Time filter

Source Type

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover. © 2015 ISB Source

Yang Y.,Xinjiang Normal University | Chen Y.,Xinjiang Institute of Ecology and Geography | Wang M.,Institute of Desert and Meteorology | Sun H.,Xinjiang Normal University
Theoretical and Applied Climatology | Year: 2016

We examined the changes in streamflow on the northern slopes of the Tianshan Mountains in northern Xinjiang, China, over two time scales: the past 500 years, based on dendrochronology data; and the past 50 years, based on streamflow data from hydrological stations. The method of artificial neural networks built from the data of the 50-year period was used to reconstruct the streamflow of the 500-year period. The results indicate that streamflow has undergone seven high-flow periods and four low-flow periods during the past 500 years. To identify possible transition points in the streamflow, we applied the Mann–Kendall and running T tests to the 50- and 500-year periods, respectively. During the past 500 years, streamflow has changed significantly from low to high flow about three to four times, and from high to low flow about three to five times. Over the recent 50 years, there have been three phases of variation in river runoff, and the most distinct transition of streamflow occurred in 1996. © 2016 Springer-Verlag Wien Source

Li J.,Fudan University | Li J.,Institute of Desert and Meteorology | Huang K.,Fudan University | Wang Q.,Fudan University | And 5 more authors.
Science China Chemistry | Year: 2010

Black carbon (BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007. In addition, TSP samples were also synchronously daily collected by medium-volume samplers with Whatman® 41 filters in the spring of 2007. BC in the dust aerosol was up to 1.14% of the total mass of PM10. A remarkable seasonal variation of BC in the aerosol was observed in the order of winter > spring > autumn > summer. The peak value of BC appeared at midnight while the lowest one in the evening each day, which was just the reverse of that in the urban area. The contribution of BC to the total mass of PM10 on non-dust storm days was ∼11 times of that in dust storm. Through back trajectory and principal component analysis, it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities, including domestic heating, cooking, combustion of oil and natural gas, and the medium-range transport from those oases located in the margins of the desert. The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3 × 104 ton yr -1. © Science China Press and Springer-Verlag Berlin Heidelberg 2010. Source

Huang J.,Institute of Desert and Meteorology
International Journal of Plant Production | Year: 2015

This study was conducted to determine whether selecting an optimum sowing date could improve yield. The experiment consisted of sowing a film-covered, drip-irrigated cotton field on four sowing dates from April to May in 2011-2012 at the Agrometeorological Experimental Station of Wulanwusu, which was in an arid region of north-western China. Late sowing dates produced less yield and water-use efficiency than did the normal sowing dates. The yield increased with the increases of mean diurnal temperature range (DTR) from full bloom to maturity, mean temperature and sunshine hours (SH) during the whole growing season (WGS), accumulated temperature (AT) and days from squaring to anthesis and mean temperature during the reproductive growth stage. However, the main effect factors of meteorological parameters were AT from squaring to anthesis, mean temperature during the WGS and AT from sowing to emergence. The main effect factors of yield component were boll number per plant, gin turnout and boll weight. Boll number per plant suffered from mean DTR from boll setting to maturity and SH during the WGS. Gin turnout was affected by mean temperature during the WGS and mean DTR from boll setting to maturity. Sowing date, year and their interactions all significantly affected the yield. Sowing date was an important factor affecting the yield and reproductive duration. With climate change, an earlier planting date might be an efficient method of increasing yield. © 2015, Gorgan Univ Agricultural Sciences and Natural Resources. All rights reserved. Source

Huang J.,Institute of Desert and Meteorology | Li J.,Xinjiang Plant Protection Station
International Journal of Biometeorology | Year: 2015

Climate change significantly affects insects’ behaviors. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most serious insect pests in the world. Much is known about the survival of the overwintering population and spring emergence of H. armigera. However, little is known about the effects of climate change on overwintering and spring emergence of H. armigera. This study investigated the effects of changes of air and soil temperatures and precipitation on overwintering pupae of H. armigera by analyzing historical data from Magaiti County in northwest China using statistical methods. The results showed that during the period of 1989–2006, the climate warming advanced the first-appearance date of overwintering pupae eclosion (FD) and end date of overwintering pupae eclosion (ED) by 1.276 and 0.193 days per year, respectively; the duration between the FD and ED (DFEPE) was prolonged by 1.09 days per year, which resulted in more eclosion of overwintering pupae. For a 1 °C increase in the maximum air temperature (Tmax) in winter, the FD became earlier by 3.234 days. Precipitation in winter delayed the FD and ED and produced little relative influence on DFEPE. A 1-mm increase of precipitation in winter delayed the FD and ED by 0.850 and 0.494 days, respectively. Mean air temperature (Tmean) in March, with a 41.3 % relative influence, precipitation in winter, with a 49.0 % relative influence, and Tmean in March, with a 37.5 % relative influence, were the major affecting factors on FD, ED, and DFEPE, respectively. Tmax in February with a 53.0 % relative influence was the major affecting factor on the mortality of overwintering pupae (MOP). Increased soil temperatures in October and November and autumn and air temperatures in winter could decrease the MOP, though the relative influences were lower than Tmax in February. Increased precipitation in winter increased the MOP, but the relative influence was only 4.2 % because of little precipitation. Tmean in October had the greatest influence on the pre-wintering density of pupae (PDP). Increasing soil temperatures in October, November, and autumn increased PDP. A higher PDP increased overwintering survival and advanced FD and prolonged DFEPE. The overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperature and snow covering. Thus, climate warming helped to enhance the survival of overwintering pupae. © 2014, ISB. Source

Discover hidden collaborations