Search Results (41)

Aquaculture effluents rich in phosphorus and nitrogen (P and N) can lead to eutrophication of aquatic ecosystems. These nutrients may contribute to harmful algal blooms, oxygen depletion, and deterioration of water quality, which poses a threat to aquatic biodiversity. In shrimp diets, environmental impacts from P and N nutrient leaching can be reduced by improving dietary P digestibility through the use of alternative ingredients. While fishmeal, with its high phosphorus content, has traditionally been a primary source, its declining use due to cost and limited availability necessitates the inclusion of inorganic P sources to meet shrimp nutritional requirements. Optimising these sources ensures adequate phosphorus availability while minimising nutrient waste. This study evaluated the effects of inorganic phosphate supplementation (monoammonium phosphate, MAP; monosodium phosphate, MSP; and sodium calcium phosphate, SCP-2%) in standard diets (35% CP) on nutrient digestibility, residue generation, and performance of Litopenaeus vannamei. Results showed that phosphorus digestibility exceeded 96% across all phosphate sources, with MSP achieving the highest values. Calcium digestibility was notably higher in diets containing monocalcium phosphate, such as SCP-2%, which demonstrated superior digestibility values. No significant differences were observed in nitrogen or phosphorus excretion; however, residue analysis revealed that SCP-2% diets generated the lowest nitrogenous waste relative to ingested nitrogen, whereas MAP diets produced the highest nitrogen residues, followed by the Control diet. For phosphorus residues, the Control diet showed the greatest proportion relative to ingested phosphorus, followed by MSP. Phosphate inclusion did not affect shrimp growth, survival, or body composition. However, phosphorus and calcium retention efficiencies were inversely proportional to their dietary content, underscoring the importance of optimising phosphate sources to enhance nutrient utilisation and minimise environmental impact. Full article

In agricultural practice, in addition to determining the nitrogen (N_f) dose, it is necessary to effectively control its effect on currently grown crops. Meeting these conditions requires not only the use of phosphorus (P) and potassium (K), but also nutrients such as magnesium (Mg) and sulfur (S). This hypothesis was verified in a single-factor field experiment with winter wheat (WW) carried out in the 2015/2016, 2016/2017, and 2017/2018 growing seasons. The experiment consisted of seven variants: absolute control (AC), NP, NPK-MOP (K as Muriate of Potash), NPK-MOP+Ki (Kieserite), NPK-KK (K as Korn–Kali), NPK-KK+Ki, and NPK-KK+Ki+ES (Epsom Salt). The use of K as MOP increased grain yield (GY) by 6.3% compared to NP. In the NPK-KK variant, GY was 13% (+0.84 t ha⁻¹) higher compared to NP. Moreover, GYs in this fertilization variant (FV) were stable over the years (coefficient of variation, CV = 9.4%). In NPK-KK+Ki+ES, the yield increase was the highest and mounted to 17.2% compared to NP, but the variability over the years was also the highest (CV ≈ 20%). The amount of N in grain N (GN) increased progressively from 4% for NPK-MOP to 15% for NPK-KK and 25% for NPK-KK+Ki+ES in comparison to NP. The nitrogen harvest index was highly stable, achieving 72.6 ± 3.1%. All analyzed NUE indices showed a significant response to FVs. The PFP-N_f (partial factor productivity of N_f) indices increased on NPK-MOP by 5.8%, NPK-KK by 12.9%, and NPK-KK+Ki+ES by 17.9% compared to NP. The corresponding N_f recovery of N_f in wheat grain was 47.2%, 55.9%, and 64.4%, but its total recovery by wheat (grain + straw) was 67%, 74.5%, and 87.2%, respectively. In terms of the theoretical and practical value of the tested indexes, two indices, namely, NUP (nitrogen unit productivity) and NUA (nitrogen unit accumulation), proved to be the most useful. From the farmer’s production strategy, FV with K applied in the form of Korn–Kali proved to be the most stable option due to high and stable yield, regardless of weather conditions. The increase in the number of nutritional factors optimizing the action of nitrogen in winter wheat caused the phenomenon known as the “scissors effect”. This phenomenon manifested itself in a progressive increase in nitrogen unit productivity (NUP) combined with a regressive trend in unit nitrogen accumulation (NUA) in the grain versus the balance of soil available Mg (Mg_b). The studies clearly showed that obtaining grain that met the milling requirements was recorded only for NUA above 22 kg N t⁻¹ grain. This was possible only with the most intensive Mg treatment (NPK-KK+Ki and NPK-KK+Ki+ES). The study clearly showed that three of the six FVs fully met the three basic conditions for sustainable crop production: (i) stabilization and even an increase in grain yield; (ii) a decrease in the mass of inorganic N in the soil at harvest, potentially susceptible to leaching; and (iii) stabilization of the soil fertility of P, K, and Mg. Full article

