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The purpose of this work is to determine the impact of selected silage maize cultivation technologies, including energy inputs in the production chain (cultivation, harvesting, heap placing), on energy efficiency. The analysis of energy inputs, energy efficiency for the silage maize production technology were estimated. The research was performed for 13 farms producing silage maize. The data from the farms covered all the activities and the agrotechnical measures performed. The calculations of energy inputs made for the silage maize production for selected technologies were performed using the method developed by the Institute of Construction, Mechanization and Electrification for Agriculture (IBMER), once the method was verified and adapted to the needs and conditions of own research. Based on the accumulated energy production and the energy accumulated in the yield, energy efficiency index values for 13 silage maize cultivation technologies were calculated. The greatest impact on the results of energy efficiency calculations was shared by fertilizer and fuel inputs. In conclusion, it can be stated that, in terms of energy efficiency, maize cultivation is justified and it can generate energy benefits.

Cover crops (CC) are planted in between cash crops to improve soil quality and to supply nitrogen (N) to cash crops through biological N fixation or soil N scavenging. Most producers use single species CC, in part because potential benefits of using mixtures of three or more CC species are poorly understood. A three-year study was initiated at Painter, Virginia to observe effects of CC mixtures on a no-till (NT) corn (Zea mays), wheat (Triticum aestivum L.), and soybean (Glycine max) rotation to measure CC performance, N cycling, cash crop yield, and soil quality in a sandy, low organic matter soil. Twelve treatments were created with conventional tillage (CT), NT, no CC control, and monoculture or CC mixtures of 3 to 9 species. Corn was grown in year 3 in all 12 treatments and four N rates were applied (0, 56, 112 and 156 kg N ha-1). Cover crop biomass, N accumulation, CC C:N ratio, and corn and soybean yield were measured annually. Soil bulk density, compaction, infiltration rate, pH, electrical conductivity, soil respiration, earthworm counts, soil microbial respiration, and soil microbial biomass carbon (C) after three years of CC. Cover crop biomass production varied significantly each year (5633 kg ha-1 in year 1, 755 kg ha-1 in year 2, 5370 kg ha-1 in year 3) due to climate and agronomic parameters, but a CC mixture always produced the highest biomass at termination. Nitrogen accumulation was strongly correlated with biomass production (R2= 0.94) and followed the same trend due to all CC having C:N < 30:1. Corn and soybean yields in years 1 and 2 were not significantly different, but corn yield was significantly affected by treatment and N fertilizer rate in year 3. After 3 years, soil respiration, earthworm populations and soil microbial biomass C increased in CC compared to CT without CC. However, infiltration rate, bulk density, microbial respiration, pH did not improve or declined compared to CT. In conclusion, adding CC mixtures to crop rotations shows promise for producing high CC biomass, accumulating N, and increasing crop yields, while improving some soil quality parameters on sandy low organic matter soils. Doctor of Philosophy Cover crop (CC) are planted in between cash crops to protect the soil from erosion, improve soil quality, and supply N to next cash crop through biological N fixation or soil N scavenging. Traditionally, CC were single species, but new CC methodologies utilize mixtures of three or more species planted together to protect soils as well as produce high biomass to suppress weeds, conserve soil moisture, and improve soil quality. A long-term study was initiated in fall 2014 in Painter, VA to observe CC mixture effects on no-till (NT) corn (Zea mays), wheat (Triticum aestivum L.), and soybean (Glycine max) rotations on CC performance, N cycling, cash crop yield, and soil quality of a sandy, low organic matter soil. Twelve treatments were created that compared NT rotations with CC monocultures, CC mixtures of 3-9 species, and without CC. In the third year corn was grown in all 12 rotations and four N rates were applied (0, 56, 112 and 156 kg N ha-1). To evaluate CC mixture performance in rotations, CC biomass, CC N accumulation and corn and soybean yield was measured over three years. To evaluate changes in soil quality, nine soil physical, chemical and biological soil properties were measured after three years of NT and CC. Biomass production varied significantly each experimental year (5633 kg ha-1 in year 1, 755 kg ha-1 in year 2, 5370 kg ha-1 in year 3) due to climate and agronomic differences, but CC mixtures were the highest biomass producing CC each spring and accumulated the highest amount of N. Cover crop mixtures had equal corn and soybean yield as CC monocultures. In year 3 corn yield and was greater in treatments with CC than in treatments without CC and was greater in legume dominated monocultures and mixtures than majority grass CC mixtures and monocultures. After 3 years of CC and NT, some soil quality parameters improved. Indicators of soil biology (soil respiration, earthworm populations, and soil microbial biomass C) increased in CC treatments. However, some soil physical and chemical properties (infiltration rate, bulk density, pH and EC) did not improve. In conclusion, adding CC mixtures to crop rotations shows promise for producing high CC biomass, accumulating N, and increasing crop yields, while also improving some soil quality parameters that are important for agricultural systems.

