scholarly journals A co-cultivation process of Nannochloropsis oculata and Tisochrysis lutea induces morpho-physiological and biochemical variations potentially useful for biotechnological purposes

2021 ◽  
Author(s):  
Michele Maglie ◽  
Costanza Baldisserotto ◽  
Alessandra Guerrini ◽  
Alessandra Sabia ◽  
Lorenzo Ferroni ◽  
...  
Keyword(s):  
Lipid Production ◽  
Maximum Yield ◽  
Pharmaceutical Products ◽  
Nannochloropsis Oculata ◽  
Production Costs ◽  
Yield Reduction ◽  
Total Biomass ◽  
Tisochrysis Lutea ◽  
Positive Effects ◽  
Cell Extracts

AbstractThe biotechnological potential of microalgae has gained considerable importance in many applied fields: biomass production for food and feed, cosmeceutical and pharmaceutical products, energy and phytoremediation. The driving force that inspires the progress in microalgae production is the need for new cultivation systems to obtain simultaneously the maximum yield, reduction of water and nutrients use, and production of economically interesting molecules, such as pigments, fatty acids and polysaccharides. We aim to test, for the first time, the co-cultivation in saline medium of Tisochrysis lutea (Haptophyta) and Nannochloropsis oculata (Ochrophyta) to obtain valuable compounds, i.e. pigments and lipids characteristic of each species, using a single culture process. Mono-cultures of each strain were used as controls. The two strains showed an increase in the concentration of chlorophylls and carotenoids in co-culture. At the end of the experiment, the fatty acid profile was analysed by gas chromatography–mass spectrometry. The lipids in the co-cultivated cell extracts were mainly attributable to N. oculata, which represented 97% of the total cells (ca. 83% of the total biomass) at the end of the experiment. Nevertheless, the ω-3 characteristic of T. lutea (DHA and SDA, absent in N. oculata) was also detectable. Although the co-cultivation of these two phylogenetically different species of microalgae did not show positive effects on the growth and on the total lipid production, however, this process resulted in a reduction of the production costs and a lower consumption of water and nutrients.

Velvetleaf (Abutilon theophrasti) Effect on Corn (Zea mays) Growth and Yield in South Dakota

1995 ◽  
Vol 9 (4) ◽  
pp. 665-668 ◽  
Author(s):  
Chad Scholes ◽  
Sharon A. Clay ◽  
Kalyn Brix-Davis
Keyword(s):  
South Dakota ◽  
Yield Loss ◽  
Maximum Yield ◽  
Abutilon Theophrasti ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Corn Yield ◽  
Total Biomass ◽  
Area Index ◽  
Large Yield

Studies were conducted at two sites in South Dakota in 1992 and at one site in 1993 to measure the effect of velvetleaf on corn growth and yield. Velvetleaf was overseeded in corn rows and thinned to densities of 0, 1.3, 4, 12, and 24 plants/m2. Velvetleaf leaf area index and total biomass were positively correlated with velvetleaf density. Biomass per velvetleaf plant and corn biomass were correlated negatively with velvetleaf density. The percent corn yield reduction was similar for locations and years in spite of large yield differences. Maximum yield loss estimated by a hyperbolic yield reduction model was 37.2% with a loss of 4.4% per unit velvetleaf density.

scholarly journals WATER MANAGEMENT STRATEGIES UNDER DEFICIT IRRIGATION

2008 ◽  
Vol 39 (4) ◽  
pp. 27 ◽  
Author(s):  
Antonino Capra ◽  
Simona Consoli ◽  
Baldassare Scicolone
Keyword(s):  
Water Management ◽  
Deficit Irrigation ◽  
Management Strategies ◽  
Yield Reduction ◽  
Research Approach ◽  
Total Production ◽  
Economic Aspects ◽  
Optimization Strategy ◽  
Full Irrigation ◽  
Positive Effects

