添加残次苹果发酵物对稻草青贮品质及其微生物数量的影响

为了探讨添加残次苹果发酵物改善稻草的青贮品质及其适宜添加比例。按残次苹果发酵物和稻草质量比为全部为稻草（Ⅰ）、1∶9（Ⅱ）、3∶7（Ⅲ）、5∶5（Ⅳ）、7∶3（Ⅴ）、9∶1（Ⅵ）混合进行青贮。青贮90 d 后开封,测定青贮前后的营养成分,鉴定青贮饲料的感官品质、发酵品质以及有氧暴露情况下pH值和微生物数量的变化。结果表明,添加残次苹果发酵物显著提高青贮原料的粗蛋白（Crude Protein,CP）和可溶性碳水化合物（Water Soluble Carbohydrate,WSC）的含量（P<0.05）,降低了原料的中性洗涤纤维（Neutral Detergent Fiber,NDF）和酸性洗涤纤维（Acid Detergent Fiber,ADF）的含量（P<0.05）;青贮90 d天后,混合青贮饲料的乳酸（Lactate Acid,LA）、乙酸（Acetic Acid,AA）含量随着残次苹果发酵物添加量的增多而增加;处理Ⅰ的LA（0.17%）、AA（0.09%）含量最低,显著低于其他5个处理（P<0.05）,而丁酸（Butyric Acid,BA）含量、AN/TN（Ammonia Nitrogen Total Nitrogen）的比值显著高于其他5个处理（P<0.05）;有氧暴露后,随着有氧暴露时间的延长,各处理的pH值、酵母菌数量、霉菌数量逐渐增多,乳酸菌数量逐渐减少;处理Ⅰ的乳酸菌数量始终显著低于其他各处理（P<0.05）,酵母菌和霉菌数量始终显著高于其他各处理（P<0.05）;而处理Ⅲ、Ⅳ的乳酸菌数量始终显著高于其他处理（P<0.05）,酵母菌和霉菌数量始终保持较低水平。未添加残次苹果发酵物处理Ⅰ的感官评分和综合评分均为劣等,添加残次苹果发酵物的稻草青贮处理Ⅲ和处理Ⅳ的感官评分和综合评分均为优等;同时添加残次苹果发酵物增加了混贮的营养价值,改善了混贮的发酵品质。综合分析,在试验中添加残次苹果发酵物能改善稻草的青贮品质,其添比例在3∶7～5∶5之间适宜。     

同/异型乳酸菌对青贮玉米开窖后品质及微生物的影响

该研究旨在分析添加不同发酵类型的乳酸菌处理对开窖后玉米（Zea mays L.）青贮发酵品质、微生物数量及有氧稳定性的影响,为生产实践提供参考。设计4个添加乳酸菌玉米青贮处理：CK处理（不加任何菌剂）;T处理（同型发酵乳酸菌）：Lactobacillus plantarum和Pediococcus acidilactici复合添加,添加量为1∶1,1×105 cfu/g;Y处理（异型发酵乳酸菌）：Lactobacillus buchneri,添加量为1×105 cfu/g;TY处理（同型+异型发酵乳酸菌）：Lactobacillus plantarum、Pediococcus acidilactici和Lactobacillus buchneri复合添加,添加量为1∶1∶1,1×105 cfu/g。发酵期为60 d,检测开窖后各处理第0、48、96、144、192、240 h发酵品质及微生物的变化,应用隶属函数法对玉米青贮发酵品质及微生物数量进行综合评判。结果表明Y和TY处理的有氧稳定时间显著高于其余处理（63.87～64.67 h,P<0.05）,分别达到195.58和196.21 h,且乙酸质量分数始终显著高于CK和T处理（P<0.05）。T处理pH值始终显著低于其余处理（P<0.05）,且乳酸质量分数始终显著高于CK和Y处理（P<0.05）。Y处理WSC（water soluble carbohydrate）质量分数始终显著高于其余处理（P<0.05）,霉菌数量始终显著低于其余处理（P<0.05）。CK处理的NH3-N质量分数,好氧细菌数量及CO2产量始终显著高于其余处理（P<0.05）。开窖时间与各处理的CO2产量、乳酸菌和酵母菌数量分别满足Allometric1,ExpDec1和Logistic非线性关系,与霉菌和好氧细菌数量呈一元线性关系。综合评价排序：Y处理>TY处理>T处理>CK处理。因此,单一添加异型发酵乳酸菌的玉米青贮,开窖后在改善发酵品质、降低有害微生物数量、提高有氧稳定性方面均优于单一添加同型或复合添加乳酸菌的玉米青贮。     