Excessive nutrient inputs from manure and synthetic fertilizers have caused great challenges for sustainable vegetable production. There is limited information about the nutritional yields and leaching losses of potassium (K), calcium (Ca), and magnesium (Mg) under various organic–inorganic fertilization practices. We hypothesized that nutritional yields and cation leaching would be influenced by different fertilization practices. A two-year cucumber-cultivating experiment was conducted in North China with the following three treatments: Farmers’ Traditional Practice (FP), based on local farmers’ practices; Current Recommended Nutrient Management (CRNM), based on pieces of literature, bio-organic fertilizer, and kaolin replacing chicken manure in FP; Nutrient Balance Management (DBNM), based on target yields and plant-based amendments replacing bio-organic fertilizers. The nutritional yields of Ca and Mg under CRNM and DBNM were 26.4–39.6% and 20.3–32.5% higher than FP. The K, Ca, and Mg leaching under CRNM were significantly reduced by 41.1%, 18.9%, and 18.5%, compared with FP. Ca leaching under DBNM was further significantly reduced by 7.9%. A significant negative relationship was observed between the leaching losses of K, Ca, and Mg and the surface soil pH (0–20 cm). These findings suggest that DBNM could play an important role in obtaining higher nutritional yields, reducing leaching losses, and alleviating soil acidification in vegetable production. Full article

Nitrogen (N) is an essential nutrient for crop growth, as N fertilizer application regulates crop nitrogen uptake, affecting leaf photosynthetic rates, crop growth, and yield formation. However, both N deficiency and excess can reduce corn yields. Hence, optimizing the N fertilizer application strategy is crucial for crop production. In this study, a field plot trial with five N fertilization application strategies was conducted in the maize field from 2021 to 2022 in the Ningxia Yellow Irrigation District, Northwest China. These strategies contain zero N application rates (CK, 0 kg ha⁻¹), the farmer practical N fertilizer application strategy (FP, 420 kg ha⁻¹), the optimized N fertilizer application strategy (OPT, 360 kg ha⁻¹), organic fertilizer and chemical fertilizer combination application (ON, 300 kg ha⁻¹), and controlled-release N fertilizer and 33 urea application (CN, 270 kg ha⁻¹). The maize yield and N balance under each treatment were investigated to propose the optimized N application strategy. The results showed that the CN treatment’s grain yield (15,672 kg ha⁻¹) was the highest in both years, which was 109.97% and 8.92% higher than the CK and FP treatments, respectively. The apparent utilization rate and partial productivity of N fertilizer decreased with the increase in the N application rate. Also, the apparent utilization rate of N fertilizer in CN was 23.02%, 19.41%, and 13.02% higher than the FP, OPT, and ON, respectively. Applying controlled-release urea and organic fertilizers improved the physical and chemical properties of the soil, increased the organic matter content and soil fertility, and ultimately increased the spring maize yield. Meanwhile, the TN, NO₃⁻-N, and NH₄⁺-N concentrations in leaching water significantly correlated with the N application rate. With the extension of the maize growth period, the concentrations of TN, NO₃⁻-N, and NH₄⁺-N in leaching water gradually decreased. The N leaching amount in FP was the highest, while the CN was the lowest. The NO₃⁻-N is the primary N leaching form, accounting for 46.78~54.68% of the TN leaching amount. Compared with the CN, the ON significantly increased the inorganic N content in the 0–40 cm soil layer, and it reduced the residual inorganic N content below 40 cm soil depths compared with FP and OPT treatments. Considering the relatively high spring maize yield and N utilization efficiency, as well as the relatively low N leaching amount and soil inorganic N residues, the ON and CN treatments with 270–300 kg ha⁻¹ N application rate were the optimized N application strategies in the spring maize field in the study area. Full article

