Effects of Deficit Drip Irrigation Ratios on Cotton (Gossypium hirsutum L.) Yield and Fibre Quality

Increasing irrigation costs and declining water availability compel producers to adapt irrigation strategies for maximum crop yield and water use efficiency. A field trial was conducted to observe the effects of various drip irrigation ratios (IR-0, IR-25, IR-50, IR-75 and IR-100) on water use efficiency (WUE), the irrigation water use efficiency (IWUE), lint yield, yield components and fibre quality at two upland cotton varieties during 2004 and 2005. WUE was found to increase from 0.62 to 0.71 kg m⁻³ as the irrigation water applied was reduced from 100 % to 75 % of soil water depletion. Deficit irrigation of cotton with drip irrigation at 75 % treatment level (IR-75) did not decrease seed cotton yield and yield components during 2 years, with the exception of the number of bolls in 2005. Among fibre quality parameters, no significant differences in fibre length, fineness, uniformity index and elongation were detected between the 100 % and 75 % irrigation levels in 2005. The results revealed that irrigation of cotton with a drip irrigation method at 75 % level had significant benefits in terms of saved irrigation water without reducing yield, and high WUE indicated a definitive advantage of employing deficit irrigation under limited water supply conditions.     

饲料中动物源性成分显微近红外光谱检测分析

探讨了应用显微近红外光谱分析技术检测饲料中动物源性成分的可行性.利用12个动物源性成分饲料样品和14个植物源性成分饲料样品建立偏最小二乘定标模型,数学预处理方法为导数+多元散射校正,利用平均光谱来优化模型实现数据压缩,模型的决定系数、交互验证标准差分别为0.969、0.090.4个配合饲料样品作为外部验证未出现误判.结果表明显微近红外光谱分析技术可用于检测饲料中动物源性成分.     

Carbon and nitrogen budgets of nematodes in arable soil

Summary The amounts of C and N that pass through the nematode biomass in four cropping systems, barley without and with N fertilization, grass ley and lucerne, has been estimated. The nematodes were sampled at the field site of a Swedish integrated research project Ecology of Arable Land: The Role of Organisms in Nitrogen Cycling. The nematode biomass was lower (200 mg dry weight m^–2) in the annual (barley) than in the perennial (grass and lucerne, 350 mg dry weight m^–2) crops. For respiration, the nematodes used 4–71 O₂m^–2 year^–1 corresponding to C liberation of 1.3%–2.0% of the carbon input to the soil. A higher relative contribution by bacterial-feeding nematodes to the C and N fluxes and a higher turnover rate of the nematode biomass is an indication of more rapid nutrient circulation in the annual than in the perennial cropping systems.     

旱稻水分利用率与碳同位素识别值之间的关系

通过温室盆栽试验 ,分析和探讨了三个水平的土壤水分条件对分蘖期和成熟期收获的旱稻(OryzasativaL .)生物量累积、水分利用率 (WUE)、植株不同部位的碳同位素识别值 (CID)的影响 ,并了解了它们之间的相互关系。水分条件包括 :饱和含水量 (W1 )、饱和含水量的 70 %(W2 )、饱和含水量的 4 0 %(W3)。结果表明当土壤水分条件从W1降低到W2时 ,分蘖期收获的生物量降低 4 5 %左右 ,成熟期收获的生物量降低 1 6 %～ 1 9%;而当从W1降低到W3时 ,分蘖期收获的生物量降低 73%左右 ,成熟期收获的生物量降低 5 5 %～ 5 7%。然而 ,根据地上部干重计算而来的WUE(WUE 地上部 )和根据全株干重计算而来的WUE(WUE 全株 )则随土壤含水量的降低而增加 ,其增幅在分蘖期为 0 .0 7～ 0 .2 8gkg-1 ,在成熟期为 0 .0 7～ 0 .4 5gkg-1 。植株的CID值变幅为 1 7.0～ 2 0 .6 ,但植株不同部位间差别显著 ,分蘖期收获的样品CID值从小到大的顺序为 :根 <最近完全伸展叶 <叶芽 <茎秆 ;而成熟期收获的样品CID值从小到大的顺序为 :籽粒 <根 <茎秆 <旗叶。随着土壤含水量的降低 ,植株所有部位的CID值亦显著减小。叶部的CID值与WUE 地上部(和WUE 全株 )之间呈一致的负相关关系。     

Are survival and reproduction of Enchytraeus albidus (Annelida: Enchytraeidae) at risk by feeding on Bt-maize litter?

Enchytraeids are saprophagous soil organisms, appearing in high abundances and contributing to ecological processes within the soil. For decades they have been used as model species for biological research. In the framework of research on genetically modified plants, however, they have not been considered to date. Following the ISO/DIS guideline, survival and reproduction of Enchytraeus albidus, fed with diets containing Bt-maize (N4640Bt Cry1Ab, DKC5143Bt Cry3Bb1) leaf material were analysed. For comparison, diets with the corresponding untransformed near-isolines (N4640, DKC5143) were examined. Additionally a high quality control diet (oat flakes) was included. Survival and reproduction showed no significant differences between the Cry3Bb1 treatment and the treatment with the untransformed counterpart. For the Cry1Ab treatment survival was significantly higher than for the treatment with the corresponding near-isoline. In contrast, reproduction was significantly lower for the Cry1Ab treatment compared to that for the isoline. For the Cry3Bb1 treatment, no effect was shown on survival or reproduction. For the Cry1Ab variety and its untransformed counterpart, a contrasting result was detected, which is unlikely to be caused by the Bt-protein but rather by differences in other plant components. Overall survival and reproduction were highest for the control.     

