湿地松产脂量与生长及树冠性状多点遗传相关及通径分析

为研究湿地松生长及树冠性状与产脂量之间的遗传相关关系及其对产脂量的控制途径,以赣北、赣中和赣南等多种典型立地条件下的28年生湿地松家系试验林为研究对象,对112个湿地松家系进行产脂量、生长及树冠性状全林调查,并对测定数据进行分析。结果表明,除枝下高外,产脂量与生长及树冠性状均呈显著或极显著遗传正相关关系,遗传相关系数排名前四的性状分别为胸径(R=0.93)、树冠表面积(R=0.83)、冠长(R=0.78)和冠幅(R=0.73);通径分析中,胸径、树高、树冠表面积和冠幅通过直接和间接作用成为影响产脂量的主导因素,其决定系数贡献率分别为0.557、0.507、0.424和0.240;产脂量与生长、树冠性状的线性回归方程为:y=-0.255+0.040x_(DBH)+0.004x_(HGT)+0.006x_(CSA)+0.036x_(CW)(F=955.907^**, R²=0.559),模型的预估精度为99.64%。本试验结果明确了湿地松生长及树冠性状与产脂量之间的关系,其中,树高、胸径、冠幅和树冠表面积对产脂量影响较大;建立的产脂量多元回归模型具有一定的现实意义,实现了对树高、胸径和树冠表面积等性状的快速测定预估产脂量,为湿地松产脂量的科学、准确与高效预测提供了依据。     

基于广告、技术、奖励的二级供应链效益最大化研究

基于技术进步视角，构建服务业FDI影响产业安全的理论模型，并采用1996-2013年的时序数据和分位数回归方法进行检验。实证结果表明，服务业FDI对技术进步的总效应为正；分位数回归进一步揭示，服务业FDI对技术进步的直接效应为正、间接效应为负，并在技术进步的低中分位点上，服务业FDI的直接效应大于间接效应，而在技术进步的高分位点上，服务业FDI的直接效应小于间接效应。研究证实，在技术进步的初期，服务业FDI会对产业安全发展产生直接的正向推动作用，但随着时间的推移，服务业FDI会威胁其产业安全。     

Prey and non‐native fish predict the distribution of Colorado pikeminnow (Ptychocheilus lucius) in a south‐western river in North America

Colorado pikeminnow (Ptychocheilus lucius) has been extirpated from a large portion of its historical range in the Colorado River basin, USA. A repatriation effort via stocking of juvenile P. lucius in the San Juan River, NM, CO and UT has resulted in limited recruitment of individuals into an adult population. Understanding biotic and abiotic factors that limit their persistence in the Colorado River basin will be a critical step in providing for their recovery. To elucidate potential recruitment barriers in the San Juan River, we assessed relationships between the numbers of two age classes of P. lucius and prey, competitors and predators collected at a 1.6 km reach scale between 2003 and 2012. We used an information theoretical approach to rank candidate models testing the relative importance of these biotic conditions in predicting the spatial distribution of P. lucius. We found positive relationships between the numbers of P. lucius ≤200 mm total length (TL) collected and catch per unit effort (CPUE) of native prey among reaches. For P. lucius >200 mm TL (individuals that are likely completely piscivorous), we found positive associations between the numbers of P. lucius collected and CPUE of total prey and CPUE of potential non‐native competitors in each reach. Our data suggest size‐specific affinities of P. lucius for native and non‐native prey as well as the potential for negative interactions between P. lucius and non‐native competitors may contribute to limited recruitment of juvenile P. lucius into an adult population in the San Juan River.     