Deficit irrigation (DI) is an optimization strategy whereby net returns are maximized by reducing the amount of irrigation water; crops are deliberated allowed to sustain some degree of water deficit and yield reduction. Although the DI strategy dates back to the 1970s, this technique is not usually adopted as a practical alternative to full irrigation by either academics or practitioners. Furthermore, there is a certain amount of confusion regarding its concept. In fact, a review of recent literature dealing with DI has shown that only a few papers use the concept of DI in its complete sense (e.g. both the agronomic and economic aspects). A number of papers only deal with the physiological and agronomical aspects of DI or concern techniques such as Regulated Deficit Irrigation (RDI) and Partial Root Drying (PRD). The paper includes two main parts: i) a review of the principal water management strategies under deficit conditions (e.g. conventional DI, RDI and PRD); and ii) a description of a recent experimental research conducted by the authors in Sicily (Italy) that integrates agronomic, engineering and economic aspects of DI at farm level. Most of the literature reviewed here showed, in general, quite positive effects from DI application, mostly evidenced when the economics of DI is included in the research approach. With regard to the agronomic effects, total fresh mass and total production is generally reduced under DI, whereas the effects on dry matter and product quality are positive, mainly in crops for which excessive soil water availability can cause significant reductions in fruit size, colour or composition (grapes, tomatoes, mangos, etc.). The experimental trial on a lettuce crop in Sicily, during 2005 and 2006, shows that the highest mean marketable yield of lettuce (55.3 t ha-1 in 2005 and 51.9 t ha-1 in 2006) was recorded in plots which received 100% of ET0-PM (reference evapotranspiration by the Penman- Monteith method) applied water. In the land-limiting case, the estimated optimal economic levels were quite similar to the optimal agronomic levels. In the waterlimiting case DI ranges, at least as profitable as full irrigation, were of 17-49% ET0-PM and of 71-90% ET0-PM in 2005 and 2006 respectively.

scholarly journals A műtrágyázás és a csapadék változékonyságának hatása a kukorica (Zea mays L.) termésére

2005 ◽  
Vol 54 (3-4) ◽  
pp. 309-324 ◽  
Author(s):  
László Márton
Keyword(s):  
Grain Yield ◽  
Maximum Yield ◽  
Maize Yield ◽  
Vegetation Period ◽  
Positive Effects ◽  
Experimental Station ◽  
Natural Rainfall ◽  
Zn Content ◽  
Set Up

The effect of natural rainfall and N, P and K nutrients on the yield of maize was investigated in 16 years of a long-term fertilization experiment set up at the Experimental Station of the Institute in Nagyhörcsök. The soil was a calcareous chernozem, having the following characteristics: pH (KCl): 7.3, CaCO 3 : 5%, humus: 3%, clay: 20-22%, AL-soluble P 2 O 5 : 60-80, AL-soluble K 2 O: 180-200, KCl-soluble Mg: 150-180; KCl+ EDTA-soluble Mn, Cu and Zn content: 80-150, 2-3 and 1-2 mg·kg -1 . The experiment had a split-split-plot design with 20 treatments in 4 replications, giving a total of 80 plots. The treatments involved three levels each of N and P and two levels of K in all possible combinations (3×3×2=18), together with an untreated control and one treatment with a higher rate of NPK, not included in the factorial system. The main results can be summarized as follows: An analysis of the weather in the 16 experimental years revealed that there were no average years, as two years were moderately dry (1981, 1982), eight were very dry (1973, 1978, 1986, 1989, 1990, 1993, 1997, 2002) and six were very wet (1969, 1974, 1977, 1994, 1998, 2001). In dry years the N, NP and NK treatments led to a yield increment of over 3.0  t·ha -1 (3.2 t·ha -1 ) (81%) compared with the unfertilized control, while the full NPK treatment caused hardly any increase in the maize yield (7.2 t·ha -1 ). In the case of drought there was a 4.0% yield loss in the N, NP and NK treatments compared to the same treatments in the dry years. This loss was only 1.0% in the NPK treatment. In very wet years the positive effects of a favourable water supply could be seen even in the N, NP and NK treatments (with yields of around 7.4 t·ha -1 ). The yield increment in these treatments compared with the droughty years averaged 8%, while balanced NPK fertilization led to a further 2% increase (10%). Significant quadratic correlations were found between the rainfall quantity during the vegetation period and the yield, depending on the nutrient supplies (Ø: R = 0.7787***, N: R = 0.8997***, NP: R = 0.9338***, NK: R = 0.9574***, NPK: R = 0.8906***). The optimum rainfall quantity and the corresponding grain yield ranged from 328-349 mm and 5.0-7.7 t·ha -1 , respectively, depending on the fertilizer rate. The grain yield increment obtained per mm rainfall in the case of optimum rainfall supplies was found to be 14.3-23.2 kg·ha -1 , while the quantity of rainfall utilized during the vegetation period for the production of 1 kg air-dry matter in the case of maximum yield amounted to 698, 449, 480, 466 and 431 litres in the control, N, NP, NK and NPK treatments, respectively. It was clear from the 43-year meteorological database for the experimental station (1961-2003) that over the last 23 years (1981-2003) the weather has become substantially drier. Compared with the data for the previous 20 years (1961-1980) there was an increase of 20, 500 and 50% in the number of average, dry and droughty years, no change in the number of wet years and a 71% drop in the number of very wet years.

