Fertilization regulates the response of wheat yield to interannual temperature variation in North China

Aims understanding the effect of long-term fertilization on the sensitivity of grain yield to temperature changes is critical for accurately assess-ing the impact of global warming on crop production.In this study,we aim to assess the impacts of temperature changes on grain yields of winter wheat(Triticum aestivum l.)under different fertilization treatments in a long-term manipulative experiment in North China.Methods We measured grain yields of winter wheat under four fertilization treatments at the Yucheng Comprehensive Experimental station each year from 1993 to 2012.We also measured air temperature at 0200,0800,1400 and 2000 h each day since 1 January 1980.We then used the first-difference method and simple linear regres-sion models to examine the relationship of crop yield changes to mean air temperature,mean daytime and nighttime air temperature in crop growing seasons.Important Findings We found that increases in mean daily temperature,mean day-time temperature and mean nighttime temperature each had a positive impact on the grain yield of winter wheat.grain yield increased by 16.7-85.6%for winter wheat in response to a 1°C increase in growing season mean daily temperature.Winter wheat yield was more sensitive to variations of nighttime temperature than to that of daytime temperature.The observed temperature impacts also varied across different fertilization treatments.balanced fertilization significantly enhanced grain yields for winter wheat under a warming climate.Wheat plots treated with nitrogen and phosphorous balanced fertilization(NPK-and NP-treated plots)were more responsive to temperature changes than those without.This report provides direct evidence of how temperature change impacts grain yields under different fertiliza-tion treatments,which is useful for crop management in a chang-ing global climate.

Does the spatial arrangement of urban landscape matter?Examples of urban warming and cooling in Phoenix and Las Vegas

This study examines the impact of spatial landscape configuration(e.g.,clustered,dispersed)on land-surface temperatures(LST)over Phoenix,Arizona,and Las Vegas,Nevada,USA.We classified detailed land-cover types via object-based image analysis(OBIA)using Geoeye-1 at 3-m resolution(Las Vegas)and QuickBird at 2.4-m resolution(Phoenix).Spatial autocorrelation(local Moran’s I)was then used to test for spatial dependence and to determine how clustered or dispersed points were arranged.Next,we used Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)data acquired over Phoenix(daytime on 10 June and nighttime on 17 October 2011)and Las Vegas(daytime on 6 July and nighttime on 27 August 2005)to examine day-and nighttime LST with regard to the spatial arrangement of anthropogenic and vegetation features.Local Moran’s I values of each land-cover type were spatially correlated to surface temperature.The spatial configuration of grass and trees shows strong negative correlations with LST,implying that clustered vegetation lowers surface temperatures more effectively.In contrast,clustered spatial arrangements of anthropogenic land-cover types,especially impervious surfaces and open soil,elevate LST.These findings suggest that city planners and managers should,where possible,incorporate clustered grass and trees to disperse unmanaged soil and paved surfaces,and fill open unmanaged soil with vegetation.Our findings are in line with national efforts to augment and strengthen green infrastructure,complete streets,parking management,and transit-oriented development practices,and reduce sprawling,unwalkable housing development.