Controlled-release Fertilizer Application Research Articles

Effects of drip irrigation coupled with controlled release potassium fertilizer on maize growth and soil properties

Drip irrigation and the application of controlled-release fertilizers are two effective and important technical measures to conserve water and fertilizer resources and promote the growth and development of maize. However, the underlying physiological mechanism of how drip irrigation combined with controlled release potassium chloride affects maize production and soil properties remains unknown. In different soil water conditions, pot experiments were conducted during the summer maize growing season in 2022 and 2023 to measure maize grain yield, irrigation water productivity, apparent recovery efficiency of potassium, plant physiological characteristics, and soil enzyme activities under the coupling of two irrigation methods (flood irrigation and drip irrigation) and three potassium fertilizer types (potassium chloride (KCl), controlled release potassium chloride (CRK), and 70 % CRK mixed with 30 % KCl). The results revealed that drip irrigation had 6.5–8.1 % and 6.7–9.4 % higher average soil volumetric water content and 3.8–8.1 % and 4.5–13.0 % higher irrigation water productivity than flood irrigation in the two maize growth seasons, respectively. Under the drought conditions, the treatments of 70 % CRK-30 % KCl application led to a significant increase in maize yield by 9.5–10.7 % and 12.2–16.8 % and apparent recovery efficiency of potassium by 8.3–14.2 % and 10.7–10.8 % compared to CRK application treatments in 2022 and 2023, respectively. Compared with the other treatments, the treatment of drip irrigation coupled with 70 % CRK-30 % KCl application under drought conditions (DIDMK) resulted in 4.5–28.7 % and 1.1–31.9 % higher grain yield, 8.2–64.4 % and 8.6–66.8 % higher irrigation water productivity, and 5.9–28.0 % and 6.7–18.9 % higher apparent recovery efficiency of potassium in 2022 and 2023, respectively. Meanwhile, the leaf net photosynthetic rate, rubisco, catalase, peroxidase, and soil enzyme activities of DIDMK treatment were also maintained at a high level. Our results indicated that drip irrigation coupled with 70 % CRK-30 % KCl application were the optimal water and potassium supply modes for maize production. This study can provide useful information regarding summer maize sustainable production and provide theoretical and technical support for summer maize irrigation and potassium fertilizer application technologies in water-scarce regions of China and other similar regions around the world.

Effects of Controlled-release Blended Fertilizer on Crop Yield and Greenhouse Gas Emissions in Wheat-maize Rotation System

The increasing use of nitrogen fertilizers exerts extreme pressure on the environment (e.g., greenhouse gas emissions, GHGs) for winter wheat-summer maize rotation systems in the North China Plain. The application of controlled-release fertilizers is considered as an effective measure to improve crop yield and nitrogen fertilizer utilization efficiency. To explore the impact of one-time fertilization of controlled-release blended fertilizer on crop yield and GHGs of a wheat-maize rotation system, field experiments were carried out in Dezhou Modern Agricultural Science and Technology Park from 2020 to 2022. Five treatments were established for both winter wheat and summer maize, including no nitrogen control (CK), farmers' conventional nitrogen application (FFP), optimized nitrogen application (OPT), CRU1 (the blending ratio of coated urea and traditional urea on winter wheat and summer maize was 5:5 and 3:7, respectively), and CRU2 (the blending ratio of coated urea and traditional urea on winter wheat and summer maize was 7:3 and 5:5, respectively). The differences in yield, nitrogen fertilizer utilization efficiency, fertilization economic benefits, and GHGs among different treatments were compared and analyzed. The results showed that nitrogen application significantly increased the single season and annual crop yields of the wheat-maize rotation system (P < 0.05). Compared with those of FFP, the CRU1 and CRU2 treatments increased the yields of summer maize by 0.4% to 5.6%, winter wheat by -5.4% to 4.1%, and annual yields by -1.1% to 3.9% (P > 0.05). N recovery efficiency (NRE), N agronomic efficiency (NAE), and N partial factor productivity (NPFP) were increased by -8.6%-43.4%, 2.05-6.24 kg·kg-1, and 4.24-10.13 kg·kg-1, respectively. Annual net income increased by 0.2% to 6.3%. Nitrogen application significantly increased the annual emissions of soil N2O and CO2 in the rotation system (P < 0.05) but had no effect on the annual emissions of CH4 (except for in the FFP treatment in the first year). The annual total N2O emissions under the CRU1 and CRU2 treatments were significantly reduced by 23.4% to 30.2% compared to those under the FFP treatment (P < 0.05). Additionally, nitrogen application significantly increased the annual global warming potential (GWP) of the rotation system (P < 0.05), but the intensity of greenhouse gas emissions was reduced due to the increase in crop yields. Compared with that under FFP, the annual GWP under the CRU1 and CRU2 treatments decreased by 9.6% to 11.5% (P < 0.05), and the annual GHGs decreased by 11.2% to 13.8% (P > 0.05). In summary, the one-time application of controlled-release blended fertilizer had a positive role in improving crop yield and economic benefits, reducing nitrogen fertilizer input and labor costs, and GHGs, which is an effective nitrogen fertilizer management measure to promote cleaner production of food crops in the North China Plain.