The application of slow-release fertilizers is essential for improving fertilizer utilization efficiency and promoting sustainable agricultural development. Unlike traditional single organic polymer-coated or inorganic-coated fertilizers, this study utilized biodegradable modified polyvinyl alcohol (PVA) as a binder and cheap, readily available phosphogypsum–bentonite as an inorganic coating material to develop a novel slow-release potassium magnesium sulfate fertilizer (SRPMSF). This study initially examined the influence of SA dosage on PVA properties. XRD, FTIR, TGA, and water resistance analyses revealed that sodium alginate exhibits good compatibility with polyvinyl alcohol, enhancing its heat and water resistance. Ultimately, PVA–SA-2 (1.2% sodium alginate) was chosen as the optimal binder for SRPMSF production. Furthermore, this study investigated the impact of bentonite on the physical and slow-release properties of the SRPMSF by varying the phosphogypsum-to-bentonite ratio. This experiment included five treatment methods: the treatments consist of SRPMSF-1 (0 g bentonite), SRPMSF-2 (phosphogypsum/bentonite ratio of 4:1), SRPMSF-3 (3:2), SRPMSF-4 (2:3), and SRPMSF-5 (1:4). A control group (PMSF) was also included. The results indicated that, as the bentonite content increased, both the particle size and compressive strength of the coated slow-release fertilizer increased, with the SRPMSF particle sizes ranging from 3.00 to 4.50 mm. The compressive strength of the SRPMSF ranged from 20.85 to 43.78 N, meeting the requirements for industrial production. The soil column leaching method was employed to assess the nutrient release rate of the fertilizers. The experimental results indicated that, compared to the PMSF, the SRPMSF effectively regulated nutrient release. Pot experiments demonstrated that the SRPMSF significantly enhanced garlic seedling growth compared to the PMSF. In conclusion, a new type of slow-release fertilizer with good slow-release performance is prepared in this paper, which can improve the utilization rate of fertilizer and reduce the economic loss and is conducive to the sustainable development of agriculture. Full article

In modern agriculture, fertilizers are commonly used to increase crop yields; however, their negligent use can lead to environmental pollution and the waste of essential nutrients such as inorganic phosphate (Pi). Encapsulated fertilizers are a feasible alternative that could prevent these issues, as they can protect Pi from leaching and extend the interval between applications. In this study, we developed and tested innovative fertilizers (IFs) manufactured with KH₂PO₄, encapsulated with chitosan modified via high-frequency ultrasound treatment. The characterization of these fertilizers consisted of Fourier-transform infrared spectroscopy analysis and scanning transmission electron microscopy to determine their sizes and forms. In addition, we evaluated the phosphate release profile using electrical conductivity. The IFs were spheroidal microcapsules with an average diameter of 0.5–2 μM and showed slow-release behavior. Their efficacy was assessed via in vivo and in vitro assays, using Arabidopsis thaliana as a study model. As expected, the IFs promoted the growth of seedlings. One of the IFs showed enhanced growth promotion, contrasting with the control. This phenotype was likely promoted by this fertilizer due to the synergistic effect of Pi and the modified chitosan used as an encapsulant matrix. Our results highlight the potential of these formulations, which have unique properties and could be used on a large scale. Full article