液态发酵饲料连续发酵工艺

为建立一套液态发酵饲料的连续生产工艺,该研究以玉米-豆粕-麦麸混合物为发酵基质进行液态发酵菌株的筛选,通过监测发酵过程中液态饲料的pH值、乳酸菌数量、大肠杆菌数量、霉菌数量、酵母菌数量、酸溶蛋白质含量、可溶性糖含量等指标变化规律探究发酵菌株、连续发酵过程中保留比例、发酵温度、外源苯甲酸和外源酶制剂对发酵进程的调控及饲料营养价值的影响。结果表明：1）筛选出的乳酸菌菌株28-7具有较强的大肠杆菌抑制能力和产乳酸能力,发酵6 h时饲料pH值下降到4.45,发酵饲料中未检出大肠杆菌;2）接种乳酸菌28-7的连续发酵过程中,20%、30%、50%的保留比例对发酵饲料的pH值、乳酸菌数量、霉菌数量的影响差异不大,大肠杆菌均无检出,20%的保留比例可使连续发酵正向进行;3）外源非淀粉多糖酶的加入可显著提高发酵饲料中酸溶蛋白含量、酸溶蛋白/粗蛋白质比值和可溶性糖含量（P<0.05）,外源苯甲酸的加入可有效抑制发酵过程中霉菌的增殖。4）37 ℃条件下发酵可显著提高饲料中酸溶蛋白含量、酸溶蛋白/粗蛋白质比值（P<0.05）,3～12 、20 、37 ℃条件下获得的饲料的pH值<4.0、乳酸菌数量大于1010 CFU/mL,大肠杆菌、酵母、霉菌未检测出。综上,本研究建立的液态发酵生产工艺为：将乳酸菌28-7（接种量1.0×108 CFU/mL）、非淀粉多糖酶（250 g/kg）、苯甲酸（0.1 g/kg）于发酵起始时同时加入,以24 h为发酵周期、20%的保留比例在3～12 （冬季室温）、20 （春秋平均室温）、37 ℃（夏季平均室温）条件下进行生产。该工艺生产所得的液态发酵饲料色泽淡黄,富有温和的酸香味,饲料pH值<4.0,乳酸菌数量>1010 CFU/mL,酸溶蛋白含量、酸溶蛋白/粗蛋白质比值均显著提升（P<0.05）,霉菌、酵母、大肠杆菌无检出,相比春、秋、冬3季,夏季生产更有利于饲料酸溶蛋白含量的提升（P<0.05）。     

盐胁迫对枸杞叶片糖代谢及相关酶活性的影响研究

试验研究盐胁迫对枸杞叶片糖代谢及相关酶活性的影响结果表明,随NaCl浓度升高和处理时间的延长,枸杞叶片多糖和可溶性糖含量显著增加(P<0.05),蔗糖含量呈上升趋势,而淀粉含量显著下降(P<0.05),还原糖含量呈下降趋势。随NaCl浓度的增加,枸杞叶片中中性转化酶活性显著降低(P<0.05);3g/kg、6g/kg NaCl处理对酸性转化酶活性影响较小,3g/kg NaCl处理降低蔗糖合成酶而对蔗糖磷酸合成酶活性基本无影响;6g/kg NaCl处理蔗糖合成酶活性随时间先降后升,而对蔗糖磷酸合成酶活性影响较小;但9g/kg NaCl处理显著降低酸性转化酶、蔗糖磷酸合成酶活性(P<0.05)。     

