Nitrogen top-dressing requirements of winter oilseed rape

Forty-one field experiments were carried out on the spring N top-dressing requirements of winter oilseed rape in the years 1973 to 1977. The experiments were in the main rape-growing areas of England and Scotland, and almost all were on rape crops following one or more cereals. Seed and oil yield were increased by N top-dressing in 38 of the 41 experiments, with a mean requirement by satisfactory crops for about 230 kg ha^?1 of N. Those experiments with no response to N or no response beyond 90 kg ha^?1 of N were mostly low yielding and suffered from lodging, drought or bird damage. N reduced oil content by about 2% on average, but there was a considerably larger depression in 10 experiments, almost always associated with low yield, drought or lodging. N fertiliser increased the N content of the seed by about 0.5%. Timing of N application within the period mid-February to late March had little influence on seed yield or oil content but applying all or half the N in April tended to give a lower yield. There was no advantage from splitting the N application.     

Seedbed fertilizer requirements of winter oilseed rape

Thirty-four field experiments were carried out on the seedbed fertilizer requirements of winter oilseed rape in the main rape-growing areas of England and Scotland. Average seed yield was increased by seedbed N from 2.711 ha^?1 to 2.881 ha^?1 (when 200 kg ha^?1 N was given in spring). Economic analysis showed 60 kg ha^?1 as likely to be the most profitable rate of seedbed N for most situations. P fertilizer increased yield significantly on soils with low or moderate levels of available soil P but there was little response to K fertilizer on soils of high or medium K status and too few experiments on low K status soils to quantify requirements thereon. S application to the seedbed (as calcium sulphate) did not increase yield. Seedbed N decreased seed oil content slightly and not always significantly while P, K and S had no effect. Nutrient removal in the seed of an average 3 t ha^?1 crop would be 90 kg ha^?1 of N, 17 kg ha^?1 of P (40 kg ha^?1 P₂O₅) and 17 kg ha^?1 of K (20 kg ha^?1 K₂O).     

油菜黑胫病菌Leptosphaeria biglobosa生物学特性研究

为了解我国油菜黑胫病病原菌（Leptosphaeria biglobosa）的生物学特性,在实验室里研究了温度、pH值、光照、碳源及氮源等条件对该病菌营养生长及分生孢子产生的影响。结果表明：病原菌在5℃～35℃均可进行营养生长并产孢,最适生长和产孢温度为25℃;在pH4～10的范围内该菌均能生长并产孢,在pH7的条件下生长最快,产孢最多。光暗交替有利于菌丝生长和产孢,而持续光照不利于菌丝生长,尤其不利于产孢。最适的碳源、氮源分别是可溶性淀粉、牛肉膏。分生孢子的致死温度为52℃。     

Agriculture group symposium recent UK research on oilseed rape

The following are summaries of papers presented at a meeting of the Agriculture Group of the Society of Chemical Industry, held on 16 February 1982 at the Society of Chemical Industry, 14 Belgrave Square, London SW1X 8PS. The papers so published are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of the Journal of the Science of Food, and Agriculture.     

氮磷钾肥施用对甘蓝型春油菜产量及肥料利用效率的影响

利用大田试验研究氮、磷、钾肥对青海省互助县种植的甘蓝型春油菜产量、养分吸收量和肥料利用效率等指标的影响。结果表明,氮肥和磷肥对春油菜（甘蓝型杂交油菜青杂2号）籽粒产量的提高有显著作用,钾肥的影响相对较小;与不施肥对照相比,氮、磷、钾肥的施用可显著促进成熟期春油菜地上部N、P、K素累积量（P〈0.05）;不同肥料的春油菜农学利用率分别为5.3kg/kg N、5.6kg/kg P2O5和1.7kg/kg K2O;肥料表观利用率分别为N 33.6%、P2O57.8%和K2O 52.0%,N、P、K肥对油菜籽产量的偏生产力分别为28.0kg/kg N、46.7kg/kg P2O5和26kg/kg K2O。青海省互助县种植条件下,当春油菜产量水平在3 504kg/hm2时,NPK配施条件下每生产100kg籽粒需要吸收N、P2O5、K2O量分别为4.6kg、2.0kg和5.6kg,氮磷钾比为1∶0.43∶1.21。油菜生产实践中实现高产目标需同时关注地力培肥和平衡施肥两方面。     

