Conventional Chemical Fertilizers Research Articles

Life cycle assessment and life cycle cost analysis of compound microbial fertilizer production in China

Compound microbial fertilizer (CMF) uses organic waste as a raw material and is an environmentally friendly alternative to conventional chemical fertilizers. However, further analyses of the environmental performance of CMF production are necessary. This study first evaluated the environmental impacts of CMF made from chemical fertilizers, organic wastes, and microorganisms, as well as economic costs. A case study, whose scope encompassed raw materials, transportation, and manufacturing stages was conducted on a fertilizer company in the Hubei Province of China through a combined “cradle-to-gate” life cycle assessment and life cycle cost methodology. Normalization of midpoint results indicated that impacts on fossil resource scarcity, water consumption, and terrestrial acidification are key contributors to the total impacts. The key stage analysis highlighted that the raw materials stage played a critical role (more than 48%) in the environmental performance of the CMF life cycle, followed by the transportation and manufacturing stages (less than 15%). Key substance analysis showed that monoammonium phosphate use is a hotspot and significantly increases the environmental burden of CMF production. Moreover, bentonite and pig manure were also identified as the key substances. Future improvements in the supply chain should focus on monoammonium phosphate, bentonite production, and pig manure extraction. Results of the sensitivity analysis confirmed that controlling pollution from monoammonium phosphate and bentonite should be a priority in realizing clean production. Additionally, an economic analysis indicated that the life cycle cost of CMF was 675.75 CNY/t and that raw material costs contributed the most to the total life cycle cost (over 70%). On the basis of these results, possible recommendations were proposed, such as promoting green procurement of main raw materials, improving the collection technology of pig manure, and extending the scale of CMF enterprises. This study can be significant in assisting relevant stakeholders with decision-making to ensure a balanced tradeoff between an environmentally friendly option and an economically feasible option.

A Green Control Release NPK Fertilizer Based on Micro/Nanoparticle of Chitosan Impregnated Activated Coir Fiber

Background: Conventional chemical fertilizers enhance agricultural output but deteriorate soil quality and fertility while causation of health and environmental issues. Therefore, continual use of chemical fertilizers is not sustainable. Control release nanofertilizer is one of the solutions to said issues. Nanofertilizers use metallic nanoparticles and toxic cross-linkers (eg. Glutaraldehyde, Glyoxal and Methacrylic Acid) which also pose risks to health and environment. Synthetic, non-biodegradable costly raw material based nanofertilizers will also create new-generation-waste in future which is not sustainable. Objective: Development of an environment friendly nanofertilizer for prolong control release of plant macronutrients - Nitrogen, Phosphorous and Potassium (NPK). Methods: Chitosan was obtained from deacetylation of chitin which was extracted from shrimp exoskeleton. Micro/nanoparticles of chitosan were synthesized with ionotropic gelation method excluding toxic cross-linkers. Macronutrient loaded nanoparticles were impregnated to micro and nano pores in activated coir fiber followed by coating with a natural exudate water diffusional barrier. Macronutrient release behaviour and efficacy of control release fertilizer were studied against conventional bulk fertilizer. Results: Mean size of nanoparticles was 100 nm. FTIR analysis showed the macronutrient interaction with micro/nanoparticles of chitosan. Macronutrients were incorporated into nanoparticles at 12 % loading efficiency and 20 % entrapment efficiency. The developed fertilizer showed control release of macronutrients even beyond 90 days whereas commercial fertilizer showed an initial burst lasting a negligible release after 30 days. Results from pot trials indicated that nanofertilizer enhances yield performance of rice plants against commercial fertilizer. Conclusion: A green nanofertilizer can be developed with a simple method using biocompatible, biodegradable, non-toxic and renewable natural based raw materials for prolong control release of plant macronutrients excluding toxic chemicals. Since the starting materials are coir fiber and shrimp exoskeleton which is a waste, it could significantly reduce the production cost hence present study discloses an economically sound, environment friendly and socially responsible nanofertilizer.

