Livestock slurries contain organic matter, nitrogen, phosphorus and potassium, which can be recycled in arable systems; however, excess applications can cause pollution problems and therefore an estimation of the nutrients in slurries is necessary. The aim of the present experiment was to test methods of rapidly estimating nutrient contents of pig slurries based on physical and chemical analysis. A total of 216 samples with a dry matter content in the range 22·5 to 91·8 g/kg were collected in Beijing during 2003 and 2004. One part of each original sample was analysed for physical and chemical properties, such as electrical conductivity (EC), pH and specific gravity (SG). The other part of each original sample was analysed in the laboratory to measure organic matter (OM), total nitrogen (TN), ammonium nitrogen (AN), total phosphorus (TP) and total potassium (TK). Analytical results showed that OM could be estimated by a single property regression with SG (R2=0·92, P<0·001), TN could be estimated by a multiple property regression with SG and pH (R2=0·86, P<0·001), AN could be estimated by a single property regression with EC (R2=0·82, P<0·001), TP could be estimated by a single property regression with SG (R2=0·81, P<0·001), and TK could be estimated by a multiple property regression with EC and SG (R2=0·81, P<0·001).
Proanthocyanidins in grape berries are synthesised mainly before véraison, and very little attention is paid to the evolution of proanthocyanidins (PAs) in grapes from véraison to harvest. The present study focused on the changes of flavan-3-ols with different degrees of polymerisation in grape skins and the difference in proanthocyandin composition of 'Shiraz', 'Cabernet Sauvignon' and 'Marselan' grapes (Vitis vinifera L.). The results show that the content of flavan-3-ols, the percentage of prodelphinidins (%P) and mean degree polymerisation (mDP) found in 'Cabernet Sauvignon' berry skins at post-véraison were higher than those in 'Shiraz' and 'Marselan' skins. Only monomeric, dimeric, trimeric and polymeric flavan-3-ols were detected in the three grape cultivars. Polymers with more than tenfold flavan-3-ol units accounted for a relatively high proportion in grape berry skins, and the content in the three cultivars declined continuously during ripening. Principal component analysis showed that proanthocyanidin content, composition and mDP at grape harvest stage depended strongly on grape cultivar. This study provides some useful information for understanding the accumulation of PAs during berry maturation and this information can be used to improve wine quality.
Net primary productivity (NPP) of grasslands is a key variable for characterising carbon cycles in grassland ecosystems. The prediction of NPP in Inner Mongolia is important for adaptation to future climate change, food security and sustainable use of the grassland resources. The output from two models, potentially suitable for simulating NPP in response to climate change, was tested against observed aboveground forage mass of dry matter at eight sites in Inner Mongolia from 1995 to 2005. The Classification Indices-Based Model (CIBM) showed an acceptable agreement with field measurements. The impact of climate change on the NPP of grasslands was subsequently analysed by CIBM using future climate projections from a Global Circulation Model based on three greenhouse gas emission scenarios: A2 (medium-high emission), A1B (medium emission) and B2 (medium-low emission) differing in assumptions about patterns of global social and economic development. Generally, significant increases in NPP, compared with the baseline NPP of 3.6 tonnes ha–1 for 1961–90, were predicted. The magnitude of the increase in NPP depended on the emission scenario, as well as on the time frame and region considered. Overall the predicted NPP stimulation increased with the level of emissions assumed, being 4.8 tonnes ha–1 in the A2 scenario, 4.3 tonnes ha–1 in the B2 scenario and 4.5 tonnes ha–1 in the A1B scenario in the 2080s (2071–2100). The increase in NPP in response to climate change differed between regions and there was an interaction with emission scenario. For the A2 and the B2 emission scenarios, the western region of Inner Mongolia was predicted to exhibit the strongest NPP increases, but, under the A1B scenario for the 2050s, the south-eastern region exhibited the greatest increase in NPP. It is concluded that the productivity of grassland in Inner Mongolia is likely to increase in response to climate change but these predicted effects are sensitive to emission scenarios and differ regionally. This will provide opportunities but also challenges for herders and policy makers in adapting to this change.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.