scholarly journals Responses of weed community, soil nutrients, and microbes to different weed management practices in a fallow field in Northern China

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7650 ◽  
Author(s):  
Xian Gu ◽  
Yu Cen ◽  
Liyue Guo ◽  
Caihong Li ◽  
Han Yuan ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Soil Nutrients ◽  
Seed Bank ◽  
Weed Management ◽  
Seed Banks ◽  
Total Biomass ◽  
Weed Seed ◽  
Soil Biodiversity ◽  
Deep Tillage ◽  
Positive Effects

The long-term use of herbicides to remove weeds in fallow croplands can impair soil biodiversity, affect the quality of agricultural products, and threaten human health. Consequently, the identification of methods that can effectively limit the weed seed bank and maintain fallow soil fertility without causing soil pollution for the next planting is a critical task. In this study, four weeding treatments were established based on different degrees of disturbance to the topsoil: natural fallow (N), physical clearance (C), deep tillage (D), and sprayed herbicide (H). The changes in the soil weed seed banks, soil nutrients, and soil microbial biomass were carefully investigated. During the fallow period, the C treatment decreased the annual and biennial weed seed bank by 34% against pretreatment, whereas the H treatment did not effectively reduce the weed seed bank. The D treatment had positive effects on the soil fertility, increasing the available nitrogen 108% over that found in the N soil. In addition, a pre-winter deep tillage interfered with the rhizome propagation of perennial weeds. The total biomass of soil bacterial, fungal, and actinomycete in H treatment was the lowest among the four treatments. The biomass of arbuscular mycorrhizal fungi in the N treatment was respectively 42%, 35%, and 91%, higher than that in the C, D, and H treatments. An ecological weeding strategy was proposed based on our findings, which called for exhausting seed banks, blocking seed transmission, and taking advantage of natural opportunities to prevent weed growth for fallow lands. This study could provide a theoretical basis for weed management in fallow fields and organic farming systems.

scholarly journals The Factors Affecting Farmland Rental Prices in Slovakia

Land ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 96
Author(s):  
Ivan Takáč ◽  
Jarmila Lazíková ◽  
Ľubica Rumanovská ◽  
Anna Bandlerová ◽  
Zuzana Lazíková
Keyword(s):  
Agricultural Land ◽  
Economic Value ◽  
Production Costs ◽  
The European Union ◽  
Total Revenue ◽  
Factors Affecting ◽  
Positive Effects ◽  
Land Rental ◽  
Land Valuation ◽  
The Impact

Agricultural land is a limited natural resource with increasing economic value. This study analyses land rental relationships in Slovakia, including legal rental regulations, and identifies the impact of certain factors, such as the European Union Common Agricultural Policy (CAP) payments, and geographical and economic factors on land rental prices. From the results of econometric models, it was found that certain CAP payments have an effect on rental prices, mainly the single area payment scheme (SAPS), payments for agri-environmental-climate schemes (AECS), and animal welfare, which were found to have positive effects. Other important factors found to influence rental prices are economic indicators (such as total revenue share of total costs, share of revenue from agricultural production in terms of total revenue, share of production costs as a percentage of total costs, wages, and number of employees) and geographical factors (such as region or partial production areas). However, the distance of the farm from the district city (LAU 1) and the share of farmland affected by natural constraints do not considerably affect rental prices in Slovakia. Land consolidation is a statistically significant factor according to the models; however, its impact is almost zero. Knowledge of these factors constitutes important know-how, not only for policy makers but also for the actors operating in the land rental market (e.g., landlords, tenants, experts on land valuation, and real estate agents).

