Maize ethanol feedstock production and net energy value as affected by climate variability and crop management practices

Ethanol from various plant resources, especially maize, is increasingly being used as a substitute for fossil fuels. The production potential of ethanol from maize varies with weather and climatic conditions and crop management practices. The merits and prospects of ethanol production have been evaluated based on its impact on greenhouse gas emissions, economic viability and national energy security. The net energy value (NEV), i.e. the output energy after all non-renewable energy inputs have been accounted for, is a measure of energy gain. At the same time, the NEV can be an indicator for the long-term sustainability of bio-ethanol production, regardless of other conditions e.g. climate change scenarios, global trade restrictions, or local variability in natural resources such as water availability. Crop management practices directly affect the NEV of ethanol. Moreover, both crop management practices and climate variability affect the NEV through the grain yield. The objective of this study was to assess the impact of crop management practices and climate variability on grain yield of maize for ethanol production and ethanol NEV for conditions that represent the southeastern USA. Maize grain yield was simulated with the dynamic crop growth model CSM–CERES–Maize and ethanol NEV was calculated using the simulated yield levels and crop management practices. The simulations were conducted for conditions representing Mitchell County, Georgia, USA, using weather data from 1939 to 2006 and local soil profile information. The impact of irrigation, nitrogen fertilizer, planting date and El Niño Southern Oscillation (ENSO) phases were determined for the maize cultivars DeKalb DKC 61-72 (RR2), Pioneer 31D58 and Pioneer 31G98. Crop management practices and ENSO phase had a significant impact on ethanol feedstock production and NEV. The NEV of ethanol produced from irrigated maize was more than two times higher and varied less than the NEV of ethanol from rainfed maize. NEV of ethanol produced from maize grown during La Niña years was significantly higher than maize grown during El Niño years, both under rainfed and irrigated conditions. This study showed the importance of crop management practices and climate variability on ethanol feedstock productivity and long-term energy sustainability as assessed by the NEV. We discuss methods of implementing the findings of this study in practical farming e.g. through market mechanisms and governmental initiatives.     

Authentication of animal fats using direct analysis in real time (DART) ionization-mass spectrometry and chemometric tools

A combination of direct analysis in real time (DART) ionization coupled to time-of-flight mass spectrometry (TOFMS) and chemometrics was used for animal fat (lard and beef tallow) authentication. This novel instrumentation was employed for rapid profiling of triacylglycerols (TAGs) and polar compounds present in fat samples and their mixtures. Additionally, fat isolated from pork, beef, and pork/beef admixtures was analyzed. Mass spectral records were processed by principal component analysis (PCA) and stepwise linear discriminant analysis (LDA). DART-TOFMS profiles of TAGs were found to be more suitable for the purpose of discrimination among the examined fat types as compared to profiles of polar compounds. The LDA model developed using TAG data enabled not only reliable classification of samples representing neat fats but also detection of admixed lard and tallow at adulteration levels of 5 and 10% (w/w), respectively. The presented approach was also successfully applied to minced meat prepared from pork and beef with comparable fat content. Using the DART-TOFMS TAG profiles of fat isolated from meat mixtures, detection of 10% pork added to beef and vice versa was possible.     

Feeding ecology of the walleye (Percidae,Sander vitreus), a resurgent piscivore in Lake Huron (Laurentian Great Lakes) after shifts in the prey community

Recovering populations of piscivores can challenge understanding of ecosystem function due to impacts on prey and to potentially altered food webs supporting their production. Stocks of walleye (Percidae, Sander vitreus), an apex predator in the Laurentian Great Lakes, crashed in the mid‐1900s. Management efforts led to recovery by 2009, but recovery coincided with environmental and fish community changes that also had implications for the feeding ecology of walleye. To evaluate potential changes in feeding ecology for this apex predator, we assessed diets in the main basin of Lake Huron and in Saginaw Bay, a large embayment of Lake Huron, during 2009–2011. Walleye switched their diets differently in the main basin and Saginaw Bay, with non‐native round goby (Gobiidae, Neogobius melanostomus) and rainbow smelt (Osmeridae, Osmerus mordax) more prevalent in diets in the main basin, and invertebrates, yellow perch (Percidae, Perca flavescens) and gizzard shad (Clupeidae, Dorosoma cepedianum) more prevalent in diets in the bay. Feeding strategy plots indicated that there was a high degree of individual specialisation by walleye in the bay and the main basin. Bioenergetic simulations indicated that walleye in Saginaw Bay need to consume 10%–18% more food than a walleye that spends part or all of the year in the main basin, respectively, in order to achieve the same growth rate. The differences in diets between the bay and main basin highlight the flexibility of this apex predator in the face of environmental changes, but changes in diet can alter energy pathways supporting piscivore production.     

