Fertilizer Supply Research Articles

A new efficiency evaluation approach with rough data: An application to Indian fertilizer

<p style='text-indent:20px;'>In the world of chaos, nothing is certain. In such an unpredictable world, measuring the efficiency of any individual is inevitable. In a conventional data envelopment analysis (DEA) model, exact input and output quantity data are needed to measure the relative efficiencies of homogeneous decision-making units (DMUs). However, in many real-world applications, the exact knowledge of data might not be available. The rough set theory allows for handling this type of situation. This paper tries to construct a rough DEA model by combining conventional DEA and rough set theory using optimistic and pessimistic <inline-formula><tex-math id="M1">\begin{document}$ \beta $\end{document}</tex-math></inline-formula> confidence values of rough variables, all of which help provide a way to quantify uncertainty. In the proposed method, the same set of constraints (production possibility sets) is employed to build a unified production frontier for all DMUs that can be used to properly assess each DMU's performance in the presence of rough input and output data. Besides, a ranking system is presented based on the approaches that have been proposed. In the presence of uncertain conditions, this article investigates the efficiency of the Indian fertilizer supply chain for over a decade. The results of the proposed models are compared to the existing DEA models, demonstrating how decision-makers can increase the supply chain performance of Indian fertilizer industries.</p>

Assessment of Selected Soil Micronutrients Status in Kwara State University Teaching and Research Farm, Malete, Nigeria

Field research was conducted to determine the availability and condition of soil micronutrients at the Teaching and Research Farm in Malete. The goal of the study is to assess the distribution and status of micronutrients and how they relate to a few key soil characteristics. A total of 173 soil samples were collected and compressed into 7 composite samples. Iron (Fe), Copper (Cu), Zinc (Zn), and Manganese (Mn) were the micronutrients determined in the laboratory using the Mehlich-III multi-nutrient extraction method. The particle size distribution (sand, silt, and clay), pH, and organic carbon of the soil were determined. The findings indicated that the soils of the teaching and research farm have a sandy loam texture, with sand concentrations of 80.64–82.64g/kg, silt at 6g/kg, and clay at 11.36–16.34g/kg. The results of the soil reaction revealed that the soils have minimal organic content (0.06-0.93g/kg) and are extremely acidic (5.1). The result of the soil micronutrients indicates that Fe content was high ((0.10-0.20mg/kg); copper was rated low (0.04-0.05 mg/kg); zinc was rated low (0.01-0.03 mg/kg) and manganese was also rated low (0.07-0.11mg/kg) respectively. The findings show that the key soil characteristics that affect the availability of micronutrients in the soil are sand particles, pH, and organic matter because of their substantial correlations. The highly substantial link between the investigated accessible micronutrients suggests that similar processes regulate both their availability and release to plants. Since the soils are suitable for the development of arable crops, additional applications of Fe-rich fertilizer won't be necessary, but a complementing supply of Fertilizers containing copper, zinc, and manganese is highly advised to improve the region's soil fertility.

Corn Value Chain in Dompu: Constraints and Alternative Policy Interventions to Improve the Value Chain

Even though corn has been a common agriculture commodity growing by Dompu farmers, few issues remain such as limited input supply especially fertilisers. As results, farmers could not follow the recomended fertiliser doses that lead to low productivity. This study was conducted to clearly identify the issues and constraints along the corn value chain, and identify options to address the issues. Quantitative and qualitative menthods were applied to the study. The findings from this study highlight that the corn value chain was very simple where farmers sell their corn to the village level collectors named as palele, then the palele sell the corn to the sub-district level collecotrs, and then they sell to the exporters. It is the roles of these exporters to sell the corn to other island and or to international markets. Issues found in the corn value chain are: the limited supply of fertilisers, broadcasting technique for fertilizer application, corn price fluctuation, and low corn productivity. It is recomended that the local government take few policy options to address the issues, and improve the value chain performance that lead to better smallholder farmers’ livelihood improvement.

