农村水环境治理探析   总被引：3，自引：0，他引：3  

王新文 《安徽农业科学》2008,36(14):6066-6067

分析了我国农村水环境治理现状及存在的问题,并提出了相应措施。  相似文献   

球坐标中应用虚功原理应注意的一个问题     

薄永红 《河北北方学院学报(自然科学版)》2009,25(5):27-29,33

运用虚功原理研究电偶极子在非均匀电场中受到的静电力.电偶极子在非均匀电场中的能量既是电偶极子坐标变量的函数,也是电偶极子与坐标轴夹角的函数.研究结果表明,在球坐标系中,假如电偶极子在坐标变量方向上发生虚位移,那么电偶极子与坐标轴夹角也发生变化,所以,对能量函数求导时,不能把电偶极子与坐标轴夹角看作常量,而应该看成变量.给出了计算电偶极子在非均匀电场中受到的静电力的方法.  相似文献   

杂交粳稻产量及其构成因素的杂种优势与衰退初步研究   总被引：2，自引：0，他引：2  

郭玉华  赵鑫闻  兰彩霞  华泽田  赵冬霞  张立爽  林团荣 《杂交水稻》2008,23(1):68-70,90

以辽宁省当前主推杂交粳稻组合辽优5215的F1代、F2代及其亲本和常规对照品种辽粳294为试验材料,对杂交粳稻产量及其构成因素的杂种优势与衰退进行了初步研究。结果表明,杂交粳稻辽优5215F1代产量的超亲优势为18.5%,竞争优势为7.8%;株高、每穗实粒数的杂种优势明显,每穴穗数、结实率、千粒重的杂种优势为负值。F2代产量、整齐度均较F1代有所下降,产量下降4.96%,但未达显著水平;F2代产量竞争优势为2.43%,说明杂交粳稻F2代在生产上仍具有一定利用价值。  相似文献   

充分发挥比较优势，积极推进甘肃草业产业化   总被引：7，自引：2，他引：5  

李新文 《草业科学》2000,17(1):83-85,F003

论述了甘肃推进草业产业化的重要意义,并通过对甘肃发展草业,实行产业化经营的气候、土地、科技、市场等比较优势的深入分析,研究提出了甘肃积极推进草业产业化的思路与对策。  相似文献   

Stem flow of seed-maize under alternate furrow irrigation and double-row ridge planting in an arid region of Northwest China          下载免费PDF全文

BO Xiao-dong  DU Tai-sheng  DING Ri-sheng  TONG Ling  LI Si-en 《农业科学学报》2015,14(7):1434-1445

Maize is widely planted throughout the world and has the highest yield of all the cereal crops. The arid region of Northwest China has become the largest base for seed-maize production, but water shortage is the bottleneck for its long-term sustainability. Investigating the transpiration of seed-maize plants will offer valuable information for suitable planting and irrigation strategies in this arid area. In this study, stem flow was measured using a heat balance method under alternate furrow irrigation and double-row ridge planting. Meteorological factors, soil water content(θ), soil temperature(Ts) and leaf area(LA) were also monitored during 2012 and 2013. The diurnal stem flow and seasonal dynamics of maize plants in the zones of south side female parent(SFP), north side female parent(NFP) and male parent(MP) were investigated. The order of stem flow rate was: SFPMPNFP. The relationships between stem flow and influential factors during three growth stages at different time scales were analyzed. On an hourly scale, solar radiation(Rs) was the main driving factor of stem flow. The influence of air temperature(Ta) during the maturity stage was significantly higher than in other periods. On a daily scale, Rs was the main driving factor of stem flow during the heading stage. During the filling growth stage, the main driving factor of NFP and MP stem flow was RH and Ts, respectively. However, during the maturity stage, the environmental factors had no significant influence on seed-maize stem flow. For different seed-maize plants, the main influential factors were different in each of the three growing seasons. Therefore, we identified them to accurately model the FP and MP stem flow and applied precision irrigation under alternate partial root-zone furrow irrigation to analyze major factors affecting stem flow in different scales.  相似文献   

不同肥料处理下蚕豆幼苗提取铀镉的生理特征研究   总被引：1，自引：0，他引：1  

徐长合  王丹  张晓雪  钟钼芝  谢新闻  张玉琳 《北方园艺》2010,(10):19-23

通过盆栽试验研究了尿素、过磷酸钙、硫酸钾(各3个浓度)运用L9(33)正交设计选出的9个肥料配方(以1~9表示)对蚕豆(Vicia faba Linn.)幼苗提取不同铀镉污染(设置3个浓度A、B、C表示)时叶绿素、细胞质膜透性和丙二醛的影响。结果表明:蚕豆幼苗叶绿素含量随铀镉浓度升高而减小,67、、8肥料配方在增强蚕豆抗逆性上效果较好;在细胞质膜透性上,A较B和C小,5、67、8、、9配方在A、B、C中趋于相等,特别是5、68、配方在A处理均达到了最大值;丙二醛含量随铀镉浓度升高而增大,6、7、8配方在A、B、C下相差不大。总之,5、67、、8肥料配方在增强蚕豆铀镉抗逆性上起到了积极的作用。  相似文献   

