to two different modes of deficit irrigation, conventional deficit irrigation and partial root zone irrigation. Three irrigation treatments were implemented: (1) FULL irrigation, the control treatment where plant water requirement, 100% Class-A pan evaporation, was fully met and the furrows on both sides of the plant rows were irrigated; (2) partial root zone irrigation (PRI), 35% deficit irrigation, compared to FULL treatment, was applied in every other furrow thus irrigating only one side of the plant rows. The furrows irrigated were alternated every irrigation; (3) conventional deficit irrigation (CDI), the same amount of water as PRI was applied in furrows on both sides of the plant rows, similar to FULL irrigation treatment. Five maize cultivars (P.31.G.98, P.3394, Rx:9292, Tector and Tietar) showing extreme growth response to water stress were selected out of ten cultivars tested with earlier completed greenhouse-pot experiment. A split-plot experimental design, comprising three irrigation treatments and five maize cultivars with four replicates, was used during two years of work, in 2005 and 2006. Total of nine irrigations, with one-week irrigation interval, were annually applied using a drip-irrigation system. Soil water status was monitored using a neutron moisture gauge, in addition to measuring leaf water potential and above-ground biomass production throughout the growing season. Grain yield and other yield attributes were measured at harvest as well as assessing differences in plant root distributions. Decrease in grain yield and harvest index of the tested cultivars, compared to FULL treatment, was proportionally less under PRI than CDI. Whether or not a significant yield advantage can be obtained under PRI compared to CDI showed significant (P < 0.05) genotypic variability. Tector and Tietar among the tested cultivars of maize showed significantly higher grain yield (P < 0.05) under PRI than CDI. The yield advantage of the genotypes (P.3394 and Tector) under PRI compared to CDI seems related to their enhanced root biomass developed under PRI.     

Influence of organic mulching and nitrogen application on essential oil yield and nitrogen use efficiency of rosemary (Rosmarinus officinalis L.)

In a field study conducted at Bangalore, India for two years (2003–2004 and 2004–2005), eight treatment combinations consisting of two variables, organic mulch (lemongrass spent material as mulch at 7.5 t ha^?1 and no mulch) and four levels of nitrogen fertilizer (0, 100, 200 and 300 kg ha^?1) were examined to observe the effect of organic mulching on nitrogen use-efficiency, and herb and essential oil yield in a multiharvested rosemary crop. The results revealed that application of lemongrass spent material as mulch increased the herb and essential oil yields in rosemary by 16.2 and 24.2%, respectively, over the non-mulched control at first harvest. Corresponding values for the regenerated crop harvest were 18.8 and 16.8%. A significant response to N was observed with 300 kg N ha^?1 in non-mulched plots compared with 200 kg N ha^?1 in mulched plots. Using lemongrass spent material as mulch, nitrogen uptake by the rosemary crop increased by 15.1% over the non-mulched control. At 200 kg N ha^?1, apparent recoveries by the crop were estimated to be 33.64% for the non-mulched control, and 37.79% with mulch. The quality of the rosemary essential oil, in terms of the concentrations of its major constituents, α-pinene, 1 : 8 cineole, camphor and verbenone, was not affected by the use of organic mulching and nitrogen fertilization, and these constituents were found to be of astandard acceptable in international trade.     

杀线虫细菌W3胞外体壁降解蛋白酶的纯化及部分特性

[目的]为筛选和开发高效新型生物杀线虫剂提供依据。[方法]以土壤中筛选的1株具有明显杀线虫活性的细菌菌株W3为供试菌种,对其进行发酵培养,采用硫酸铵沉淀、疏水层析、阴离子柱层析等方法从发酵液中分离W3菌株的杀线虫活性成分,并对各活性成分的杀线虫活性进行测定。[结果]W3菌株粗蛋白处理线虫4h后,虫体活动异常,部分虫体静止不动,处理36h后大部分虫体不活动,部分虫体体壁断裂现象,最终所有线虫被完全消解;从发酵液中纯化出1种能降解线虫体壁的胞外蛋白酶,该酶的分子量约为45KDa,其作用的最佳pH值为7～8,最佳温度为45℃。[结论]W3菌株胞外蛋白酶具有明显的杀线虫活性和线虫体壁降解活性。