Fertilizer demand-supply gap and avenues for policy revisits in Nepal

Nepal's farmers report fertilizer shortages yearly, especially for rice, wheat, and maize production. A reliable and established approach to estimating the actual demand for fertilizers for different crops and cropping seasons is lacking. Therefore, it is difficult to project the types and quantity of fertilizer to import and allocate across various regions in the country. With the direct involvement of the Government of Nepal (GoN) in fertilizer import, price (subsidy), and distribution, together with the high affinity of farmers for the subsidy, there is no incentive for the private sector to import and distribute fertilizers. Thus, farmers’ access to fertilizers in the country depends primarily on the subsidy budget, quantity and types of fertilizers imported, and their distribution management. In this study, the fertilizer demands, both at the national and sub-national levels, were estimated through a survey of cooperatives that distribute subsidized fertilizers in the country. Our estimate suggests that the fertilizer supplied in 2018/19 was only 60% of the total effective demand in the country. With this estimate of the demand-supply gap and the price variability across provinces, short, medium, and long-term policy recommendations are made to improve the supply of chemical fertilizer in the country SAARC J. Agric., 20(2): 223-234 (2022)

Effects of different dose of nitrogen and lime on soil properties and maize (Zea mays L.) on acidic nitisols of Northwestern Ethiopia

This study was carried out on the nitisols of Burie district, Ethiopia to examine the effect of integrated use of lime and nitrogen on soil physicochemical properties and maize yield. Two levels of lime (0 and 0.5 t/ha) and five-level of nitrogen (0, 46, 92, 138 and 184 kg N/ ha) were laidout in randomized complete block design with three replications. The results indicated that among before planting, soil bulk density (BD), pH, soil organic carbon (OC), total nitrogen (TN), available P and CEC were 1.42 g/cm3, 5.2 (strongly acidic), 1.32% (very low), 0.12% (low), 8.86 mg /kg (very low), and 19.57 cmolc /kg (medium), respectively. The physicochemical properties except bulk density increased. The lowest soil BD (1.21 g/m3) was from plots treated with 0.5 t/ha lime and 184 kg N/ ha. The maximum soil pH (6.85) was obtained from plots treated with 184 kg N/ ha and 0.5 t/ha lime. The maximum soil CEC (35.38 (cmolc /kg) was obtained from plots treated with 184 kg N/ ha and 0.5 t/ha lime. Level of lime, nitrogen fertilizer, and interaction effects of lime and nitrogen fertilizer (L×N) significantly affected maize yield (p<0.001). Indeed yield of maize has positive correlations with most soil physicochemical properties but negative with BD (r= -0.543). The adjusted yield and net benefits was 6.4 t/ha and 1101.77$. Inherent physicochemical properties of the soil are changed either by sole or combined use of lime and N fertilizer. Soils tilled with 0.5 t/ha lime and 138 kg/ha nitrogen were found in maximum net benefit. Residual long-term effects should be researched. Thus, liming should be given an emphasis on acidic soil amelioration. Moreover, the government may facilitate the supply of lime and nitrogen fertilizer to the farmers.

THE POLITICAL ROLE OF THE UNITED STATES OF AMERICA IN THE 21ST CENTURY IN THE SOUTH CHINA SEA REGION

The USA and China are the two most powerful and accountable states in the world. As for the right, 7 countries have access to the China Sea. The countries maintain intensive relations using economic ties and maritime routes. The US is trying to gather more allies to prevent Chinese hegemony. The United States is also not going to lose its strong position in Asia, which can be expressed by trying to put pressure on other countries in the Asia and Pacific region. At the same time, its main interest in the region is to ensure freedom and safety of navigation. The area is attractive because of its abundant supply of organic fertilizer, which is very popular in world markets. This is why the US is interested in the region, and Beijing wants to have the largest fleet and infrastructure in the region.

