Interactive effects of water and controlled release urea on nitrogen metabolism,accumulation, translocation,and yield in summer maize

To investigate the interactive effects of water and N from controlled release urea (CRU) on N metabolism, accumulation, translocation, and yield in Zhengdan958 (a summer maize cultivar planted widely in China), three water levels (adequate water W3, mild water stress W2, severe water stress W1) and four amounts of CRU (N) (N0, N1, N2, and N3 were 0, 105, 210, and 315 kg N ha^?1, respectively) were carried out under the waterproof shed and soil column conditions. The results showed that yield, N metabolism, accumulation, and translocation were significantly affected by water, CRU, and their interactions after tasseling. Yields showed an increasing trend in response to N rates from 100.2 to 128.8 g plant^?1 under severe water stress (W1), from 124.7 to 174.6 g plant^?1 under mild water stress (W2), and from 143.7 to 177.0 g plant^?1 under adequate water conditions (W3). There was an associated optimum amount of N for each water level. Under W1 and W2, N3 treatments showed significant advantages in three N metabolism enzymes’ activities and the N accumulations, and yield and its components were highest. But the nitrogen harvest index (NHI) of N3 had no significant difference with other nitrogen treatments. Under W3, the N translocation efficiency (NTE) and N translocation conversion rate (NTCR) of N2 in stem and leaf were higher than those of N3, but the N metabolism enzymes’ activities and yields of N2 and N3 had no significant difference, which indicated that N2 was superior to N3. The N3 treatment under W2 and N2 under W3 increased the N accumulation capacity in maize grain as well as the N translocation to grain that contributed to the increase of 1000-gain weight and grains per ear after tasseling. Under this experimental condition, a CRU rate of 225 kg ha^?1 was the best treatment when the soil moisture content was 75 ± 5% of field capacity, but an N rate of 300 kg ha^?1 was superior when soil moisture content was maintained at 55 ± 5% of field capacity during the entire growing season.     

Local authorities and sustainable development: Turning policies into practical action through performance review—a case study of the London borough of hackney

Local authorities are increasingly undertaking policy initiatives which aim to achieve local sustainability. Indeed, the rapid development in this area since its first tentative steps in the late 1980s is very impressive. However, it is legitimate to question whether any real progress has been made in improving local environmental conditions. This is almost impossible to determine as very few have translated policy rhetoric into measurable environmental achievement. Although the development of sustainability indicators will, in the long term, provide some means of measuring success, few authorities have the necessary precursor for its achievement in place: performance-based environmental programmes. This important stage of development has been all but missed in the rush for national and international credibility, often at the expense of local communities and their environment rather than for their benefit. This paper examines the activities of one local authority, the London Borough of Hackney, and its efforts to translate policy principals into practical Action for the Environment through the mechanism of performance review. It is concluded that performance review has a valuable role to play in achieving environmental improvements to help move society towards sustainability but, like any mechanism, there are limitations in its use which need to be acknowledged if it is to be used effectively. These are explored in detail in the paper in the hope that they assist others when developing similar performance-based environmental programmes.