Challenges and opportunities for more efficient water use and circular wastewater management. The case of Campania Region, Italy

By 2050, global demand for water is expected to increase by some 55% due to population growth and urbanization. The utilization of large amounts of freshwater in the world, generate huge volumes of wastewater of which, globally, more than 80% is discharged without treatment, thus causing impacts on aquatic ecosystems, human health and economic productivity. More sustainable practices of wastewater management are expected as a way towards circular bioeconomy (CBE) processes, whose goal is to implement closed systems promoting the systematic use of recycling, reuse and recovery of bioproducts and by-products and the reduction of waste generation. This approach, if adopted in the water and wastewater sector, can ensure environmental, economic and social benefits. The reuse of wastewater, on the one hand, reduces the volume of wastewater and the pressure on water bodies; on the other hand, the recovery of nutrients (P or N) and/or other high value bioproducts (biogas, cellulose, biopolymers) from wastewater offers numerous advantages in terms of supplying new raw bio-based materials that can be refed back to supply chains (thus substituting fossil resources) and, at the same time, producing cleaner water to be reused. Nevertheless, while in Europe many industries have demonstrated the ability to recycle and reuse water, in many regions of Italy the sustainable management of water and wastewater is not yet consolidated. In this study we explore the available technological, economic and environmental options concerning water use and wastewater treatment and we apply them to design appropriate scenarios for improved use efficiency and circular management. A comprehensive literature review of the most promising wastewater treatment processes for resources and energy valorization was conducted. The recovery of PHAs, struvite, nitrogen and algal biomass, as potential substitutes for conventional PET, phosphate and nitrogen chemical fertilizers and electricity, respectively, in addition to reusable treated water, were hypothesized and carefully discussed. Resulting scenarios are tested against the present situation of Campania Region (situated in Southern Italy) based on population and demand statistics, in order to develop strategies and policies potentially applicable locally and elsewhere.

The Study of Chicken Manure and Steel Slag Amelioration to Mitigate Greenhouse Gas Emission in Rice Cultivation

Organic matter, fertilizers, and soil amendments are essential for sustainable agricultural practices to guarantee soil productivity. However, these materials can increase the emission of greenhouse gases (GHGs) such as CH4 and N2O. Thus, technologies for reducing GHG emissions in concert with the increase in rice production from rice fields are needed. The objectives of this study were to determine the best chicken manure (CM) and steel slag (SS) combination to mitigate CH4, N2O, and CO2 emissions in an incubation experiment, to identify the best CM:SS ameliorant mixture to mitigate CH4 and N2O, and to evaluate dry biomass and grain yield in a pot experiment. A randomized block design was established with four treatments, namely conventional (chemical fertilizer only) and three combinations of different ratios of CM and SS (1:1, 1:1.5, and 1:2.5), with five replications in a pot experiment. CM:SS (1:2.5) was identified as the best treatment for mitigating CH4, N2O, and CO2 in the incubation experiment. However, CM:SS (1:1.5) was the best CM and SS ameliorant for mitigating CH4 and N2O in the pot experiment. The global warming potential of CH4 and N2O revealed that CM:SS (1:1.5) had the lowest value. None of the combinations of CM and SS significantly increased dry biomass and grain yield.

Effects of Combined Application of Chemical Fertilizer and Microbial Fertilizer on the Chemical Components Contents of Flue-Cured Tobacco Leaves

