The history of genetic modification and improvement of perennial grasses used for turf and sport can be traced back to the earliest events leading to the evolution of traits such as perenniality, asexual reproduction by rhizomes or stolons, apical dominance and hardening or acclimation responses to environmental stress. Human influences on perennial grasses likely began with the dawn of agriculture and the domestication of livestock about 8–10000 years ago with the movement of grasses from forest margins and meadows to pastures and cropland. As agrarian cultures found more time for leisure and recreation, perennial grasses became multi-functional, taking on a greater role with the invention of ball games, sports and a sod industry. Early human selection of superior turf grasses was largely based on individual clones that were vegetatively propagated for commercial purposes, dating back as far as 12th century Japan. The science of turf breeding began in 1962 with the initiation of extensive efforts to collect superior clones from old turf sods in highly stressful environments, followed by numerous cycles of recurrent selection for turf traits in harsh environments and under realistic mowing regimes. These efforts spawned many public and commercial breeding ventures and thousands of cultivars that have spread throughout the world, improving the quality, persistence and functionality of turf for many uses.

Varietal identification is an important aspect of crop research and utilization. Identification using computer-based image analysis could be an alternative to visual identification. However, the effectiveness of image analysis systems needs to be established under various real conditions. Three wheat varieties were sown on three different dates. Variation in the grain size and shape of these varieties, brought about by changes in the environmental conditions, was measured using Comprehensive Image Processing Software (CIPS). Some parameters showed considerable grain-to-grain variation, which was either inherent or due to environmental changes during grain filling. Euclidean distances were calculated using either means of all the parameters (ED1), or using only those parameters that did not show a high coefficient of variation (ED2). For samples of the same variety sown at different times, Euclidean distances were smaller compared with samples of different varieties, indicating that grains of the same variety resembled one another. By using the criterion of minimum Euclidean distance it was possible to distinguish between varieties, in spite of variation in grain shape and size due to environmental conditions. It was possible to identify correctly an unknown sample, taken as a test case.

Volatilization of ammonia (NH3) from slurry applied in the field is considered a risk to the environment and reduces the fertilizer value of the slurry. To reduce volatilization a better understanding of the slurry–soil interaction is needed. Therefore, the present study focuses on measuring NH3 volatilization as affected by differences in infiltration. Livestock slurries with different dry matter (DM) composition and viscosity were included in the experiments by using untreated cattle and pig slurry, pig slurry anaerobically digested in a biogas plant and pig slurry anaerobically digested and physically separated. NH3 volatilization was measured using dynamic chambers and related to infiltration of the livestock slurries in the soil by measuring chloride (Cl−) and Total Ammoniacal Nitrogen (TAN=ammonium (NH4+)+NH3) concentrations in soil at different depths from 0·5 to 6·0 cm from the soil surface. The slurries were applied to sandy and sandy-loam soils packed in boxes within the chambers. There were no significant differences in relative volatilization of NH3 from untreated cattle and pig slurries, but anaerobic digestion of pig slurry increased volatilization due to increases in pH. However, physical separation of the digested slurry reduced the volatilization compared with untreated slurry, due to increased infiltration. In general, the volatilization decreased significantly with increased infiltration. The present study shows that NH3 volatilization from applied slurry can be related to infiltration and that infiltration is related to slurry composition (i.e. DM content and particle size distribution) and soil water content. The infiltration of liquid (measured by Cl− infiltration) was affected by soil water potential, therefore, Cl− infiltrated deeper into the sandy loam soil than the sandy soil at similar gravimetric soil water values. Dry matter (DM) and large particles (>1 mm) of the slurry reduced infiltration of liquid. A high proportion of small particles (<0·025 mm) facilitated infiltration of TAN.

Cratylia argentea (Desv.) O. Kuntze is a drought-tolerant tropical shrub legume that can help to ensure continuity of forage supply in smallholder systems either through direct grazing or as a cut-and-carry plant for fresh foliage or silage. A collection of 38 accessions was characterized agronomically and nutritionally. High diversity was detected between accessions. Time to flowering ranged from 217–329 days after transplanting seedlings to the field and from 129–202 days after cutting. Flowering is probably induced by reduction of day length. Seed production was high but variable. Dry matter production ranged from 190–382 g/plant in the rainy and from 124–262 g/plant in the dry season, content of in vitro digestible dry matter from 589–690 g/kg, crude protein content from 184–237 g/kg and fibre content from 403–528 g/kg (neutral detergent fibre, NDF), 240–335 g/kg (acid detergent fibre, ADF), and 9–13 g/kg (acid detergent fibre-bound nitrogen, N-ADF). Accessions CIAT 18674 and CIAT 22406 were identified as promising for further study. They were superior to the commercial cultivar in terms of dry matter (DM) production, particularly in the dry season. Further research is required to determine the prevailing reproduction strategy of C. argentea and to quantify outcrossing-rates. Multilocational trials with a selected set of accessions should be conducted under different environmental conditions.