Biochar is a carbon-rich material that has recently received attention due to its increasing agronomical potential. The agricultural utilization of biochar relates to its potential to act in the soil as a soil conditioner; nevertheless, complex information on the direct dependence of biochar’s physical properties (texture, particle size) and corresponding leaching and availability of organic molecules (e.g., the polycyclic and heterocyclic organic compounds) and inorganic mineral salts (based on micro- and macroelements) is still inconsistent. Multi-elemental analysis by using inductively coupled plasma atomic emission spectroscopy (ICP-OES) was used to assess the information on the contents and availability of macro- and microelements in studied commercial biochar samples. The results showed a statistically significant indirect relation between an increase in the size fraction of biochar and the content of aqueous-extractable K and Na and the direct relation with the aqueous-extractable Ca, Mg, and P. Compared to the macroelements, the detected contents of aqueous-extractable microelements were almost three orders lower, and the dependence on fraction size was not consistent or statistically significant. In addition, gas chromatography (GC) coupled with mass spectroscopy (MS) was further used to reveal the concentrations of available polycyclic aromatic and heterocyclic compounds in biochar samples. The detected concentrations of these types of organic compounds were far below the certified limits, and a statistically significant indirect correlation with particle size was also observed for all the studied biochar samples. The proposed methodological concept could provide the necessary insights into the description of biochar mineral content and its connection to biochar texture, the physicochemical properties, and the potential of biochar to release nutrients into the soil. These findings could help in the further assessment of biochar as a soil conditioner in modern agriculture. Full article

In order to address the increasingly prominent issues of water resource protection and agricultural non-point source pollution in the Erhai Lake Basin, this study conducted a two-year field experiment in Gusheng Village, located in the Erhai Lake Basin. In 2022, two irrigation treatments were set up: conventional flooding irrigation (CK) and controlled irrigation (C), with three replicates for each treatment. In 2023, aiming to enhance the utilization rate of rainwater resources and reduce the direct discharge of dry-farming tailwater from upstream into Erhai Lake. The paddy field was used as an ecological storage basin, and the water storage depth of the paddy field was increased compared to the depth of 2022. Combined with the deep storage of rainwater, the dry-farming tailwater was recharged into the paddy field to reduce the drainage. In 2023, two water treatments, flooding irrigation with deep storage and controlled drainage (CKCD) and water-saving irrigation with deep storage and controlled drainage (CCD) were set up, and each treatment was set up with three replicates. The growth and physiological index of rice at various stages were observed. Nitrogen leaching of paddy field in surface water, soil water, and groundwater under different water treatments after tillering fertilizer were observed. The research results show that the combined application of organic and inorganic fertilizers under organic planting can provide more reasonable nutrient supply for rice, promote dry matter accumulation and other indices, and also reduce the concentration of NH₄⁺-N in surface water. Compared with CK, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of C are increased by 4.8%, 4.1%, 20.9%, and 9.7%, respectively. Compared with CKCD, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of CCD are increased by 6.5%, 3.8%, 19.6%, and 21.9%, respectively. The yield in 2023 is 19% higher than that in 2022. Treatment C can increase the growth indicators and reduce the net photosynthetic rate to a certain extent, while CCD rain-flood storage can alleviate the inhibition of low irrigation lower limit on the net photosynthetic rate of rice. Both C and CCD can reduce nitrogen loss and irrigation amount in paddy fields. CCD can reduce the tailwater in the Gusheng area of the Erhai Lake Basin to Erhai Lake, and also can make full use of N, P, and other nutrients in the tailwater to promote the formation and development of rice. In conclusion, the paddy field rain-flood storage methodology in the Erhai Lake Basin can promote various growth and physiological indicators of rice, improve water resource utilization efficiency, reduce direct discharge of tailwater into Erhai Lake, and decrease the risk of agricultural non-point source pollution. Full article

