An approach to multi-criterion evaluation of irrigation system performance

Irrigation systems aim to meet multiple objectives and performance must therefore be assessed using quantifiable measures for each. It therefore becomes an extremely difficult task to capture the valuation of all of them simultaneously and to mentally process the trade-offs between them in order to arrive at an overall impression of system performance. There is a need for a methodology which provides a systematic approach to comparing and combining the components of overall performance.Multi-Attribute Utility Theory offers an attractive approach to assessing performance of irrigation systems in the form of a utility function which reflects the strength of preferences and trade-offs between individual performance criteria. The method is described and demonstrated on the basis of a case study of irrigation in Sudan.     

苏丹草诱集带对玉米田亚洲玉米螟的诱集效应

[目的]以新疆近年来引进种植的优质牧草苏丹草作为诱集植物,探讨不同播种方式对亚洲玉米螟的诱集效应,为玉米螟治理的生态调控技术提供科学依据.[方法]通过在玉米田以不同播种期、不同密度播种苏丹草诱集带和玉米-苏丹草同行混作以及不同品种的玉米田种植苏丹草诱集带等方式对玉米田的亚洲玉米螟发生、为害情况进行比较,明确苏丹草诱集带对玉米螟的生态调控作用.[结果]5月2日、5月27日和6月14日三个不同播种期的苏丹草诱集带对降低玉米田亚洲玉米螟为害率都有显著作用,效果达14.29;～100;;以不同密度播种的苏丹草诱集带和苏丹草-玉米按不同比例同行混作对亚洲玉米螟的诱集效果不显著;玉米螟为害甜玉米美糯2号的程度显著高于普通饲料玉米SC704.[结论]尽管美糯2号甜玉米田的苏丹草诱集带对玉米螟的诱集率较SC704普通饲料玉米田显著高9.4;,但苏丹草的诱集作用对减轻玉米受害程度在玉米品种间并无显著差异.     

食品中苏丹红HPLC检测方法研究

[目的]建立食品中简便、易行检测苏丹红Ⅰ～Ⅳ的高效液相色谱方法。[方法]采用液相萃取样品处理,C18色谱柱,流动相A为1％冰醋酸的水溶液,流动相B为1％冰醋酸、20％丙酮的乙腈溶液,梯度洗脱,检测波长478nm,对辣椒食品中的苏丹红Ⅰ～Ⅳ号进行了分离和检测。[结果]苏丹红I～Ⅳ的标准曲线呈良好的线性关系,相关系数分别为0．9999、0．9966、0．9974、0．9937,精密度相对标准偏差分别为4．25％、5．34％、1．99％、7．56％;辣椒粉样品中的苏丹红Ⅰ～Ⅳ号的加样回收率分别为89．87％、90．90％、87．55％、81．07％;辣椒油样品中的苏丹红Ⅰ～Ⅳ号的加样回收率分别为94．83％、91．99％、88．83％和86．86％;苏丹红Ⅰ～Ⅳ号的最低检测限分别为5．02、2．46、2．30、5．02¨∥kg。[结论]该方法样品处理简单、快速,灵敏度、精密度符合要求,可在基层实验室推广应用。     

香梨果园套种苏丹草对土壤养分及产草量的影响

探讨库尔勒香梨果园套种苏丹草对果园土壤性状的影响和产草量。果园内,分别设距树干0.5m处外和1.5m处外2个采样区,测定采样区内苏丹草产量和0~60cm土层的土壤容重及土壤养分。结果表明,离树干1.5m处外干草产量为2.25kg/m^2,显著高于离树干0.5m处外的1.34kg/m^2。离树干0.5m处外0~20、20~40cm土层地下生物量分别为81.26g/m^2、14.38g/m^2约为离树干1.5m处213.62g/m^2、32.89g/m^2的38.03%、56.27%,且90%以上的牧草根量分布在0~20cm的果园土层,苏丹草与果树的根系几乎无重叠现象。可见,香梨果园套种苏丹草对土壤性状及养分无负面影响,1a可以收草3次,其产草量可达大田产量的60%左右。     

Responses of Lowland NERICA and Improved Oryza sativa Rice to Phosphorus and Nitrogen in Sudan Savanna Agroecosystem

The responses of five inter-specific lowland rice cultivars （NERICA-L-19, NERICA-L-20, NERICA-L-41, NERICA-L-42, and NERICA-L-60） and four improved Oryza sativa cultivars （FKR 19, BW 348-1, WITA 4, and SIPI 6923033） to levels of phosphorus and nitrogen fertilization were compared on a Typic Natrustalfat Kadawa in the Nigerian Sudan Savanna in 2006 and 2007 The responses of the NERICA-L eultivars to N and P fertilization were similar to the O. sativa cultivars. In a dry year （2007）, the NERICA-L cultivars gave higher yields than O. sativa cultivars. Phosphorus level did not significantly affect crop physiology, yield, and yield components of all the cultivars. Pooled across cultivars, N and P levels, days to panicle initiation, mid-flowering and maturity were, respectively delayed by 17.0, 15.6 and 6.4 days in 2007 compared to 2006. NERICA-L-42 and NERICA-L-41 were the most stable, exhibiting the least difference in duration to maturity between the two years （3.5 and 4.4 days, respectively）, and could therefore be more adapted to rain-fed environments prone to frequent droughts. Increasing N levels from 0 to 120 kg hal produced yield increments of 62.9 and 37.2% in 2006 and 2007, respectively. Cultivars FKR 19 and WITA 4 gave higher yields in 2006 （3940 and 3542 kg ha^-1, respectively）, while in 2007, NERICA-L-42, NERICA-L^-19 and NERICA-L-20 ranked among the highest in grain yield （3935, 3807 and 3726 kg hal, respectively） and could be recommended to resource-poor farmers. a     