Eco-friendly cellulose hydrogels as controlled release fertilizer for enhanced growth and yield of upland rice

The effect of urea-loaded cellulose hydrogel, a controlled-release fertilizer (CRF) on growth and yield of upland rice were investigated in upland rice. As with the initial research, nitrogen (N) treatments were applied as CRF treatments; T2H (30 kg N ha−1), T3H (60 kg N ha−1), T4H (90 kg N ha−1), T5H (120 kg N ha−1) and recommended dose of fertilizer (RDF) at 120 kg N ha−1 RDF (T6U) in split application and T1 (0 N) as control. Results from this study indicated that applying CRF at the optimum N rate, T4H resulted in maximum grain yield, increasing by 71%. The analysis of yield components revealed that higher grain yield in T4H CRF was associated with an increase in panicle number and number of grains per panicle. Maximum grain N uptake of 0.25 g kg−1 was also observed in T4H CRF. In addition, T4H CRF recorded the highest harvest index (HI) and N harvest index (NHI) of 45.5% and 67.9%, respectively. Application of T4H CRF also recorded the highest N use efficiency (NUE) and N agronomic efficiency (NAE), 52.6% and 12.8 kg kg−1, respectively. Observations show that CRF with only 75% N applied (T4H) in soil improved grain yield when compared to CRF with 100% N and 100% RDF in farmers’ conventional split application. This suggested that CRF with a moderate N application might produce the highest potential yield and improved N efficiencies while enhancing crop production and further increase in N supply did not increase yield and N efficiencies. The results suggest that the application of T4H CRF for upland rice would enhance HI, N efficiencies and improve the yield of upland rice. Also, all growth parameters and yield were positively influenced by the application of CRF as a basal dose compared to split application of conventional urea fertilizers.

Soil Bacteriome Resilience and Reduced Nitrogen Toxicity in Tomato by Controlled Release Nitrogen Fertilizer Compared to Urea

Controlled release fertilizers (CRFs) mitigate negative effects of high nitrogen (N) fertilization rates, such as N toxicity and soil N loss. However, it is unknown if potentially toxic rates of CRF and quick release fertilizer differentially affect soil bacterial communities. To examine potential N toxicity effects on soil microbial communities, we grew tomato (Solanum lycopersicum “Rutgers”) for eight weeks in soils that were fertilized with high levels of quick release or controlled release urea and in soils with either low or high initial microbial N competitor populations. In both soils, we observed N toxicity in urea-fertilized tomatoes, but toxicity was ameliorated with CRF application. Controlled release fertilization increased soil N retention, thereby reducing soil N loss. While N toxicity symptoms manifested in the plant, the soil microbiome was only minorly affected. There were subtle differences in soil bacterial populations, in which nitrifying bacteria accumulated in soils fertilized at high N rates, regardless of the type of N fertilizer used. Ultimately, CRF reduced plant N toxicity symptoms but did not change the soil microbiome compared to quick release urea. These results show that while there are clear benefits of CRF regarding N toxicity tolerance on crops, the soil microbiome is resilient to this abiotic stressor.

