黄瓜缺钙症的识别与防治

<正>1.症状识别黄瓜缺钙,新生叶变小,叶缘稍干枯,叶缘向内侧或外侧卷曲,呈匙状或勺状。成龄叶片向叶背面卷曲,呈蘑菇状或降落伞状,逐渐从边缘向内干枯;多数叶脉间失绿,主脉尚可保持绿色。有时上位叶叶脉镶金边,叶间出现白色斑点。植株矮化,节间变短,尤以顶部附近节间变短最明显,上位叶片小,叶缘枯死。严重缺钙时,叶柄变脆,容易脱落。植株长势减弱,花比正常的小,果实也小,风味差。     

茄果类蔬菜制种缺素症的防治

1症状1.1番茄症状1.1.1缺氮：植株生长缓慢呈纺缍形，全株叶色黄绿色，早衰，初期老叶黄绿色，后变浅绿色。小叶细小，直立，叶片主脉由黄色变为紫色至紫红色，下部叶片更加明显。茎秆细，果实小。后期下部黄色叶片出现浅褐色斑点。1.1.2缺磷：初期叶背紫红色，叶片上出现褐点，叶片僵硬，叶脉变紫色，下部叶片上卷，老叶变黄，茎部细弱，叶尖变黑褐色枯死，结果受到明显抑制。1.1.3缺钾：发病初期叶缘出现针尖大小黑褐色点，后茎部也出现黑褐色斑点，后融合成片。叶缘呈鲜橙黄色，叶脉间逐渐变黄，最后叶片边缘开始枯萎。质地变脆，茎变硬…     

水稻硫肥施用技术要点

<正>1.缺硫症状水稻缺硫时新叶失绿呈淡绿色或黄绿色,叶片变薄,有的叶尖焦枯;分蘖少或不分蘖,植株瘦弱矮小;根系生长不良,移栽后发根少,返青慢;成熟期推迟,结实率低,秕粒增加,产量降低。水稻缺硫症状类似于缺氮症状,即失绿和黄化比较明显;但由于稻株体内硫的移动性不大,缺硫症状首先在中上部叶片出     

提防玉米顶腐病流行危害

<正>去年江苏省不少地区的玉米上出现了一种新病害。苗期发病表现植株生长缓慢,叶片边缘失绿,出现黄色条斑,叶片皱缩、扭曲。成株期发病植株矮小,有的病株叶基部或边缘出现刀切状缺刻,叶缘和顶部褪绿呈黄亮色;有的叶片基部边缘褐色     

草莓定植后注意防治红中柱根腐病毁苗

<正>最近,有朋友咨询笔者,说是下了几天雨后天晴时发现种植的草莓成片地死亡,表现为叶片边缘微卷,叶尖出现萎蔫,逐渐发展成整个叶片萎蔫。病株呈矮化萎缩状,下部老叶叶缘变紫红色或紫褐色(图1),逐渐向上扩展,全株萎蔫或枯死。新叶有的具有蓝绿色金属光泽。检视根部,可见根系开始都由幼根先端或中部变成褐色或黑褐色而腐烂(图2),后中柱变为红褐色并腐朽(图3),继而扩展到根颈,病株易拔起并根颈部断开。据病症判断这是草莓红中柱根腐病的典型症状。     

春季冬小麦异常苗的识别与防治办法

1．缺氮黄苗植株矮小细弱,分蘖少而弱,叶片失绿、窄小直立,叶尖枯萎,植株下部老叶发黄。补救办法：苗期每亩追施尿素7．5～10千克,起身或拔节期每亩再追施尿素12～15千克,同时进行叶面喷肥,即用1％的尿素液喷施2次,每次间隔7天左右。     

对症分析草莓叶片卷缩原因及防治

<正>在草莓栽培中常见叶片卷缩的现象,防治须根据不同症状,辨别是什么原因造成的叶片卷缩?然后有针对性地开展防治。缺素引起的卷缩。比如草莓早期缺硼,幼叶皱缩或焦枯,叶片边缘黄色,生长点受损。随着缺硼加重,有的老叶叶脉间失绿,有的叶片上卷。缺硼植株的花小,授粉和结实率低,果实小,易畸形呈瘤状,品质差。可以喷施0.15%硼砂溶液2～3次,花期喷施浓度适当降低。缺钼时草莓叶色褪绿,最终黄化,严重时叶片焦枯,叶缘向上卷曲。可以喷施0.03～0.05%的钼酸溶液1～2次,以缓解症状。     

