Nutrient utilization with and without recycling within farming systems

Nutrient balances are used as a measure of nutrient utilization. It is, however, difficult to compare the nutrient utilization between farms, especially if their production systems are different. New analytical tools and methods of interpreting nutrient utilization based on nutrient balances are introduced

Evaluation of nitrogen utilization by means of the concept of primary nutrient efficiency

The aims of this study were: To introduce a new method, primary nutrient efficiency, for the evaluation of nutrient utilization. To demonstrate and find key factors to reach a high utilization rate of nutrients

Primary nutrient balance as a new tool to evaluate nutrient utilization

A new tool, utilization rate of primary nutrients, is introduced to evaluate parallel nutrient load and efficiency of nutrient utilization. It is independent of the quality and quantity of final products and therefore allows comparison between any production systems or farms

The regulatory and transcriptional landscape associated with carbon utilization in a filamentous fungus.

Filamentous fungi, such as Neurospora crassa, are very efficient in deconstructing plant biomass by the secretion of an arsenal of plant cell wall-degrading enzymes, by remodeling metabolism to accommodate production of secreted enzymes, and by enabling transport and intracellular utilization of plant biomass components. Although a number of enzymes and transcriptional regulators involved in plant biomass utilization have been identified, how filamentous fungi sense and integrate nutritional information encoded in the plant cell wall into a regulatory hierarchy for optimal utilization of complex carbon sources is not understood. Here, we performed transcriptional profiling of N. crassa on 40 different carbon sources, including plant biomass, to provide data on how fungi sense simple to complex carbohydrates. From these data, we identified regulatory factors in N. crassa and characterized one (PDR-2) associated with pectin utilization and one with pectin/hemicellulose utilization (ARA-1). Using in vitro DNA affinity purification sequencing (DAP-seq), we identified direct targets of transcription factors involved in regulating genes encoding plant cell wall-degrading enzymes. In particular, our data clarified the role of the transcription factor VIB-1 in the regulation of genes encoding plant cell wall-degrading enzymes and nutrient scavenging and revealed a major role of the carbon catabolite repressor CRE-1 in regulating the expression of major facilitator transporter genes. These data contribute to a more complete understanding of cross talk between transcription factors and their target genes, which are involved in regulating nutrient sensing and plant biomass utilization on a global level

Ideotyping integrated aquaculture systems to balance soil nutrients.

Due to growing land scarcity and lack of nutrient inputs, African farmers switched from shifting cultivation to continuous cropping and extended crop area by bringing fragile lands such as river banks and hill slopes into production. This accelerated soil fertility decline caused by erosion, harvesting and insufficient nutrient replenishment. We explored the feasibility to reduce nutrient depletion by increasing nutrient utilization efficiencies, while diversifying and increasing food production through the development of integrated aquaculture – agriculture (IAA). Considering the climatic conditions prevailing in Kenyan highlands, aquaculture production scenarios were ideotyped per agro-ecological zone. These aquaculture production scenarios were integrated into existing NUTrient MONitoring (NUTMON) farm surveydata for the area. The nutrient balances and flows of the resulting IAA-systems were compared to present land use.The effects of IAA development on nutrient depletion and total food production were evaluated. With the development of IAA systems, nutrient depletion rates dropped by 23–35%, agricultural production increased by 2–26% and overall farm food production increased by 22–70%. The study demonstrates that from a bio-physical point of view, the development of IAA-systems in Africa is technically possible and could raise soil fertility and total farm production. Further studies that evaluate the economic feasibility and impacts on the livelihood of farming households are recommended

Function and dysfunction of fatty acid mobilization: a review

Western populations have a growing obesity epidemic due in part to excessive nutrient intake from high-fat diets, which are increasingly common. Overindulgence of nutrients is associated with a greater incidence of metabolic dysfunction and a greater risk for obesity, diabetes, hypertension, and other metabolic disorders that lower quality of life. Research in humans and animal models has improved our understanding of how excess circulating free fatty acids negatively impact the ability of muscle and other tissues to regulate nutrient uptake and utilization. It is generally accepted by the scientific community that excess circulating fatty acids lead to insulin resistance, but there is little clarity regarding the underlying mechanisms. In the present review, we will outline the current understanding of the characteristics associated with fatty acid mobilization and fatty acid utilization within specific tissues. We will also discuss the potential mechanistic role of hyperlipidemia on metabolic dysfunction associated with type 2 diabetes