Mineral Nitrogen Release Patterns in Various Soil and Texture Types and the Impact of Urea and Coated Urea Potassium Humate on Barley Biomass

Controlled-release urea fertilization is an innovative approach and effective means to reduce the loss of nitrogen and enhance fertilizer use efficiency to optimize crop yield while minimizing the environmental impact. The objective of this study was to investigate the dynamic process of mineral nitrogen (Nmin) release in Luvisols, Cambisols, Retisols, and Arenosols to understand the interaction between soil characteristics and mineral nitrogen release and evaluate the impact of conventional urea compared to coated urea potassium humate on barley biomass production. A pot experiment was conducted under glasshouse conditions (20 ± 2 °C and 60% Humidity). Five treatments including no fertilization as a control (C), 100 kg·N·ha−1 of urea (U100), 200 kg·N·ha−1 of urea (U200), 100 kg·N·ha−1 of coated urea potassium humate (UPH100), and 200 kg·N·ha−1 of coated urea potassium humate (UPH200) were applied to four soil and texture types. Our findings indicate that there are different patterns of mineral nitrogen release across the different soil and texture types. Ammonium levels reached their peak point in all soils within 2–7 days after application. On the other hand, the concentration of nitrate NO3−–N showed a linear increase over 45 days during the experiment. The Retisol, which had a sandy clay texture, obtained the highest concentration of mineral nitrogen in both forms (NH4 and NO3), while the sandy texture of Arenosol showed the lowest accumulation of mineral nitrogen and its forms. The application of potassium humate caused a delay of 1–4 days in the peak of soil ammonium, which at peak accounted for approximately 25–44% of the mineral nitrogen in the soil. Furthermore, the application of urea and coated urea potassium humate exhibited significant effects on barley biomass with an increase of approximately 14–91% compared to the unfertilized treatment (control). This research contributes to our understanding of nutrient dynamics in diverse soil environments and provides insights into optimizing sustainable fertilization strategies such as controlled-release fertilizer application. The implications of these findings highlight the significance of tailored nutrient management practices based on soil texture type, which can lead to improved agricultural productivity and environmental impact.

Integrating the Soil Microbiota and Metabolome Reveals the Mechanism through Which Controlled Release Fertilizer Affects Sugarcane Growth.

Root-soil underground interactions mediated by soil microorganisms and metabolites are crucial for fertilizer utilization efficiency and crop growth regulation. This study employed a combined approach of soil microbial community profiling and non-targeted metabolomics to investigate the patterns of root-associated microbial aggregation and the mechanisms associated with metabolites under varying controlled-release fertilizer (CRF) application rates. The experimental treatments included five field application rates of CRF (D1: 675 kg/ha; D15: 1012.5 kg/ha; D2: 1350 kg/ha; D25: 1687.5 kg/ha; and D3: 2025 kg/ha) along with traditional fertilizer as a control (CK: 1687.5 kg/ha). The results indicated that the growth of sugarcane in the field was significantly influenced by the CRF application rate (p < 0.05). Compared with CK, the optimal field application of CRF was observed at D25, resulting in a 16.3% to 53.6% increase in sugarcane yield. Under the condition of reducing fertilizer application by 20%, D2 showed a 13.3% increase in stem yield and a 6.7% increase in sugar production. The bacterial ACE index exhibited significant differences between D25 and D1, while the Chao1 index showed significance among the D25, D1, and CK treatments. The dominant bacterial phyla in sugarcane rhizosphere aggregation included Proteobacteria, Actinobacteriota, and Acidobacteriota. Fungal phyla comprised Rozellomycota, Basidiomycota, and Ascomycota. The annotated metabolic pathways encompassed biosynthesis of secondary metabolites, carbohydrate metabolism, and lipid metabolism. Differential analysis and random forest selection identified distinctive biomarkers including Leotiomycetes, Cercospora, Anaeromyxobacter, isoleucyl-proline, and methylmalonic acid. Redundancy analysis unveiled soil pH, soil organic carbon, and available nitrogen as the primary drivers of microbial communities, while the metabolic profiles were notably influenced by the available potassium and phosphorus. The correlation heatmaps illustrated potential microbial-metabolite regulatory mechanisms under CRF application conditions. These findings underscore the significant potential of CRF in sugarcane field production, laying a theoretical foundation for sustainable development in the sugarcane industry.