[Objective] To determine the effect of microbial fertilizer combined with compound fertilizer on the chemical composition content of flue-cured tobacco leaves. [Method] Before planting the flue-cured tobacco, the local conventional fertilizer varieties and microbial fertilizer were applied to tobacco pond annular hole according to the conventional dosage. The experiment has four groups with different treatments, namely T1: without any fertilization; T2: 4 kg of pure nitrogen per mu, applying humic acid organic-inorganic compound fertilizer with 50 g/plant when planting tobacco; T3: reducing the total amount of conventional fertilization by 50%, and applying 80 g/plant of microbial fertilizer; T4: applying only 80 g/plant of microbial fertilizer. The trial adopted a randomized block design, with 3 replicates for each treatment. After the tobacco leaves were harvested and cured at the maturity stage, 5 kg of the lower (X2F), middle (C3F) and upper (B2F) first-cured samples were taken for chemical composition determination and analysis. [Results] The results show that T3 treatment can effectively increase the total sugar, reducing sugar, total nitrogen, nicotine, potassium, and chlorine content in X2F, C3F, and B2F grade tobacco leaves, which ratios are between 20.10% ∼ 21.03% and 18.90% ∼ 19.90%, 2.68% ∼ 3.26%, 2.28% ∼ 3.15%, 2.21% ∼ 2.50%, 0.56% ∼ 0.72%, meeting the production standards of high-quality tobacco. Secondly, T4 treatment can significantly improve the sugar-alkali ratio, nitrogen-alkali ratio, and potassium-chloride ratio of X2F grade tobacco leaves, and it can improve the sugar-nitrogen ratio of C3F and B2F grade tobacco leaves, but the effect is not significant; T3 treatment has a significant effect on B2F grade tobacco. The nitrogen-nitrogen ratio of tobacco leaves has a significant effect on improving the sugar-nine ratio, potassium-chloride ratio and the sugar-nitrogen ratio of X2F ∼ B2F grade tobacco leaves, but the effect has not reached a significant level. [Conclusion] Microbial fertilizer combined with compound fertilizer can improve the content of chemical components in flue-cured tobacco. On the whole, the application effect of T3 treatment is better, that is, the application effect of 80 g/plant microbial fertilizer and 50% reduction of conventional chemical fertilizer is more ideal.

Conventional vs. nano-Ca fertilizers effects on traditional table grape Tfiefihi

Lebanon’s land mostly consists of carbonate rocks, which are generally calcareous. Calcium carbonate is not easily penetrable by vine roots except via cracks. Farmers resorted to the application of the conventional chemical calcium fertilizer. The study compared the effect of a conventional Ca fertilizer to two organic Lithovit Nano-Ca fertilizers on “Tfiefihi” variety. These products were applied once or twice. Shoot length, leaf number and composition, berry characteristics, and production indicators were investigated for two consecutive years. The highest shoot length was induced by the two-time application of Lithovit standard (T6) (346.70 cm). One-time application of Lithovit Amino25 (T3) recorded the highest leaf number (206 leaves). One-time application of Lithovit standard (T5) increased phosphorus in leaves by 0.04%. The lowest sugar content at harvest was detected in T5 and the highest one in T6. The two-time application of Lithovit Amino25 (T4) caused the highest delay in veraison (26 d). T3 recorded the highest acidity content in berry (3.83%). Nano-fertilizer has hastened harvest by around 25 d compared to conventional Ca fertilizer. T3 significantly reduced the cluster weight compared to all treatments and reduced the yield. Lithovit standard could be a beneficial substitution to the conventional fertilizer especially when applied twice.

Nanotechnology: an Emerging Hope in Crop Improvement

The application of nanotechnology in the field of agriculture completely changed the present farming practices. One of the emerging challenges in the current agricultural system is developing disease resistance and increased productivity without accumulating environmental pollutants. Most of the applied conventional chemical fertilizers and pesticides have several side effects on both plants and the environment. Nanotechnology-based crop protection strategies have the potential to induce disease tolerance and enhancement of crop yield. Benefits of using nanoparticles in the agricultural fields include reducing environmental pollutants, rapid disease diagnosis, simple preparation process, less toxicity, and cost-effectiveness. Green synthesis of nanoparticles using plant extracts gained special attention as it is reproducible, biodegradable, and very effective against several plant pathogenic microbes. In the present review, we have discussed how different nanoparticles are being used to induce disease tolerance in crops, different types of nanoparticles, synthesis and characterization, uptake, and translocation process in plants. The molecular approaches of disease management using nanoparticles and the application of nanobiosensors are also enlightened in this review.