Yield of spring barley depending on the hydrothermal conditions of vegetation in the conditions of the Middle Trans-Urals

The purpose of the research is to study the influence of hydrothermal conditions of vegetation of 2011-2022 on the yield of spring barley of the Rodnik Prikamya variety in the conditions of the Middle Trans-Urals. Barley was cultivated in a traditional field grain-grassfallow seven-field crop rotation against two backgrounds of mineral nutrition (without fertilizers, N60P30K60). In the conditions of a long stationary experiment, the influence of indicators of moisture and heat supply of vegetation periods (air temperature, precipitation amount, G. T. Selyaninov hydrothermal coefficient) and mineral fertilizers on barley yield was analyzed. The analysis proves the reliability of the relationship, and the regression equations for the curvilinear dependence make it possible to predict the yield of spring barley for both backgrounds of mineral nutrition in typical soil and climatic conditions for the Middle Trans-Urals. For the variant with the introduction of mineral nutrition, with a prediction accuracy of 84.56 %: Y = -1.22163X2 + 0.69X + 4.01388626, where Y is the predicted yield, t/ha, X is the hydrothermal coefficient of May. For the variant without mineral fertilizers: Y = -0.080X2 + 0.5844X + 2.5506, where Y is the predicted yield, t/ha, X is the hydrothermal coefficient of June. The accuracy of forecasting the yield of spring barley by the hydrothermal coefficient of June is 77.89 %.

Global Wheat Production and Threats to Supply Chains in a Volatile Climate Change and Energy Crisis

As climate change and energy crises increase, NPK (nitrogen, phosphorus and potassium) fertilizer supply chains become more volatile. Globally, the Russian attack on Ukraine has caused the cost of gas to rise and fertilizer supplies to decline. This aggression may worsen the energy and wheat resource crisis in global supply chains. As a result of the escalation of hostilities, natural gas, oil, and coal prices have rapidly increased. In the years preceding the conflict, the agricultural sector had already begun to suffer, caused by unprecedented increases in the prices of natural gas and raw materials for the production of fertilizers stemming from Russian manipulation, especially in the gas market. Prior to the growing season, farmers were still unable to afford fertilizer prices. This situation will be exacerbated by the war. We can conclude from our results that European countries and the United States have high wheat production potential. Developed countries have significant nitrogen, phosphorus, and potassium fertilizer resources. Ukraine has a large yield gap, ranging between 4.5 and 7 Mg/ha. Wheat supply crises can be caused by tense geopolitical affairs, including military aggression and economic embargoes. Based on this, we recommend that decision-makers focus on crop quality to increase the country’s own production.

Push and pull factors of red pepper (capsicum) market supply: Evidence from south western Ethiopia

The growth and development of the spices sector depend upon market-oriented production system and good marketing infrastructure. However, for smallholder farmers, it is difficult to supply theirs produces to markets because of different problems and barriers. Therefore, this study was aimed at analyzing the push and pulls factors of red pepper market supply in Southwest Ethiopia. The primary data were collected from 267 randomly selected sample households’. The Tobit model was used to determine the volume of red pepper supplied to the market. The results shows that the education level of household head, land allocated for red pepper production, access to credit, and lagged price of red pepper significantly affect the volume of red pepper supplied to the market. The major production constraints that hamper red pepper yield were red pepper disease, lack of fertilizer supply, lack of improved variety, lack of pesticide, harvesting before maturity, and poor post-harvest handling. The marketing constraints were lack of marketplace, low and unstable price of the product, and low quality of product, improper scale, lack of government support, and lack of transport. Therefore, Policies that give more emphasis on the provision of modern inputs, improving infrastructure, strengthening institutions of collective action, and improving the marketing extension system are recommended. • Push and pull factors are direct and indirect cause of market supply. • An efficient marketing system is the building block of economic growth. • Proper and stable pricing system increase producer's net gain. • Red pepper is the second most important vegetable.