甜高粱茎秆固态发酵生产燃料乙醇研究

该文通过研究甜高粱茎秆M-81E固态发酵生产燃料乙醇的主要影响因素,确定发酵条件为:耐高温酿酒酵母接种量为3%,发酵初始基质含水率为76%,添加0.25?Cl2,0.25%MgS04·7H2O,40℃发酵24 h,乙醇得率为6.42 g/(100g)甜高粱茎秆,转化率为90.5%,残糖含量低于0.3%;添加10 FPU/g纤维素酶和10 CBU/g β-葡萄糖苷酶,进行同步糖化固态发酵,乙醇得率为7.53 g/(100 g)甜高粱茎秆,与不添加纤维素酶和β-葡萄糖苷酶的相比,乙醇得率提高了14.6%.     

苹果渣固态发酵苹果醋工艺研究

以新鲜苹果渣为主要原料,采用果胶酶法对苹果渣的酒精发酵和醋酸发酵工艺进行优化研究,通过正交试验确定最优酿造工艺参数。初步获得的苹果渣酒精发酵条件是果胶酶添加量0.06%、酵母接种量8%、初始糖度16 °Brix;苹果渣醋酸发酵过程的最优工艺条件是干湿苹果渣的配料比为1 ∶ 10、醋酸菌接种量15%、发酵温度32 ℃,此条件下总酸含量增长到38.267 6 g/L。     

利用小麦秸秆生产木霉分生孢子及其生物有机肥对黄瓜的促生效果

【目的】木霉是重要的植物根际促生功能菌,然而木霉类生物肥料生产的应用基础研究很薄弱。本研究以小麦秸秆为发酵基质,探究哈茨木霉T-E5产分生孢子的固体发酵工艺条件,并验证发酵物作为生物有机肥的促生效果。【方法】在实验室条件下,以小麦秸秆为固体发酵基质,研究固体发酵的不同发酵方式,温度、酸浓度、酸种类、接种量、含水量、外加碳源和氮源等单因子条件下的产孢量;再利用正交试验设计,研究温度、酸浓度、含水量、接种量、外加氮源和碳源的发酵条件优化。利用两季温室盆栽试验测定包括施用化肥、有机肥、发酵物和不同肥料组合的5个不同施肥处理的黄瓜地上部生物量、株高和叶面积。采用稀释涂布法测定黄瓜盆栽根际土中总真菌数量和木霉菌数量。【结果】单因素条件优化:基质用稀硝酸 (0.1 mol/L) 调节酸度值后接种3%(v/w) 的1 × 107个/mL的T-E5孢子液,调节水分使初始含水量达到75%;在此条件下,添加尿素和玉米粉,在28℃下发酵培养8天,最大产孢量可达到8.87 × 109个/g。通过正交优化,每10 g小麦秸秆,加入调节酸度值的0.05 mol/L硝酸18.3 mL,含水量70%(湿基),接种量9%,添加尿素的量为1%,30℃浅盘培养8天,产孢量达到1.1 × 1010个/g。第1季盆栽试验结果表明,与单施化肥处理 (CCK) 相比,发酵产物与化肥配施 (CT) 使黄瓜的地上部分生物量、株高和叶面积分别提高14.97%、16.75%和14.64%;与单施有机肥处理 (OCK) 相比,发酵产物与有机肥配施 (OT) 使黄瓜的地上部分生物量、株高和叶面积分别提高10.62%、26.06%和9.53%。第2季盆栽也有类似的促生效果,与CCK相比,CT使上述指标分别提高12.83%、11.49%和26.93%;与OCK相比,OT使上述指标分别提高5.96%、34.29%和18.01%。两季盆栽添加木霉发酵物的处理中根际土总真菌数和木霉菌数量相比CCK、OCK和不施肥照 (CK) 均增加1个数量级以上。【结论】以小麦秸秆为主要原料,采用固体发酵工艺可生产高分生孢子含量的哈茨木霉菌剂及其生物有机肥,表明利用农业废弃物生产高附加值的木霉菌剂及其生物有机肥具有可行性。但木霉孢子数量主要受发酵条件影响,今后应在中试和工厂化生产水平进一步研究木霉孢子固体发酵的工艺参数。     