The response of double-low winter oilseed rape to fertiliser sulphur

The effect of soil-applied ammonium sulphate (10, 20, 30, 50 and 80 kg S ha^?1) and agricultural gypsum (20 and 50 kg S ha^?1) and of foliar-applied elemental sulphur (20 kg S ha^?1) on the seed yield and chemical composition of double-low cultivars of winter oilseed rape was determined at 11 sites in England during 1989-1991. Significant (P ? 0.05) mean seed yield responses to applied sulphur (S) of 10 and 17% were obtained at two sites on sandy soils in northern England which showed symptoms of severe S deficiency. At a third site on a shallow calcareous soil in south-west England, which did not show S deficiency symptoms, seed yield was consistently but not significantly increased by an average of 8%. At one of the sites in 1989, application of ammonium sulphate caused leaf scorch and, at the maximum rate of S applied, seed and oil yield were decreased. No conclusions were reached regarding the amount of S required for maximum yield response. The S treatments decreased seed oil content by an average maximum of 9 mg g^?1. Seed glucosinolate content was increased by a greater amount at the two sites in northern England compared to other sites, where increases averaged only 3 μmol g^?1. Analysis of individual glucosinolates in the harvested seed from one of the sites in northern England showed that only the alkenyl glucosinolates were increased by S application. Yield responses were best predicted by total S concentrations and N : S ratio values in young fully-expanded leaves at flowering. Foliar-applied elemental S was consistently less effective in raising leaf S content than ammonium sulphate. Gypsum was occasionally found to be less effective than ammonium sulphate as an S fertiliser.     

Fertiliser requirements of potatoes in relation to kind of soil and soil analysis

Responses of maincrop potatoes to N, P and K fertilisers were measured in 119 experiments done by Soil Scientists of the National Agricultural Advisory Service in the years 1955-62. The experimental sites were spread over 13 soil groups, most of which corresponded to particular soil series. Average crop responses to P and K are given for each soil group. The amount of response was related to soil texture and to content of soluble P or K in the soil. For a given content of soluble P in the soil, crops on loamy sand and sandy loam soils gave a larger response to the first level of P fertiliser (0.5 cwt P₂O₅ per acre) than did those on silty loams, clay loams and clays; but the additional response to the second level of P fertiliser and, consequently to the optimum dressings of P, was greater for crops grown on the heavier-textured soils. P response was also related to depth of freely drained soil, sites with impeded drainage giving larger responses to P than freely drained sites. The proportion of soils poor in K, crop responses to K and optimum dressings of K fertiliser were all greater for the loamy sands and sandy loams than for the silty loam, clay loam and clay soils. The optimum dressings of N and K for almost all the soil groups were less than the average amounts currently used on maincrop potatoes in Great Britain; however, the seasons seem to have been relatively unfavourable to N and K responses. For P, the average amounts used were less than the optimum for most of the silty loam, clay loam and clay soils but more than the optimum for most soils of lighter texture.     

Immunological investigation of lipases in germinating oilseed rape,Brassica napus

An anti-lipase antibody has been used to investigate the lipases of cotyledons from germinating seedlings of oilseed rape, Brassica napusL, var Mikado. Immunological and enzymic assays revealed that lipases were confined to germinating seeds and were absent from other tissues, such as developing seeds, leaves, roots and flowers. The antibody totally inhibited microsomal lipase activity at a ratio of 12 μg IgG protein: 10 μg microsomal protein. It was shown by immunoblotting of microsomal, oil-body and total cotyledon proteins separated by gel electrophoresis that, in each case, the antibody specifically bound to a single polypeptide. This polypeptide had an electrophoretic mobility consistent with a molecular weight of 56 kDa. The appearance and subsequent decline of the 56 kDa polypeptide during the first 10 days of germination closely followed that of the lipase activity, both in microsomal protein and total cotyledon protein fractions. An ELISA for the lipase demonstrated that the amount of immunoreactive microsomal lipase present at each stage of germination was proportional to its enzymic activity. The enzymic and immunological activities of the microsomal lipase each exhibited buoyant densities of 1.087 g ml^?1 on sucrose density gradients. Lipases were present in only very small amounts in dry seeds and were synthesised de novo after 2–3 days of germination.     

安徽冬油菜新害虫——油菜叶露尾甲

2008年在安徽省巢湖市发现一种危害冬油菜的新害虫,经初步鉴定为油菜叶露尾甲Strongyllodesvarie—gatus（Fairmaire,1891）。田间调查和试验表明：油菜叶露尾甲在安徽主要分布于巢湖市、马鞍山市、宣城市、安庆市、六安市,以及合肥市和滁州市的部分地区。该害虫在安徽年发生2代,每年3～5月及9～11月出现。3～5月是其主要的为害期和繁殖期。成虫取食油菜叶片、嫩茎和花蕾,形成“半月牙”状伤口和“秃梗”状;幼虫潜叶取食叶肉,形成不规则“亮泡”状,导致叶片枯死,提前脱落。老熟幼虫在土中化蛹、羽化;成虫入土或混在油菜种子中越夏、越冬。其在油菜上危害有加重的趋势。     