Sustainable fertilizer supply chain network design using evolutionary-based resilient robust stochastic programming

Phosphorus is an unsustainable substance that plays an essential role in modern agricultural systems and crop yield. Due to phosphorus growing demand and the importance of sustainable application of this critical resource, there is increasing concern about its supply chain network sustainability and resiliency. In this paper, a multi-objective, multi-product, multi-period mathematical model is developed for the sustainable phosphorus supply chain management in an uncertain environment. The parametric uncertainties such as demand and supply are aggravated by disruptions with devastating effects on strategic, tactical, and operational decisions. Given the potential adverse effects of the phosphorus supply chain on the environment and human beings, a sustainable-resilient supply chain network of the fertilizer industry is designed by considering the related environmental, social, and economic challenges of the phosphorus managing. A reactive strategy is adapted to encounter the disruptions and breakdowns along with the network, while a robust stochastic programming is extended and solved using genetic algorithm to cope with the real-world uncertainties. The proposed model effectively controls the uncertainty and risk-aversion of output decisions and confronts the adverse effects of disruptions. The effectiveness and applicability of the model are validated through a real case study. Besides, the performance and reliability of the model are proved by the realization under new scenarios. The results indicate that the proposed model performs well in capturing real-world uncertainties and promoting the sustainability and resiliency of the network.

An Optimal Decision Support System Based on Crop Dynamic Model for N-Fertilizer Treatment.

The efficient handling of nitrogen has become a critical issue in modern agriculture, from a financial standpoint, as well as in regard to reducing the environmental impacts of using an excessive amount of nitrogen fertilizer. Manure compost is useful for maintaining or raising soil chemical levels without excessive accumulation; however, for the best grain yield, it should be combined with N fertilizer. Via this study, we aimed to develop an optimal decision support system that indicates when to initiate fertilization based on nitrogen-limited (N-limited) crop growth dynamics. An optimal nitrogen fertilizer (N-fertilizer) management system increases crop yield while maintaining a balance between fertilizer supply and crop demand. This study used the N-limited crop growth model (LINTUL3) to develop an optimal decision support system. In this work, we formulated and resolved two optimization challenges: (i) maximization of biomass growth; and (ii) maximization of growth with the least cost paid on N-fertilizer and its application. Furthermore, two case studies were developed based on the number of fields: (i) optimization for a single field, and (ii) optimization for multiple fields. In the case of multiple fields, it is hypothesized that a fertilizer treatment for one field can leak to other fields and affect the nitrogen dynamics of different fields. Finally, numerical simulations were carried out supporting the theory developed in the paper. The simulations showed that when the proposed work was employed to achieve the goal of optimal nitrogen management for a crop, a to increase in biomass growth under certain scenarios was attained.

Effect of phosphorus application on economic yield, quality and phosphorus utilisation efficiency of purple-fleshed sweetpotato

This study aims to explore the effect of phosphorus (P) application on the economic yield, quality, P accumulation, and P utilisation efficiency of purple-fleshed sweetpotato and to provide a basis for the P efficient utilisation and high crop yield. Field experiments were conducted in 2018–2019, and five P application rates (0, 10.9, 21.8, 32.7, and 43.6 kg P/ha, expressed as P0, P1, P2, P3, and P4, respectively) were set. The results showed that P application significantly increased the yield and commodity potato yield of purple-fleshed sweetpotato, and that of P3 treatment was the highest, followed by P2 treatment. P application also increased the starch content in the storage root and increased the reducing sugar and soluble sugar (except for P2 treatment). P fertiliser supply significantly increased P accumulation and dry matter production of purple-fleshed sweetpotato during the growth period of 90 to 120 days. When the P application rate was over 21.8 kg/ha, the fertiliser investment rate, apparent P utilisation efficiency and P agronomic efficiency decreased with the increase of the application rate. Considering all the indexes, the supply of 21.8 kg/ha P fertiliser can meet the demand for high economic yield and P efficient utilisation in purple-fleshed type sweetpotato under the condition of this experiment.

Effects of Fertilization Approaches on Plant Development and Fertilizer Use of Citrus.

