The African armyworm Spodoptera exempta (Walker) is an important migratory pest of cereal crops and grasslands in sub-Saharan Africa. It demonstrates great variability in the extent and severity of infestation of its host crops. The African armyworm is known to cause extensive damage to maize crops and rangeland in the transition zone of Ghana. The work reported here was an investigation of the relationship between the Normalized Difference Vegetation Index (NDVI), rainfall and temperature and how they influence the outbreak of this moth species in the Ejura-Sekyeredumase district of Ghana. The temporal patterns of the variables and their interrelationships were evaluated through graphical, logistic and standardization z-score transformations. A strong similarity between temporal patterns of vegetation index and rainfall was established. On the other hand, the temporal pattern of temperature runs opposite to NDVI and rainfall patterns. Standardized NDVI anomaly revealed periods of low vegetation index with corresponding high wetness denoting damage to vegetation due to the activities of the insects during outbreaks. These revelations confirm reports gathered from local famers. NDVI therefore appears to be a good predictor of armyworm outbreaks. Indeed a relationship was established between the occurrences of the moth species and multi-temporal 10-day NDVI signals. The study confirmed that rainfall and temperature influence the occurrence of armyworms.
Simulated studies indicated that early sowing i.e 15th April (D1) predicted highest grain yield during all the years from 1986-2013. Under irrigated conditions increasing levels of N predicted increased grain and stover yield from N levels up to 90 kg N ha-1. Under irrigated and mulched conditions increased level of N predicted increase in maize grain and stover yield upto 120 kg N ha-1. Whereas under un-irrigated mulched conditions highest grain and stover yield was predicted at 60 kg N ha-1. Maize yield was also simulated at different sowing dates and in combination with variable spacings and it was predicted that under irrigated condition closer spacing 40 cm × 20 cm at 15th April sowing recorded highest grain and stover yield of maize. Under un-irrigated mulched conditions highest grain yield was predicted at 30th April sowing with spacing 65 cm × 20 cm. Soil water balance under simulation studies indicated that potential ET was recorded comparatively higher with early sowing date than late sowing date under both irrigated un-irrigated mulched conditions. Similar trend was recorded with respect to transpiration under both irrigated and un-irrigated mulched conditions. Simulated soil evaporation was more in wider spacing than closer spacing. Similar trend was recorded with regard to simulated run-off. Predicted nitrate content (final) of irrigated soil decreased where under un-irrigated mulched conditions 15th April (D1) sowing predicted lowest NO3 leaching than later sowing dates. Under un-irrigated mulched conditions leached nitrate was nominal. Nitrogen denitrification was comparatively more under un-irrigated mulched conditions than irrigated condition. It is concluded that DSSAT v 4.5CERES-Maize model is very robust in predicting the growth and yield of maize as influenced by agrotechniques and could be used in wider perspective.
In 2012 and 2013 annual tree rings were measured in two co-occurring, yet contrasting tree species, the mesic red oak (Quercus rubra) and the more xeric chestnut oak (Quercus montana) across a topographic gradient to access differential impacts of climate and disturbance events. The study sites were located on the lower slope, southeast aspect, northwest aspect, and ridge top in the Ridge and Valley province of central Pennsylvania, USA. During the 20th century, but prior to 1980, growth rates on most sites were statistically similar. After 1980, both species experienced significantly higher basal area increment (BAI) on southeast aspects than northwest sites. Increased growth rate was significantly correlated with increasing tree size. However, this relationship varied across site types and was impacted by disturbances from severe storms in the mid-1950s, 1966, and mid-1990s and gypsy moth outbreaks in the 1980s. Both species exhibited the highest frequency of tree ring releases on southeast aspects. Tree growth was also affected by temperature, precipitation and topographic position. Red oak growth was negatively correlated with current year temperature, particularly on northwest and ridge top sites. Chestnut oak growth responded positively to increasing temperature on southeast and lower slope sites. Moreover, red oak growth on northwest and ridge top locations were negatively correlated with winter temperatures while chestnut oak growth was positively correlated with winter temperatures on lower slope and southeast sites. We conclude that changing climate patterns, including increased temperature, precipitation, and extreme climatic events and site variability affected the growth rates of red oak and chestnut oak.
Aims: To identify whether the urban heat island (UHI) phenomena occurs in Jakarta, a metropolitan city with business and industrial background, and Bandar Lampung, a growing city with agricultural background; to identify community vulnerability and adaptation to UHI impacts.
Place and Duration of Study: This research was conducted in selected area in Jakarta and Bandar Lampung, between September to November 2013.
Methodology: This study used direct air temperature measurements and satellite observation to identify UHI phenomena. The communities vulnerability was assesed with distributing questionnaires and interviewing households,the questions were tailored to fit the components of vulnerability: exposure, sensitivity and adaptive capacity. Vulnerability index is composed of exsposure and sensitivity. The exposure was compiled from community knowledge about climate change and temperature rising and the observed air temperature. The sensitivity was composed of water availability, health related to temperature rising, electricity need; and the adaptive capacity was composed of social relationship, education, income and house environment.
Results: UHI profile was identified in the morning in Bandar Lampung but not in Jakarta. In the afternoon, the UHI still existed in Bandar Lampung but weaker than in the morning, in Jakarta the UHI existed stronger; in the evening UHI was not identified in both cities. The temperature difference could be 4°C in Bandar Lampung and 5°C in Jakarta. Both the LVI and the LVI-IPCC index indicated that Bandar Lampung was less vulnerable to UHI impacts compared to Jakarta (0.303 compared to 0.311 and -0.011 compared to -0.017) both were categorized as moderate.
Conclusion: UHI is present both in Jakarta and Bandar Lampung, and this effect might related to the patterns of land cover in general. The residents both Bandar Lampung and Jakarta have average levels of vulnerability to temperature rises, with Bandar Lampung slightly less vulnerable compared to Jakarta.
The Central England Temperature (CET) record is the world's longest instrument-based temperature record and covers the years 1659-present. The temperature variation of 0.8°C between the Maunder Sunspot Minimum in the late 17th Century and the beginning of the Industrial Revolution in the mid-late 18th Century can be explained by fluctuations in solar output (TSI) alone. Thereafter, approximately one third of the temperature increase to the present may be attributed to increases in atmospheric CO2, with the anthropogenic contribution to Global Warming/Climate Change up to the end of the 20th Century estimated at 0.4 to 0.5°C.