Soil forming and plant density effects on carrot yield and internal quality

The effects of soil forming (SF) and plant density (PD) on the carrot yield, mean root weight and internal quality was studied in field experiments in 1993 and 1994. Fontana BZ carrots were grown in flat land, a narrow ridge, a broad ridge, and a compacted broad ridge soil configurations with low (LD) and high (HD) target plant densities, four and seven hundred thousand carrots per hectar. The total and marketable yields were larger in flat land and narrow ridge than in the broad- and compacted broad ridges in 1993 and in 1994 at HD. The number of marketable carrots were highest with the flat land soil configurations in both years. A dry spring in 1993 favored flat land growing conditions; in ridges the fine sand dried quickly. SF did not influence the mean weight of a marketable carrot in 1993, but in 1994 the narrow ridge configuration resulted in heavier carrots than the flat land or broad ridge growing conditions. In the climatically more unfavorable year of 1993, SF and PD affected quality; dry matter was lower in flat land than in the ridges. At HD, the flat land soil configuration produced higher glucose and fructose than carrots grown in the narrow and broad ridges. Dietary fiber and vitamin C were higher in narrow ridge than in compacted broad ridge grown carrots. At LD the flat land and broad ridge produced highest and compacted broad ridge the lowest beta-carotene contents; alpha-carotene was higher at LD than at HD.     

Steam treatment to prevent carrot decay during storage

Organically grown carrots (Daucus carota L.) have a relatively short storage and shelf life, mainly because chemical measures cannot be implemented to control plant pathogens. Laboratory experiments demonstrated that steam treatments substantially reduced decay of stored organically grown carrots. Prior to being packaged, winter carrots were exposed to 3 s of steam. After 60 days of storage at 0.5°C plus an additional week at shelf conditions (20°C), 2% of the carrots were decayed, as opposed to 23% in the nontreated control. When carrot was inoculated with the fungi Alternaria alternata, [(Fr. : Fr.) Keissler] A. radicina (Meier) and Sclerotinia sclerotiorum [(Lib.) De Bary], percentages of decay, after similar periods of storage and shelf life, were 5% for steam-treated carrot and 65% for the nontreated control. In semi-commercial experiments carrots were treated with steam during the sorting process, and similar results were obtained. Higher decay was found in spring-grown carrots because of the presence of the bacterium Erwinia carotovora.sub. sp. carotovora     

Influence of treatment of soil with carbofuran on the subsequent performance of insecticides against cabbage root fly (Delia radicum) and carrot fly (Psila rosae)

A sandy loam soil was treated with 2·5 kg carbofuran/ha on each of five occasions between May and October 1984. In 1985, the field performance of benfuracarb, carbofuran, carbosulfan, chlorfenvinphos and furathiocarb against cabbage root fly (Delia radicum) and carrot fly (Psila rosae) was studied in this soil and in identical but previously untreated soil by applying exponentially increasing doses of granular formulations to radish and carrots at drilling. Chlorfenvinphos reduced numbers of larvae of both pests by >90% in both soils but the performance of all the carbamates was significantly worse in the previously treated soil than in the previously untreated soil. Dazomet, a partial soil sterilant, was applied to part of the experimental area in October 1985 and the performance of aldicarb, carbofuran, carbosulfan, chlorfenvinphos and thiofanox against cabbage root fly was assessed in 1986. The efficiency of aldicarb and chlorfenvinphos was not affected by any of the pre-treatments but that of carbofuran and carbosulfan was reduced in all the pre-treated soils, including the soil treated with dazomet. Carbofuran residues in radish were detectable only in plants grown in previously untreated soil. In laboratory incubations, a dustless base formulation of carbofuran was degraded more quickly in pre-treated than in untreated soils but a granular formulation was degraded more slowly and at a similar rate in both soils.     