渍水对油菜苗期生长及养分吸收的影响

为了解渍水对油菜的影响和恢复期油菜养分的变化,采用盆栽试验,研究不同持续时间的渍水对油菜（Brassica napus L.）品种中双11号苗期生长及养分吸收的影响。结果表明,渍水对苗期生长的不利影响不仅在于渍水期间,还在于渍水后生长恢复所需的时间。随渍水时间延长,叶片氮（N）、磷（P）、钾（K）、铁（Fe）、锌（Zn）、铜（Cu）含量显著降低,锰（Mn）含量显著升高;根系N、Fe、Zn、Cu含量显著升高,P含量显著降低,Mn含量3d时显著升高之后显著降低,而K含量没有显著变化。渍水使土壤中硝态氮与铵态氮的比例显著降低;速效P含量显著降低;速效K和有效态Fe、Zn含量出现先升高后降低的波动;有效态Cu在渍水期间没有显著变化,渍水后显著降低。     

生物肥料对油菜的促生及菌核病防治的研究

盆栽试验证明,施用枯草芽孢杆菌Tu-100制作的生物肥料,在油菜5叶期,植株干重比对照增加1．80％,叶绿素含量增加17．15％;油菜根际的好气性细菌总数比对照有一定的提高,产量比对照增加7．90％。田间小区试验表明,施用生物肥料的处理,在油菜5叶期,植株干重比对照增加3．88％,叶绿素含量增加3．67％,植株全磷和全钾的含量也有不同程度的增加,产量增加4．90％;此生物肥料对油菜菌核病菌核的萌发有一定的抑制作用。     

The impact of climate change on disease constraints on production of oilseed rape

Weather data generated for different parts of the UK under five climate change scenarios (baseline, 2020s low CO₂ emissions, 2020s high emissions, 2050s low emissions, 2050s high emissions) were inputted into weather-based models for predicting oilseed rape yields and yield losses from the two most important diseases, phoma stem canker and light leaf spot. An economic analysis of the predictions made by the models was done to provide a basis to guide government and industry planning for adaptation to effects of climate change on crops to ensure future food security. Modelling predicted that yields of fungicide-treated oilseed rape would increase by the 2020s and continue to increase by the 2050s, particularly in Scotland and northern England. If stem canker and light leaf spot were effectively controlled, the value of the crop was predicted to increase above the baseline 1980s value by ￡13 M in England and ￡28 M in Scotland by the 2050s under a high CO₂ emissions scenario. However, in contrast to predictions that phoma stem canker will increase in severity and range with climate change, modelling indicated that losses due to light leaf spot will decrease in both Scotland and England. Combined losses from both phoma stem canker and light leaf spot are predicted to increase, with yield losses of up to 40% in southern England and some regions of Scotland by the 2050s under the high emission scenarios. For this scenario, UK disease losses are predicted to increase by ￡50 M (by comparison with the baseline losses). However, the predicted increases in fungicide-treated (potential) yield and phoma stem canker/light leaf spot yield losses compensate for each other so that the net UK losses from climate change for untreated oilseed rape are small.     

Contamination of edible double-low oilseed rape crops via pollen transfer from high erucic cultivars

Contamination of double-low oilseed crops with pollen from high erucic varieties grown primarily on set-aside land may result in erucic acid concentrations above 2% resulting in its rejection as a double-low edible oilseed. An analysis of cross contamination between high and low erucic acid crops was carried out in field trials at Cockle Park, and Purley Farm, Essex in the 1992–1993 and 1993–1994 seasons. Contamination was generally low and at random across the test areas. This random fluctuations in erucic acid concentrations appeared to be due to insect activity rather than wind mediated pollen transfer. Roto-rod traps used at Cockle Park to measure pollen flow downwind from isolated blocks of oilseed rape showed that in both seasons a rapid exponential decline in pollen concentration occurred with distance from the source. Results presented in this study would suggest that contamination between edible and high erucic crops does not present a major problem under field scale cultivation. © 1998 SCI.     

