判断两种量成正、反比例的诀窍

判断两种量是不是成比例,成什么比例,一般分三步进行。1.找出“两个相关联的变量”和“定量”。2.根据“两个相关联的变量”和“定量”写出数量关系式(一般把需要判断的两种量单独写在等号的左边,余下的写在它的右边)。3.按照正、反比例的意义作出判断。例如,判断下列各题中的两个量是不是成比例,成什么比例。(1)小麦每公顷产量一定,小麦的公顷数和总产量。①变量是小麦的公顷数和总产量,定量是小麦每公顷的产量。②关系式:小麦的总产量÷小麦的公顷数=小麦每公顷的产量(一定)③由关系式可知,小麦的总产量与公顷数的商一定,所以小麦的公顷数…     

新型高效麦田除草剂——巨星

巨星,是目前麦田最新型高效的除草剂品种之一。它具有活性高、用量少、革谱广、对作物安全等特点,并兼有使用方便、施药时期宽及经济效益高等长处,深受广大农民朋友的青睐。 一、剂量。巨星为75％干燥悬浮剂,其包装为小铝箔袋,袋重量2.5克。 二、防除对象。适用小麦、大麦田,对麦田里一年生及多年生阔叶类杂草有显著的防效。据有关几年来的     

禾枯灵防治小麦赤霉病研究

禾枯灵(又名唑灵)是一种新型复合杀菌增产剂.采用禾枯灵500PPM对小麦赤霉病进行常规喷雾,每隔7天喷一次,共喷2—3次,其防治效果达80.29%.保产率在27.31%以上.田间试验结果表明,禾枯灵对小麦赤霉病菌有较好的抑制作用,防效优于多菌灵.     

大白菜中后期“十喷”增产法

大白菜中后期“十喷”增产法一、喷施尿素。从莲座期开始，每隔１０天喷施一次０．２％－０．５％尿素液，共喷２—３次，可增产１５％－２０％。二、喷施草木灰。从莲座期开始，配合中耕，每亩穴施草木灰３０—５０公斤，可增产２０％左右。三、喷施米醋。在大白菜莲座期...     

小麦增根促蘖抗倒剂爱得福(ADF)1995年示范试验报告

1994年种麦期间,我们进行了关于“小麦增根促蘖抗倒剂爱得福(ADF)在小麦上应用示范项目”的研究。该项目安排在洪门乡定国村郭日明家麦田,现将示范试验情况报告如下:1 试验地基本情况试验地设在定国村郭日明家菜地,面积1.5亩,前茬为大白菜,土质为两合土,上等肥力,排灌方便,历年小麦单产在500公斤左右。     

以百米为单位,解公顷计算之难——“认识公顷”教学一得

五年级的一节公开课,课题是“认识公顷”.在学生认识了公顷,知道1公顷=10000平方米并做了一些简单的练习后,教师让学生运用所学的知识解决一道生活问题. 题目:(1)一块小麦田(如下图),每公顷约收小麦6吨,这块小麦田大约可收小麦多少吨?     

两种特优杂交红薯

湖南双环实业公司薯类研究发展中心繁育成功的特种优质高产杂交红薯“686”和“红心王”两个新品种，最近通过专家鉴定，平均亩产量12375公斤，最大单株重达30公斤，鲜薯含淀粉率24％以上，是传统品种的两倍多，成为目前国内薯类含淀粉率最高的品种。     

砂土生态类型区强筋小麦氮肥施用分配方式研究

为了在次适宜种植区的砂土地上栽培强筋小麦提高产量并改善品质,采用常规田间试验及统计分析方法并结合品质测试进行研究.结果表明,在砂粒含量632 g/kg、粉砂粒含量293 g/kg、黏粒含量75 g/kg的豫东平原砂土地上种植强筋小麦,在施氮（N）总量均为300 kg/hm2的试验条件下,采取“底追均衡供应”（底、追肥量各占50％）、“追肥两次分配”（拔节期追施30％、孕穗期追施20％）,即“532”施肥模式,强筋小麦产量和品质因素更为协调,可作为豫东砂土区现行生产、生态及技术条件下.,种植强筋小麦实现高产优质目标,氮肥合理分配和运筹的主要技术措施来运用.     

紫外可见分光光度法测定野地瓜植株的总黄酮

通过研究野地瓜老叶、嫩叶、茎总黄酮含量的差异,为采集和保存药用价值较高的植株部位及选择采摘季节提供参考,为可持续开发利用野地瓜资源提供依据.采用乙醇加热回流提取野地瓜植株的总黄酮,用Al(NO3)3-NaNO2比色法测定.同时考察了乙醇的体积分数,提取时间,料液比,温度对黄酮提取效率的影响以及方法学考察.以95％的乙醇作提取溶剂,料液比(g/mL)为1:45,70℃加热回流提取2h,对照品在0.0128～0.0768mg/mL浓度范围内与溶液的吸光度之间呈良好的线性关系(r=0.99976),精密度(n=6) RSD为2.28％,平均回收率为87.75％,RSD为2％,该方法精密度高,重现性好,回收率达实验要求.野地瓜植株的不同部位中总黄酮含量不同,老叶、嫩叶、茎中总黄酮的含量分别147.5 mg/g、107.67 mg/g、91.69 mg/g.可见,老叶中总黄酮的含量最高.     