Valorization of selenium-enriched sludge and duckweed generated from wastewater as micronutrient biofertilizer

Selenium (Se) is an essential trace element for humans and animals with a narrow window between deficiency and toxicity levels. Application of conventional chemical Se fertilizers to increase the Se content of crops in Se deficient areas could result in environmental contamination due to the fast leaching of inorganic Se. Slow-release Se-enriched biofertilizers produced from wastewater treatment may therefore be beneficial. In this study, the potential of Se-enriched biomaterials (sludge and duckweed) as slow-release Se biofertilizers was evaluated through pot experiments with and without planted green beans (Phaseolus vulgaris). The Se concentration in the bean tissues was 1.1–3.1 times higher when soils were amended with Se-enriched sludge as compared to Se-enriched duckweed. The results proved that the Se released from Se-enriched biomaterials was efficiently transformed to health-beneficial selenoamino acids (e.g., Se-methionine, 76–89%) after being taken up by beans. The Se-enriched sludge, containing mainly elemental Se, is considered as the preferred slow-release Se biofertilizer and an effective Se source to produce Se-enriched crops for Se-deficient populations, as shown by the higher Se bioavailability and lower organic carbon content. This study could offer a theoretical reference to choose an environmental-friendly and sustainable alternative to conventional mineral Se fertilizers for biofortification, avoiding the problem of Se losses by leaching from chemical Se fertilizers while recovering resources from wastewater. This could contribute to the driver for a future circular economy.

Effect of Organic and Chemical Fertilizer Application on Apple Nutrient Content and Orchard Soil Condition

Apple cultivation in Japan typically involves the use of chemical fertilizers and pesticides which can damage the environment. Therefore, in this study we investigated the orchard soil biochemical characteristics as well as the fruit nutrient contents, and pesticide residues of apples grown either organically (organic fertilizers + reduced pesticides) or with conventional chemical fertilizers and pesticide rates. Compared with conventional chemical fertilizer treatment, the organic fertilizer treatment produced fruit with significantly higher contents of sugar, as well as soil with higher total carbon, total nitrogen, and total phosphorus. There were also significantly greater soil bacterial biomass and N circulation in the organically fertilized treatments. Minimal pesticide residues were detected in the organically fertilized fruits, but in the apples cultivated with conventional rates of fertilizers and pesticides there were significantly higher levels of propargite that was used to control spider mites. These residue levels from the conventionally fertilized orchards exceeded European and Codex residue standards. These results indicate that environmentally friendly arboricultural soil management practices, such as organic fertilizer and reduced pesticide cultivation can enhance nutrient cycling in soil, reduce the burden on the environment, and promote food safety and security.

Comparative Advantage of Using Biofertilizers in Indian Agroecosystems: An Analysis from the Perspectives of Stakeholders

The use of excessive chemical fertilizers and pesticides have decreased soil microbial life and upset the balance between soil microbes and plants, negatively impacting plant nutrition, production and soil health. Biofertilizers hold the potential to revive soil biology and increase farmers’ current agricultural productivity, while at the same time contributing to the soil’s ability to produce more in the future. This article is part of a larger Université de Montréal study conducted with the support of Mitacs and Earth Alive Clean Technologies. The responses of farmers using and not using biofertilizers, manufacturers or suppliers of biofertilizers, and research and development scientists are captured to build cases of how microbial products (biologicals) prove to be advantageous when applied in field crops. The agronomic advantage of biofertilizers compared to conventional chemical fertilizers is well proved biologically and in economic terms. The farmers interviewed stated their preference of biofertilizers over chemical fertilizers. However, production and distribution of biofertilizers are inadequate compared to the demand for them. Studies need to be pursued to understand reasons for the supply gaps and the slow growth of biofertilizers in the agriculture sector of India and methods of linking them to farmers’ preferences in order to advance protections of soil and plants in India.

