基于GIS技术的内蒙古兴安盟春玉米种植气候区划

利用兴安盟8个气象观测站及周边相邻省份及地区的18个气象观测站1971-2000年标准气候统计资料,建立了兴安盟玉米种植气候区划因子与地理信息的回归模型,确定了兴安盟地区玉米种植综合气候区划指标,并利用GIS技术将兴安盟玉米种植划分为适宜、较适宜及不适宜种植地区,进行分区评述的同时提出了趋利避害的建议。分区结果对合理利用气候资源,降低玉米产量风险和调整种植业结构具有重要参考意义。     

Re-Introduction of Quínoa into Arid Chile: Cultivation of Two Lowland Races under Extremely Low Irrigation

Annual rainfall in Chile at 30°S decreased from 170 to 70 mm in the last century, forcing a search for new low-rain adapted crops. Chenopodium quinoa Willd. was cultivated by pre-Hispanic cultures, but it disappeared in this region since the Spanish conquest. Two quínoa landraces (Don Javi and Palmilla) were re-introduced from lowlands of central Chile (34°S) evaluating seed saponin content and grain yields under low irrigation. Replicated assays were conducted in two sites with distinct microclimates after august (end of the rains in 2004 and 2005). Treatments included low (40–75 mm) and high (150–250 mm) irrigation and were distributed along the five cultivation months. Fertilization, with the humus of the worms, was carried out in the second season, as soils are poor in organic matter. Results showed significantly higher saponin content in the seeds of Don Javi landrace (1.2 %) with respect to Palmilla seeds (0.3 %). However, grain yields were not different between landraces under the same treatments. Yields were instead affected by microclimate, irrigation and fertilization. Although higher yields corresponded with higher irrigation, 2.6 tons ha⁻¹ was obtained under high irrigation, but surprisingly, also under low irrigation in the more humid site. Yields of 2006 harvesting season (ca. 7 tons ha⁻¹) were higher than that of the previous season (ca. 5.5 tons ha⁻¹), mainly because of the addition of organic matter. We suggest that re-introduction of Quinoa in arid Chile is feasible even under the prevailing conditions of low rainfall and deficient soils, but better yields will need some irrigation and addition of organic matter.     

Application of natural plant extracts improves the tolerance against combined terminal heat and drought stresses in bread wheat

Drought and heat are among the main abiotic stresses causing severe damage to the cereal productivity when occur at reproductive stages. In this study, ten wheat cultivars were screened for combined heat and drought tolerance imposed at booting, heading, anthesis and post‐anthesis stages, and role of the foliage applied plant extracts was evaluated in improving the performance of differentially responding wheat cultivars under terminal heat and drought stresses. During both years, wheat crop was raised under ambient temperature and 70% water holding capacity (WHC) till leaf boot stage. The plant extracts (3% each) of sorghum, brassica, sunflower and moringa were foliage applied at booting, anthesis and post‐anthesis stage; and after one week of application of these plant extracts, combined heat and drought was imposed at each respective stage. Heat and drought stresses were imposed at each respective stage by placing pots in glass canopies with temperature of 4 ± 2°C above than the ambient temperature in combination with drought stress (35% WHC) until maturity. Combination of drought and heat stresses significantly reduced the performance of tested wheat cultivars; however, stress at the booting and heading stages was more damaging than the anthesis and post‐anthesis stages. Cultivars Mairaj‐2008 and Chakwal‐50 remained green with extended duration for grain filling, resulting in the maintenance of number of grains per spike and 100‐grain weight under stress conditions and thus had better grain yield and water‐use efficiency. However, in cultivars Fsd‐2008, and Shafaq‐2006, the combined imposition of drought and heat accelerated the grain filling rate with decrease in grain filling duration, grain weight and grain yield. Foliar application of all the plant extracts improved the wheat performance under terminal heat and drought stress; however, brassica extract was the most effective. This improvement in grain yield, water‐use efficiency and transpiration efficiency due to foliage applied plant extracts, under terminal heat and drought stress, was owing to better stay‐green character and accumulation of more soluble phenolics, which imparted stress tolerance as indicated by relatively stable grain weight and grain number. In crux, growing of stay‐green wheat cultivars with better grain filling and foliage application of plant extracts may help improving the performance of bread wheat under combined heat and drought stresses.     