In this study, crude, purified, and pure glycerol were used to cultivate Trichosporon oleaginosus for lipid production which was then used as feedstock of biodiesel production. The purified glycerol was obtained from crude glycerol by removing soap with addition of H3PO4 which converted soap to free fatty acids and then separated from the solution. The results showed that purified glycerol provided similar performance as pure glycerol in lipid accumulation; however, crude glycerol as carbon source had negatively impacted the lipid production of T. oleaginosus. Purified glycerol was later used to determine the optimal glycerol concentration for lipid production. The highest lipid yield 0.19g/g glycerol was obtained at 50g/L purified glycerol in which the biomass concentration and lipid content were 10.75g/L and 47% w/w, respectively. An energy gain of 4150.51MJ could be obtained with 1tonne of the crude glycerol employed for biodiesel production through the process proposed in this study. The biodiesel production cost estimated was 6.32US$/gal. Fatty acid profiles revealed that C16:0 and C18:1 were the major compounds of the biodiesel from the lipid produced by T. oleaginosus cultivated with crude and purified glycerol. The study found that purified glycerol was promising carbon source for biodiesel production.

The effect of nitrogen replenishment on the kinetics of secondary carotenoids, triacylglycerol (TAG) and primary cell components was studied in nitrogen-starved Chromochloris zofingiensis (Chlorophyta), an oleaginous and carotenogenic microalga. Nitrogen resupplied after a period of starvation was initially consumed at a more than four times higher rate than in an equivalent nitrogen-replete culture. Simultaneously, chlorophylls, primary carotenoids, polar (membrane) lipids and proteins were rapidly produced. After 2 days, the contents of these primary metabolites, as well as the nitrogen consumption rate and the overall biomass production rate, had returned to values equivalent to those of cells grown under nitrogen-replete conditions, indicating that culture recovery required 2 days. Nitrogen resupply was immediately followed by rapid degradation of TAG and starch, suggesting that these metabolites served as carbon and energy source for the recovery process. Also, the secondary carotenoids canthaxanthin and ketolutein were rapidly degraded upon nitrogen resupply, whereas degradation of astaxanthin, the main secondary carotenoid, started only when the cells were fully recovered 2 days after nitrogen resupply. This is the first time that such culture recovery has been described in detail and, moreover, that astaxanthin was found to be not immediately degraded after nitrogen resupply. The observed rapid recovery of C. zofingiensis and the delay in astaxanthin degradation suggest that a repeated batch cultivation may result in a higher secondary carotenoid productivity than a series of classical single batch cultivations.