Long-term application of controlled-release fertilizer enhances rice production and soil quality under non-flooded plastic film mulching cultivation conditions

Agricultural practices that integrate plastic film mulching (PM) cultivation and controlled-release urea have been widely used to conserve water and increase crop yields. The interactive responses of rice productivity and soil quality to long-term plastic film mulching cultivation and controlled-release urea have not yet been comprehensively elucidated, and whether or not plastic film mulching cultivation combined with controlled-release urea is suitable for rice production remains unclear. A 12-year field experiment with two water regimes (continuously flooded [CF] and PM) and three nitrogen (N) fertilization treatments (no N fertilizer, urea, and controlled-release urea) was conducted to explore the long-term effects on rice yield, soil physicochemical and biological properties, and soil quality in a single rice cropping system. Compared to continuously flooded system, the plastic film mulching system maintained rice productivity (CF: 6.9 t ha−1; PM: 7.1 t ha−1) with higher water productivity (CF: 0.9 g L−1; PM: 2.0 g L−1). Controlled-release urea treatments improved rice yield by 11.9% and 44.6% compared to treatments with urea and no N fertilizer, respectively. Random forest analysis indicated that enzyme activity was the main factor affecting rice yield. Compared to continuously flooded system, the plastic film mulching system significantly increased soil pH by 3.4% and decreased soil organic matter content by 9.3%. Moreover, the plastic film mulching system exhibited significantly higher enzyme activity than the continuously flooded system. Principal coordinate analysis of enzyme activities showed that N fertilization influenced enzyme activities considerably more than water regime. According to Pearson’s analysis, soil fungal alpha diversity was more sensitive to soil physicochemical properties than bacterial alpha diversity. Overall, treatment with controlled-release urea in the plastic film mulching system resulted in the highest soil quality index values, which were positively correlated with rice yield (R2 = 0.61, p = 0.000). The positive direct effects induced by continuously flooded cultivation (i.e., satisfying the water requirements of rice) were counterbalanced by the negative indirect effects of altered enzyme activity. The N fertilizer type indirectly influenced rice yield by altering soil nutrients, enzyme activity, and microbial diversity. Therefore, controlled-release urea could maintain rice production with high soil quality under non-flooded plastic film mulching cultivation conditions.

Production of Beauregard Sweet Potato in vertical farming under different fertilization technologies

Ipomoea batatas, popularly known as sweet potato, is a species of the Convolvulaceae family, with probable origin between Mexico and northern South America. Among the genotypes with economic potential, the biofortified cultivar Beauregard (Ipomoea batatas) stands out due to its rusticity and easy handling. Controlled-release fertilizers were mostly used in studies developed in other countries, and their study being necessary in Brazilian soil and climatic conditions. This study aimed to evaluate the development of Beauregard biofortified cultivar, submitted to different fertilization technologies in vertical farming system. The plantlets received different doses of controlled-release fertilizer: 0.0 (control); 30; 60; 90; 120g and a dose of 40g per pit of NPK 13-13-28 of ready solubility. At 180 days, biometric and production parameter data were collected and submitted to regression analysis and variance analysis followed by the Scott-Knott test for mean separation. The application of controlled-release fertilizer showed a positive effect on the production of the studied cultivar, favoring the performance of the plants and promoting the increase especially in height, length of branches and number of leaves. The base application of controlled-release fertilizer at a dose of 30g per plant and traditional NPK fertilizer at a dose of 40g per plant promote higher yields of dry mass of shoots and root when compared to unfertilized plants in the cultivation of sweet potatoes in vertical farming.

