Monitoring vegetation drought in the nine major river basins of China based on a new developed Vegetation Drought Condition Index

The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecological environments.In this study,we constructed a new drought index(i.e.,Vegetation Drought Condition Index(VDCI))based on precipitation,potential evapotranspiration,soil moisture and Normalized Difference Vegetation Index(NDVI)data,to monitor vegetation drought in the nine major river basins(including the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin,Yangtze River Basin,Southeast River Basin,Pearl River Basin,Southwest River Basin and Continental River Basin)in China at 1-month–12-month(T1–T12)time scales.We used the Pearson's correlation coefficients to assess the relationships between the drought indices(the developed VDCI and traditional drought indices including the Standardized Precipitation Evapotranspiration Index(SPEI),Standardized Soil Moisture Index(SSMI)and Self-calibrating Palmer Drought Severity Index(scPDSI))and the NDVI at T1–T12 time scales,and to estimate and compare the lag times of vegetation response to drought among different drought indices.The results showed that precipitation and potential evapotranspiration have positive and major influences on vegetation in the nine major river basins at T1–T6 time scales.Soil moisture shows a lower degree of negative influence on vegetation in different river basins at multiple time scales.Potential evapotranspiration shows a higher degree of positive influence on vegetation,and it acts as the primary influencing factor with higher area proportion at multiple time scales in different river basins.The VDCI has a stronger relationship with the NDVI in the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin and Yangtze River Basin at T1–T4 time scales.In general,the VDCI is more sensitive(with shorter lag time of vegetation response to drought)than the traditional drought indices(SPEI,scPDSI and SSMI)in monitoring vegetation drought,and thus it could be applied to monitor short-term vegetation drought.The VDCI developed in the study can reveal the law of unclear mechanisms between vegetation and climate,and can be applied in other fields of vegetation drought monitoring with complex mechanisms.

Formation of Assimilating Surface Areas and Photosynthetic Potential of Various Assimilating Parts of Wheat Species under Drought Conditions

Some of environmental factors (weather sharp fluctuations) may accrue stress within a few minutes, while others may not be long for this period of stress in this situation. It has formed stress in organisms, to eliminate the stress, there starts over various biochemical and physiological mechanisms for protection. Therefore, a large variety of plants to examine ways of increasing the resistance against stress factors have a scientific and practical importance. Thus, the primary processes of photosynthesis, based on the results of the study and its corresponding morphophysiological higher photochemical activity, has been found in a range of genotypes. Their leaves and plants assimilate the biological productivity of the intensity of the symptoms associated with the use of photosynthetic learned of the opportunity to create a new perspective varieties. This allows the research to prove the expansion of the electronic delivery of high-yielding genotypes and phosphorised chloroplast high speed, as well as the pH of thylacoid membranes are characterized by a great price, also photosynthetic electron transport, CO2 assimilation and it was approved to be the link between productivity.

Analysis of Drought in Poyang Lake

[Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and 'five lakes',hydraulic project,industrial and agricultural water increase and other aspects.[Conclusion] The study provided theoretical basis for the formulation of drought prevention measures by relevant departments.

Analysis of the forest fires in the Antalya region of Turkey using the Keetch–Byram drought index

We investigated the correlation of large fires（[300 ha） from 1992 to 2013 within the borders of the Antalya Regional Directorate of Forestry using the Keetch–Byram drought index（KBDI）. Daily KBDI values were calculated for each year, and values for the period before the year 2000 differed significantly from those after2000. After 2000（large fires occurred in 2004, 2006, 2007,2008, 2010, and 2013）, when KBDI values increased, the KBDI, but not the number of fires, was inversely correlated with the natural log of the burned area（NLBA）. While there were both high and low KBDI values when the NLBA was small, only high KBDI values were associated with high NLBA values. Particularly for logarithmic values of 4 and higher, KBDI values increased in parallel with increases in NLBA values. On the basis of a Mann–Whitney U test done in addition to a Pearson correlation test, we found that when the burned areas were grouped according to small and large areas, the KBDI could be used to distinguish the two groups. Using a conditional probability analysis, we found that 4th, 5th and 6th class KBDI values may lead to large fires at the 60 % possibility.Similarly, the possibility of large fires greater than the median burned area in any given 6 years was found to be48 %. In addition, while the mean value of KBDI is 390.51 for the period from May to September for these 6 years, it is 359.93 for the other years. Consequently, the area burned also increased as the KBDI classes（Class 0： 0–99, Class 1：100–199, Class 2： 200–299, Class 3： 300–399, Class 4：400–499, Class 5： 500–599, Class 6： 600–699, and Class 7：700–800） increase.