Fertilization is an important part of citrus crop management. However, limited details are available about the fertilization approach on citrus plant development. A pot experiment for the fertilization approaches and fertigation levels were conducted in this study. Four fertilization approaches, namely, drip fertigation (DF), broadcast fertilization (CK+), hole fertilization (HF) and pour fertilization (PF) were tested. The fertigation level treatment included 100% (DF-337.5), 80% (DF-270), 60% (DF-202.5) and 40% (DF-135) fertilizer supply with DF, and the 100% fertilizer supply with broadcast fertilization were served as control (CK). The results showed that DF not only increased the absorptions of nitrogen (N), phosphorus (P) and potassium (K) but also promoted citrus plant height, stem diameter and dry weight. In fruit quality, DF had the highest fruit total soluble solid (TSS) and titratable acidity (TA) contents. For fertilizer loss, DF had the lowest N and K leaching losses of 9.26% and 4.05%, respectively, and the lowest N and K runoff losses among the approaches. Isotopic tracing with 15N indicated that DF had the highest fertilizer use efficiency. Based on the analysis of fertigation levels, DF approach with 60% fertilizer reduction could improve citrus plant development. Therefore, DF promoted citrus plant growth and fruit quality by accelerating fertilizer utilization and impairing fertilizer loss. The fertilizer amount in citrus production could be reduced significantly using DF.

ANALISIS KELAYAKAN INVESTASI DALAM PENGAJUAN FASILITAS KREDIT PADA PT. XYZ

Abstract: PT. XYZ working in fertilizer trade to fulfill XYZ Group's fertilizer needs. The fertilizer supply is constrained by PT XYZ’s suppliers. In order to meet these fertilizer needs, PT. XYZ plans to build NPK plant located in Central Java. Investation is planned to use a bank credit facility. Based on the requirement in the credit application, an analysis of investment feasibility is carried out on the submission of PT. XYZ credit facilities. This research was conducted using a qualitative approach and a quantitative approach. A qualitative approach is used to examine non-financial aspects including review of the NPK fertilizer industry and business plan analysis. The quantitative approach is used to examine financial aspects including financial projections and sensitivity analysis. Review from NPK fertilizer industry, Indonesia have a market prospect of 4.8 million tons NPK fertilizer needs for palm oil plantation sector. The business plan for the construction of the NPK fertilizer plant includes a 300,000 MTPY capacity, chemical granulation based technology, fertilizer product with formulas 12-12-17 and 13-6-27, and Engineering, Procurement and Construction duration of project is 26 months. The results showed that the construction of NPK Fertilizer Plant was feasible in business and feasible to be financed with credit from creditors with an investment credit of Rp. 541,725,406,300 and working capital loans of Rp. 92,245,261,932, -. The feasibility of providing credit facilities is seen from the positive cash flow ability of NPK fertilizer sales and financial indicators, namely the Payback Period for 5.62 years, NPV (DF 11%) of Rp. 756,104,248,537, -, Internal Rate of Return 23.25%, Profitability Index 1.88.Keywords: NPK Fertilizer Industry, Business Plan Analysis, Financial Projection, Sensitivity Analysis, Payback Period, Internal Rate of Return, Net Present Value, Profitability Index

Quantifying source-sink relationships of drip-fertigated potato under various water and potassium supplies

