秸秆覆盖对黑土区大豆生长及产量构成因素的影响

为研究秸秆覆盖对黑土区土壤水热及大豆生长状况的影响，以垦丰16为试验材料，基于大田试验，分别设置秸秆表面覆盖(T1),0～10 cm土层秸秆还田覆盖(T2),10～20 cm土层秸秆还田覆盖(T3)和无秸秆覆盖(CK)4种处理。通过测定大豆生育期内的耕作层土壤温度及含水率，以及大豆株高、茎粗和叶面积等生长指标，对比分析不同秸秆覆盖处理对土壤水热、大豆生长及产量等性状的影响。结果表明：大豆生育期初T1处理0～10 cm土层含水率明显高于T2及T3处理；在10～20 cm差异逐渐缩小，20～30 cm土层差异变大；秸秆覆盖会影响播种初期的出苗率，而在播种10 d后T1处理的出苗情况最好；T2处理的大豆株高、茎粗、LAI及产量表现最佳。通过统计学分析不同秸秆覆盖之间的差异，秸秆覆盖具有一定的阻碍热量传递的作用，有利于土壤含水率的提高，对大豆生长状况、光合特性及产量产生影响，0～10 cm土层秸秆还田覆盖为最佳处理。     

秸秆带状覆盖对旱地冬小麦土壤温度及产量的影响

为了解小麦秸秆带状覆盖栽培的效果,以冬小麦兰天26号为研究对象,分析了秸秆带状覆盖3行(SC1)、秸秆带状覆盖4行(SC2)、全膜覆土穴播(PC)和无覆盖露地(CK)下旱地冬小麦土壤温度及产量。结果表明,秸秆带状覆盖可显著提高冬小麦籽粒产量,穗数、穗粒数和产量较CK分别增加13.4%~20.2%、26.7%~33.3%和41.3%~69.1%,但秸秆带状覆盖与PC间产量差异不显著。秸秆带状覆盖显著降低了全生育期0~25cm土壤平均温度,土温较CK低1.4~2.0℃;随着生育进程的推进和土层的加深,秸秆带状覆盖表现出增温和降温的"双重效应",SC1在返青期5cm土层和拔节期5和10cm土层增温,SC2在越冬期5和10cm土层及拔节期5cm土层增温,其余各时期各土层秸秆带状覆盖均表现出降温效应,且总体上降温效应大于增温效应;秸秆带状覆盖较PC和CK减小全生育期土壤日变化幅度;SC1、SC2的全生育期有效积温较CK分别减少86.6和69.8℃,使得秸秆带状覆盖下冬小麦较CK晚熟15d。从环保和可持续发展等方面综合考虑,秸秆带状覆盖较全膜覆土穴播在西北旱作区更具优越性。     

覆盖栽培方式对旱地冬小麦越冬期间土壤温度的影响

为筛选出旱地冬小麦适宜覆盖栽培方式,通过微型温度记录仪连续观测越冬期间冬小麦田10和20 cm深度土壤温度的变化,比较旱地秸秆覆盖（SM）、地膜覆盖（FM）、垄沟模式（CM）和无覆盖模式（CK）的麦田土壤温度效应。结果表明,整个越冬期间所有覆盖处理的土壤日均温显著升高,总体增幅表现为CM>FM>SM。越冬后期（2月1日-2月20日）土壤温度变化与总体趋势差异明显,FM的增温幅度大于CM;与CK相比,SM的土壤日均温显著降低,具体表现在温度昼夜变化上,其中10 cm土层温度除在8:00-11:00升高外,其他时间降低,20 cm土层温度均下降（10∶00-14∶00差异不显著）。越冬前期,覆盖栽培10 cm土层的增温值均高于20 cm土层,越冬中期以后则相反（越冬后期土层间增温值差异显著）。SM的土壤日最高温度相对于CK没有变化或者显著降低,而日最低温度则提高,因此降低了土壤温度日较差;CM的土壤日最高温度在越冬后期降低,而在越冬中前期升高,而且土壤日最低温度也升高且增幅更大,因此土壤温度变幅显著降低;FM同时提高了土壤日最高温度和最低温度,最终没有显著改变土壤温度变幅。     