Improving resistance against terminal drought in bread wheat by exogenous application of proline and gamma‐aminobutyric acid

Scarcity of water is a severe constraint, which hinders the wheat productivity worldwide. However, foliage application of osmoprotectants may be useful in reducing the drought‐induced yield losses in wheat (Triticum aestivum L.). In this study, potential of foliage applied osmoprotectants (proline, gamma‐aminobutyric acid) in improving the performance of bread wheat against terminal drought was evaluated. Both proline and gamma‐aminobutyric acid (GABA) were foliage applied at 50, 100 and 150 mg/L at anthesis stage (BBCH‐identification code‐ 61), in two bread wheat cultivars viz. Mairaj‐2008 and BARS‐2009. After 1 week of foliage application of these osmoprotectants, drought was imposed by maintaining the pots at 35% water holding capacity. Imposition of drought caused significant reduction in the grain yield of both tested bread wheat cultivars; nonetheless, foliage applied osmoprotectants at either concentration improved the chlorophyll contents, accumulation of proline, glycinebetaine and total soluble phenolics and reduced the malondialdehyde contents, which resulted in better stay green, maintenance of grain weight and grain number under drought stress, thus resulting in better grain yield, water‐use efficiency and transpiration efficiency in both wheat cultivars. However, foliage applied proline at 150 mg/L, and GABA at 100 mg/L was most effective than other concentrations of these osmoprotectants. Performance of cultivar Mairaj‐2008 was quite better than cultivar BARS‐2009. In crux, foliar application of proline and GABA at pre‐optimized rate can be opted as a shotgun approach to improve the performance of wheat under terminal drought.     

Governing climate change in Hong Kong: Prospects for market mechanisms in the context of emissions trading in China

Hong Kong continues to struggle over which environmental governance approach is in its best interest while fulfilling its environmental obligations. With regard to climate change, Hong Kong's approach is characterised by a passive form of governance that is highly dependent on China's national policy directions. This is reflected, for example, in Hong Kong having not set its own mitigation targets. Market mechanisms have received little attention in developing a city‐wide climate change strategy. A transformative impulse, China's national emissions trading scheme, may provide momentum to a market‐based approach. However, the necessary conditions for such a market mechanism to be successfully implemented in China remain relatively undeveloped. This raises question about early participation by Hong Kong. Direct benefits are likely to be limited, due to Hong Kong's economic structure and weak demand for emissions reduction. Besides, there are regulatory barriers to enforcing emissions targets and/or recognising emissions allowances and credits from China. We therefore argue that nationwide emissions trading may, at this time, present more challenges than opportunities for Hong Kong to leverage its efforts on climate change mitigation. An alternative is to promote voluntary emissions trading that will require active involvement and leadership by businesses.     

残膜回收机防膜回带机构分析及发展思考

机械化残膜回收是现阶段解决残膜污染问题的主要方法。在当前已存在的残膜回收机中,残膜回带影响了机具的工作效率,膜回带逐渐成为残膜回收工作的技术难题。为此,总结了防膜回带机构种类及机理特点,对其实际效果进行了分析,并按当前膜回带形式分类并提出发展思路,旨在为残膜回收机防膜回带机构的设计及优化提供理论参考。     

人类活动和气候变化对岚河流域河川径流的影响

径流变化归因识别是流域治理开发和水资源管理的重要基础工作。[目的]识别岚河流域河川径流的主要影响因素。[方法]采用水文模拟的途径定量评估了气候要素变化和人类活动对山西省岚河流域河川径流的影响。[结果]RCCC-WBM模型对岚河天然径流过程具有较好的模拟效果,NSE超过80%,总量模拟误差RE小于2%;由于气候和人类活动等环境要素变化的影响,1968年之后,上静游站实测径流量较前期减少了50%以上;1969 2015年,人类活动的影响量占径流总减少量的76.1%,是岚河径流减少的主要原因;由于近期降水增加,气候要素变化对径流减少的影响有减弱趋势。[结论]人类活动是岚河径流的主要影响因素。     

云南省地域气候特征与温室建造的探讨

具体分析了云南省地域气候特征,同时阐述了不同气候特征对云南温室建造的影响,以及云南省现存的不同类型的温室.通过分析云南省的地域气候特征得到了不同地区影响温室设计的不同影响因子,根据该因子把云南省划分为4个不同的气候区域并在理论上建立了不同气候区域的温室模型,为以后云南省能够更科学地建造和设计温室提供了有力的理论依据.     

塔里木河流域未来农业水价对灌水量的需求弹性效应分析

在塔里木河流域农业供水成本水价基础上,基于流域节水灌溉技术的成本投入,首先构建了流域农业节水水价;然后,利用流域农业水价和灌水量资料构建了流域农业水价的需求效应模型,分析了未来塔河流域节水水价的节水效应,研究结果表明:基于节水水价的未来农业水价的调整可大幅降低灌水量,提高水价的节水效应;而且,如果农业水价弹性系数同时被提高,较单独提高农业水价,未来塔河流域水价的节水效应更高;尤其是,未来农业水价的需求效应分析事关流域用水户的水价承受力和粮食安全问题,是未来塔河流域农业水价调整需要重点探讨的内容.     

暖冬气候对新疆北疆冬小麦的影响

以新疆北疆地区塔城、乌苏、车排子三地(1981～2001年)冬小麦生长发育资料和相应的气象资料为依据,分析了北疆地区气候变暖的状况和年型.根据冬季气候变暖对冬小麦越冬死亡率、产量和病虫害的影响,并依据大气环流模式(GCMs)输出结果,对北疆地区冬小麦生产潜力进行模拟计算,提出了适应性对策.