Ecological restoration has great significance on cut rock slopes, which are considered extremely degraded habitats. The development of moss–soil crusts on cut rock slopes as a critical pathway to ecological restoration in mountain areas has been poorly reported. A total of 335 quadrats were selected on cut rock slopes with formation ages between 0 and 60 years to evaluate the evolution characteristics of moss–soil crusts under various geographical conditions (e.g., aspect, lithology, and altitude) in the mountainous area of western Sichuan, Southwest China. The results suggested that moss growth decoupled from soil accumulation within the crusts and was controlled by multiple factors. Moss growth depended on lithology, altitude, and age, while soil weight was mainly influenced by slope aspect. The development of mosses on limestone was better than on sandstone. Moss biomass varied with altitude, consistent with that of rainfall with respect to moss development dependent on moisture. Furthermore, moss development under a semiarid climate was more distinctly impacted by moisture with altitude relative to a humid region, likely owing to the higher sensitivity of the mosses to moisture in the former than in the latter. Moss biomass increased with recovery time, while the rate of moss biomass development was diverse in different geographical areas. The vegetation developed rapidly in low-altitude areas (~1000 m above sea level), resulting in moss biomass increasing from 0 to 24.08 g·m−2 with formation time increasing from 0.5 to 1.5 years and subsequently being restricted by the evolution of higher plants on cut rock slopes, leading to an insignificant difference in moss biomass between 1.5 and 60 years. In high-altitude areas, when the altitude changed slightly (from 2024 to 2430 m above sea level), the moss biomass on cut rock slopes increased linearly with increasing age from 5 to 27 years. Influenced by the surrounding fertile soils and moss bioaccumulation, there were high levels of soil major nutrient content, especially the organic matter content, which reached 377.42 g·kg−1. More soils accumulated on south-facing slopes than on north-facing slopes. This study provided field data to clearly reveal the influence of geographic factors on moss–soil crust development in natural restoration processes in high-altitude mountainous areas.

ABSTRACT: Oleaginous yeast Trichosporon oleaginosus was studied for lipid production using municipal sludge with or without fortification of crude glycerol in a 15‐L fermenter. The maximum lipid content (concentration) was 32.0% w/w (9.35 g/L), 33.6% (10.13 g/L), 33.3% (9.13 g/L), and 33.1% (9.03 g/L) w/w with the addition of 25, 50, 100, and 150 g/L glycerol, respectively. Glycerol concentration had little effect on lipid accumulation. However, glycerol concentration substantially affected increase of biomass concentration and cell count. The suitable glycerol concentration was approximately 40 g/L for Trichosporon oleaginosus growing in sludge medium with initial suspended solids (SS) concentration 30 g/L. Addition of nitrogen to sludge‐glycerol medium enhanced lipid and biomass concentration. The energy conversion efficiency was 1.78, 1.55, and 1.71 with no nitrogen added, with addition of 1 g/L urea, and 3.7 g/L peptone, respectively. The biodiesel production cost was estimated nearly 0.75 US$/L.

To evaluate the potential of Chlorococcum pamirum for producing biodiesel, the effects of nitrogen, phosphate, initial cell concentrations and NaCl on lipid accumulation and growth were studied. The highest specific growth rate (μ(max)), biomass productivity and lipid content achieved was 1.888 d(-1), 350.1 mg L(-1) day(-1), and 64.9%, respectively. Under nitrogen-deficient condition, the cells accumulated lipids faster at low initial cell concentration. Additional NaCl to nitrogen-deficient media accelerated the lipid accumulation. When adding 10 g L(-1) NaCl to nitrogen-deficient media, the lipid content and productivity of cells cultured outdoors with high initial cell concentration increased from 38.2% and 153 mg L(-1) day(-1) to 54.3% and 192 mg L(-1) day(-1) respectively. Moreover, NaCl enhanced the saturated fatty acids content from 56.40% to 73.41% of total fatty acids. The results show that C. pamirum is a promising organism for biofuel production.

A critical review was made of reported information from laboratory studies of plant uptake of transplutonic elements plus neptunium. The available data are meager but indicate that the uptake of Np is the greatest followed by Am and Cm. The data are not sufficient to provide recommended values for use in hazard calculations but they do indicate that the actinides other than plutonium will be accumulated in plants to a greater degree than plutonium.