Effects of Organic Fertilizer on Bok Choy Growth and Quality in Hydroponic Cultures

Effects of corn steep liquor (organic fertilizer, OF) and conventional chemical fertilizer (CF) on the growth and yield of bok choy (Brassica rapa var. chinensis) in summer and autumn hydroponic growing systems were compared. When OF and CF were applied with the same amount of total nitrogen in summer cultivation, there was no significant difference between yields; however, the growth rate in OF was slower than in CF. When OF was applied with twice the amount of nitrogen in CF (OF2), bok choy growth and yield were significantly inhibited in summer cultivation, likely owing to dissolved oxygen deficiency and different rates of nitrification and nitrogen absorbance by the plant root. Although the contents of potassium, calcium, and magnesium in bok choy showed no difference among the three treatments in both cultivation seasons, the carbon/nitrogen ratio tended to be higher in OF and OF2 than in CF. Lower nitric acid and higher ascorbic acid content was found in OF and OF2 than in CF. Overall, our results suggest that a comparable yield is expected by using the same nitrogen amount with a conventional recipe of chemical fertilization in autumn cultivation. However, further improvement of hydroponic management is needed in summer cultivation.

Assessment of Shelf Life and Quality of Biofertilizers using Tricalcium Phosphate as an Anticaking Agent and Aluminium Silicate as the Inert Carrier

Background: Bio-fertilizers are the substances which contain living microorganisms, when applied to soil, seeds and plant root these fertilizers increases soil fertility and promote growth of the plant. Biofertilizers help plants to utilize important mineral resources, phosphorous and nitrogen. Microorganisms like Rhizobacteria, fungi and algae which provide nutrient to the soil and which are produced commercially are known as biofertilizers. The microorganisms which present in biofertilizers are Rhizobium species, Pseudomonas species and Azospirillum species etc. These biofertilizers have potential to replace conventional chemical fertilizers. The quality of biofertilizers is utmost important as they have to be used by farmers and should work well when applied to the soil. It should not form clumps after preparation. In this study, anticaking property provided by tricalcium phosphate (TCP) to individual biofertilizer containing Pseudomonas, Rhizobium and Azospirillum respectively (each separately) was studied. Methods: In our study, we have used serial dilution and direct count method (CFU) for checking viability of live microorganism for 15, 30 and 90 days duration in respective biofertilizers in our laboratory. Different percentage viz 5%, 10%, 15% and 20% of tricalcium phosphate (TCP) was used in addition to aluminium silicate as an inert carrier.Conclusion: Our study has validated that all percentage (5%, 10%, 15% and 20%) of tricalcium phosphate (TCP) is reducing clump formation as compared to control with no TCP added. On the basis of plate count method (CFU result) 10% TCP is found to be optimum to be used as an anticaking agent for biofertilizer containing Pseudomonas, Rhizobium and Azospirillum respectively.

Rethinking Crop Nutrition in Times of Modern Microbiology: Innovative Biofertilizer Technologies

Global population growth poses a threat to food security in an era of increased ecosystem degradation, climate change, soil erosion, and biodiversity loss. In this context, harnessing naturally-occurring processes such as those provided by soil and plant-associated microorganisms presents a promising strategy to reduce dependency on agrochemicals. Biofertilizers are living microbes that enhance plant nutrition by either by mobilizing or increasing nutrient availability in soils. Various microbial taxa including beneficial bacteria and fungi are currently used as biofertilizers, as they successfully colonize the rhizosphere, rhizoplane or root interior. Despite their great potential to improve soil fertility, biofertilizers have yet to replace conventional chemical fertilizers in commercial agriculture. In the last 10 years, multi-omics studies have made a significant step forward in understanding the drivers, roles, processes, and mechanisms in the plant microbiome. However, translating this knowledge on microbiome functions in order to capitalize on plant nutrition in agroecosystems still remains a challenge. Here, we address the key factors limiting successful field applications of biofertilizers and suggest potential solutions based on emerging strategies for product development. Finally, we discuss the importance of biosafety guidelines and propose new avenues of research for biofertilizer development.