Genome size variation in three Saccharum species

Saccharum species are autopolyploids with ploidy level ranging from 5× to 16x, and are considered the most complex genomes among crop plants. In present study, the genome sizes of 28 Saccharum spontaneum accessions, 15 Saccharum officinarum accessions, 28 Saccharum robustum accessions, and 12 Saccharum hybrids spp. were analyzed using flow cytometry. The estimated genome sizes of S. officinarum accessions ranged from 7.50 to 8.55?Gb with an average size of 7.88?Gb. In S. robustum, the estimated genome sizes ranged from 7.65 to 11.78, reflecting the variation of ploidy level. In S. spontaneum, the estimated genome sizes varied widely, with a range from 3.36 to 12.64?Gb, also due to variation of ploidy level. The average monoploid genome size of S. officinarum was 985?Mb, and that of S. spontaneum was 843?Mb. The results also showed that genome sizes were correlated with chromosome numbers, and based which, that the unknown chromosome numbers of some accessions could be predicted. The estimated genome sizes of Saccharum germplasm also helped identify some mislabeled accessions and yielded information critical for sugarcane breeding and genome sequencing programs.     

A potential use of color ultrasound as a tool for reproductive management: New observations using color ultrasound scanning that were not possible with imaging only in black and white

Ultrasonography (US) has been applied to the ovary and the uterus of domestic animals from the late 1980s, and established in 1990s as a practical tool for animal production. US made it possible to detect pregnancy at a very early stage and, most importantly, to observe the real-time dynamics of follicular development and hence the discovery of follicular waves. This has greatly contributed to our understanding of ovarian physiology and helped us to develop several "pin-point" protocols for hormonal treatment. While US may not seem to fit preconceived ideas of a "green" technology, it does not contravene environmental priorities, and it is non-invasive ("ethical") and non-hormonal ("clean"). Using the US technology that is now commercially available at a reasonable price, we are able to estimate the best timing for AI and this allows us to plan either the use of precisely-timed nutritional supplements for fetal development or an immediate 2nd AI service to achieve a better economic efficiency. During the last few years, we have also begun to be able to observe in detail the local blood flow in individual ovarian follicles and CL using color Doppler ultrasonography in the cow. From the series of observations, we have found that: 1) the change of blood supply to an individual follicle closely relates to the dynamics of follicular growth and atresia; 2) the local blood flow detected in the theca externa of mature follicles rapidly increases around the onset of LH surge and is most active before ovulation; 3) the blood supply to the developing CL increases in parallel with CL volume and plasma progesterone concentrations; and 4) the local blood flow surrounding the mature CL acutely increases prior to the onset of luteolysis in response to uterine as well as exogenous PGF(2alpha). It is now clear that color Doppler ultrasound is very useful for observing echogenicity with local blood flow thereby providing an easily obtained estimation of the physiological status of follicles, CLs and early conceptus. Widespread commercial application of color US will depend on further technological developments that reduce the cost and improve performance and ease-of-use. Overall, US is now a most effective non-invasive tool for managing reproduction, at the level of both the individual animal and the herd system. In particular, US can help us to clarify potential problems in high-producing dairy cattle during the postpartum period.     

Sugar fragmentation in the maillard reaction cascade: isotope labeling studies on the formation of acetic acid by a hydrolytic beta-dicarbonyl cleavage mechanism

The formation of acetic acid was elucidated based on volatile reaction products and related nonvolatile key intermediates. The origin and yield of acetic acid were determined under well-controlled conditions (90-120 degrees C, pH 6-8). Experiments with various 13C-labeled glucose isotopomers in the presence of glycine revealed all six carbon atoms being incorporated into acetic acid: C-1/C-2 ( approximately 70%), C-3/C-4 ( approximately 10%), and C-5/C-6 (approximately 20%). Acetic acid is a good marker of the 2,3-enolization pathway since it is almost exclusively formed from 1-deoxy-2,3-diulose intermediates. Depending on the pH, the acetic acid conversion yield reached 85 mol % when using 1-deoxy-2,3-hexodiulose (1) as a precursor. Hydrolytic beta-dicarbonyl cleavage of 1-deoxy-2,4-hexodiuloses was shown to be the major pathway leading to acetic acid from glucose without the intermediacy of any oxidizing agents. The presence of key intermediates was corroborated for the first time, i.e., tetroses and 2-hydroxy-3-oxobutanal, a tautomer of 1-hydroxy-2,3-butanedione, also referred to as 1-deoxy-2,3-tetrodiulose. The hydrolytic beta-dicarbonyl cleavage represents a general pathway to organic acids, which corresponds to an acyloin cleavage or a retro-Claisen type reaction. Although alternative mechanisms must exist, the frequently reported hydrolytic alpha-dicarbonyl cleavage of 1 can be ruled out as a pathway forming carboxylic acids.     