Nitrogen cycling in pasture soils differing in drainage characteristics and fertilization legacy needs more research to determine efficient nutrient management strategies. This study compared differences in nitrate (NO₃⁻), ammonium (NH₄⁺), inorganic N (IN = NO₃⁻ + NH₄⁺), potentially mineralizable nitrogen (PMN), loss-on-ignition carbon (C), and soil pH in 10, 0.7 ha pastures in Eatonton, Georgia, historically fertilized with the same amount of N as either broiler litter (BL; >15 years, 6 pastures) or mineral fertilizer (Min; 4 pastures). We sampled to 90 cm (0–5, 5–10, 10–20, 20–40, 40–60, and 60–90 cm) on a 20 m grid. An analysis of variance indicated that below 5 cm BL pastures had significantly greater amounts of NO₃⁻, IN, PMN, and soil pH compared to Min pastures. Comparisons of drainage classes (well drained~WD, moderately well drained~MWD, and somewhat-poorly drained~SPD) for each BL and Min were analyzed using linear regression for C:IN, C:PMN, pH: NO₃⁻, and pH: NH₄⁺ with all depths combined. In MWD soils, BL had 0.1 and 0.2 mg N kg⁻¹ greater PMN and IN, respectively, for each unit increase in C. In WD soils NO₃⁻ decreased in BL by 7.4 and in Min by 12.1 mg N kg⁻¹, while in MWD soils, this level decreased in BL by 7.8 and in Min by 4.5 mg N kg⁻¹ for each pH unit. Five years after N fertilization stopped, BL soils have retained more inorganic N but are losing more NO₃⁻ at a greater rate in the MWD soils when all depths are considered. These losses are a combination of plant uptake, emissions, runoff and leaching. While more research is needed, these results strongly suggest the need to design N fertilization practices with drainage class and fertilization legacy in mind to improve N-use efficiency. Full article

The intricate processes of surface water erosion are vital for ecological systems and river-scale management; yet, understanding them comprehensively remains a challenge. Forested agricultural catchments, especially in the Carpathian region, face significant degradation, potentially leading to inorganic nutrient leaching and total suspended solid (TSS) flux. Continuous rainwater inundation of soils in river valleys exacerbates this issue. Utilizing innovative tools like SWAT+, studies have revealed higher concentrations of inorganic nutrients in main watercourses from flysch catchments, with agricultural use linked to N-NO₃⁻ concentrations and pasture use linked to anion P-PO₄³⁻. Maintaining detailed records is crucial for researchers comparing data. SWAT+ proves valuable for studying TSS washing out and inorganic nutrient leaching, informing collaborative watershed management policies involving stakeholders from agriculture, conservation, and water management sectors. The insights on nutrient leaching, particularly phosphorus (P) and nitrogen (N), are instrumental for shaping policies targeting nutrient pollution within pasture land use for EU agriculture. These findings can guide policy frameworks focused on sustainable practices, especially for eco-schemes, and encourage collaborative watershed management efforts. Full article

Due to containing an abundance of essential nutrients, straw has significant potential to mitigate carbon (C), nitrogen (N), phosphorus (P), and potassium (K) deficits in soil. However, a lack of comprehensive and systematic reviews on C, N, P, and K release and conversion from straw and on the impact of available nutrients in soils supplemented using straw-returning (SR) practices is noticeable in the literature. Therefore, we investigated straw decomposition, its nutrient release characteristics, and the subsequent fate of nutrients in soils. At early stages, straw decomposes rapidly and then gradually slows down at later stages. Nutrient release rates are generally in the K > P > C > N order. Nutrient fate encompasses fractions mineralized to inorganic nutrients, portions which supplement soil organic matter (SOM) pools, and other portions which are lost via leaching and gas volatilization. In future research, efforts should be made to quantitatively track straw nutrient release and fate and also examine the potential impact of coordinated supply-and-demand interactions between straw nutrients and plants. This review will provide a more systematic understanding of SR’s effectiveness in agriculture. Full article

This study aimed to evaluate the effects of plant growth-promoting Rhizobacteria (PGPR) treatments, B1, Azosprillium lipoferum Sp2 and B2, A. lipoferum Sp2 + Pseudomonas sp. SARS12, as well as inorganic nitrogen doses (60, 100, 140 and 180 kg N ha^–1) on some soil physical characters, physiological, anatomical and yield parameters as well as nitrogen use efficiency (NUE) of wheat under water deficit stress. Results showed that water stress significantly decreased physiological characters such as chlorophyll content (6.7 and 9.8%) and relative water content (13.7 and 11.2%) in both seasons, respectively. Nevertheless, proline and malondialdehyde (MDA) were increased significantly (26.9, 12.3% and 90.2, 96.4%) in both seasons, respectively, as signals for water stress. The anatomical characteristics of flag leaves were negatively affected. Inoculation of wheat grains with PGPR significantly increased field capacity and RWC, adjusted enzymes’ activity and thus improved the physiological and yield traits and NUE as well as improving the anatomical features of flag leaves. Moreover, the combination of integrated PGPR and 140 kg N ha⁻¹ significantly improved grain yield and its components as well as grain N uptake in comparison to control treatments. In conclusion, PGPR improved wheat productivity and NUE; they are an eco-friendly and cost-effective approach for improving plant production, and reducing nutrient leaching hazards and the negative impact of water stress. Full article