锥栗林土壤呼吸动态变化与主要影响因子分析

通过LI-6400对闽北锥栗林的土壤呼吸进行测定与分析。结果表明,不同季节土壤温度的变化较为一致,呈单峰变化趋势,最大值出现在15：00;土壤呼吸速率昼夜变化趋势大致呈单峰变化,不同季节里呼吸速率最大值出现的时间不同,春季与冬季最高值出现在13：00,而夏季与秋季分别出现在17：00与15：00;不同季节土壤呼吸速率的日变化幅度以冬季较小,春季最大;土壤呼吸Q10值的季节变化中,冬季Q10值最大,夏季最小,Q10值随土壤温度的增高而降低。     

全生物降解地膜对南疆花生产量及土壤理化性质的影响

为研究全生物降解地膜覆盖对南疆花生产量及土壤理化性质的影响,采用PBAT(聚己二酸/对苯二甲酸丁二酯)型聚酯全生物降解地膜(简称:降解膜)覆盖为处理、普通聚乙烯PE地膜覆盖为对照(CK),分析降解膜覆盖对花生试验区土壤温度、水分、养分及产量等相关指标的影响.结果 显示:①降解膜的破损率随花生生育进程表现为6-8月较小(3%~14%),到10月收获期显著增大(29%).②降解膜处理的花生产量与CK无显著差异.③花生生育期内,降解膜覆盖0~30 cm平均土壤温度较CK高0.35℃,其中,膜下5cm、15cm和25cm分别较CK高0.38℃、0.39℃和0.27℃,但两处理间的平均土壤温度差异均不显著.降解膜覆盖0~30 cm平均土壤含水率较CK高2.08%,其中,膜下5 cm和25 cm分别较CK高3.39%和4.74%(p<0.05),而膜下15 cm的较CK低1.89%(p<0.05).④降解膜覆盖对花生不同生育时期(6月和10月)、不同土层(0~20 cm和20~40cm)的土壤速效氮磷钾养分、盐分、土壤容重以及土壤pH均无显著影响.因此,本研究认为,全生物降解地膜替代普通PE地膜应用于南疆花生栽培生产是可行的.     

玉米秸秆覆盖对春小麦田土壤物理性状的影响

为了明确生物覆盖对塔里木盆地绿洲区土壤性能的影响,采用田间试验研究了玉米秸秆不同覆盖处理方式对土壤容重、温度及含水量的影响。结果表明,覆盖处理、立秆处理都较常规处理降低了土壤容重。在春小麦播种期和分蘖期,覆盖处理的5cm土层温度最低,较常规处理的分别低2.13℃和1.79℃;15cm土层温度较常规处理的分别低2.36℃和1.90℃;土层加深10cm土壤温度的最高点和最低点都延迟3h出现。土壤含水量表现为0～10cm土层立秆、覆盖处理的土壤含水量均较常规处理的高,而10～20cm土层则表现为立秆、覆盖处理的土壤含水量均较常规处理的低。     

不同年龄橡胶树各器官养分含量比较研究

本试验以开割巴西橡胶树无性系PR107为研究材料,在2a的不同月份研究了10个年龄段(2～28龄)橡胶树各器官中矿质养分N、P、K、Ca、Mg的含量情况,同时分析了树龄及季节对橡胶树各器官养分含量的影响。结果表明:(1)各养分元素在树体内含量高低顺序为:CaNKMgP;一年中的不同季节,橡胶树不同器官养分含量有所不同:树叶为冬季夏季秋季春季,胶乳为冬季秋季夏季,而树枝、树皮、树干、树根养分含量规律基本相同,为春季冬季秋季夏季。从树龄来看,各养分元素在不同月份(或季节)的差异较为明显,但其年度平均值的波动幅度则较小。(2)不同器官总养分含量高低顺序为:树叶树皮树枝树根胶乳树干。树叶和树皮(具有乳管)是橡胶树的同化器官和生物合成器,是橡胶树生理最活跃的器官,其养分含量通常是其它器官的2～4倍。     