Effect of mineral nutrients on spot blotch severity in wheat,and associated increases in grain yield

Spot blotch, caused by Cochliobolus sativus, is a serious disease of wheat (Triticum aestivum L.) in the warm lowlands of South Asia. A field study was conducted using two wheat varieties (Bhrikuti and Sonalika) during the 2001 and 2002 wheat seasons in Rampur, Nepal, to determine the effect of nitrogen, phosphorus, potassium, and chlorine fertilization on reducing spot blotch severity in wheat, and its associated increase in grain yield. Application of N alone reduced spot blotch severity by 8% in 2002. Phosphorus fertilization had no effect on spot blotch development. The balanced application of N, P, and K reduced disease severity by 15 and 22% in 2001 and 2002, respectively. Application of KCl as well as CaCl₂ reduced spot blotch severity, but the former caused 11% greater reduction than the latter. The two varieties responded differently to the mineral nutrients’ effect on spot blotch severity, suggesting the nutrients’ importance in cultivar selection when considering the effect of soil fertility on susceptibility to foliar diseases. The lower disease severity and higher grain yield observed after the application of KCl compared to CaCl₂ showed that KCl should be used on K-deficient soils in the warmer wheat growing regions of South Asia where spot blotch is a serious perennial wheat disease in intensive rice–wheat cropping systems.     

耕作方式对连作大豆生长发育及产量的影响

采用秋旋耕起垄、秋深松旋耕起垄、春旋耕起垄和春顶浆打垄4种土壤耕作方式,进行田间大区试验,以探讨土壤耕作方式对连作大豆生长发育及产量的影响。试验结果表明,秋旋耕起垄和秋深松旋耕起垄出苗率高于春旋耕起垄和春顶浆打垄,出苗率均达85%以上,秋整地大豆生育期间干重、根瘤重和叶面积指数均高于春整地,秋旋耕起垄大豆根际微生物总数最多,细菌和放线菌数量明显高于春顶浆打垄。秋季整地地下害虫——蛴螬（Holotrichia diomphalia Bates）危害率比春季整地低10%左右,春顶浆打垄危害率高达34.3%。秋整地大豆的灰斑病发生程度、籽粒紫斑粒率和虫食率均低于春整地,秋整地产量较春整地增产16%以上,从本试验可以看出黑龙江省黑土平原区秋整地对连作大豆效果更好。     

Nutritional composition of selected green leafy vegetables,herbs and carrots

Six green leafy vegetables and herbs – spinach, amaranth, bengal gram, cauliflower, mint, coriander and carrots – were analyzed for moisture, protein,ascorbic acid, -carotene, total iron, ionizable iron (as % of total iron) in vitro iron (% of total iron), copper, manganese and zinc. Moisture content of the leaves and carrots varied from 75.1 percent (bengal gram) to 95.4 percent (carrot) and protein from 9.83 percent (carrots) to 30.9 (mint) percent. Ascorbic acid, -carotene, total iron and ionizable iron contents were at a maximum in case of bengal gram leaves whereas level of ionizable iron and in vitro iron as a percent of total iron was highest in carrots. Copper, manganese and zinc contents were maximum in spinach.     

玉米纹枯病菌的分子检测

近年来随着气候的变化和玉米种植密度的加大,玉米纹枯病发生日益严重,该病株残体残留在田土表面土层较浅的区域进行越冬。为准确诊断玉米纹枯病,根据玉米主要病害玉米大斑病、玉米弯孢菌叶斑病、玉米灰斑病rDNA的ITS区间序列差别,设计合成1对特异性扩增引物（LZ-F+LZ-R）用于玉米纹枯病检测。该引物能从玉米纹枯病菌扩增到特异性的分子片段,说明设计的特异性引物可以用来检测玉米纹枯病菌。采集田间玉米纹枯病、玉米大斑病、玉米弯孢菌叶斑病、玉米灰斑病病株样本进行病原菌分离,同时提取其病原菌和土壤总DNA,利用上述引物进行扩增。结果表明,只有以R.solani基因组DNA为模板通过反应体系在PCR仪中进行扩增最终能扩增出1条460 bp左右清晰的特异性条带,其他菌株均无特异性条带。利用该特异性引物只能从受到该病害侵染的发病组织DNA中扩增出特异性条带,对照及健康玉米植株均无扩增条带。接种该病原菌的土壤DNA也扩增出相应的特异性条带,表明特异性引物LZ-F/LZ-R可用于玉米纹枯病菌的分子检测和早期诊断。     