Contrasting effects of straw and straw-derived biochar applications on soil carbon accumulation and nitrogen use efficiency in double-rice cropping systems

Increasing cropland soil carbon (C) sequestration and improving crop nitrogen use efficiency (NUE) are vital for sustainable agriculture and environmental protection. The incorporation of straw and application of straw-derived biochar to croplands may help to achieve these goals; however, the long-term effects on soil C sequestration and NUE in double-rice cropping systems are poorly understood. Here, a 6-y field experiment was conducted in a double-rice cropping system to investigate the variations in soil C sequestration and NUE with straw and straw-derived biochar amendments. The treatments were as follows: control with zero nitrogen (N0); conventional chemical fertilizer application (NPK); NPK plus 3 t rice straw dry matter (DM) incorporated per ha−1 season−1 (NPK + LS); NPK plus 6 t rice straw DM incorporated per ha−1 season−1 (NPK + HS); NPK plus 24 t straw-derived biochar DM incorporated per ha−1 (NPK + LC) applied once; and NPK plus 48 t straw-derived biochar DM incorporated per ha−1 (NPK + HC) applied once. Both the straw and biochar additions increased the soil C content in the topsoil, and the NPK + LC treatment sequestered 2.6-fold more soil C than the NPK + HS treatment over the 6-y period, when the input amounts of straw as well as the straw derived C were similar for both treatments. Besides input C directly into the fields, biochar application also increased soil original organic C accumulation in the NPK + LC treatment. Compared with NPK, 50 % and 100 % straw incorporation to the field increased the mean NUE by 22.3 % and 39.8 %, respectively, in the late rice season of 4–6 y, mainly due to increasing soil organic C. Rice grain yields decreased in the early rice season for the first 3 y of the straw treatments but increased in the first season when the biochar was applied, when compared with NPK. However, in the second 3 y after straw application, the grain yield of NPK + HS was significantly higher than that of NPK in late rice season. This investigation has indicated that biochar application had a higher potential in soil carbon sequestration than straw incorporation, and long-term (> 3 y) straw incorporation favored for the enhancement of NUE in paddy fields.

Experimental Study on the Optimal Threshold of Water and Nitrogen Quantities for Tomato Growth under the Irrigation with Biogas Slurry in Greenhouse