Assessment of Nutrient Leaching Losses and Crop Uptake with Organic Fertilization, Water Saving Practices and Reduced Inorganic Fertilizer

The increasing world population has forced excessive chemical fertilizer and irrigation to complete the global food demand, deteriorating the water quality and nutrient losses. Short-term studies do not compile the evidences; therefore, the study aimed to identify the effectiveness of reduced doses of inorganic fertilizer and water-saving practices, hence, a six-year experiment (2015–2020) was conducted in China to address the knowledge gap. The experimental treatments were: farmer accustomed fertilization used as control (525:180:30 kg NPK ha−1), fertilizer decrement (450:150:15 kg NPK ha−1), fertilizer decrement + water-saving irrigation (450:150:15 kg NPK ha−1), application of organic and inorganic fertilizer + water-saving irrigation (375:120:0 kg NPK ha−1 + 4.5 tones organic fertilizer ha−1), and application of controlled-release fertilizer (80:120:15 kg NPK ha−1). Each treatment was replicated thrice following a randomized complete block design. The results achieved herein showed that control has the highest losses in the six-year study for total nitrogen (225.97 mg L−1), total soluble nitrogen (121.58 mg L−1), nitrate nitrogen (0.93 mg L−1), total phosphorus (0.57 mg L−1), and total soluble phosphorus (0.57 mg L−1) respectively. Reduced fertilizer and water application improved crop nutrient uptake, nitrogen concentration was significantly enhanced with organic and inorganic fertilizer + water-saving irrigation, P concentration was increased with fertilizer decrement + water-saving irrigation, and K concentration was improved with fertilizer decrement + water-saving irrigation. Hence, this study concludes that reduced inorganic fertilizer dose combined with water-saving practices is significantly helpful in reducing nutrient leaching losses and improving nutrient uptake and water pollution. Further studies are needed to explore the impacts of reduced fertilization and water-saving irrigation on leaching losses. The benefits at different climatic conditions, soil types, and fertilizer types with application methods are also a research gap.

Evaluating the Effects of Sustainable Chemical and Organic Fertilizers with Water Saving Practice on Corn Production and Soil Characteristics

The rapidly growing world population, water shortage, and food security are promising problems for sustainable agriculture. Farmers adopt higher irrigation and fertilizer applications to increase crop production resulting in environmental pollution. This study aimed to identify the long-term effects of intelligent water and fertilizers used in corn yield and soil nutrient status. A series of field experiments were conducted for six years with treatments as: farmer accustomed to fertilization used as control (CON), fertilizer decrement (KF), fertilizer decrement + water-saving irrigation (BMP1); combined application of organic and inorganic fertilizer + water-saving irrigation (BMP2), and combined application of controlled-release fertilizer (BMP3). A significant improvement was observed in soil organic matter (14.9%), nitrate nitrogen (106.7%), total phosphorus (23.9%), available phosphorus (26.2%), straw yield (44.8%), and grain yield (54.7%) with BMP2 treatment as compared to CON. The study concludes that integrating chemical and organic fertilizers with water-saving irrigation (BMP2) is a good approach to increasing corn productivity, ensuring water safety and improving soil health. The limitations of the current study include the identification of fertilizer type and its optimum dose, irrigation water type, and geographical position.

