Digestion and nitrogen metabolism in beef cattle and in vitro rumen fermentation of autumn grass differing in fertilizer nitrogen application rate

Beef cattle partition dietary nitrogen (N) into meat or excrete it mainly in faeces and urine, which can contribute significantly to water and air pollution. The effects of two inorganic nitrogen (N) fertilizer application rates—15 (LN) or 80 (HN) kg N/ha—to Lolium perenne‐dominant swards in autumn, on herbage chemical composition, intake, digestion and N balance in beef cattle, and in vitro fermentation and methane production were studied. Four growing beef steers used in a 2 × 2 crossover design experiment were offered zero‐grazed grass harvested 21 days post‐N application between July and October. The same grasses were incubated in an eight‐vessel rumen simulation technique in a randomized complete block experiment. Grass dry‐matter (DM) concentration was 26 g/kg lower and crude protein (CP) concentration was 35 g/kg DM higher for HN compared to LN. There was no difference in herbage DM intake or in vivo DM digestibility between treatments. Nitrogen intake and the digestibility of N were higher for HN compared to LN. Total and urine N loss were 41 and 45 g/day greater, respectively, for HN compared to LN, but faecal N loss did not differ between treatments. The quantity of N retained and therefore N‐use efficiency did not differ between LN and HN (25% vs. 22%). In vitro rumen pH and ammonia‐N concentrations were higher for HN compared to LN, whereas volatile fatty acid concentrations and molar proportions did not differ between treatments. In vitro methane and total gas production were 0.9 mmol/day and 280 ml/day lower for HN than LN respectively. Under the particular conditions of this experiment, reducing fertilizer N application rate reduced total and urinary N excretion, which has potential environmental benefits; however, methane output measured in vitro was increased.     

Interrogating the production of urban space in China and Vietnam under market socialism

This paper explores two issues. First, it focuses on the question of what is the most appropriate theoretical framework for the study of the urbanisation process in China and Vietnam over the last 30 years? It is argued that Le Fefebvre's theory of the ‘production of urban space’ offers the most useful approach because the political economy it adopts helps identify the major driving forces in the urbanisation process in these formerly socialist societies. The second issue involves the investigation of the differences and similarities in the urbanisation process in the two countries that are engaged in similar processes of structural economic transformation. The conclusion suggests that despite historical and cultural differences between Vietnam and China, the urbanisation process in both countries is exhibiting converging features as both countries are adopting a form of ‘hybrid urbanisation’ that involves a combination of socialist and market economies that does not involve an inevitable move to ‘capitalism’.