云南德宏州草果产业规模化发展要素分析

基于德宏州落后的经济现状,通过对发展草果产业的资源要素和市场要素分析,提出大力发展草果产业并规模化经营的方法要素。     

微粒群优化求解van Genuchten方程参数

van Genuchten方程参数的求解是复杂的非线性拟合问题,用传统方法难以有效解决。应用微粒群优化目的在于找到一条求解van Genuchten方程参数新的有效途径。以粉壤土吸湿和脱湿实测数据为实验,利用VisualBasic.NET语言进行编程,首先建立目标函数,然后计算每个微粒的适应值,通过微粒的自动寻优过程,找到最小误差平方和,最后记录下与之对应的参数,即为方程所求得解。通过最小误差平方和与其他方法进行比较,表明微粒群优化程序设计简洁、运行时间短、拟合精度高,是一种求解van Genuchten方程参数的有效方法。     

河南省茶树适宜种植气候区划研究

利用河南省119个气象台站1971~2010年气候资料,结合茶树生物学特性,筛选出影响茶树生长发育和产量形成的关键气候因子,并进行相关性检验,把通过检验的因子作为气候区划指标。运用层次分析法构造各区划指标的判断矩阵,并对判断矩阵的一致性进行检验,确定各区划指标的权重。采用加权指数求和法计算出河南省茶树种植综合区划指数,在GIS平台的支持下实现精度为250 m细网格的气候适宜性区划,将河南省茶树种植区分为适宜、次适宜和不适宜3个等级,其中适宜种植面积占评价区域的11.8%,次适宜种植面积占28.8%,不适宜种植面积占59.4%。将区划结果与茶树实际种植情况进行对比验证,发现两者吻合度较高,说明区划结果能够较客观真实地反映河南省茶树种植状况,该研究结果有望为河南省茶树种植科学布局提供依据。     

确定监测区域建立森林郁闭度估测方程最优样地的研究

在对监测区域样地进行合理分类的基础上,需抽取一定数量能代表监测区域森林资源分布状况的最优样地,根据所抽样地对应影响郁闭度估测的主要遥感和GIS因子,可建立以样地为单位的郁闭度估测方程. 最优样地是指能代表监测区域森林种类及分布状况的样地,它包含样地的数量及样地的代表性两个方面的含义. 如何抽取最优样地属多目标优化问题. 该文在理论描述特定监测区域最优样地数学模型的基础上,通过实例进行了系统研究与分析,有效解决了最优样地的抽样问题,所得结果可用于指导生产实践.      

多项式趋势曲线预测模型及软件设计

在文献[1]的基础上,讨论了多项式趋势曲线预测模型的参数估计方法,并用Turbo C语言建立相应的软件进行了趋势曲线的预测与误差分析.     

多性状综合评定的秩和测验方法及其应用

 【目的】秩和比较作为一种非参数方法,虽在作物品种评价方面得到一定的应用,但对多品种多性状的综合评定仍缺乏必要的统计测验基础。【方法】利用“H0：各品种在各性状上的秩次随机分布”假设。【结果】导出了多品种多性状秩和的理论分布;并据之给出了进行品种间多性状综合评价秩和测验的临界值。通过定义任意长度整数C++运算律,解决了当品种数和性状数较多时,因常用软件内置数据类型有效位数不足所导致的计算误差问题。最后,以糯玉米12个品种5个淀粉粘度性状为例演示了分析程序。【结论】该方法操作简便,评定结果具有一定参考意义。     

The incubation period of beet yellowing viruses in sugar-beet under field conditions