Water and fertilizer supply can affect the processes of assimilate production (source) and assimilate accumulation (sink), thereby causing differences in potato yield. However, little is known about the coupling effects of irrigation amount and potassium rate on potato tuber yield and its potential source-sink relationships. The objective of this study was to quantify how water and potassium supplies affected the source-sink relationships of drip-fertigated potato after tuber emergence. A two-year field experiment was conducted during the potato growing seasons of 2019 and 2020, with three irrigation levels (W1: 60% ET c , W2: 80% ET c and W3: 100% ET c , where ET c is the crop water requirements) and four potassium rates (K0: 0 kg ha -1 , K1: 135 kg ha -1 , K2: 270 kg ha -1 and K3: 405 kg ha -1 ). The results showed that compared with K0, the treatments viz ., K1, K2 and K3 increased average tuber yield by 1.3%, 17.3% and 15.5% in 2019 and 10.7%, 24.0% and 19.3% in 2020, respectively. However, compared with W3, the treatments viz ., W1 and W2 reduced the average tuber yield by 8.0% and 12.9% in 2019 and 8.9% and 14.7% in 2020, respectively. The beta sigmoid growth function well fitted the relationship of source capacity and sink capacity. The source capacity and source activity increased with the increase of potassium rate under W2 and W3 in 2019 and under W3 in 2020, while the sink capacity and sink activity first increased and then declined with the increasing potassium rate. Increasing water and potassium supply generally increased the vegetative growth and tuber growth time. The tuber growth rate first increased and then decreased with the increase of potassium rate, while it increased with the increasing irrigation amount. The sink-source ratio decreased with the increase of potassium rate, but there was no significant difference between K1 and K2, and the sink-source ratio under K3 was significantly lower than that in the other potassium treatments. It was concluded that potato was in source-sink balance under K1 and K2, but not under K3. The quantitative approach produced parameters that characterized the differences of source and sink capacity in response to various water and potassium supplies. Sufficient irrigation (W3) with moderate potassium application (K2) increased potato yield mainly by maintaining its source-sink balance. • A model approach was proposed to quantify source-sink relationships of potato under various water and potassium supplies. • The mechanism analysis of yield difference from various water and potassium supplies was conducted by source-sink balance. • Source-sink capacity was affected by different water and potassium management practices. • The sink-source ratio was not significantly different between 135 and 270 kg ha -1 , indicating the source-sink balance. • Various water and potassium application amounts influenced plant potassium absorption and tuber yield.

Economics of Cereal and Vegetable Crops under Organic and Conventional Production Systems in Nepal

Chemical fertilizers have a great contribution in agricultural production in Nepal. So far, only about 50% of total demand for chemical fertilizer has been met. Government has been providing subsidy protecting farmers from high cost of imported fertilizers. However, the supply of chemical fertilizer is not smoothened as expected. With the tragedy of different problems of fertilizer importation, distribution, and use, stakeholders have started thinking organic production as an alternative of conventional agriculture in Nepal. However, transforming from conventional to organic agriculture is questioned because of conflicting finding regarding the real profitability of organic production technique. Responding to the situation, a study was conducted to analyze comparative economics of organic and conventional production system using gross margin and cost-benefit analysis covering five selected crops (rice, tomato, potato, bitter gourd, and cauliflower). The study was carried out by random sampling of 250 producers where 200 were conventional and 50 organic farms from five rural/municipalities of Sindhupalchhok, Dhading, Gorkha, Chitwan, and Rupandehi districts. Estimated gross margins and benefit cost analysis indicated that organic products are as profitable as conventional products except in tomato. In overall, vegetables were more profitable than cereals both for organic and conventional systems.

Behavior of Private Retailers in a Regulated Input Market: An Empirical Analysis of the Fertilizer Subsidy Policy in Nepal

The private sector in Nepal participates in the regulated import and distribution of three types of subsidized fertilizer. However, almost 55% of the agrovets (family-owned microenterprises) that retail agricultural inputs do not comply. Many farmers rely on the fertilizer purchased through these agrovets, including subsidized ones. There is no private sector importer of the three types of fertilizer covered by the subsidy program, which indicates that the agrovets either acquire these through leakage in the government distribution system or through illegal cross-border trade from India, both of which are considered legal noncompliance. We discern the determinants for this noncompliant behavior of agrovets using logistic regression. The results from logistic regression suggest that the agrovets that are more likely to comply are registered, have membership in business associations, and have a higher number of competitors. Those with diversified business portfolios and covering a greater number of districts are less likely to comply. Key informants, consisting of both public and private sector stakeholders, were solicited for their views on solving this noncompliant behavior. The private sector unanimously asserts the need for deregulation of fertilizer imports and the participation of agrovets in the distribution of the subsidized fertilizer. In contrast, the public sector is skeptical of the ability and trustworthiness of the private sector in the import and distribution of quality fertilizer. We propose a middle ground to mitigate private sector noncompliance and suggest a policy revisit to increase the fertilizer supply and distribution efficiency.

