云南省水电开发中森林资源的保护与恢复对策

简要地介绍了云南省水能资源及开发的现状,从林业发展的角度分析了水电站开发对森林资源产生的正、负面影响,并提出水电开发中森林资源的恢复和保护对策.     

田面微地形对滴灌灌水均匀性的影响

首先分析了田面微地形对滴头实际工作压力的影响,田面越不平整,滴头实际工作压力与设计工作压力的差值越大,当田面局部高差大于滴头设计工作压力时,滴头流量等于零;然后提出了田面微地形产生的流量偏差率公式,并用泰勒级数展开;最后利用描述统计方法和独立样本T-检验的方法对余项进行分析,置信度为99%的余项取值区间为0.001￣0.002,说明余项能够被忽略,田面微地形产生的流量偏差率公式可以用简单的形式来表示。     

辽西地区主要造林树种抗旱性的研究

辽西地区属于半干旱季风气候区,年平均温度为7.1—8.2℃,年降水量为400—600mm,年蒸发量为1600mm,为降水量的3—4倍。干燥是该区总的气候特点。该区的植物群落主要为旱生的森林灌丛或草本植物群落,针叶树建群种为油松,阔叶树为蒙古栎,元宝槭,黄榆;灌木主要为荆条和酸枣。土壤是在各种岩石风化物残积母质上,以及黄土、红土母质上发育的淋溶褐土和褐色性土,土壤干旱瘠薄。水分是这一地区限制造林树种成活及生长的主要因子,本文试图通过对树种抗旱性的测定和分析,确定树种的抗旱能力,从而为辽西地区的造林提供树种选择的依据。     

The Optimal Model of Repaying Debt for Construction Projects and Its Applications

In this paper the optimal model of repaying debt combined with operational research and technology economics was presented. It is for solving the problem to increase the benefit of project in terms of planning to repay capital with interest.     

Relationship between stable carbon isotope discrimination and water use efficiency under regulated deficit irrigation of pear-jujube tree

To investigate the relationship between stable carbon isotope discrimination (Δ) of different organs and water use efficiency (WUE) under different water deficit levels, severe, moderate and low water deficit levels were treated at bud burst to leafing, flowering to fruit set, fruit growth and fruit maturation stages of field grown pear-jujube tree, and leaf stable carbon isotope discrimination (Δ_L) at different growth stages and fruit stable carbon isotope discrimination (Δ_F) at fruit maturation stage were measured. The results indicated that water deficit had significant effect on Δ_L at different growth stages and Δ_F at fruit maturation stage. As compared with full irrigation, the average Δ_L at different growth stages and Δ_F at fruit maturation stage were decreased by 1.23% and 2.67% for different water deficit levels, respectively. Δ_L and Δ_F among different water deficit treatments had significant difference at the same growth stage (P < 0.05). Under different water deficit conditions, significant relationships between the Δ_L and WUE_i (photosynthesis rate/transpiration rate, P_n/T_r), WUE_n (photosynthesis rate/stomatal conductance of CO_2, P_n/g_s), WUE_y (yield/crop water consumption, Y/ET_c) and yield, or between the Δ_F and WUE_y and yield were found, respectively. There were significantly negative correlations of Δ_L with WUE_i, WUE_n, WUE_y and yield (P < 0.01) at the fruit maturation stage, or Δ_L with WUE_i and WUE_n (P < 0.01) over whole growth stage, respectively. Δ_F was negatively correlated with WUE_y, WUE_n and yield (P < 0.05), but positively correlated with ET_c (P < 0.01) over the whole growth stage. Thus Δ_L or Δ_F can compare WUE_n and WUE_y, so the stable carbon isotope discrimination method can be applied to evaluate the water use efficiency of pear-jujube tree under the regulated deficit irrigation.     

马尾松,大头茶针阔混交林森林结构的研究

典型选样调查测定,分析马尾松、大头茶常绿针阔混交林的森林特征、种群结构、林分结构、生物量结构及生态功能。结果表明:1.该混交林是亚热带常绿阔叶林前一阶段的过渡性森林类型,在干扰状态下保持其相对的稳定性。2.复层、异龄现象是该混交林的主要特征。建群种充分利用了林地空间营养面积,发挥了林地的生产潜力。叶面积指数达6.86～8.83,林分木材蓄积量达160～222m~3/ha,林分总生物量达114～163t/ha。其中,乔木层生物量达105～154t/ha。光照充足的林下,草本层生物量可达2.5t/ha,对庇护地表起到了最直接、最明显的作用,而调节林冠密度,可控制或促进草本层生物量的增长。3.此种混交林改善了森林立地的蓄水功能和贮水方式。林地土壤最大贮水量达2645～4100t/ha,降水贮存量达565～1256t/ha,林地枯枝落叶层饱和持水量达4589～8702kg/ha。该类型达到了生态与经济效益兼顾,可在我国南方亚热带山地各类工程造林中推广应用。     

基于MSP430F149芯片的便携式发动机窜气量测量仪的研制

介绍了在不解体车用发动机的情况下,通过测试曲轴箱窜气量的大小,即可检测活塞环与气缸壁的磨损程度的一种专用检测仪器,并以EQ6100发动机的结构特点为例,设计了专用测试用传感器,测出了其特性曲线,用低功耗单片机MSP430作为微控制器核心,构造了该测量仪器。测试结果表明:该仪器抗扰能力强,测试精度高,测试简单、方便,为发动机故障诊断提供了依据,用户可把仪器的结构、参数稍加改动即可应用于其它类型发动机的不解体故障诊断,具有一定的通用性。     

不同施氮量对谷子产量和效益的影响

摘要;以赤谷9号、赤谷10号和峰谷12为材料,研究不同的施氮量（O、150、300、450、600kg／hm2）对谷子品种产量的影响。结果表明：从产量和肥料投资的经济效益两方面考虑,3个谷子品种的产量均在施氮量为450kg／hm2时达到最高,得到的经济效益最大。     

分层供水施磷对冬小麦磷效率及产量的影响

研究分层供水施磷对冬小麦磷效率及产量的影响,为指导旱地施磷提供一定理论和实践依据。试验设整体湿润(W1)和上干下湿(W2) 2 种水分处理,不施磷(CK)、表施(SP)、深施(DP)3 种施磷处理,供试品种选用水分敏感型（‘小偃22’）和抗旱型（‘长旱58’）。研究结果表明：磷肥施用深度对冬小麦磷根效率比、磷肥利用效率、磷肥偏生产力(PFPP)及产量的影响随土壤水分和品种而异。2 种水分条件下,‘小偃22’DP较SP处理磷肥利用率、PFPp均显著降低(P＜0.05),磷根效率比及产量则差异不显著;W1 处理下,‘长旱58’DP较SP处理除磷根效率比外其他指标均显著降低(P＜0.05),W2 处理下则相反,上述指标均显著增加(P＜0.05)。本试验结果表明,土壤水分供应不足时,磷肥深施有利于提高抗旱性较强冬小麦品种对磷素的吸收利用能力,从而提高磷肥利用率及产量。