Enhanced-Efficiency Fertilizers Impact on Nitrogen Use Efficiency and Nitrous Oxide Emissions from an Open-Field Vegetable System in North China

Open vegetable fields in China are a major anthropogenic source of nitrous oxide (N2O) emissions due to excessive nitrogen (N) fertilization. A 4 yr lettuce experiment was conducted to determine the impacts of controlled-release fertilizers (CRFs) and nitrification inhibitors (NIs) on lettuce yield, N2O emissions and net economic benefits. Five treatments included (i) no N fertilizer (CK), (ii) conventional urea at 255 kg N ha-1 based on farmers' practice (FP), (iii) conventional urea at 204 kg N ha-1 (OPT), (iv) CRF at 204 kg N ha-1 (CU) and (v) CRF (204 kg N ha-1) added with NI (CUNI). No significant differences were found in the lettuce yields among different N fertilization treatments. Compared with FP, the cumulative N2O emissions were significantly decreased by 8.1%, 38.0% and 42.6% under OPT, CU and CUNI, respectively. Meanwhile, the net benefits of OPT, CU and CUNI were improved by USD 281, USD 871 and USD 1024 ha-1 compared to CN, respectively. This study recommends the combined application of CRF and NI at a reduced N rate as the optimal N fertilizer management for the sustainable production of vegetables in China with the lowest environmental risks and the greatest economic benefits.

Comparative Approach on the Effects of Soil Amendments and Controlled-Release Fertilizer Application on the Growth, Nutrient Uptake, Physiological Performance and Fruit Quality of Pepper (Capsicum annuum L.) Plants

Under the economic pressure from the increase of fertilizers’ prices due to the recent energy crisis, more efforts are needed to search for alternative and cheaper sources of nutrients for crops. The purpose of our study was to compare the effects of manure and inorganic amendments’ application to those derived from the application of a controlled-release fertilizer (CRF) on the growth, nutrition, physiology and fruit quality of pepper plants. For that reason, zeolite (ZEO) and vermiculite (VER) were applied either independently, or in combination between them, or with manure (MAN), in a pot experiment. Insignificant differences for plant growth among the treatments were recorded, while higher foliar N, Mg and Mn concentrations were determined in CRF. In contrast, a significantly higher K uptake was recorded in the ZEO and VER + ZEO treatments; the highest leaf P levels (0.47 and 0.44% D.W.) were recorded in the MAN + VER and ZEO treatments, respectively. The optimum photosynthetic II (PSII) performance was observed in the VER and in the MAN + ZEO (based on the performance index—PI) treatments. The highest stomata opening was found in the CRF treatment, while the photosynthetic rate of pepper plants showed its maximum values both in the CRF and VER treatments. Finally, fruit quality (as indicated by total soluble solids, total phenols and antioxidant activity—FRAP) was significantly influenced by treatment. In conclusion, significant differences in the growth, nutrition and physiological performance of pepper plants between soil amendments’ application (inorganic, such as zeolite and vermiculite, and organic, such as manures) and CRF application were recorded; thus, these amendments should be more thoroughly studied in future projects to investigate if they could partially decrease high inorganic fertilization rates in Capsicum annuum L.

Controlled release fertilizers (CRFs) for climate-smart agriculture practices: a comprehensive review on release mechanism, materials, methods of preparation, and effect on environmental parameters.

Fertilizers play an essential role in increasing crop yield, maintaining soil fertility, and provide a steady supply of nutrients for plant requirements. The excessive use of conventional fertilizers can cause environmental problems associated with nutrient loss through volatilization in the atmosphere, leaching to groundwater, surface run-off, and denitrification. To mitigate environmental issues and improve the longevity of fertilizer in soil, controlled release fertilizers (CRFs) have been developed. The application of CRFs can reduce the loss of nutrients, provide higher nutrient use efficiency, and improve soil health simultaneously to achieve the goals of climate-smart agricultural (CSA) practices. The major findings of this review paper are (1) CRFs can prevent direct exposure of fertilizer granule to soil and prevent loss of nutrients such as nitrate and nitrous oxide emissions; (2) CRFs are less affected by the change in environmental parameters, and that can increase longevity in soil compared to conventional fertilizers; and (3) CRFs can maintain required soil nitrogen levels, increase water retention, reduce GHG emissions, lead to optimum pH for plant growth, and increase soil organic matter content. This paper could give good insights into the ongoing development and future perspectives of CRFs for CSA practices.