In three years field trials, the incubation period, i.e. the time between infection and the appearance of symptoms, of beet yellows virus (BYV) and beet mild yellowing virus (BMYV) increased with later infection during the growing season. The incubation period of BYV, a closterovirus, increased from 3 weeks in young plants infected before canopy closure, to 9 weeks in old plants infected in August. The incubation period of BMYV, a luteovirus, increased from 4 to 5 weeks in young plants to 9 weeks in old plants. Symptoms were observed c. one week earlier on the inoculated leaves than on those infected systemically, except on young BYV-infected plants. On these plants, symptoms developed in 3 weeks on both leaf types.The incubation period decreased at increasing temperature, a fixed temperature sum being required for the development of symptoms on plants of a certain age. This temperature sum increased with plant age. Symptom development was related to leaf growth; the systemic symptoms appeared after the infected leaves attained their final size. Young, expanding leaves did not show symptoms. Thus the development of symptoms seems to be related to physiological conditions occurring only in full-grown leaves. A low rate of leaf expansion may constitute the underlying reason for the long incubation period of virus symptoms in old plants and at low temperatures.The incubation period was not substantially affected by: (1) the number ofMyzus persicae used to inoculate the plants, (2) the number of leaves inoculated, (3) the development stage of the inoculated leaf and (4) the source plant of BMYV, beet or shepherd's-purse,Capsella bursapastoris. The incubation period can be used to obtain rough estimates of the infection-date of individual plants, given the date on which symptoms appear.Samenvatting De incubatieperiode van het bietevergelingsvirus, BYV, en het zwakke-bietevergelings-virus, BMYV, nam toe naarmate suikerbieteplanten later in het seizoen geïnfecteerd werden. Jonge planten ontwikkelden BYV-symptomen na ongeveer 3 weken terwijl na gewassluiting de incubatieperiode geleidelijk toenam tot 9 weken. De incubatieperiode van BMYV nam toe van 4 à 5 weken na inoculatie in juni tot 9 weken na inoculatie in augustus. Geïnoculeerde bladeren ontwikkelden ongeveer een week eerder symptomen dan de systemisch geïnfecteerde bladeren, behalve bij jonge planten, geïnfecteerd met BYV, waar de symptomen zich op beide typen bladeren tegelijkertijd ontwikkelden.De incubatieperiode nam bij hogere temperatuur af en, afhankelijk van de leeftijd van de plant (aantal bladeren) was een bepaalde temperatuursom nodig voor de ontwikkeling van symptomen. Deze temperatuursom nam toe met de ouderdom van de plant. Van alle systemisch besmette bladeren, vertoonden de oudste, welke juist verschenen op het moment dat de plant werd geïnfecteerd, als eerste symptomen. Dit gebeurde zodra of kort nadat ze hun uiteindelijke grootte hadden bereikt. Groeiende bladeren vertoonden nooit vergelingssymptomen. De trage bladexpansie in oude planten en bij lage temperaturen is een mogelijke oorzaak van de lange incubatieperiode aan het einde van het seizoen.De incubatieperiode werd niet duidelijk beïnvloed door inoculatieomstandigheden, zoals (1) het aantal groene perzikluizen,Myzus persicae, dat werd gebruikt voor inoculatie, (2) het aantal geïnoculeerde bladeren, (3) de ouderdom van het geïnoculeerde blad, (4) de bronplant van BMYV, biet of herderstasje, of (5) de vector species. Omdat de incubatieperiode niet in belangrijke mate afhankelijk is van deze factoren kan bij kennis van de datum waarop symptomen verschenen de infectiedatum worden bepaald op basis van de incubatieperiode.     

灌区节水改造综合评估指标权重确定方法研究

为了科学合理地确定指标权重,从而对灌区节水改造项目综合后评估作出理想的评价结果,在阐述基于离差平方和的综合赋权法和基于博弈论的综合赋权法原理的基础上,将这两种综合集成赋权法分别应用于关中洛惠渠等4个灌区的节水改造项目综合评估,发现两种综合赋权法得出的权重向量大小排序结果并不相同,但根据两种权重值计算的多个灌区综合评价值大小排序结果相同.对这一现象进行的进一步分析表明,两种综合集成赋权法的指导思想虽然不同,但其原理都是科学合理的.在确定灌区评价指标权重时,若为了对各灌区评价对象充分拉开档次,可选用基于离差平方和的综合赋权法,当希望尽可能保留各主客观权重值的信息时,可选用基于博弈论的综合赋权法.     

论退耕还林地替代天然林地种植草果的生态学意义

草果对自然环境务件有特殊要求,在天然林下种植草果有不少弊端。退耕还林工程使替代天然林种植草果成为可能,有利于保护原有天然林和巩固退耕还林成果。     

Long-term evolution and prediction of feed value for permanent mountain grassland hay: Analysis of a 32-year data set in relation to climate change

Elevation of mean air temperature related to climate change speeds up plant maturity, which influences mostly forage feed value. The objective of the study was to assess variation in hay quality harvested over 32 years at the same experimental site, and whether feed value is better predicted by combining agro-climatic variables with chemical composition. From 1979 to 2010, the in vivo digestibility (OMd) and voluntary dry matter intake (VDMI) of 271 hays, harvested during the first vegetation cycle on permanent grasslands, were measured in sheep. Over 32 years, the mean air temperature between February and August increased significantly by 1.34°C. Cutting date was advanced by 6 days, but the average sum of temperature at cutting (ST) increased significantly by 13%. Crude protein (CP) content declined (−22%, p < .001), crude fibre content increased (+8%, p < .001), OMd decreased (−3%, p = .012) and VDMI increased (+9%, p = .011). Changes in the chemical composition and OMd were consistent with the increase in ST. Finally, the prediction of OMd from CP and crude fibre contents (R² = .57, RMSE = 2.99) was slightly improved by the addition of ST and hay drying time (R² = .60, RMSE = 2.83). Climate change may have a negative indirect effect on hay quality if an earlier cutting date does not compensate for its effect on the faster maturation of the plants. Moreover, agro-climatic criteria could help to monitor and predict hay quality in relation to intra- and inter-annual climatic changes.