蚕豆主要病虫害的识别与防治

<正>1.蚕豆立枯病又称丝核菌茎腐病。蚕豆各生育阶段均可发病,主要侵染蚕豆茎基或地下部。茎基染病多在茎的一侧或环茎出现黑色病变,致茎变黑,有时病斑向上扩展达十几厘米,干燥时病部凹陷,几周后病株枯死。地下部染病呈灰绿色至绿褐色,主茎略萎蔫,后下部叶片变黑,上部叶片仅叶尖或叶缘变色,后整株枯死。     

苎麻的缺肥症状与施肥技巧

<正>苎麻是我国南方重要的经济作物,据测定,亩产100千克苎麻需施纯氮30~35千克、五氧化二磷10~15千克、氧化钾20千克。给苎麻施用氮、磷、钾肥,以氮肥和钾肥增产率大,磷肥次之。对苎麻种植而言,正确识别其缺肥症状,并掌握科学的施肥技巧非常重要。1.缺肥症状缺氮时,麻蔸发育不良,叶片变黄,植株矮小,分株数和有效分株数少,茎细叶稀,根系生长缓慢,出苗少而迟,纤维层薄。缺磷时,叶片呈暗绿或灰绿色且缺乏光泽,严重时叶尖、叶缘发生灰色干枯,茎细而脆,麻株成熟缓慢,根系发育不良,纤维品质差。缺钾时,叶片由黄白色斑点扩大成褐斑,叶片枯死,提     

水稻除草剂药害的诊断与补救

随着伊犁垦区水稻面积的逐年扩大，杂草危害也日益严重。除草剂大多数为复配除草剂，都含有苄磺隆、毗嘧磺隆、乙草胺、甲磺隆等，容易造成药害，主要表现为：白根少或无白根，根变黄、变黑或腐烂，根生长停止或变畸形；茎叶失绿，出现黄（褐、白）斑，茎叶扭曲变形，叶尖或整叶黄化枯萎；新叶和分蘖伸出缓慢或停止、叶和分蘖丛生、植株矮化等。现将除草剂药害的判断与补救方法介绍如下。     

A rapid method for screening barley for aluminium tolerance

Summary A method for rapid screening of large numbers of barley genotypes for aluminium tolerance is described, and the results of a small scale screening of composite cross CC XXX-C given.     

农业植物品种权申请前的准备

一项能够取得品种权的植物新品种,必须同时具备以下几个条件:属于国家植物新品种保护名录范围;不违反国家法律、妨害公共利益或者破坏生态环境;必须具备新颖性、特异性、一致性和稳定性;应当具备适当的品种名称.另外,品种权是不能自动取得的,即使合乎授权条件的植物新品种,也必须履行<中华人民共和国植物新品种保护条例>(以下简称<条例>)和<中华人民共和国植物新品种保护条例实施细则>(以下简称<实施细则>)所规定的品种权申请程序.为了减少品种权申请的盲目性,节省品种权申请人和植物新品种保护办公室双方的人力、物力和财力,品种权申请人在提出申请以前一定要做好以下准备工作.     

Nitrogen response models for winter cereals grown for forage

Forage double cropping can increase production, reduce erosion risk and improve soil health. Farmer experience in the north‐eastern USA shows that winter cereals can, in 3–4 weeks (Feekes 9 harvest), produce high quality forage given sufficient N at dormancy break. Here, we evaluate crop response models to determine the most economic rate of N (MERN) for forage winter cereals. Sixty‐three on‐farm N‐rate trials (0, 34, 67, 101, 135 kg N/ha) were conducted in New York from 2013 to 2016. Trials were divided into four categories: (a) no yield response to N (group 1; 20 trials); (b) yield plateau exceeded the highest N rate (group 2; one trial); (c) the MERN was below the lowest N rate (group 3; seven trials) and (d) all other N‐responsive trials (group 4; 35 trials). For group 4, three statistical models were compared (quadratic plateau, exponential and square root plateau). Statistical, environmental and economic criteria showed that the quadratic plateau fits the data best and had the most stable predictions across scenarios. The four‐category analysis is effective in determining MERNs of individual trials, and the quadratic plateau is best for determining forage winter cereal MERNs and yields at MERNs for individual trials in the north‐eastern USA.     