山西四种鸮形目鸟类生态习性的初步研究

本研究于山西吴城地区对4种鸮形目鸟类的生态习性进行了研究,旨在积累该地区鸮形目鸟类的生态学基础资料。利用样线法记录迁徙时间,并收集繁殖季栖息地、巢卵特征的数据资料;利用食团内容物分析法分析食性。结果表明不同年份红角鸮、长耳鸮、短耳鸮的迁徙具有相似特点,均是北迁持续期时间短、间隔时间长,南迁持续期时间长,间隔时间短。红角鸮与纵纹腹小鸮在巢址选取、育雏行为等方面存在差异,营巢地更接近居民区的纵纹腹小鸮的繁殖成功率相对较高。4种鸮形目鸟类均以小型哺乳类和鸟类为主要食物,此外也取食少量昆虫和部分家畜、家禽。不同物种之间需求的重叠会导致种间竞争的增加,考虑到鸮形目鸟类在生态系统中的重要作用及其偏低的种群数量,应对其加以关注并实施保护。     

Root architecture of sorghum genotypes differing in root angles under different water regimes

Plant root architecture offers the potential for increasing soil water accessibility, particularly under water-limited conditions. The objectives of this study were to evaluate the root architecture in two genotypes of sorghum (Sorghum bicolor (L.) Moench) differing in root angles and to assess the influence of different deficit irrigation regimes on root architecture. The response of two sorghum genotypes, ‘Early Hegari-Sart’ (EH; steep root angle) and ‘Bk7’ (shallow root angle) to four irrigation treatments was investigated in two replicated outdoor studies using large pots. The results indicated that EH possessed steeper brace and crown root angles, fewer brace roots, greater root biomass, and root length density than Bk7 at deeper soil depths (i.e., 15–30 and 30–45 cm) compared with a shallower depth (i.e., 0–15 cm). Across the soil profile, EH had greater root length density and length of roots of small diameter (<1 mm) than Bk7. Accordingly, EH showed more rapid soil-water capture than Bk7. Different levels of irrigation input greatly affected root architecture. Severe deficit irrigation (25% of full crop transpiration throughout the season) increased the angle and number of crown roots, root biomass, and root length density compared with 75 and 100% of full crop transpiration treatments. Consequently, root system architecture can be effectively manipulated through both genotypic selection and irrigation management to ensure optimal performance under different levels of soil available water.     

在干旱胁迫下饲料型刺槐无性系保护酶活性的差异

以3个饲料型刺槐无性系为研究对象,对干旱胁迫下保护酶类的活性差异进行了研究.结果表明,饲料型刺槐无性系在干旱胁迫下调动各种保护酶来清除体内的活性氧,以保护细胞膜不受活性氧的攻击,但不同的无性系对干旱胁迫有着不同的响应.3个无性系中韩国四倍体主要调动POD酶、匈牙利多倍体主要调动SOD、CAT酶、长叶刺槐主要调动POD、CAT酶.MDA的含量随着干旱胁迫的加剧逐渐增加达到最大值,然后出现下降.     

杂交中籼稻生殖期间气象要素与结实率的相关性分析

以1992～2004年湖北省中稻区域试验及武汉、荆州、襄樊气象站的资料为依据,分析杂交中籼稻生殖期间各种气象要素与年度间结实率变化的相关性。结果表明:各种气象要素与水稻年度间结实率变化存在不同程度的相关性,其相关程度依次为7～9月累计日照时数、7～8月日平均地温和7～9月日平均昼夜温差;7～9月累计日照时数对水稻结实率的影响最大。     

不同水分状况下红壤水稻土中有机物料分解及酶活性的变化

[目的]为阐明红壤区土壤中有机物料的分解速率及酶活性的变化提供参数。[方法]设置好气、淹水、干湿交替3种处理进行室内培育试验,研究不同水分状况下红壤水稻土中有机物料分解和土壤酶活性的变化。[结果]3种处理有机物料玉米叶、根茬的分解速率均表现为好气>淹水>干湿交替,且玉米叶的分解速率高于玉米根茬。培养90 d时好气处理下玉米叶、根茬的分解速率分别比淹水处理高19.9%和92.3%。好气处理的土壤脲酶、酸性磷酸酶、转化酶活性较高。好气处理下,添加有机物料可提高土壤脲酶活性,但在淹水和干湿交替处理下,添加有机物料却抑制土壤脲酶的活性。[结论]不同水分状况处理下,添加有机物料均可提高土壤酸性磷酸酶和转化酶活性。