适宜茶园套种的绿肥型油菜资源筛选及初步应用

为推广生态茶园的油菜绿肥套种模式，于2017-2018年在茶园系统筛选和评价适宜套种的油菜资源。比较23个不同油菜品种（品系）的盛花期鲜草的生长与养分还田量，结果发现：茶园套种油菜的生物量、株高、养分还田量等指标表现存在差异；种植后根际土pH、有机质、碱解氮含量发生改变或提升。综合比较分现，品种阳光131、 圣光86和中双11表现相对较好：单株生物量达0.81～1.00 kg；植株养分还田量高，三者的氮磷钾养分还田量分别为 49.21～72.48 kg/hm2、12.64～17.40 kg/hm2和33.64～56.29 kg/hm2，可基本满足茶青的生长需求，且三个品种种植后土壤有效养分和有机质的改善较为明显。大地69和油肥1号株高相对较矮，适宜在低龄或矮枞茶园中套种。于2018-2019年探索油菜品种阳光131作为绿肥在不同树龄的茶园套种的应用，发现土壤的有机质含量显著改善，pH 值显著提升。综上，认为优选油菜品种应用于冬季茶/油菜（绿肥）套种模式     

Modeling height-diameter relationship for artificial monoculture Metasequoia glyptostroboides in sub-tropic coastal megacity Shanghai,China

Tree height is a key variable in forest monitoring studies and for forest management. However, tree height measurement is time consuming, and the recommended procedure is to use estimates from tree height (H) - diameter at breast height (DBH) models. Increasingly, H-DBH models are being developed for urban forests, providing tools to forest management and ecosystem services estimation. Here, we compared model forms and approaches for predicting H as a function of DBH and additional stand level covariates variables. Four model forms were evaluated: (i) basic models (which only used DBH as predictor variable); (ii) generalized models (which used DBH and other predictor variables based on the best basic model); (iii) a mixed-effects model based on the best basic model; and (iv) a mixed-effects model based on the generalized model. Several sampling designs aimed at minimizing height measurement were tested in terms of accuracy and applicability. Taking predicted accuracy and investigation cost into account, we recommend generalized non-linear mixed-effects model (NLME) when there were two or less tree height measurements taken in a given stand. The basic NLME model could be calibrated when there were 3 or more tree height measurements, depending on the required level of accuracy and investigation cost. Additionally, we first reported that soil pH as a covariate variable in H-DBH model and our generalized NLME model implied that the difference in the H-DBH relationship caused by pH varies among different stands. This finding may be attributable to differing biological properties of the similar alkaline tolerance species.     

The economic benefits and costs of trees in urban forest stewardship: A systematic review

Understanding the benefits provided by urban trees is important to justify investment and improve stewardship. Many studies have attempted to quantify the benefits of trees in monetary terms, though fewer have quantified the associated costs of planting and maintaining them. This systematic review examines the methods used to jointly analyse the costs and benefits of trees in the urban landscape, assesses the relative balance of benefits and costs, and attempts to understand the wide variation in economic values assigned in different studies. The benefits most frequently studied are those related to environmental regulation and property values, and the available data show that these usually outweigh the costs. Aesthetic, amenity, and shading benefits have also been shown to provide significant economic benefits, while benefits in terms of water regulation, carbon reduction and air quality are usually more modest. Variation in benefits and costs among studies is attributed largely to differences in the species composition and age structure of urban tree populations, though methodological differences also play a role. Comparison between studies is made difficult owing to differences in spatiotemporal scope, and in the way urban forest composition and demographic structure were reported. The overwhelming majority of studies concern deciduous trees in Northern America, and much less is known about urban forests in other regions, especially in the tropics. Future work should thus seek to fill these knowledge gaps, and standardise research protocols across cities. In light of ambitious goals in many cities to increase tree cover, ongoing advances in valuation methods need to provide a more comprehensive accounting of benefits and costs, and to better integrate economic assessment into the decision-making process.     