Contracting for Migration for the Reason of Zoological Environment

Migration for the reason of zoological environment is the measure for solving the crisis of zoological environment. Nowadays, governments play the chief role in the Migration for the reason of zoological environment, but the migration themselves do not have the freedom to decide whether migrate or not. Because the activity of migration is related to the restraint of economy, culture, law, etc. It is the object of migration that protect the zoological environment and improve the welfare of habitant, which must be concerned when constructing the systems of migration. This paper proves the possibility of contracting for migration based on the methodology of the cost-income analysis. On the other hand, it also argues for changing the mode of migration from that controlled by governments to being decided by habitant themselves.     

Method for screening bread wheat for tolerance to boron

A new method for screening wheat for boron tolerance has been developed to overcome the problems of methods used in the past. Seedlings were grown for 10 days while suspended over B-rich solutions. Their root lengths were then measured as an index of tolerance. Five varieties of wheat were screened at seven concentrations of B. Results were obtained more quickly and easily than from the alternative methodologies and compared favourably. Screening of 128 doubled haploid lines from a cross between Halberd and (Wl*MMC) suggested that transgressive segregation had occurred. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genotype-environment relationships for repening time in blackberries and prospects for breeding an early ripening cultivar for Scotland

Summary When grown in Scotland, eight blackberry cultivars of diverse origin showed considerable variation in the dates when their first fruits ripened. These dates were determined in part by variation in the date of their first open flower and in part by variation in the number of days required from flowering to ripening. Genotype x environment interactions were important for both components, but especially for the second, where they could be attributed to heterogeneity of regressions against the environmental means. Temperature was considered the important environmental factor determining the number of days required from flowering to repening, and accumulated heat units successfully quantified the differences between cultivars for this component: cultivars required similar numbers of heat units in each season and there were no interaction effects. Heat units were not useful for study of flowering dates, however.The implications for breeding early ripening cultivars for Scotland are discussed.     

A General Method for the Initial Values for Two-Sided Iteration

In the study on finding a group of inital values for solving operator equation x=G(x)by the two-sided iterative method,some stronger conditions forG(x)have been demandedand some new parameters have to be introduced since 1978,But,as it will be proved in this paper,Itis unnecessary to use any new parameters and other stronger conditions to get a group of initial val-ues of two-sided iterative, as those initial values can be obtained by means of an auxiliary iterativebeginning with operator G(x)itself. The numerical example in this paper illustraves that the methodproposed in this paper is a general method.     

A Composite Index for Statistical Inference for Ranking Metropolitan Areas

ABSTRACT The construction of a composite index is described to rank U.S. metropolitan areas for educational attainment. The suggested methodology departs from traditional rank sum methods in that this approach utilizes data resulting in a continuous scale, whereas in the rank sum method, no use is made of the actual values of the data, but merely their rankings. The proposed index circumvents several practical problems because the numbers generated are metric measures allowing the use of arithmetic and statistical operations. Data used are pupil/teacher ratio, an effort index, and academic options in higher education. Comparisons are made across areas by population size and by geographic region.     

Assessment of techniques for screening alfalfa cultivars for aluminum tolerance

Screening toxicity tests are an effective method to characterize aluminum tolerant plants. In this paper, three screening procedures were used to assess aluminum tolerance among 13 cultivars of alfalfa (Medicago sativa L.). The procedures used were: Petri dish screening, black glass plot method and the soil-on-agar procedure. Major biological indices used to analyze aluminum tolerance were relative root length (RRL), relative germination rate (RGR), relative hypocotyl length (RHL), relative fresh weight (RFW) and root emergence (RE). Aluminum negatively affected all five indices. A Pearson correlation test indicated that the results of the three screening procedures were consistent, suggesting that all three could be used for screening purposes. However, because of the short test period and the simplicity of operation, the black glass plot method might be the best choice. Overall, cv. Super No. 7 and WL-525HQ were the most aluminum-tolerant alfalfa cultivars, while Pondus S was the most sensitive.