不同播期和不同肥力条件下向日葵干物质形成和物质分配对杂交种产量的影响

不同的播期明显影响向日葵籽实产量及病害发生的程度。通过调整播期，可防止或减轻叶部斑病和菌核病的发生，在向日葵生产上起着很大作用。向日葵不同品种干物质积累规律符合Logistic生长曲线，可用方程y=k/(1 ae^-bx）模拟。向日葵植株的器官平衡依次为：除空壳外，茎秆（28.5%)、籽实（24.5%)、叶片（22.5%)、葵盘（17.3%)、叶柄（4.9%)。土壤肥力对向日葵的器官平衡有较大影响。经济系数不高是向日葵的一个特点。栽培条件不同，经济系数差异较大。在一般情况下，春播条件下经济系数较高，夏播条件下经济系数较低。     

不同氮、磷、钾肥配施对辽单565光合特性和产量的影响

以耐密型玉米辽单565为试验材料,研究不同氮、磷、钾肥配施对其光合特性和产量的影响。结果表明,氮肥试验中,辽单565穗上叶和穗位叶叶面积、穗位叶和穗下叶光合速率均以施氮量为135 kg/hm2时达到较高值,叶面积指数较高,穗位层叶片消光系数较小,产量较高;磷肥试验中,辽单565穗上叶和穗位叶叶面积、穗下叶光合速率均以施磷量为120 kg/hm2时达到较高值,穗位层叶片消光系数较小,产量较高;钾肥试验中,辽单565穗上叶光合速率和穗下叶叶面积均以施钾量为90 kg/hm2时处理较高,穗位层叶片消光系数较小,产量较高。不同氮、磷、钾肥配施试验中,以施氮量180 kg/hm2、施磷量75 kg/hm2、施钾量为90 kg/hm2时辽单565的产量最高。相关分析表明,穗上叶和穗位叶叶面积、穗下叶光合速率与产量均呈极显著正相关,穗位层消光系数与产量呈负相关。     

玉米褐斑病流行规律及GEM种质资源抗病性鉴定

近几年玉米褐斑病发生逐渐严重,已成为玉米生产上的一种主要病害。2007～2009年连续3年对冀东地区玉米褐斑病的发生规律进行了调查,并对57份美国GEM种质资源进行了田间自然发病条件下的抗病性鉴定。结果表明,7月份的降雨量是褐斑病流行的重要因素,Logistic模型能较好地拟合降雨量对褐斑病流行的影响;玉米拔节期是褐斑病防治关键期,当累积降雨量达到247.7 mm时要及时进行防治。抗病性鉴定结果表明,GEM种质资源中有37份免疫材料,占鉴定总数的64.91%;有8份抗性材料,占总数的14.03%。     

吉林省玉米推荐施肥指标体系的建立

通过总结2004~2014年间课题组在吉林省开展的田间试验及2005~2013年吉林省玉米"3414"田间肥效和校验试验资料,按土壤养分(播前耕层土壤硝态氮、速效磷、速效钾及10叶期0~90 cm土层土壤硝态氮)含量对土壤进行分级,进一步结合目标产量,初步建立以根层硝态氮调控为核心的总量控制、分期实时实地精确监控的玉米氮肥推荐施肥指标体系以及基于养分平衡和土壤测试的磷、钾肥恒量监控推荐施肥指标体系,为吉林省玉米合理科学施肥提供一定参考。     