不同油茶品种对重庆市气候的适应性评价          下载免费PDF全文

黄志伟  曹剑  柏玉平 《南方农业学报》2016,47(8):1338-1343

[目的]评价不同油茶品种对重庆市不同区(县)气候因子的适应性,为重庆市油茶引种、栽培提供参考依据.[方法]对我国29个油茶主栽区(县)和12个国家油茶良种基地的年均气温、极端最高温等11个气候指标进行主成分分析和聚类分析,筛选出影响油茶生产的主要气候因子;利用模糊理论中的隶属函数方法,计算重庆市31个区(县)栽培油茶的气候适应性指数,进而对重庆市油茶栽培区进行区划.[结果]影响重庆市油茶栽培的最重要气候因子为热量因子,即年均气温、11~12月平均气温、无霜期、最冷月平均气温、≥10℃有效积温和极端最低温;其次为日照时数、年降水量、最热月平均气温等水分和光照因子.对重庆市的气候适应性评价结果表明,重庆市大部分区(县)油茶栽培的气候适应性指数(CAI)与油茶最适区基本一致,均大于0.80.[结论]重庆市大部分区(县)气候条件适合油茶生长,建议从相似性总分值小于1.50且热量、降雨和光照条件较一致的贵州天柱、湖南长沙、浏阳及江西分宜等地区引种.  相似文献   

Absorption,Accumulation and Distribution of Zinc in Highly-Yielding Winter Wheat     

DANG Hong-kai  LI Rui-qi  SUN Ya-hui  ZHANG Xin-wen  LI Yan-ming 《中国农业科学(英文版)》2010,9(7):965-973

Zinc（Zn） is an important essential microelement for wheat.In order to study the characteristics of Zn absorption,accumulation and distribution in highly-yielding winter wheat（with a grain yield of 9 000 kg ha-1）,field experiments were conducted in Gaocheng County of Hebei Province,China.Four winter wheat cultivars,i.e.,Shimai 14,Jifeng 703,Shimai 12,and Shixin 828,and four cultivars,i.e.,Temai 1,Shimai 12,Shixin 531,and Shixin 828,were used in the experiment,during 2004-2005 and 2005-2006,respectively.Plant samples were taken from the plots at each growing stage for Zn concentration analysis.The main results showed that the concentration of Zn in various above-ground organs of wheat was 9.5-112.5 mg kg-1 at different growing stages.The organ with the highest Zn concentration differed with the change of growth center at different growing stages.Accumulation of Zn in leaf blades was the highest among all the organs during early growing period,and more than 50% of the Zn accumulation was distributed to leaf blades before jointing,and higher than that to other organs.In late growing period,however,the accumulation of Zn in grains was the highest,and 58.1% of the Zn accumulation was distributed in grains at maturity.The total accumulation of Zn in wheat plant during its life span ranged from 384.9 to 475.9 g ha-1.The amount of Zn required for the formation of 100 kg grain yield ranged from 4.3 to 5.2 g.All the organs were ordered in such a sequence that leaf blades 〉 spikes 〉 leaf sheaths 〉 stems according to their net absorption and transportation of Zn as well as their contribution to Zn accumulation in grains.58.2-60.3% of the Zn accumulated in grains was redistributed from other organs,mostly from leaf blades.Concentration and accumulation of Zn in all the organs of wheat was high during early and middle growing periods,while accumulation of Zn in grains during late growing period mainly depended on the redistribution from other organs.According to these characteristics of Zn absorption and accumulation,Zn should be applied as seed dressing or basal fertilizer,so as to accelerate the early growth and Zn absorption of wheat.  相似文献   

吡虫啉在番茄果实中的残留降解动态   总被引：1，自引：0，他引：1  

杜蕙  孙新纹  吕和平  漆永红  杨发荣 《甘肃农业科技》2010,(9):3-5

采用高效液相色谱分析法研究了10%吡虫啉可湿性粉剂在番茄果实中的残留降解动态。结果表明,在推荐使用剂量225 g/hm2下,吡虫啉在番茄中的降解半衰期为4.4 d;在加倍剂量450 g/hm2下,降解半衰期为5.8 d。采收前7 d按推荐剂量(有效成分)22.5 g/hm2喷药,其残留量均低于国际上现行的限量指标。  相似文献   

干酪乳杆菌LC-03的培养条件优化研究   总被引：1，自引：0，他引：1  

金桩  彭健  胡新文  林声汉  马燕 《中国畜牧兽医》2010,37(6):223-226

本研究通过单因子优化试验和正交试验对干酪乳杆菌LC-03培养条件和培养基成分进行初步优化。结果表明,干酪乳杆菌LC-03属于兼性厌氧菌,最佳培养基成分为:蛋白胨12g,酵母提取物6g,牛肉膏6g,葡萄糖18g,乙酸钠5g,柠檬酸铵2.15g,Tween801mL,MgSO4.7H2O0.58g,MnSO4.4H2O0.05g,K2HPO42g,水1000mL;最佳培养条件:温度为35℃,培养基起始pH为6.5,接种量为1.0%,培养时间为24h;优化培养后D610nm值达到1.832,活菌数达到3.22×1010CFU/mL。  相似文献