The Effects of Tidal Forcing on Nutrient Fluxes in the Tidal, Freshwater James River Estuary, VA

A 12-month study (January to December 2015) focused on the effects of tidal forcing on nutrient fluxes in the tidal, freshwater segment of the James River Estuary (JRE). Discrete sampling of nutrient chemistry and continuous monitoring of tidal discharge were used to determine the volume and timing of the tides, and differences in nutrient concentrations between incoming and outgoing tides. The goal of this study was to improve understanding of tidal influence on nutrient fluxes and their role in nutrient transport to the lower estuary. Results suggested that differences in nutrient concentrations between incoming and outgoing tides were small throughout the year. This finding suggests that nutrient fluxes at the study site, near the tidal fresh-oligohaline boundary of the James, are largely determined by tidal volume owing to weak concentrations gradients. Changes in water quality during seaward and landward tidal excursions into deeper versus shallower segments were analyzed to infer biogeochemical processes. Differences in oxygen production and nitrate utilization suggest greater autotrophy during landward excursions, consistent with more favorable light conditions. This work was conducted as a collaborative effort between Virginia Commonwealth University, the USGS, Randolph-Macon College, and Washington and Lee University participating in the “Mountains to the Sea” project

A comparison of foliar and soil uptake of nutrients in French bean (Phaseolus vulgaris L.): a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science in Soil Science, Massey University

An aspect of each of three factors relating to efficiency of fertilizer use were studied in glasshouse experiments using beans Phaseolus vulgaris var. Gallatin 50. These three factors were: the quantities that can be applied; physiological aspects of nutrient utilization following foliar uptake; and interactions with other sources of nutrient supply. Distribution patterns of S35, P32 and Zn65 were examined following application to soil and foliage of beans. It was found that a greater proportion of P32 and Zn 65 was present in the fruit following foliar uptake than was the case following root uptake. This difference was not evident for S35. Retention of a commercial nutrient spray on the foliage of bean plants was measured and found to correlate well with both leaf area and leaf fresh weight. The effect of sprays on leaf chlorophyll was also examined. Environmental effects were found to have more influence on leaf chlorophyll than nutrient sprays. Root uptake of 32 was increased by spraying the foliage with either nutrient solution or water. It was concluded that the effect was water related and not connected with nutrient application. The implications of the above findings were discussed in the context of efficiency of fertilizer use

Microalgae for municipal wastewater nutrient remediation: mechanisms, reactors and outlook for tertiary treatment

This review explores the use of microalgae for nutrient removal in municipal wastewater treatment, considering recent improvements in the understanding of removal mechanisms and developments of both suspended and non-suspended systems. Nutrient removal is associated to both direct and indirect uptake, with the former associated to the biomass concentration and growth environment (reactor). Importantly, direct uptake is influenced by the Nitrogen:Phosphorus content in both the cells and the surrounding wastewater, with opposite trends observed for N and P. Comparison of suspended and non-suspended systems revealed that whilst all were capable of achieving high levels of nutrient removal, only non-suspended immobilized systems could do so with reduced hydraulic retention times of less than 1 day. As microalgae are photosynthetic organisms, the metabolic processes associated with nutrient assimilation are driven by light. Optimization of light delivery remains a key area of development with examples of improved mixing in suspended systems and the use of pulsating lights to enhance light utilization and reduce costs. Recent data provide increased confidence in the use of microalgae for nutrient removal in municipal wastewater treatment, enabling effluent discharges below 1 mg L−1 to be met whilst generating added value in terms of bioproducts for energy production or nutrient recovery. Ultimately, the review suggests that future research should focus on non-suspended systems and the determination of the added value potential. In so doing, it is predicted that microalgae systems will be significant in the delivery of the circular economy

The Influence of Reservoir Basin Morphometry on Phytoplankton Community Structure

The research protocol was designed to compare three reservoirs with similar physical environments but different morphometry. Three reservoirs on the western edge of the Ozark uplift were selected because of their similar substrate and climatic condition. The reservoirs primarily differed in morphometry. Two of the reservoirs were of identical size, Bob Kidd and Prairie Groves Lakes, but of different configuration, semicircular and linear, respectively. The bifurcated lake, Lincoln Lake, was of smaller size. Each lake is dimictic. Each of the lakes were nitrate-N limited while soluble reactive phosphorus-P is available and not restricting the growth of phytoplankton. Although the pattern of nutrient utilization was similar among the nutrient concentrations varied. Phytoplankton succession was alike in each reservoir but differed in quantity