地膜覆盖对玉米田间土壤含水率和地温变化的影响

2013年5~10月在内蒙古阿荣旗进行大田玉米膜下滴灌试验,测定玉米苗期、拔节期、灌浆期及成熟期不同深度土层土壤含水率和土壤温度,研究覆膜(滴灌)和裸地对玉米田间土壤含水率及土壤地温变化的影响。结果表明,在玉米整个生育期,覆膜条件下0~60 cm层土壤含水率高于常规裸地,玉米蜡熟期两种处理田间土壤含水率变化不明显;玉米生育期内0~20 cm层土壤平均含水率均高于播前土壤含水率,生育后期21~60 cm土壤含水率均低于播前土壤含水率。降雨对土壤温度的影响较为显著,雨后土壤表层温度急剧下降,25 cm以下深层土壤温度下降相对缓慢;地膜覆盖对玉米苗期和拔节期增温效果明显,平均增温2℃左右,对玉米生长发育有积极作用,灌浆期及玉米生育后期覆膜增温作用不明显。     

不同覆盖材料对西北旱地冬小麦地温及产量的影响

为探寻不同覆盖材料下西北旱地冬小麦地温与产量的特征及其相关性,以冬小麦兰天26号为材料,在秸秆带状覆盖(常规条播:SM1;宽幅条播:SM2)、全膜覆土穴播(PM)条件下,以无覆盖露地种植为对照(CK),研究了冬小麦生育期地温的差异及其与产量构成的相关性。结果表明,秸秆带状覆盖种植技术可有效平抑气温对小麦的激变,实现了小麦的稳定增产。与CK相比,秸秆带状覆盖冬小麦0~25cm土层全生育期平均降温0.61℃,但在不同生育时期却存在增温和降温的双重效应,苗期至返青期平均增温0.76℃,SM1增温效应低于SM2;返青期以后平均降温1.43℃,SM1降温效应高于SM2;地膜覆盖全生育期平均增温1.01℃。秸秆带状覆盖全生育期各土层总体均表现降温效应,且以降温效应突出的SM1在25cm降幅最大,平均为1.20℃,5cm处最低,为0.55℃;地膜覆盖全生育期各土层均表现增温效应,以5cm处增幅最大,平均为1.14℃,15cm最低,平均为0.84℃。从生育时期和土层看,各处理间地温以越冬期差异最大,变异系数为17.25%~46.6%;土层间以25cm最大,变异系数为5.5%~46.6%。与CK相比,秸秆带状覆盖全天均具有降温效应,降温幅度依次为中午傍晚早晨,且SM1全天的降温效应均高于SM2;而地膜覆盖全天均具有增温效应;覆盖均可使冬小麦显著增产,秸秆带状覆盖平均增产25.3%,SM2增产率(27.0%)高于SM1(23.0%),地膜覆盖增产30.4%。产量与有效穗数和千粒重呈显著正相关,增产的原因主要是有效穗数的增加和粒重的提高,土壤温度指标与产量、产量构成要素间相关不显著。     

全生物降解膜对南疆棉花产量及土壤理化性质的影响

为研究全生物降解膜对南疆农业生产中棉花农艺性状及土壤理化性质的影响,采用PBAT(聚己二酸/对苯二甲酸丁二酯)型聚酯全生物降解地膜(简称"降解膜")为处理、普通聚乙烯(PE)地膜为对照(CK),分析降解膜对棉花试验区土壤温度、水分、养分以及棉花产量等相关指标的影响。结果表明:(1)降解膜的破损率表现为棉花生育期5-8月较小(0.03%～3.3%),到9月收获期显著增大(29%)。(2)降解膜处理的棉花出苗率显著小于CK。(3)棉花生育期内,降解膜膜下5 cm、15 cm和25 cm的平均土壤温湿度均小于CK。(4)棉花生育期内,0～20 cm和20～40 cm土层,降解膜和CK间的土壤速效氮、磷、钾、盐分和pH均无显著差异。(5)降解膜处理的棉花产量及其构成均与CK无显著差异。表明南疆棉花生育期5-8月,全生物降解地膜降解不明显,但吐絮期后,降解率显著增大。尽管降解膜处理的棉花出苗率、棉花生育期不同土层(5 cm、15 cm、25 cm)的平均土壤温湿度均小于CK,但是降解膜处理对棉花生育期不同土层(0～20 cm和20～40 cm)的土壤养分(速效N、P、K)含量、盐分和pH无显著影响,且对棉花产量无显著影响。综上分析认为,在南疆棉花生产中使用全生物降解地膜取代普通聚乙烯地膜是可行的。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).