一种土壤调理剂对玉米幼苗抗旱性的影响

为研究新型高效土壤调理剂M3T对作物抗旱性的影响,开展水分胁迫下不同浓度M3T对盆栽玉米幼苗的抗旱性影响的试验。结果表明：添加M3T可增强土壤保水能力;M3T处理延长玉米幼苗的存活时间3～11天,增加玉米幼苗的株高和生物量;玉米幼苗体内叶绿素、丙二醛、脯氨酸、可溶性蛋白含量及过氧化物酶和超氧化歧化酶活性的动态测定结果表明,未加M3T的处理玉米幼苗最早感受到水分胁迫而产生生理生化反应,M3T处理的玉米幼苗出现水分胁迫反应延迟。干旱胁迫下,0.01%～0.03%M3T处理有利于玉米幼苗生长,0.04%～0.05%M3T处理增强了玉米幼苗抗旱性,其存活时间更长;0.02%～0.03%M3T处理下农作物在干旱胁迫下可正常生长发育,且具有较好的抗旱性,为较佳处理。

“艾佐迈”土壤调理剂在节水抗旱稻上的应用

为了研究土壤调理剂"艾作迈"(Azomite)对节水抗旱稻(WDR)生长发育和产量的影响,在节水栽培模式下,以杂交节水抗旱稻品种‘旱优8号’为试验材料,按照施氮量设160kg/hm2(LN)、200kg/hm2(NN)和240kg/hm2(HN)3种肥力水平,以不施"艾佐迈"土壤调理剂为对照进行田间试验。结果表明:在3种氮肥水平下,施用"艾佐迈"都使‘旱优8号’植株剑叶叶绿素含量、株高、单株有效穗、穗长、单株产量增加,在LN和NN水平下实际产量显著增加6.41%和11.1%。在土壤营养方面,施用"艾佐迈"对土壤pH没有影响;3种氮肥水平下土壤全氮含量、速效钾含量比对照降低,在LN和NN水平下,施用"艾佐迈"使土壤有机质含量和速效磷含量增加,在NN和HN水平下,施用"艾佐迈"的处理土壤速效氮含量比对照增加。

黑液制备的腐植酸液肥和调理剂的棉花田间应用研究

为了给黑液实现资源化利用提供依据。在新疆进行了黑液腐植酸产品的田间试验,设计了3个处理,采用棉花定点定株方法调查其生理指标,并测定其生化指标,研究了它们对棉花的生长、产量和抗旱能力的影响。结果表明,在滴灌中应用腐植酸液肥,与常规固体肥料相比可明显促进棉花在各生育期的生长、能增加蕾、花和铃的数量、并且延长成熟时间、作物不易早衰。同时,液肥还可提高棉花的经济性状,能够显著增加籽棉的产量,增产率可达12.3%。在棉花上使用该腐植酸产品后可降低叶片的蒸腾速率,提高叶片的保水能力和CAT活力,从而明显增强棉株的抗旱能力。黑液腐植酸产品对棉花具有良好的促长、增产和抗旱效果。

提高草坪草抗旱性措施的研究进展

干旱胁迫是限制草坪草生长的一个主要因素。抗旱性一直是草坪草建植的研究焦点之一。从现有的种质资源、外源性物质、土壤改良剂以及管理措施等方面对近几年提高草坪草抗旱性措施的研究进展进行综述,提出了增强草坪草抗旱性未来研究的方向,旨在为进一步开展草坪草抗旱措施研究提供理论基础。

土壤改良剂对干旱胁迫下青稞幼苗形态及生理特性的影响

采用盆栽试验研究了施用菌剂(2 g/kg土)、腐植酸钾(2 g/kg土)对干旱胁迫下青稞幼苗形态及生理特性的影响。结果表明,腐植酸钾和菌剂均能有效促进干旱胁迫下青稞幼苗的生长,其中腐植酸钾效果更好,不仅能提高青稞幼苗株高、鲜重、干重、根冠比、根平均直径、茎粗和叶面积、根的投影面积、表面积、体积及分支数等形态指标,也提高了根系活力、叶绿素含量、过氧化物酶、超氧化物歧化酶、过氧化氢酶活性,降低丙二醛含量。

贯流空调柜机在普通模式和低吹风感模式下的实验与数值研究

基于实验手段,首先在舒适性实验室得到了某贯流空调柜机在普通模式和低吹风感模式下的吹风感指数,实验结果表明低吹风感模式下的多孔射流有助于降低吹风感指数。随后通过仿真方法对该柜机空调的内部流场进行数值模拟分析,指出在低吹风感模式下,气流在导风板前进行了全局范围内的二次增压,使得压力能得以重新回收;回收的压力能随后通过导风板上的多孔射流进行了能量的重新分配释放,一方面提升了送风均匀性和送风范围,另一方面降低了最大出风速度,继而降低了房间的吹风感指数。最后通过仿真手段分析了低吹风感模式下出风口两侧凝露问题的产生机理,并依此对出口两侧进行结构优化,解决了低吹风感模式下出风口两侧的积水问题。