Spatio‐temporal,ontogenetic and interindividual variation of age‐0 diets in a population of yellow perch

Dietary niches of fishes have traditionally been evaluated at the population level, with diet pattern central tendencies compared spatio‐temporally among habitats and populations. More recently, however, studies have emphasised the importance of within‐population diet variation and niche partitioning. Several studies have examined diets of young yellow perch (Perca flavescens) at the population level and have described an ontogenetic transition from zooplankton to benthic prey during the first year of life. However, independent of ontogenetic diet shifts, intrapopulation variation of young yellow perch diets remains largely unexplored. We quantified patterns of diet composition in age‐0 yellow perch collected from Saginaw Bay, Lake Huron, USA during July–October, 2009 and 2010. We observed substantial variation in diet composition among individuals across and within sites, but found relatively weak evidence indicating an ontogenetic diet shift. Zooplankton were the dominant prey for age‐0 yellow perch on most occasions, and individual diets were composed primarily of either zooplankton (e.g. Daphnia spp., Calanoida) or benthic (i.e. Chironomidae larvae, Chydoridae) prey. These patterns were not simply attributable to differences in prey availability and ontogenetic diet shifts, because a) not only diet composition, but also prey selectivity (Chesson's α) varied among sites and b) individual and spatial diet differences were evident independent of ontogeny. Within‐cohort differences in diet composition may be an important, but often overlooked, phenomenon with implications for cumulative trophic interactions and intracohort growth and survival among young fish.     

Species‐specific effects of subdaily temperature fluctuations on consumption,growth and stress responses in two physiologically similar fish species

Fluctuations in water temperature can have important physiological consequences for fishes. Effects of daily thermal cycles are well studied and can be beneficial, increasing prey consumption and growth rates when mean and maximum temperatures of the fluctuations are at or below the species’ optimum temperature. While less studied, subdaily temperature fluctuations are also common in many aquatic habitats and can be caused by both natural and anthropogenic processes. We performed laboratory experiments to examine how two fish species (yellow perch, Perca flavescens, and walleye, Sander vitreus) with similar thermal preferences respond to chronic exposure to subdaily temperature variability. We selected temperature treatments that reflected observed thermal variation after examining water temperature data from multiple aquatic systems. We then separately exposed yellow perch and walleye to a stable 23 °C treatment and 12‐h cycles of 23 ± 2 °C or 23 ± 4 °C for 45 days. Adult yellow perch exposed to fluctuations of 23 ± 4 °C over 12 h expressed higher consumption, growth and food conversion efficiency than fish experiencing stable 23 °C. Temperature fluctuations, though, resulted in mortalities and the development of skin ulcers in yellow perch that did not occur under stable temperatures. In contrast, the same 12‐h temperature fluctuations did not result in mortalities or stress responses in juvenile walleye. Moreover, unlike yellow perch, growth rates of walleye were lower under 12‐h temperature fluctuations compared with the stable 23 °C treatment. Our results indicate that species with similar thermal preferences can respond differently to the same subdaily temperature fluctuations.     

Effects of seedbed properties on crop emergence: 1. Temporal effects of temperature and sowing depth in seedbeds with favourable properties

Abstract

Rapid and uniform crop establishment is a prerequisite for efficient crop production and minimal environmental impact. Experiments were carried out in shallow plastic boxes placed directly on the ground in the field for studies of the effects of seedbed properties on emergence of various crops. This paper presents an analysis of the time required for germination and emergence under near-optimal seedbed conditions. The crops studied were barley, oats, wheat, pea, rape seed, white mustard, sugar beet, red clover and timothy. The time required for germination generally increased with size of the seeds, presumably because larger seeds needed more water to initiate germination. This applied both when comparing different crops and different seed sizes of the same crop. However, considerable differences occurred between seed lots of the same crop and there were greater differences between seed lots of the same crop than between the three small grain crops studied. Growth rate of the seedlings generally increased with seed size, presumably because of increased energy content in the seed. Consequently, the most rapid emergence was obtained from small seeds at shallow sowing and from large seeds at deep sowing. The crops studied had a minimum temperature for germination and seedling growth close to 0 °C. Under optimal seedbed conditions, thermal time required for 50% germination of barley was typically about 65 °C days over this base temperature and for seedling growth about 6 °C days cm^?1. From 4 cm sowing depth, about 80 °C days were required for emergence but with considerable variations between seed lots. For rape seed or white mustard about 40 °C days were required for germination and about 8 °C days cm^?1 for the seedling growth.