Management of Avena ludoviciana and Phalaris paradoxa with barley and less herbicide in subtropical Australia

2001 ◽  
Vol 41 (8) ◽  
pp. 1179 ◽  
Author(s):  
S. R. Walker ◽  
G. R. Robinson ◽  
R. W. Medd
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Field Experiments ◽  
Management Strategies ◽  
Maximum Yield ◽  
Yield Reduction ◽  
Weed Seed ◽  
Tiller Density ◽  
Weed Emergence ◽  
Subtropical Australia

The competitive advantage of barley compared with wheat was quantified for suppressing seed production of Avena ludoviciana Durieu. (wild oats) andPhalaris paradoxa L. (paradoxa grass), and for improving herbicide effectiveness on these major winter grass weeds of the subtropical grain region of Australia. Eight field experiments were broadcast with weed seed before sowing wheat or barley, in which the emerged weeds were then treated with 4 herbicide doses (0, 25, 50, 100% of recommended rates). Yield reduction from untreated weeds was on average 4 times greater in wheat than in barley, with greater losses from A. ludoviciana than P. paradoxa. Barley did not affect weed emergence, but suppressed weed tiller density and, to a lesser extent, the number of weed seeds per tiller. Seed production was, on average, 4340 and 5105 seeds/m2 for A. ludoviciana and P. paradoxa, respectively, in untreated wheat compared with 555 and 50 seeds/m2 in untreated barley. Weed seed production following treatment with 25% herbicide rate in barley was similar or less than that after treatment with 100% herbicide rate in wheat. Overall, 25% herbicide rate was optimal for both conserving yield and minimising weed seed production in barley. For wheat, maximum yield was achieved with 50% herbicide but weed seed production was lowest with 100% herbicide rate. This indicates that weeds can be effectively controlled in barley with considerably less herbicide than required in wheat, highlighting the importance of including barley as a part of weed management strategies that aim to reduce herbicide inputs.

Tolerance of Phalaris aquatica L. lines and some other agricultural species to excess manganese, and the effect of aluminium on manganese tolerance in P. aquatica

1985 ◽  
Vol 36 (5) ◽  
pp. 695 ◽  
Author(s):  
RA Culvenor
Keyword(s):  
Wheat Cultivar ◽  
Maximum Yield ◽  
Acid Soils ◽  
Subterranean Clover ◽  
Solution Culture ◽  
Yield Reduction ◽  
Manganese Tolerance ◽  
Manganese Uptake ◽  
Selection For ◽  
Manganese Concentrations

Tolerance to excess manganese in 13 Mediterranean accessions and 3 Australian cultivars of phalaris was determined in solution culture with manganese concentrations from 0.5 to 210 ppm. The effect of aluminium (0, 2.5, 5-0 ppm) on the response of two accessions to excess manganese was studied in a second experiment. Phalaris was very tolerant to excess manganese. Shoot yield at 150 ppm manganese ranged from 25 to 50% of the maximum yield, which was achieved at 0.5 ppm in some lines and at 40 ppm in others. The cultivars Australian and Sirosa were among the most tolerant types. With one exception, Algerian accessions were the least tolerant. These accessions were of similar tolerance to Egret, the most tolerant wheat cultivar examined. All phalaris lines were much more tolerant than Isis wheat, Clipper barley, Woogenellup subterranean clover and Jumbuck rape. Variation in tolerance of high internal manganese levels was the principal determinant of relative tolerance within phalaris. Shoot manganese concentrations causing 10% yield reduction ranged from 730 to 2200 8g g-1 dry wt. The greater tolerance of phalaris compared with the other species was due to lower manganese uptake and higher internal tolerance. Presence of aluminium in the solution did not increase the susceptibility of phalaris to manganese toxicity. Aluminium strongly reduced manganese uptake in phalaris. It is concluded that selection for manganese tolerance need be only of low priority in developing a phalaris cultivar with improved tolerance of acid soils.

scholarly journals Genetic engineering of microalgae lipid biosynthesis for sustainable biodiesel production

2021 ◽  
Vol 11 (3) ◽  
pp. 072-077
Author(s):  
Siti Zulaiha
Keyword(s):  
Genetic Engineering ◽  
Metabolic Pathways ◽  
Alternative Energy ◽  
Fossil Fuels ◽  
Lipid Production ◽  
High Growth ◽  
Lipid Biosynthesis ◽  
Production Costs ◽  
Biodiesel Production ◽  
Promising Alternative

Biofuel is one of the most promising alternative energy sources for reducing human reliance on fossil fuels. Microalgae has recently emerged as the most promising biofuel source. However, biofuels from microalgae are still not feasible to replace fossil fuels because of their high production costs, therefore, it is necessary to pick microalgae species with high growth rates and lipid content. Overexpression of lipid biosynthesis enzymes and inhibition of competitive metabolic pathways are two genetic engineering strategies that can be developed to assess microalgae lipid production. Malate and multienzyme enzymes (GPAT, LPAAT and DGAT) can be overexpressed in microalgae to boost lipid production. The strategy of blocking competitive metabolic pathways can be carried out through suppression of starch metabolism and lipid catabolism. The strategy of blocking competitive metabolic pathways has been carried out in several microalgae and is effective for enhancing lipid biosynthesis. Several mutations that block both the starch metabolic and lipid catabolic pathways can result in increased levels of microalgal lipid accumulation.