东华北春玉米区玉米品种对主要病害和玉米螟的抗性评价

对东华北春玉米区24份玉米主栽品种进行玉米大斑病、弯孢菌叶斑病、灰斑病、丝黑穗病、茎腐病和玉米螟的抗性鉴定。高抗和抗大斑病品种11份,占参试品种的45.83%;高抗和抗灰斑病品种11份,占参试品种的45.83%;高抗和抗玉米弯孢菌叶斑病品种16份,占参试品种的66.67%;高抗和抗丝黑穗病品种10份,占参试品种的41.67%;高抗和抗茎腐病品种18份,占参试品种的75.0%;高抗和抗玉米螟品种6份,占参试品种的25.0%。综合抗性评价筛选出广谱抗性品种9份,占所有参试品种的37.5%。     

The effect of lygus bugs (Exolygus prantensis L.) on marketing price of red lentil in Anatolia, Turkey

The aim of this study was to assess the damage commonly known as chalky spot syndrome caused by the lygus bug on red lentil and the negative relation to the resulting marketing price in the commodity market of Sanliurfa, Turkey. Analysis showed that there was significant difference among the content (%) of chalky spot damage (range 1.45–29%) of lentil samples collected from the farmers who brought their crops to sell in the commodity market and this was negatively related to the market price that farmers received. Marketing prices of samples were also found to be significantly affected. The correlation between visually inspected chalky spot damage (%) and that of decorticated and weighted lentils was found to be positive and significant. Marketing prices also were found to be negatively correlated with the results of both inspection methods. Further analysis indicated that regression equations could be used for price estimation of lentil with different ratios of chalky spot. It was concluded that 10% chalky spot can reduce the marketing price from 0.426 to 0.396 $ kg⁻¹ when visually inspected and from 0.438 to 0.358 $ kg⁻¹ when decorticated.     

The Content of Phenolic Compounds and Radical Scavenging Activity Varies with Carrot Origin and Root Color

The contents of phenolic compounds and radical scavenging activities were assessed in a carrot collection comprising 35 cultivars, landraces and breeding populations. The accessions originated from various world regions and they represented Eastern and Western carrot gene pools. In two-year field trial carrot roots of orange, red, yellow, white and purple color were cultivated, freeze-dried and analyzed for phenolic content by Folin-Ciocalteu assay and UV/Vis assay. Radical scavenging activity in the extracts was determined with a stable DPPH radical. Carrots developing purple roots possessed on average 9 times more phenolics than roots of other colors. Furthermore, they were rich in anthocyanins that caused very high antiradical activity. Red carrots showed higher antioxidant activity than orange, yellow and white carrots and in the season of lower rainfall they accumulated higher amounts of phenolic compounds. Carrots of Asian origin belonging to Eastern gene pool were more often purple or red and richer in phenolics and had higher antiradical activity than those from the Western gene pool with mainly orange roots.     

Physical Quality and Carotene Content of Solar-Dried Green Leafy and Yellow Succulent Vegetables

The effects of vegetable type, vegetable dimensions, and solar drier load on dehydration rate; and texture, color, water activity, and carotene content of solar-dried carrots, sweet potatoes, and collard greens were studied. Mean dehydration rates (moisture loss,%/hr) for solar dried loads of 430 g/m² and 715 g/m² were 3.3 ± 0.30% and 3.8 ± 0.20% for carrots and sweet potatoes, respectively. Loads of 360 g/m² and 465 g/m² of collard greens had dehydration rates of 6.3 ± 0.10% moisture loss per hr. The results showed that vegetable type accounted for significant differences (p < 0.01) in dehydration rate, and beta-carotene content. Vegetable dimensions affected (p < 0.05) water activity. Solar drier load affected water activity (p < 0.01), and hue angle (p < 0.05). Beta-carotene contents (dry basis) of dehydrated carrot, sweet potato, and collard treatments were 10.9–17.4%, 7.6–9.8%, and 11.9–21.5%, respectively. Among the carrot treatments, the 5-mm thick slices packed at a load of 715 g/m² contained the highest beta-carotene (17.4%, dry basis) and vitamin A activity (362 IU/g, dry basis), and good physical properties. For collard greens, the 2-cm and 3-cm wide strips packed at 360 g/m² loads had the best combinations of high beta-carotene (21.5% and 17.2%, dry basis, respectively), vitamin A activity (357.2 and 293.1 IU/g, dry basis, respectively), and optimal color, texture, and water activity. Beta-carotene losses due to solar dehydration were 48.9–67.5%, 4.0–5.8%, and 1.9–19.8% (dry basis) in carrots, sweet potato and collard greens, respectively.     