土壤因子与小粒咖啡品质产量形成关系研究

土壤因子是影响小粒咖啡品质产量的主要因子。本研究通过对土壤因子进行相关性分析、改进的灰色关联分析、通径分析及多元线性回归分析,明确影响小粒咖啡品质和产量的主要因子,以指导科学施肥。结果表明:小粒咖啡咖啡因含量的土壤决定因子为海拔（-0.296^*）,总糖含量的土壤决定因子为有机质（0.607^**）和速效磷（-0.232^*）,蛋白质的土壤决定因子为pH（-0.387^**）和有机质（0.227^*）,灰分含量的土壤决定因子为速效磷（0.334^**）,水溶性浸出物含量的土壤决定因子为海拔（-0.494^**）,脂肪含量的土壤决定因子为碱解氮（-0.461^**）,产量的土壤决定因子为速效钾（0.339^**）和有机质（0.248^*）。研究结果可为小粒咖啡优质高产的土壤条件筛选和肥料的减施增效提供一定的理论基础,以期增强优质咖啡种质的适宜性和目的性。     

Analysis of green total factor productivity trend and its determinants for the countries along silk roads

In coping with increasing energy consumption and the consequential environmental pollution, green development is becoming an important part of social development. Since the inauguration of China’s Silk Road Economic Belt Initiative (BRI), economic cooperation between China and other countries along BRI has seen much growth. Therefore, it is of great significance to study the levels of green total factor productivity (GTFP) of the countries in the Silk Roads Economic Belt (B&R) and examine how these levels vary spatially and evolve temporally. In this paper, a panel regression analysis with DEA windows is used to study the spatiotemporal trends of the levels of GTFP. The results are: (1) The B&R countries have seen an increase in their overall levels of GTFP over time; (2) There are regional differences in the levels of GTFP, with higher efficiency in Western Asia and Central and Eastern Europe, and lower efficiency in Southeast and Central Asia; (3) The analysis of GTFP for countries in these regions shows that the efficiencies of most countries have been improving, with that of only a few countries have been decreasing; (4) By using regression analysis, we find that variables such as import, export, industrial structure, and urban affect the B&R countries with growing GTFP.     

The loss of large wood affects rocky mountain trout populations

Western U.S. rivers are currently influenced by legacy effects of reduced large wood (LW) loading and retention that has substantially reduced in‐stream habitat complexity. Large wood is typically associated with streams in undisturbed old‐growth forest and in the correct geomorphic context can drastically alter stream and valley habitat complexity. Streams with LW are typically multichannel and depositional, while streams lacking LW, due to relatively recent wildfire or logging (<200 years ago), are usually single channelled and erosional. We compared population biomass and individual growth rates of Brook Trout Salvelinus fontinalis in streams across a gradient of wood volumes. At both the square metre and valley length scales, standing stock biomass of aquatic invertebrates was the best predictor of trout biomass. However, at the valley scale, the number of pools was important in predicting trout biomass in combination with standing stock biomass of aquatic invertebrates. Individual growth rates of age‐1 Brook Trout were negatively affected by increasing density; however, growth rates for the largest and smallest individuals at each site were unaffected by density. Our results suggest the pool habitat created by LW acts synergistically with prey availability to dramatically increase trout populations. However, in streams lacking LW, negative effects of detrimental land use practices have persisted >100 years, suggesting that recovering lost animal production in mountain stream networks will only occur at decadal to century time scales.     

Enhancing pedotransfer functions with environmental data for estimating bulk density and effective cation exchange capacity in a data‐sparse situation