HighlightsApplication of biogas slurry can significantly improve the integrated growth, yield, quality of tomatoes.Water-nitrogen coupling model was established based on multi-index evaluation system of tomatoes.The optimal application quantitative range of water and nitrogen was obtained based on the water-nitrogen coupling model.Abstract. Biogas slurry, a liquid organic fertilizer, has been widely used in agricultural production. However, the characteristics of high water content and low fertility make it always applied empirically and a scientific and reasonable application of biogas slurry is urgent needed in practical agricultural production. This study aims to explore the effects of various biogas slurry concentrations on the yield, comprehensive nutritional quality (CNQ), irrigation water use efficiency (IWUE) and partial factor productivity of nitrogen (PFPN) of tomatoes in a greenhouse. Seven treatments, including T1(BS1:4; 0.8Ep), T2 (BS1:6; 0.8Ep), and T3(BS1:8; 0.8Ep), T4(BS1:4; 0.6Ep), T5(BS1:4; 1.0Ep), CK (no fertilization; 1.0Ep), CF (conventional chemical fertilization; 1.0Ep) were set up, where BS1:4, BS1:6,and BS1:8 are the volume ratio of biogas slurry to water, 0.6, 0.8, and 1.0 were crop dish coefficients, respectively. Ep is the evaporation amount of a 20 cm standard evaporating dish. The results showed that appropriate application of biogas slurry had a positive impact on crop growth such as total dry biomass, plant height, stem diameter and finally increased the yields, in which T1 treatment was the best. The fruit yield increased with the increase of biogas slurry ratio for treatments at the same irrigation level of 0.8Ep and the maximum yield of single tomato can reach 5.174 kg. The IWUE increased with the decrease of irrigation for treatments at the same biogas slurry ratio of BS1:4 and T4 treatment had the highest IWUE. The CNQ first increased and then decreased with the increase of biogas slurry ratio under the same irrigation level of 0.8Ep and T2 treatment obtained the highest CNQ; but the PFPN decreased with the increase of biogas slurry ratio and T3 treatment acquired the largest PFPN. Within an 80% confidence interval, when the irrigation amount was in a range of 39.233~43.134 L and the nitrogen quantities was 7.983~8.426 g, the yield, IWUE, CNQ, and PFPN can reach =80% of their maximums at the same time. Taking into account the growth, yield, fruit quality, and water and fertilizer use efficiency, T1 treatment was the best fertigation strategy for a higher production and better quality. The results can provide some help for scientific management of biogas slurry application in greenhouse. Keywords: Biogas slurry, Quality, Spatial analysis method, Tomato (Lycopersicum esculantum Mill), Yield.

Substitution of Conventional Organic and Chemical Fertilization by Some Biostimulants and Their Effect on Growth, Flowering and Bulb Productivity of Narcissus Tazetta Plant.

Substitution of Conventional Organic and Chemical Fertilization by Some Biostimulants and Their Effect on Growth, Flowering and Bulb Productivity of Narcissus Tazetta Plant.

Effects of drought stress on some phytochemical characteristics of rice cultivars under different chemical and organic nutritional sources

To study the phytochemical properties of rice cultivars using different nutrients (chemical and organic) under drought stress, a split-plot factorial experiment with randomized complete block design with three replications at Dasht-e-Naz field in Sari city, in the crop years 2016 and 2017 were repeated. The drought stresses were fully performed in three levels; stress on the time of tillering initiation (15 days after transplanting), in remobilization stage (the end of flowering and the beginning of grain filling stage), and no stress (control) as the main factors in terms of elimination of irrigation and re-irrigation after the appearance of hairy cleavage. The type of nutrition system was considered as the sub-factors in the factorial pattern in terms of four levels of vermicomposting and Azolla compost, in the quantities of 6 and 8 tons per hectare respectively, humic acid (4.5 per one thousand), the conventional chemical fertilizers (Nitrogen, Phosphor, and Potassium), and two cultivars (Shirodi and the local Tarom). The highest proline, CAT, POX, APX, and enzymes ABA were also carried out under drought stress conditions in the remobilization stage using conventional fertilizer (Nitrogen, Phosphor, and Potassium) in the local Tarom cultivar. Therefore, according to this experiment’s results, the local Tarom cultivar, due to increased activity of enzymes under stress conditions, is a tolerant cultivar. One can also consider humic acid’s role in increasing drought tolerance of rice cultivars by reducing the oxidative damage caused by active oxygen species created under drought stress and protecting plants’ physiological processes.

Repurposing distillation waste biomass and low-value mineral resources through biochar-mineral-complex for sustainable production of high-value medicinal plants and soil quality improvement

