在小流域双季稻区的"水稻苗情预报"研究

本研究应用ＲＩＣＡＭ／ＲＩＣＯＳ试为农业单位在计算机的水稻生产管理决策方面提供苗情预报。经１９９７～２０００年在小流域双季稻区的试验表明：在ＲＩＣＡＭ１．３的支持下，提供初始条件：品种、播种期、移栽期、移栽期叶龄和主 气象要素，用“当前日驱动模型”，即可模拟“当前日”（从播种到成熟期间的某一天）的水稻苗情及其措施：（１）预测水稻生育进程（主茎叶龄、叶面积、干物质产量、稻谷产量）；（２）查询其相应时期的各项措施建议。     

对西部农村代课教师问题的探讨

在对西部农村代课教师存在基础进行客观分析的前提下,提出解决西部农村代课教师问题的相关建议。     

蔗区降雨分布与甘蔗需水及加肥灌溉效应

1材料与方法 1．1试验概况选择有代表性的甘蔗种植区广西壮族自治区来宾市进行田间试验，供试甘蔗品种为“台糖22”，种植密度45000芽段／hm^2。各生长阶段降雨观测在田间试验旁进行，试验地养分测定按常规方法。     

淮河流域(安徽段)主要湿地维管植物研究

淮河流域(安徽段)主要湖泊湿地维管植物有68科165属259种;科、属、种分别占全省维管植物科的30.2%、属的13.4%、种的7.1%。包含5种以上的11个较大科构成了淮河流域湿地植物的主体,其中禾本科和莎草科种类最多。区系分布区类型:蕨类植物主要有4种分布区类型,世界分布为主要类型;种子植物属有14种分布类型,其中温带分布类型占总属数的38.4%,该区湿地维管植物具有典型温带性质。湿地植物资源包括食品类,工业原料类,绿肥类,观赏类,环保类及种质资源类等。     

哈尔滨市规模住区人居环境实态研究

对照“金牌住区”七大特色目标,对哈尔滨市近年开发的规模住区人居环境进行深入调研,分析总结现状存在的共性特征和发展的优劣势,指出今后规模住区人居环境改进方向。     

Relationships between numbers of main stems and yield components of potato (Solanum tuberosum L. cv. Erntestolz) as influenced by different daylengths

Summary The relationshops between numbers of main stems and some measures of growth and yield, as well as total tuber yield, were examined for potatoes grown under different daylengths. Leaf area, tuber number and tuber yield per plant increased significantly with increasing daylength and number of main stems. Numbers of main stems and leaf area were correlated positively with tuber number and tuber yield and negatively with average tuber weight. The correlations were stronger with stem number than with leaf area and were differently affected by daylength. Standard regression coefficients indicated that stem number has strong positive and negative relationships with tuber number and average tuber weight, respectively. Since tuber number was a better determinant of yeild than average tuber weight, the final relationship between the numbers of main stems and tuber yield remained positive for all daylengths. Determinants that will best explain variation in tuber total yield, tuber number, and average tuber weight are suggested.     

Tresca与Mises屈服理论的两种简明比较法

本文采用代数法和应力圆面积法对Tresca和Mises屈服理论进行了简明的定量分析比较，其结论与文献[4]、[5]和[6]相同。此方法简单明了，应用到教学中收到了良好的效果，且耗时很少。     

厚层基材喷播技术在北方半干旱区岩石边坡植被恢复中的应用——以京承高速公路(三期)植被恢复工程为例

以京承高速公路(三期)岩石边坡植被恢复工程为例,研究厚层基材喷播技术的施工工艺及植被恢复效果,从抗旱乡土植物的筛选与配置、技术适宜性评价以及养护措施效果方面,综合分析归纳出厚层基材喷播技术,在北方半干旱地区岩石边坡植被恢复中的应用效果及关键技术,对于完善我国裸露边坡植被恢复理论体系,指导裸露坡面工程绿化,都具有非常重要价值。     

人工低产林改造对生态恢复区土壤理化性质的影响

为了解人工低产林改造对土壤理化性质的影响,于2010年9月-2011年8月对甘肃定西华家岭生态恢复区4个人工低产林改造后的混交林和1个杨树纯林、1个荒草坡对照点的土壤主要理化性质进行了研究.结果表明,杨树纯林的土壤有机质、总N和总P含量均处于较低水平,分别低于荒草坡10.98、0.78、0.10 g/kg;低产林改造后,土壤含水量、有机质和总N含量均有所升高,且随着改造时间的延长呈现出明显的增加趋势.改造8、18、25、31 a的混交林土壤含水量分别高出杨树纯林2.01、7.79、11.38、12.07个百分点,有机质含量分别高出2.96、15.23、20.80、24.96g/kg,总N含量分别高出0.41、1.02、1.48、1.96 g/kg;总P含量在改造初期有所增加,后期维持稳定,改造8、18、25 a的混交林总P含量分别高出杨树纯林0.02、0.06、0.10 g/kg,改造31a和25 a的混交林总P含量相等;低产林改造后土壤pH值略有降低.结果显示,人工低产林改造大大改善了该区土壤环境质量,有利于该区生态环境的恢复重建.     

Fruit Yield,Plant Growth and Nutrient Status in Mango

Abstract

Fruit yield and nutrient concentration of mango (Mangifera indica L.) cultivar ‘Osteen’ were studied in relation to rootstocks Gomera-1 and Gomera-3 for three years. The results indicated that the Gomera-3 root system had higher nutrient uptake and transport towards the scion. Data from grafted and ungrafted Gomera-1 and Gomera-3 trees proved similar with respect to N, P, and K utilization profile, with post-harvest accumulation and a decline during flowering, P and K concentrations significantly decreasing during fruit growth. These trends were largely the opposite for Ca and Mg. The Fe, Zn, Mn, and Cu concentrations rose during dormancy and fell at flowering. Fruit yield was higher with Gomera-1, while Gomera-3 gave fruit with greater weight and width. Tree height, trunk cross-sectional area, canopy diameter and volume were greater in grafted and ungrafted Gomera-3, this rootstock being the most vigorous. The yield efficiency was significantly greater on Gomera-1. Thus, cv. ‘Osteen’ grafted to Gomera-1 offered better yield and required a lower amount of nutrients.