scholarly journals Growth and Yield Sensitivity of Four Vegetable Crops to Soil Compaction

1995 ◽  
Vol 120 (6) ◽  
pp. 956-963 ◽  
Author(s):  
David W. Wolfe ◽  
Daniel T. Topoleski ◽  
Norman A. Gundersheim ◽  
Betsy A. Ingall
Keyword(s):  
Field Study ◽  
Sweet Corn ◽  
Soil Layer ◽  
Growth And Yield ◽  
Yield Response ◽  
Yield Reduction ◽  
Total Biomass ◽  
Snap Bean ◽  
Rainfall Events ◽  
Compacted Soil

A 3-year field study conducted on an Eel silt loam soil (Aquic Udifluvent) compared cabbage (Brussica oleracea L. capitata group), cucumber (Cucumis sativus L.), snap bean (Phaseolus vulgaris L.), and sweet corn (Zea mays L.) for their growth and yield response to an artificially compacted soil layer beginning at about the 10-cm depth. Slower growing cabbage seedlings in compacted plots were more subject to flea beetle damage than the uncompacted controls. Prolonged flooding after heavy rainfall events in compacted areas had a more adverse effect on cabbage and snap bean than on cucumber or sweet corn. Sweet corn showed almost no growth reduction in one of the three years (1993) when relatively high fertilizer rates were applied and leaf nitrogen deficiencies in compacted plots were prevented. Maturity of cabbage, snap bean, and cucumber was delayed, and the average reduction in total marketable yield in (direct-seeded) compacted plots was 73%, 49%, 41%, and 34% for cabbage, snap bean, cucumber and sweet corn, respectively. Yield reduction in transplanted cabbage (evaluated in 1993 only) was 29%. In a controlled environment greenhouse experiment using the same soil type and similar compaction treatment as the field study, compaction caused a reduction in total biomass production of 30% and 14% in snap bean and cabbage, respectively, while cucumber and sweet corn showed no significant response. The growth reductions of snap bean and cabbage in the greenhouse could not be attributed to compaction effects on soil water status, leaf turgor, nutrient deficiency, or net CO, assimilation rate of individual leaves. Root growth of sweet corn was least restricted by the compacted soil layer. The contrast between our field and greenhouse results indicates that the magnitude of yield response to compaction in the field was often associated with species sensitivity to secondary effects of compaction, such as prolonged flooding after rainfall events, reduced nutrient availability or uptake, and prolonged or more severe pest pressure.

scholarly journals Potential of Microalgae for the Production of Different Biotechnological Products

2019 ◽  
Vol 33 (2) ◽  
pp. 161-181 ◽  
Author(s):  
Marina Grubišić ◽  
Mirela Ivančić Šantek ◽  
Božidar Šantek
Keyword(s):  
Nutritional Value ◽  
Bioactive Peptides ◽  
Biogas Production ◽  
Animal Health ◽  
Point Of View ◽  
Production Costs ◽  
Economic Point ◽  
Positive Effects ◽  
Cell Factories ◽  
Food And Feed

Microalgae have been recognized as powerful phototrophic cell-factories whose applications range from biomass production for food and feed purposes to the production of high-value products and biofuels. Microalgae have been considered a source of functional ingredients, such as polyunsaturated fatty acids, polysaccharides, essential minerals, vitamins and bioactive peptides that can have positive effects on human and animal health. Besides having high nutritional value due to the high percentage of proteins in their composition, microalgae generate high-value products, such as pigments, polysaccharides, bio-hydrogen, and even bio-polyesters with plastic-like properties. Algal biomass that remains after product recovery can be used as forage, biofertilizer or feedstock for biogas production. This step in overall algal production is important from an economic point of view due to the reduction in production costs. This paper presents the detailed study of the biotechnologically most important microalgae strains, and the design principles of photobioreactors for their cultivation. In addition, the main existing and potential high-value products derivable from microalgae, as well as utilization of microalgae for phytoremediation and biogas production, were reviewed.

Sign in / Sign up

Export Citation Format

Share Document