Soil organic carbon storage encompasses both soil productivity and environmental capabilities. The influence of fertilizer (nitrogen and phosphorus) levels (0 NP, 0·5 NP, 1·0 NP (recommended standard) or 1·5 NP) on total system productivity, sustainable yield index and soil organic carbon storage in Vertisols (Typic Haplustert) under groundnut and fallow-based cropping systems were examined in a field experiment over 6 years. The aim was to identify a system that provided an acceptable balance between total system productivity and soil organic carbon restoration. The experiment comprised two rainy season crops (groundnut or fallow) and five post-rainy season crops (wheat, mustard, chickpea, sunflower or summer groundnut), each post-rainy season crop with four levels of NP fertilizer. The total system productivity was 130% higher in the groundnut-based than in the fallow-based system and was in the order: groundnut–groundnut>groundnut–chickpea>groundnut–wheat>groundnut–mustard>groundnut–sunflower. The sustainable yield index was highest in the groundnut–groundnut system. The gross C input was relatively higher in the groundnut-based system but the C loss rate was greater. The amount of residue needed per ha per year to compensate for loss of soil organic carbon was estimated to be 4·3 t in the fallow-based and 7·6 t in the groundnut–based cropping system. Though the total system productivity was greater in groundnut–groundnut and groundnut–chickpea systems, soil organic carbon declined. The groundnut–wheat system contributed more C, particularly root biomass C, than other systems, improved the restoration of soil organic carbon and maintained total system productivity. It was concluded that current fertilizer recommendations are adequate for maintaining yields in groundnut-based systems but the addition of crop residues at regular intervals along with fertilizer is necessary to maintain restoration of soil organic carbon.

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).

Castrated male black Bengal kids were supplemented daily with 0, 0·5, 1·0, 1·5 and 2·0 mg chromium (Cr3+ as chromic chloride hexahydrate) for 150 days. Metabolic stresses such as a feeding challenge, an intravenous glucose tolerance test (IVGTT) and a short-term (72 h) feed deprivation were imposed on the animals to ascertain if supplemental Cr could alleviate these stresses and whether the stress-alleviating effect could provide an explanatory basis for the performance traits of the supplemented animals. The kids were fed with a concentrate diet containing 0·197 mg Cr/kg DM. DM intake (g/kgw0·75) was lower (P=0·006) in the 0·5 and 1·5 mg groups. Feed efficiency tended (P=0·086) to improve in the Cr-supplemented kids, although a distinct dose response was absent. Basal serum T3 increased linearly (P=0·01) with increased dose of Cr although the post-prandial change did not follow any definite trend. Basal serum insulin increased (P=0·001) linearly while the post-prandial increment was higher (P=0·037) in the control group. The IVGTT indicated that the kids supplemented with 1·5 mg Cr had significantly (P<0·05) higher serum clearance rate and lower half-life for insulin. Serum Cr during the IVGTT declined (P<0·05) until 45 m after glucose infusion and then increased again (P<0·10) at 60 m in the 0·5 and 1·5 mg groups although in the rest of the experimental groups serum Cr was stable during the entire course of the IVGTT. The body weights at the beginning of the fast were higher (P=0·036) in the kids supplemented with 0·5 and 1·5 mg Cr. However, the change in body weight at the end of the 72 h fast did not vary (P>0·10) between the groups. Cr supplementation reduced (P<0·05) serum cortisol level in the supplemented animals consistently throughout the duration of the feed deprivation. Moreover, as the fast progressed serum cortisol tended to increase (P=0·059) in all the experimental groups irrespective of the level of Cr supplementation. It was concluded that inorganic Cr supplementation might appreciably increase serum T3 concentration and reduce the level of cortisol which might augment animal productivity. However, further research with a more sensitive design is required to establish the exact level of Cr supplementation for enhancing performance of livestock.