野败×广选三号(B_4F_1)与广选三号的细胞形态观察比较

我区水稻杂种优势利用的研究,在毛主席革命路线正确指引下,在批林批孔运动推动下,今年又取得了新的进展。其中野生稻(包括野败)与栽培稻杂交的材料,在“三系”(即雄性不育系、保持系和恢复系)配套的基础上,已进入到小量制种和选配强优势组合,测定杂种优势,为“广积粮”服务阶段。为了配合水稻“三系”选育工作,探索水稻雄性不育的规律,为水稻“三系”选育提供细胞学方面的指标,为此,我们用野败×广选三号(B_4F_1)的73C1—818及其父本广选三号作材料,从细胞形态方面进行比较观察。 一、材料和方法 野败×广选三号(B_4F_1)中的73C1—818,及其父本广选三号均来自1974春广西农科院海南岛南繁材料。于早上5—6点和下午4—5点分别采集花粉发育不同时期的小穗,用3∶1的酒精(95％)冰醋酸固定,24小时后用70％酒精保存。 方法以石蜡切片为主,同时做些临时压片,石蜡切片厚度8μ,铁凡苏木精染色。     

Targeted yield concept and a framework of fertilizer recommendation in irrigated rice domains of subtropical India

Soil test crop response （STCR） correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture （loamy to clay）, organic carbon content （4.4 to 9.8 g/kg）, cation exchange capacity （10,2 to 22.4 cmol （p＋）/kg） and pH （5.3 to 6,4）, Soil fertility status for N is low to medium （224 to 348 kg/ha）, P is medium to high （87 to 320 kg/ha） and K ranges from medium to high （158 to 678 kg/ha）. Database regarding nutrient requirement in kg/t of grain produce （NR）, the percent contribution from the soil available nutrients [CS （%）] and the percent contribution from the applied fertilizer nutrients [CF （%）] were computed for calibrating and fbrmulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers＇ fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.     

Potential production simulation and optimal nutrient management of two hybrid rice varieties in Jinhua,Zhejiang Province,China

Potential growth of two widely-grown hybrid rice varieties in the Jinhua district of Zhejiang Province, Shanyou63 for mid-rice and Xieyou46 for late rice, was simulated using a crop growth model of WOFOST. Parameters of the rice growth in WOFOST were calibrated through field experiments from 1999 to 2002 in Jinhua. The potential yield simulated with WOFOST was about 12 t/ha for Shanyou63 and 10 t/ha for Xieyou46, which are in good agreement with the highest recorded yield obtained in this area. Under farmers practice, current yield is about 7.5 t/ha for Shanyou63 and 6.5 t/ha for Xieyou46. There is a gap between the actual rice yield and the potential yield for these two hybrid rice varieties grown in this area. The attainable target yields were set to 70% to 75% of their potential yields for the two varieties. A recently developed software ＂Nutrient Decision Support System （NuDSS）＂ for irrigated rice was used to optimize nutrient management for these two rice varieties. According to NuDSS, the optimal fertilizer N requirement for the target yields was about 150 kg/ha for Shanyou63 and about 120 kg/ha for Xieyou46, which were only about 70% of the fertilizer N application under current farmers＇ practice. Comparing with farmers＇ practice, there is great potential to increase actual rice yields and to reduce fertilizer N use rates by improving rice crop management practice in Jinhua.     

Influence of nitrogen and sulfur fertilization on quality of canola (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) under rainfed conditions

Field experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, during winter 2003~2004 and 2004~2005 to evaluate the effect of nitrogen and sulfur levels and methods of nitrogen application on canola (Brassica napus L. cv. Bulbul-98) under rainfed conditions. Four levels of S (0, 10, 20, and 30 kg/ha) and three levels of N (40, 60, and 80 kg/ha) and a control treatment with both nutrients at zero level were included in the experiments. Sulfur levels were applied at sowing while N levels were applied by three methods (100% soil application, 90% soil 10% foliar application, and 80% soil 20% foliar application). The experiments were laid out in randomized complete block (RCB) design having four replications. Oil content increased significantly up to 20 kg S/ha but further increase in S level did not enhance oil content. Glucosinolate content increased from 13.6 to 24.6 μmol/g as S rate was increased from 0 to 30 kg/ha. Protein content increased from 22.4% to 23.2% as S rate was increased from 0 to 20 kg/ha. Oil content responded negatively to the increasing N levels. The highest N level resulted in the highest values for protein (23.5%) and glucosinolate (19.9 μmol/g) contents. Methods of N application had no significant impact on any parameters under study.     