High cost of synthetic fertilizers and their hazardous effects catapult the exploration of alternative nutrient formulations and soil amendments. This study aimed to synthesize a novel biochar-mineral-complex (BMC), and evaluate its nutrient supplying and soil improvement performances. In a hydrothermal reaction, the BMC was prepared using a biochar derived from distillation waste of Lemongrass (Cymbopogon flexuosus) and farmyard manure, for the first time via fortification with low-grade rock phosphate and waste mica. The BMC showed improved physico-chemical properties and nutrient availability than the pristine biochar. When applied to a deeply weathered acidic soil, the BMC significantly (P < 0.05) improved the herbage and bioactive compound (sennoside) yields of a medicinal plant (senna; Cassia angustifolia Vahl.) compared to the pristine biochar, farmyard manure, vermicompost, and chemical fertilizers. The BMC also improved the soil quality by increasing nutrient and carbon contents, and microbial activities. Soil quality improvement facilitated greater nutrient uptake in senna plants under BMC compared to the pristine biochar, and conventional organic and chemical fertilizer treatments. This study thus encourages the development of BMC formulations not only to overcome the limitation of sole biochar application to soils, but also to phaseout chemical fertilizers in agriculture. Moreover, BMC could bestow resilience and sustainability to crop production via value-added recycling of waste biomass and low-grade mineral resources.

Contrasting short-term responses of soil heterotrophic and autotrophic respiration to biochar-based and chemical fertilizers in a subtropical Moso bamboo plantation

Application of biochar-based fertilizer (BF), produced by combining biochar with chemical fertilizer, is known to be an effective way to increase plant growth and soil organic carbon (SOC) stock, but its impact on soil respiration (RS) components and associated mechanisms in subtropical plantations remain unclear. The objectives of this 12-month field study were (1) to examine the effects of the application of a BF versus a chemical fertilizer (CF) on seasonal variations in soil heterotrophic (RH) and autotrophic (RA) respiration in a subtropical plantation of Moso bamboo (Phyllostachys edulis), and (2) to investigate relationships between soil RH and RA and soil environmental factors in different fertilizer treatments. Four treatments were tested: control (no fertilizer applied), BF application, CF application, and a 50: 50 mixture of BF and CF (BCF). Irrespective of the treatment, both RS and RH exhibited strong seasonal patterns. However, adding CF in the soil significantly increased the soil RH whereas BF decreased it (P < 0.05). Both CF and BF significantly (P < 0.05) increased soil RA. The RS, RH and RA were all exponentially related (P < 0.05) to soil temperature regardless of the treatment, and the Q10 value of RH was greater than that of RA (P < 0.05). Applying CF increased the Q10 for RH (P < 0.05), yet the application of BF did not affect it. Although the RS, RH and RA were not related to the soil moisture content in all treatments, both RS and RH were correlated (P < 0.05) with soil water soluble organic C and microbial biomass C concentrations, and also with soil invertase and β-glucosidase activities. In conclusion, compared with the conventional chemical fertilizer use, the novel management practice of biochar-based fertilizer application offers advantages, such as reducing soil C emissions and increasing SOC content, which has the implication of mitigating soil greenhouse gas emissions in subtropical Moso bamboo plantations.

A review on valorization of oyster mushroom and waste generated in the mushroom cultivation industry

A review of valorization of oyster mushroom species and waste generated in the mushroom cultivation is presented, with a focus on the cultivation and valorization techniques, conditions, current research status and particularly the hazard mitigation and value-added recovery of the waste mushroom substrate (WMS) - an abundant waste in mushroom cultivation industry. Based on the studies reviewed, the production rate of the present mushroom industry is inadequate to meet market demands. There is a need for the development of new mushroom cultivation methods that can guarantee an increase in mushroom productivity and quality (nutritional and medicinal properties). This review shows that the cylindrical baglog cultivation method is more advantageous compared with the wood tray cultivation method to improve the mushroom yield and cost efficiency. Approximately 5 kg of potentially hazardous WMS (spreading diseases in mushroom farm) is generated for production of 1 kg of mushroom. This encourages various valorization of WMS for use in agricultural and energy conversion applications, mainly as biocompost, plant growing media, and bioenergy. The use of WMS as biofertilizer has shown desirable performance compared to conventional chemical fertilizer, whilst the use of WMS as energy feedstock could produce cleaner bioenergy sources compared to conventional fuels.