Tire-derived aggregate (TDA) is an entirely recycled material created by processing scrap tires, which are shredded into a fundamental geometric shape, typically measuring from 5 to 30 cm in size. TDA possesses desirable properties such as low earth pressure, improved drainage, and a lightweight structure, making it an ideal material for numerous civil engineering applications. Unfortunately, the environmental suitability of TDA use has previously been questioned. This article outlines that TDA does not release a significant amount of potentially toxic compounds, the leaching rate in surrounding water environments is low, and TDA can even be a medium to remove nutrients and toxic organic and inorganic compounds commonly found in agricultural land and urban runoff. This study aims to collect the most up-to-date scientific data on the environmental impact of scrap tires and evaluate the data specifically for TDA applications in civil and environmental engineering applications. TDA has been proven to be an environmentally safe, long-lasting, cost-effective, and sustainable resource with many potential applications in civil engineering. Guidelines should be developed for specific projects to achieve a circular economy for end-of-life tires in the form of TDA to avoid potential environmental issues and problems. Full article

Biochar has been widely reported to improve soil conditions and affect plant growth. However, its effectiveness is limited by soil type and production technology. Considering the application effect of biochar in saline alkali soil, there is currently a lack of in-depth mechanism explanations in the research. Therefore, we designed an experiment to explore the effect of biochar on plant growth in saline alkali soil and conducted soil column experiments in a greenhouse environment using composite inorganic fertilizer (NPK). The results showed that biochar significantly affected the distribution of soil nutrient content at different depths, with a significant increase in fertility levels in the surface and middle layers and a decrease in fertility levels in deep soils. Compared to using fertilizers alone, the combined use of biochar and fertilizers further expands the enrichment effect and significantly reduces the leaching of fertilizers into deeper layers. At the same time, the application of biochar also improved soil properties, including an increase in electrical conductivity and organic matter content, as well as an increase in soil enzyme activity. On the other hand, the application of biochar also increases the activity of antioxidant enzymes and the content of osmoregulation substances in plants, reducing the environmental stress that plants are subjected to. Therefore, our results indicate that biochar can reduce the leaching of fertilizers into deep soil layers, improve soil properties, and promotes the growth of Miscanthus in saline alkali soils. Full article

Most water systems that support ecosystems and feed humans are depleted or stressed. Aquifer characteristics, topography, subsurface activities, climate, and geochemical processes regulate groundwater availability, a reliable source of fresh water. Globally, agriculture, industries, and the domestic sector are the three major sectors that consume vast quantities of freshwater resources. Further anthropogenic activities, such as soil leaching, acid rain, fertilizer, pesticides, mining, and other industrial activities, resulted in the release of organic and inorganic pollutants that affected global water resources. In India, groundwater is used in huge quantities, resulting in groundwater depletion of 1 to 2 m a year. Low-income countries face many issues related to water pollution, and the availability of safe water is minimal. In 2019, deaths due to unsafe sanitation accounted for 2.2% of the total global deaths, amounting to 1.2 million people’s deaths. India recorded 6.6% of deaths due to unsafe sanitation in 2019. India and China accounted for around 90.41% and 60.4% of the groundwater utilization for agricultural purposes, respectively. In 2020, China and India utilized vast quantities of nutrients (nitrate and phosphate) for crop growth to enhance crop yield, resulting in the highest nitrate and phosphate concentrations in groundwater. Remediating contaminants from different sources requires knowledge of their concentration, behavior, cycling, and degradation pathways. According to safety guidelines, limiting and optimizing crop organic and inorganic fertilizer, pesticide waste disposal, and empty container disposal can reduce groundwater contamination. The present study summarized groundwater utilization in various sectors, potential sources of groundwater contamination impacts on human health and the environment, preventive measures, and mitigation methods to overcome groundwater pollution. Full article