Effect of harvest date and pod position on glucosinolates in oilseed rape (Brassica napus)

Pod samples from four varieties of winter oilseed rape (Brassica napus L) were taken twice weekly from 26 to 3 days before harvest from upper, middle and lower third portions of the main raceme. Seeds were analysed for individual glucosinolate concentration by HPLC. Total glucosinolate content increased suddenly during the sampling period. The timing of the increase depended on variety but occurred before harvest would have been practical. Proportions of individual glucosinolates in Rafal, the only “high” glucosinolate variety examined, did not change over the sampling period. In the other varieties, the proportion of 2-hydroxy-but-3-enyl (progoitrin) increased and the proportion of 2-hydroxy-pent-4-enyl decreased as sampling progressed, so that the concentration of individual glucosinolates could not be predicted from total glucosinolate content. The ‘low’ glucosinolate varieties contained a significantly smaller concentration of progoitrin and summed aromatic glucosinolates than Rafal. Variations in glucosinolate content with pod position were smaller than those due to sampling date, but there was a greater concentration of glucosinolates in seeds from pods lower on the terminal raceme. The results would indicate that care should be taken if seed samples from the plant are taken.     

施肥对贵州直播油菜产量和养分吸收的影响

2011-2012年于贵州省油菜主产区设置直播油菜氮磷钾硼肥田间试验,以推广品种油研599为材料,研究施肥对产量、养分累积量、肥料利用率及经济效益的影响,了解当地（典型的南方水稻土）的养分限制因子,为该地区直播油菜的合理施肥提供依据。结果表明,与不施肥相比,施肥提高了直播油菜的产量,各处理中以NPKB处理的产量最高,平均为2 189kg/hm2。缺氮、缺磷、缺钾和缺硼处理相比NPKB处理分别减产961、342、295和184kg/hm2,表明该地区直播油菜的养分限制因子依次为N〉P〉K〉B。与当地农民习惯施肥（FFP）相比,NPKB处理增加了施肥量,产量明显提升,平均增产430kg/hm2;养分累积量和肥料利用率也均有明显提高,氮、磷、钾及相应肥料利用率分别增加28.6kg/hm2和13.5%、9.6kg/hm2和3.3%、71.4kg/hm2和23.9%。从经济效益看,NPKB处理相比FFP处理收益平均增加1 109元/hm2。肥料合理配施可以明显提高直播油菜产量、养分累积和经济效益,在当前贵州省直播油菜的生产中,应积极推行合理的平衡施用技术和科学的施肥方法,从而达到高产、高效、高收益的目的。     

我国油菜生产布局时空演变及影响因素分析

为进一步优化我国油菜生产布局,基于生产集中度指数、生产规模指数、空间重心分析、产地集中度系数等数据模型对21世纪以来我国油菜生产布局时空演变及影响因素进行分析。结果表明：进入21世纪以来,我国油菜主产省基本无变化,但受各省不同产业定位的影响,四川、湖南、重庆、云南油菜生产集中度指数逐年上升,安徽、江苏、浙江逐年下降;油菜产业扶持政策的陆续实施推动南方地区油菜生产规模自2007年逐渐上升,北方对应下降,东、中、西三部及七大产区不同的区位特性导致国内油菜生产在空间布局上总体呈现“东减、中稳、西移”的特征;油菜籽产量及油菜播种面积空间重心则由中部逐渐向西南迁移;油菜产地集中度系数总体呈波动上升的趋势,即油菜生产趋向于主产地。受自然环境、产业模式、政策扶持、科技创新等综合影响,我国油菜产业的区位优势更加明显,空间布局日益优化。建议通过长江流域油菜优势产业带建设、油脂加工企业政策扶持、北方盐碱地开发、南方冬闲田扩种及油菜多功能开发利用等措施进一步提升我国油菜产业国际竞争力。     

Determination of total glucosinolates in oilseed rape by X-ray spectrometric analysis for oxidised sulphur (S6+)

A rapid X-ray spectrometric (XRS) method has been developed for the determination of the total glucosinolate content of oilseed rape and other Brassica oilseeds. The method is based on analysis for fully oxidised sulphur (S⁶⁺), which includes half the sulphur (S) in the glucosinolate molecule, and the S in sulphate. Results are highly correlated with glucosinolate content determined by glucose release, a standard method widely used in Australia. The relationship is total glucosinolates = (23·97 S⁶⁺ -9·43) r² = 0·987, where the glucosinolate content is expressed as μmol g^?1 and the S⁶⁺ content in mg g^?1. The relationship is applicable to seed of any glucosinolate content and to meal, and is unaffected by changes in protein sulphur content. The correlation of glucosinolates with S⁶⁺ is shown to be closer than the correlation with total S. The latter correlation forms the basis of the existing XRS method, used within the European Community in recent years. The advantages of S⁶⁺ derive from the linearity of the regression and the elimination of errors caused by variation in protein content. The method should be valuable to the Australian oilseed industry because it allows the rapid screening of breeding lines to ensure low glucosinolate content and the assessment of deliveries for crushing and of meal.