Using QUEFTS model for estimating nutrient requirements of maize in the Northeast China

Accurate estimating of the balanced nutrition for maize is necessary for optimizing fertilizer management to prevent nutrient supply surplus or deficiency. Data from 300 field experiments in the Northeast China conducted between 2006 and 2011 were gathered to study the characteristics of maize yield, and using the QUEFTS model to estimate the balanced nutrition at different yield potential. The average grain yield was 10 427 kg/ha, and average internal efficiencies were 54.3, 251.5 and 78.2 kg grain per kg plant nitrogen (N), phosphorus (P) and potassium (K), respectively. With the harvest index values < 0.40 as outliers were excluded, the model simulated a linear-parabolic-plateau curve for the balanced N, P and K uptake when the initial yield target increased to the yield potential levels of 10 000 to 14 000 kg/ha. When the yield target reached approximately 60–70% of the yield potential, 16.7 kg N, 3.8 kg P, and 11.4 kg K were required to produce 1000 kg grain. The corresponding internal efficiencies were 60.0, 265.7 and 88.0 kg grain per kg plant N, P and K, respectively. These results contributed to improving nutrient use efficiency, and to demonstrate that the QUEFTS model could be a promising approach for estimating the balanced nutrition.

Inner-city transformation between reurbanization and gentrification: Leipzig, eastern Germany

After the beginning of the post-socialist transformation, the eastern German city of Leipzig underwent various changes within a short time span. These changes have been especially dynamic in its inner city. Whereas it was hit by the loss of large parts of its population and increasing housing vacancies in the 1990s, the 2000s brought about a revitalization and new attractiveness of many inner-city districts. Since then, reurbanization and – in some places – gentrification have become the predominant trends in a rising number of inner-city districts. This development has also reshaped patterns of socio-spatial differentiation in the city as a whole and its inner parts. Set against this background, the paper describes the development of Leipzig’s inner city after 1990. The focus of the paper is it to show how various concepts – reurbanization and gentrification – help to explain this development. Of particular interest thereby is the impact of Leipzig’s specific housing market situation that is characterized by long-term experiences of supply surplus and shrinkage.