Diversity and activity of cellulolytic bacteria,isolated from the gut contents of grass carp (Ctenopharyngodon idellus) (Valenciennes) fed on Sudan grass (Sorghum sudanense) or artificial feedstuffs

Herbivorous grass carp (Ctenopharyngodon idellus) has a powerful capability to digest cellulose from aquatic plants, depending on the cellulase complex produced by the cellulolytic bacterial community in the gastrointestinal (GI) tract. However, it remains uncertain which bacteria taxa may actively participate in the digestion of food fibre. In this study, a total of 499 cellulolytic bacteria from the gut content of grass carp fed on Sudan grass (242 strains) and artificial feedstuffs (257 strains) were randomly isolated and characterized using carboxymethyl‐cellulose, microcrystalline cellulose and cellobiose agar media. The results showed that more than half of the isolates were capable of degrading carboxymethyl‐cellulose and cellobiose, while the remaining isolates were restricted to microcrystalline cellulose decomposition, exclusively. The cellulolytic bacterial community was dominated by Aeromonas, followed by Enterobacter, Enterococcus, Citrobacter, Bacillus, Raoultella, Klebsiella, Hydrotalea, Pseudomonas, Brevibacillus and some unclassified bacteria, as revealed by 16S rDNA sequence analysis. Notably, grass carp fed on grass with high‐fibre content harboured a higher diversity of cellulolytic bacteria than the ones fed on low‐fibre feedstuffs. Our results provided evidence for a positive correlation between the content of food fibre and the diversity of cellulolytic bacteria in grass carp intestines. Thus, improving growth conditions and cellulase activities for GI cellulolytic microorganisms in grass carp intestines are critical for effective utilization of feedstuffs containing high fibre levels.     

Sorghums of the Sudan: analysis of regional diversity and distribution

Sorghum [Sorghum bicolor (L.) Moench] is a very important crop in the Sudan serving as a primary source of food, beverage, and total livelihood for millions of people in the country. The crop originated in the Northeast quadrant of Africa, and the Sudan is widely recognized as a major center of diversity. Although Sudanese sorghum germplasm has been assembled and stored over the last 50 years, careful analysis of this valuable germplasm has not been made. The objectives of this study were to assess phenotypic diversity and compare pattern of distribution among Sudanese sorghum landraces collected from different geographical regions. Phenotypic diversity among landraces was high, as expressed by the large range of variation for mean quantitative traits and the high (0.81) Shannon-Weaver diversity index. Landraces from Gezira-Gedarif tended to be shorter in stature, earlier in maturity and less sensitive to changes in photoperiod. They also had long, narrow and compact panicles that may result from adaptation to low rainfall and early adoption of mechanized farming practices. In contrast, taller and later maturing plant types characterized sorghums from Equatoria, most of which delayed their flowering in response to increased day-length. These sorghums included many genotypes with small and light kernels. Collections from Kassala showed a higher frequency of landraces with kernels that were more difficult to thresh. Landraces from Blue Nile tended to have greater agronomic eliteness with higher proportion of landraces with white kernels, poorly covered and that were easy to thresh. Sorghums from the Upper Nile tended to have loose panicles with poorly covered kernels that may result from adaptation to high rainfall of the Southern region. Although distinct distributions of types were represented by geographical origin, a high level of within-region diversity was present among all Sudanese sorghums.     

Changes in fatty acids composition during seed growth and physicochemical characteristics of oil extracted from four safflower cultivars

Fatty acid contents at different stages ofmaturity and physicochemical characteristics of oilextracted from mature seeds of four safflowercultivars (S208, S400, S541, and S303) were studied. Results indicated that for all cultivars bothsaturated and unsaturated fatty acid contentsfluctuated with seed growth and development. Palmiticacid content decreased up to day 20 after which itstarted to increase for the S400, S541, and S303cultivars, while for S208 it progressively decreased.Stearic acid fluctuated with seed growth anddevelopment. Oleic acid showed slight changes withseed growth and development, while linoleic aciddecreased with seed growth and development for theS400, S541, and S303 cultivars while for S208 afterday 30, it started to increase significantly. For allcultivars, glyceride contents varied among thecultivars with maximum values of 97.70, 2.80 and0.20 for tri-, di- and monoglycerides, respectively. Physicochemical investigation of mature seed oilsshowed that the color, density, refractive index, free fatty acids, peroxide value, saponificationvalue and unsaponifiable matter were similar for allcultivars while viscosity, iodine value, and acetoneinsoluble matter varied among the cultivars.     

杂交苏丹草中CN-含量的测定

对传统的异烟酸－吡唑啉酮比色法测定CN^-的条件进行了优化，并用于测定杂交苏丹草体内CN^-的含量。结果表明，苏丹草在苗期体内CN^-含量较高，达163mg/kg，以后呈逐渐下降的趋势。