Protective effect of oat bran extracts on human dermal fibroblast injury induced by hydrogen peroxide

Oat contains different components that possess antioxidant properties;no study to date has addressed the antioxidant effect of the extract of oat bran on the cellular level.Therefore,the present study focuses on the investigation of the protective effect of oat bran extract by enzymatic hydrolysates on human dermal fibroblast injury induced by hydrogen peroxide(H2O2).Kjeldahl determination,phenol-sulfuric acid method,and high-performance liquid chromatography(HPLC) analysis indicated that the enzymatic products of oat bran contain a protein amount of 71.93%,of which 97.43% are peptides with a molecular range from 438.56 to 1 301.01 Da.Assays for 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity indicate that oat peptide-rich extract has a direct and concentration-dependent antioxidant activity.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) colorimetric assay and the TdT-mediated digoxigenin-dUTP nick-end labeling(TUNEL) assay for apoptosis showed that administration of H2O2 in human dermal fibroblasts caused cell damage and apoptosis.Pre-incubation of human dermal fibroblasts with the Oatp for 24 h markedly inhibited human dermal fibroblast injury induced by H2O2,but application oat peptides with H2O2 at same time did not.Pre-treatment of human dermal fibroblasts with Oatp significantly reversed the H2O2-induced decrease of superoxide dismutase(SOD) and the inhibition of malondialdehyde(MDA).The results demonstrate that oat peptides possess antioxidant activity and are effective against H2O2-induced human dermal fibroblast injury by the enhanced activity of SOD and decrease in MDA level.Our results suggest that oat bran will have the potential to be further explored as an antioxidant functional food in the prevention of aging-related skin injury.     

野生柳叶蜡梅叶营养成分分析

以黄山市休宁县齐云山野生香风茶为研究对象,应用高效液相色谱、原子吸收光谱以及其他常规化学分析技术测定其中成分。结果为:蛋白质、粗脂肪含量分别为27．86％、31．2％,粗纤维、可溶性总糖分别为11．7％、7．26％,水分和灰分分别为7．467％、7．15％;游离氨基酸总量为1．12％;维生素B1、B2和维生素C分别为0．1001mg/100g、1．301mg/100g、33．6mg/100g;矿质元素Ca、Mg分别为300mg/100g、340mg/100g,Fe、Zn和Se等分别为15．37mg/100g、8．11mg/100g及0．0135mg/100g。     

先玉335夏玉米高产栽培优化研究

为揭示密度、氮、钾肥施用量与先玉335玉米品种产量的关系,采用二次通用旋转组合设计,建立各因素与产量之间的数学模型,筛选高产栽培优化模式。结果表明,最佳农艺方案：种植密度62．175-71．160千株／hm2,配施纯氮266．875-284．010kg／hm2和K20207．645-246．270kg／hm2,产量可达10125kg／hm2以上。     

Bread wheat varieties as influenced by different nitrogen levels

INTRODUCTION Dera Ismail Khan lies in Pakistan’s arid zone (71.07° longitude, 31.57° latitude and 500 m above sea level). This zone is in the extreme south of (NWFP) Pakistan at the bank of the River Indus. Dera Ismail Khan is bounded by Sulaiman Range to the West, the Indus River on the East, Marwat and Bhit- tani Ranges on the North and Vehowa Nala (Punjab) on the South. Besides certain local variability the area is comprised of four basic divisions viz mountains, a series …     

玉米高产栽培综合农艺措施模式优化研究

作物产量的形成受到可控因素和不可控因素的综合影响。且其内在关系极为复杂,单凭经验和传统的研究分析方法,对有效地控制生产过程中的某些条件,已难于做出准确、及时和全面的判断及结果预测。为了作物的高产稳产和平衡增产,配合并加快新品种的推广进程,本文根据农业系统工程的最佳模拟理论,运用二次通用旋转组合设计和计算机模拟选优的方法,研究了皖单3号玉     

大葱高产栽培氮磷钾优化配施技术研究

采用二次回归通用旋转组合设计方法,对河西走廊川水区大葱高产栽培氮磷钾优化配施技术进行了研究。结果表明,试验条件下大葱产量与氮磷钾配施的关系遵从试验建立的一元二次回归模型的变化规律。三因子对产量的影响顺序是:施氮量>施钾量>施磷量。高产优化组合是:纯N187.5～252.0kg/hm~2,P_2O_5 112.5～144.0kg/hm~2,K_2O 262.5～357.0kg/hm~2,N、P、K三项比为1:0.6:1.4,为科学施肥提供了依据。     

密度、N和K对玉米品种隆平206产量和品质的影响及栽培组合优化

本文采用二次通用旋转回归设计的方法研究了密度、N和K对玉米产量和品质的影响,并对三个栽培因子进行了组合优化研究.结果表明：玉米产量与3因子成二次回归关系,产量高于10772.83kg/hm2的优化区间为：密度74655～82155株/hm2;施氮量257.9～305.9kg/hm2;施钾量261.3～315.9kg/hm2;蛋白质含量与氮肥的施用量正相关,与钾肥的施用量负相关;淀粉含量与氮肥的施用量负相关,与钾肥的施用量正相关;脂肪含量钾肥的施用量正相关;蛋白质、淀粉、脂肪含量均与密度相关不显著.