施肥措施对重金属污染土壤-植物系统影响的研究进展

植物修复作为一种原位修复方法，因其投入成本低、拥有良好的经济效益和生态协调性等优点而成为国内外研究热点，在重金属污染农田实地得到广泛应用。本文综述施肥农艺措施强化重金属污染土壤植物修复以及对土壤-植物系统影响的研究进展，如土壤重金属含量和生物有效性的影响等，以便进一步提高植物修复效率，为今后规模化修复重金属污染农田土壤提供参考。     

Relationship of calcium nutrition to internal brown spot of potato tubers and sub-apical necrosis of sprouts

Potato tubers from field plots of calcium experiments in 1983 and 1984 were examined for the presence of internal brown spot. Presence of sub-apical necrosis on sprouts was also determined after storage in both years. Peel calcium concentration of 1983 tubers ranged from 0.226% to 0.130%; the range in percentage of these tubers with internal brown spot after 7 months storage was from 5.0% to 42.5%. The incidence of internal brown spot as well as sub-apical necrosis of sprouts was negatively correlated with tuber peel calcium levels (r = ?0.754 and r = ?0.792, respectively). Peel calcium concentration of 1984 tubers ranged from 0.224% to 0.104%; as in 1983, tuber calcium concentration was negatively correlated with the incidence of internal brown spot and sub-apical necrosis. Sub-apical necrosis of sprouts was present on 86.3% of the 1984 tubers with internal brown spot, and 65.3% of tubers with sub-apical necrosis on sprouts showed internal brown spot symptoms. The presence of sub-apical necrosis on tuber sprouts may serve as an indirect indicator of low calcium concentration in tubers.     

不同杀菌剂对花生叶斑病防治效果及产量影响的研究

为筛选出有效防治花生叶斑病的新型药剂,以传统药剂多菌灵为对照,采用三次叶面喷雾法测定了12种新型杀菌剂对叶斑病的防治效果及产量影响,结果表明:12种新型杀菌剂对花生叶斑病的防治效果在18.27%~44.24%之间,其中有效成分为25%吡唑醚菌酯、60%唑醚·代森联、32.5%嘧菌酯·苯醚甲、12%氟环唑、490g/L丙环·咪鲜胺、30%苯甲·丙环唑、46.1%氢氧化铜的防治效果较好,达到30%以上。从产量结果来看,各处理对花生产量增幅在10.53%~25.00%之间,其中增产效果最好的是75%肟菌·戊唑醇、25%吡唑醚菌酯、60%唑醚·代森联,增产效果分别为25%、20.8%和20.3%,显著优于其他药剂。总体来看,12种杀菌剂对花生叶斑病的防治效果与增产效果呈一致趋势。     

杜邦福星防治甜菜褐斑病田间药效试验

通过田间药效试验,研究了杜邦福星(40%氟硅唑EC)对甜菜褐斑病的防治效果。田间试验结果表明:杜邦福星3种剂量(30 mL/hm2;60 mL/hm2;90 mL/hm2)对甜菜褐斑病都有明显的防治效果且优于对照药剂禾本卡克(20%三苯基醋酸锡WP)和12.5%烯唑醇WP,3种剂量的防效分别为73.9%、85.3%、87.9%,根产量较空白对照分别增产24%、38%、30.2%,增糖0.46度、0.65度、1.94度。