龙眼果浆复合乳酸菌发酵工艺优化

为筛选出适合龙眼发酵的复合乳酸菌,优化建立其发酵工艺,比较分析了7种不同的乳酸菌发酵龙眼的降糖能力和释放结合态酚类物质的能力,发现明串珠菌降糖能力最强,植物乳杆菌释放结合态酚能力最强。利用植物乳杆菌和明串珠菌复合发酵龙眼果肉,以游离酚质量分数和还原糖质量分数结合的综合模糊评判值为指标,通过Box-benhnken中心组合试验设计,确定复合乳酸菌发酵龙眼的最佳工艺条件。结果表明,各因素对复合乳酸菌发酵龙眼果浆的模糊评判值影响程度从强到弱依次为:发酵时间发酵温度接种量料液比。复合乳酸菌发酵龙眼的最佳工艺为:料液比为1∶7(g/m L),发酵温度为37℃,发酵时间为53 h,接种量为1.4%,菌种配比为1∶1。在最佳工艺条件下,发酵龙眼果浆的游离酚质量分数为(161.77±3.93)mg/(100 g),还原糖质量分数为(122.80±3.64)mg/g。该研究为开发低糖含量,且适合糖尿病、肥胖症等病人食用的龙眼乳酸菌发酵饮料新产品提供参考。     

接种菌剂对鸡粪堆肥的影响

将鸡粪与稻草混合均匀后接种芽孢杆菌菌剂,接种发酵菌剂处理发酵温度显著提高,堆体温度≥50℃的时间比对照增加3 d.发酵前期接种处理的pH值高于对照,第7 d接种处理和对照的pH值分别为9.23和8.87.发酵后期接种处理的pH值低于对照,发酵结束时,接种处理和对照的pH值分别为8.22和8.31.接种处理和对照的电导率和碳氮比总体变化趋势相同,都呈现下降趋势,但是接种处理的电导率和碳氮比在堆肥后期显著低于对照.发酵结束时,接种处理和对照的电导率值分别为1.78和2.12 mS/cm,碳氮比分别为14.2和16.9.     

植物乳杆菌ST-Ⅲ脱脂乳的发酵工艺优化

为研发富含植物乳杆菌ST-Ⅲ新型益生菌发酵乳制品,该试验尝试用植物乳杆菌ST-Ⅲ和嗜热链球菌共发酵,并对植物乳杆菌ST-Ⅲ发酵乳的工艺进行了优化研究。通过单因素试验分析了大豆多肽添加量、葡萄糖酸锰添加量、嗜热链球菌的接种量和发酵温度对发酵乳的pH值和植物乳杆菌ST-Ⅲ活菌数的影响。通过响应面法优化并确定了最佳工艺条件:大豆多肽添加质量分数11 g/kg;葡萄糖酸锰添加质量分数11 mg/kg;嗜热链球菌的接种量106 CFU/g;植物乳杆菌ST-Ⅲ的接种量106 CFU/g;发酵温度为37℃。在此优化最佳工艺条件下,发酵乳的植物乳杆菌ST-Ⅲ的活菌数为1.88×109 CFU/mL,有效地提高了发酵乳中植物乳杆菌ST-Ⅲ的活菌数。研究结果可为拓展植物乳杆菌ST-Ⅲ在乳制品领域的应用提供参考。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.