Soil bulk density (BD) and effective cation exchange capacity (ECEC) are among the most important soil properties required for crop growth and environmental management. This study aimed to explore the combination of soil and environmental data in developing pedotransfer functions (PTFs) for BD and ECEC. Multiple linear regression (MLR) and random forest model (RFM) were employed in developing PTFs using three different data sets: soil data (PTF‐1), environmental data (PTF‐2) and the combination of soil and environmental data (PTF‐3). In developing the PTFs, three depth increments were also considered: all depth, topsoil (<0.40 m) and subsoil (>0.40 m). Results showed that PTF‐3 (R²; 0.29–0.69) outperformed both PTF‐1 (R²; 0.11–0.18) and PTF‐2 (R²; 0.22–0.59) in BD estimation. However, for ECEC estimation, PTF‐3 (R²; 0.61–0.86) performed comparably as PTF‐1 (R²; 0.58–0.76) with both PTFs out‐performing PTF‐2 (R²; 0.30–0.71). Also, grouping of data into different soil depth increments improves the estimation of BD with PTFs (especially PTF‐2 and PTF‐3) performing better at subsoils than topsoils. Generally, the most important predictors of BD are sand, silt, elevation, rainfall, temperature for estimation at topsoil while EVI, elevation, temperature and clay are the most important BD predictors in the subsoil. Also, clay, sand, pH, rainfall and SOC are the most important predictors of ECEC in the topsoil while pH, sand, clay, temperature and rainfall are the most important predictors of ECEC in the subsoil. Findings are important for overcoming the challenges of building national soil databases for large‐scale modelling in most data‐sparse countries, especially in the sub‐Saharan Africa (SSA).     

三江平原水稻潜叶蝇发生规律及预测预报研究

研究旨在明确黑龙江省水稻主产区(三江平原)的水稻潜叶蝇的发生规律及影响水稻潜叶蝇发生的主要气象因子。试验从2006年开始连续10年在黑龙江省三江平原对水稻潜叶蝇的发生情况进行定点调查,收集水稻潜叶蝇发生时期的气象因子及第一代的虫口基数,采用通径分析及逐步回归的方法对6月末水稻潜叶蝇百株虫口数、气象因子及第一代虫口基数进行了研究,研究结果明确了第一代虫口基数及5月中旬的平均气温为影响水稻潜叶蝇的主要直接因子,而5月上旬的平均温度和5月下旬的平均温度是通过影响第一代虫口基数而间接影响了6月末的百株虫口数。通过逐步回归建立的短期预测模型Y=-150.012-1.432X_1+7.79X_4+0.17X_6+5.96X_7-0.121X_9-0.14X_(12)-0.09X_(15)+1.43X_(19)回归拟合效果好。可对黑龙江省三江平原水稻潜叶蝇的发生进行中短期预测。     

Hyper-spectral estimation of wheat biomass after alleviating of soil effects on spectra by non-negative matrix factorization

Hyper-spectral technology has been proven to be an effective method for the fast and non-destructive monitoring of crop biomass. However, the biomass estimation accuracy of this method is limited due to the effects of background factors, such as soils and water. In this study, a spectral separation method, non-negative matrix factorization (NMF), was proposed to alleviate the effects of soil on spectra. With the application of the NMF method, pure vegetation spectra were extracted from the field-observed spectra of wheat canopy, which were collected in four growing seasons from the tillering to the booting stages of wheat. Then, prediction models of wheat biomass (WB) were established and validated using the extracted spectra with the partial least squares regression (PLSR) method. The results showed that the NMF method could effectively separate the vegetation spectra from the mixed canopy spectra. Based on the extracted vegetation spectra, the WB prediction accuracy could be greatly improved with an increase of 31.7% for the R²_p and an increase of 46.6% for the ratio of performance to deviation (RPD) as compared to the original spectra, indicating that the NMF method could significantly improve the performance of the WB prediction model. This method has potential application in the estimation of biomass using remote sensing technology.     

自然降水与太行山区玉米单产形成的关系——以武安市为例

为了研究太行山区降雨量对玉米单产的变化规律,指导玉米实际生产。本研究选择武安市降雨量和玉米单产为研究对象,采用散点图、建立线性方程、线性回归显著性分析等方法,通过统计、对比描述等方式,分析武安市降雨量对玉米单产的关系。结果表明,降雨与玉米的单产之间具有一定关系,且生育期降雨量对玉米单产具有显著性影响。(1)在490 mm降雨范围内,玉米的单产随着降雨量的增加而增加,大于490 mm降雨时,玉米的单产与降雨量负相关。(2)玉米的单产受7月和8月的降雨量影响显著,且降雨量约278 mm时,玉米的单产较大。