Greenhouse gas emissions from global production and use of nitrogen synthetic fertilisers in agriculture

The global agri-food system relies on synthetic nitrogen (N) fertilisation to increase crop yields, yet the use of synthetic N fertiliser is unsustainable. In this study we estimate global greenhouse (GHG) emissions due to synthetic N fertiliser manufacture, transportation, and field use in agricultural systems. By developing the largest field-level dataset available on N2O soil emissions we estimate national, regional and global N2O direct emission factors (EFs), while we retrieve from the literature the EFs for indirect N2O soil emissions, and for N fertiliser manufacturing and transportation. We find that the synthetic N fertiliser supply chain was responsible for estimated emissions of 1.13 GtCO2e in 2018, representing 10.6% of agricultural emissions and 2.1% of global GHG emissions. Synthetic N fertiliser production accounted for 38.8% of total synthetic N fertiliser-associated emissions, while field emissions accounted for 58.6% and transportation accounted for the remaining 2.6%. The top four emitters together, China, India, USA and EU28 accounted for 62% of the total. Historical trends reveal the great disparity in total and per capita N use in regional food production. Reducing overall production and use of synthetic N fertilisers offers large mitigation potential and in many cases realisable potential to reduce emissions.

Sole carbon source utilization (SCSU) pattern of nodule forming rhizobia of Sesbania species

Nitrogen fixing rhizobia promises another method to plant N fertilizer supplies. Growing high N2-fixingplants like Sesbania is useful not only for economic perspective but also for soil amelioration. Along withthe phenotypic criteria, carbon utilization is more perceptive than other methods like intrinsic antibioticresistance. Selected rhizobial isolates of various Sesbania spp. were used to evaluate the sole carbon sourceutilization (SCSU) pattern by means of twenty two diverse sugars. The analysis of the data using NTSYSPCsoftware resulted in diversification of the rhizobial isolates into two major groups and divergenceamong them started at 48% level of similarity coefficient. Dextrose was the isolates’ most commonly usedcarbon source (88%), whereas inulin was the least.

Microalgae biomass production from cultivation in availability and limitation of nutrients: The technical, environmental and economic performance

Microalgae cultivation offers the potential to produce different biomass compositions while preventing pollution, treating waste and recovering resources. However, the energy, environmental and economic performance of the production of microalgae biomass should be advantageous compared to that of conventional biomass sources. The goal of this research was to quantify the performance of energy demand, carbon footprint and financial cost of microalgae biomass production in cultivation with availability and limitation of nutrients. The product system is composed of microalgae cultivation in open raceway ponds with carbon dioxide injection and harvesting with settling, filtration and centrifugation. The average annual biomass productivity in the cultivation was 18 g (m2 day)−1 in the base scenarios with availability (S1) and limitation (S2) of nitrogen and phosphorus, which was changed to 8.5 g (m2 day)−1 in S1LOWER and S2 LOWER and 25 g (m2 day)−1 in S1HIGHER and S2HIGHER. The methods used in this study were attributional life cycle assessment (LCA) for energy demand (Cumulative Energy Demand – CED) in Megajoule (MJ) and carbon footprint (IPCC-2021, Global Warming Potential 100 years) in kilogram of carbon dioxide equivalent (kg CO2eq) and techno-economic analysis (TEA) for financial cost in United States dollar (USD). The energy demand, carbon footprint and financial cost, respectively, in S1 were 10 MJ kg−1, 0.48 kg CO2eq kg−1 and 0.59 USD kg−1 for a dewatered biomass in total solids, while those varied by: +30%, +24% and +72% in S1LOWER; −11%, −8.9% and −19% in S1HIGHER; −38%, −46% and −15% in S2; −6.1%, −20% and +62% in S2LOWER; and −50%, −56% and −36% in S2HIGHER compared to S1. The largest contribution of energy demand and carbon footprint, respectively, in S1 was the fertilizer supply (52% and 61%), while in S2 it was the electricity supply (51% and 48%). The use of residual N and P and photovoltaic electricity supply were considered in the sensitivity analysis, which showed a potential to reduce up to 61% in energy demand, 84% in carbon footprint and 37% in financial cost compared to S1. Therefore, limiting nutrients and using nutrients from residual sources in cultivation along with providing electricity from a cleaner and affordable source are strategies for commodity production from microalgae biomass.