Sacred sites as habitats of culturally important plant species in an Indian megacity

Cultural ecosystem services related to urban green spaces contribute significantly to liveable cities. While previous studies highlight the intersection of cultural ecosystem services with societal values, spiritual or religious values associated with urban nature have received less attention. In India, as in other parts of the world, sacred sites are known for their biological richness, but analyses from urban sacred sites are largely missing. Based on a stratified random sampling approach, we analysed the cultivated and wild plant species assemblages of 69 sacred sites in the megacity of Bengaluru, India, in relation to biological and cultural features, and parameters related to the urban matrix and type of sacred sites (temple vs. katte). Unlike other urban studies, we found a dominance of native species in the cultivated and spontaneous species pools (121 species in total), with Ficus religiosa and Azadirachta indica as most frequently planted species. Culturally relevant species prevailed in the species pool (89%), with overlaps between religious (36%), medicinal (50%) and ornamental (62%) plants; only 11% of species were weeds. Urban matrix parameters (age of development, housing density) and size and type of sacred sites were related to differences in species assemblages. We identified key species for different classes of age and housing density, and for types of sacred sites. Our study demonstrates that urban sacred sites have an important potential in harbouring both native and culturally significant species that can support urban livelihoods in developing countries by a range of cultural and provisioning ecosystem services, including medicinal uses. As such sites are conserved by communities for spiritual or cultural beliefs, local biodiversity can be enhanced, e.g. by adapting management practices through community participation. This would strengthen the important contribution of sacred sites within the green infrastructure of rapidly growing megacities.     

绿色超级稻品种的农艺与生理性状分析

探明绿色超级稻的农艺与生理性状,对于培育和选用绿色超级稻品种有重要意义。本研究以4个绿色超级稻品种为材料,1个超级稻品种和1个非超级稻品种为对照,观察了绿色超级稻的农艺与生理表现。结果表明,与对照品种相比,绿色超级稻品种具有较高的产量和氮素利用效率。绿色超级稻品种较高的产量得益于总颖花数和结实率的同步提高,较高的氮素利用率主要在于较高的植株氮素籽粒生产效率(氮素内部利用效率)。绿色超级稻具有较高的茎蘖成穗率和粒叶比,抽穗期较高的糖花比,灌浆期较高的作物生长速率、净同化率、根系氧化力和茎中同化物向籽粒的运转率和成熟期较高的收获指数。这些性状与产量及植株氮素籽粒生产效率均呈极显著的正相关。建议将上述性状作为培育和选用绿色超级稻品种的参考指标。     

卢氏绿壳蛋鸡育成期适宜能量水平的研究

试验旨在通过研究不同能量水平对卢氏绿壳蛋鸡育成期体尺、生长性能及屠宰性能的影响，得出其育成期能量的需要量。选用150 只体重相近的8 周龄卢氏绿壳蛋鸡，按能量水平（A组10.52 MJ/kg、B组10.90 MJ/kg、C组11.29 MJ/kg、D组11.70 MJ/kg、E组12.10 MJ/kg）随机分为5 组（5 个重复，每个重复6 只鸡）。试验采取单因素试验设计，预试期1 周，正试期10 周。结果表明：不同能量水平显著影响卢氏绿壳蛋鸡育成期的胫长、胸宽和胸深(P<0.05)。D和E 组的终末体重和平均日增重差异不显著(P>0.05)，但均显著高于A、B和C组(P<0.05)。能量过高时（E组），终末体重和平均日增重又有所下降。不同能量水平对卢氏绿壳蛋鸡的屠宰性能影响显著(P<0.05)。在本试验条件下，日粮能量水平为11.70 MJ/kg时，更有利于提高卢氏绿壳蛋鸡育成期的生产性能和屠宰性能。     

基于随机森林算法的自然光照条件下绿色苹果识别

果实识别是自动化采摘系统中的重要环节，能否快速、准确地识别出果实直接影响采摘机器人的实时性和可靠性。为了实现自然光照条件下绿色苹果的识别，本文采集了果实生长期苹果树图像，并利用随机森林算法实现了绿色苹果果实的分类和识别。针对果树背景颜色和纹理特征的复杂性，尤其是绿色果实和叶片在很多特征上的相似性，论文基于RGB颜色空间进行了Otsu阈值分割和滤波处理，去除枝干等背景，得到仅剩果实和叶片的图像。然后，分别提取叶片和苹果的灰度及纹理特征构成训练集合，建立了绿色苹果随机森林识别模型，并使用像素模板验证数据集，对模型进行预测试验，正确率为90%。最后，选择10幅自然光照条件下不同的果树图像作为检测对象，使用该模型进行果实识别并使用霍夫变换绘制果实轮廓，平均识别正确率为88%。结果表明，该方法具有较高的鲁棒性、稳定性、准确性，能够用于自然光照条件下绿色果实的快速识别。