An Integrated Nitrogen Management Strategy Promotes Open-Field Pepper Yield, Crop Nitrogen Uptake, and Nitrogen Use Efficiency in Southwest China

Excessive nitrogen (N) fertilizer application is a serious issue in intensive vegetable production and can negatively affect vegetable productivity and N use efficiency (NUE). The optimization of the N fertilizer rate and application of enhanced efficiency N fertilizers (EENFs), including nitrification inhibitors (Nis) and controlled-release fertilizer (CRF), are widely recognized as feasible N management strategies to resolve the problem of unreasonable N fertilizer input. Therefore, we conducted a 2-year field experiment (2019–2020) in an open-field vegetable system (pepper, Capsicum annuum L.) in southwest China to investigate the effects of an optimized N application rate and EENFs on vegetable yield, NUE, and crop N uptake. The following N management treatments were established: control without N fertilizer input (CK); optimized N fertilizer rate as urea (OPT); farmers’ fertilizer practice (FP); application of a nitrification inhibitor (NI) within the optimized N fertilizer rate; and application of controlled-release fertilizer (CRF) within the optimized N fertilizer rate. The results showed that the OPT treatment based on root zone N management achieved a 37.5% reduction in the N application rate without compromising vegetable yield and increased the recovery efficiency of N (REN) by 31.5% compared to the FP treatment. Furthermore, the combined application of the NI or CRF treatments with the OPT treatment resulted in greater vegetable yields, fruit N uptake, and REN (9.54%, 26.8%, and 27.6%, respectively, for NI; 10.5%, 28.7%, and 28.8%, respectively, for CRF) than the OPT treatment alone. The absorption ratio of fruit N uptake to total crop N uptake was also increased. Our results clearly showed that the combined application of EENFs with the OPT treatment could achieve the win–win benefits of a yield increase and improved REN in Chinese vegetable production.

Examination of the Effectiveness of Controlled Release Fertilizer to Balance Sugarcane Yield and Reduce Nitrate Leaching to Groundwater

Groundwater pollution by nitrate leaching from sugarcane fields in Okinawa is recognized as a critical issue. Controlled release fertilizer (CRF) has the potential to reduce N leaching from cropping systems. The study focused on confirming the effectiveness of CRF at balancing sugarcane yield and reducing nitrate leaching from sugarcane fields via a water footprint (WF) approach. A lysimeter study was conducted using four treatments: (i) bare land, (ii) P and K fertilization without N, (iii) urea fertilization, and (iv) CRF application. According to the results, for both plant cane and ratoon, the total sugarcane dry weight obtained for CRF was higher compared to urea application. The cumulative nitrate-N leaching of the plant cane season for all treatments was higher than of the ratoon season. For the total crop cycle (plant cane plus ratoon), heavier nitrate-N leaching was observed in the urea-applied condition than in the CRF-applied condition. For both crop seasons, the total sugarcane WF of the CRF application (plant cane: 192.33 m3/t, ratoon: 190.47 m3/t) was lower than that of the urea application (plant cane: 233.47 m3/t, ratoon: 237.59 m3/t). WF values indicated that the CRF application had a lower impact on the groundwater of the area.

Controlled and Prolonged Release Systems of Urea from Micro‐ and Nanomaterials as an Alternative for Developing a Sustainable Agriculture: A Review

The world population requires the increase of food products from agricultural fields and also the improvement of agricultural practices to avoid the environmental pollution. Urea is the most used fertilizer worldwide; however, it is lost to the environment by processes such as leaching, volatilization, and denitrification. As an alternative to avoid these losses, controlled‐release fertilizer (CRF) and prolonged release fertilizer (PRF) have been proposed. With this type of system, the plants could take the necessary amount of nutrients for their growth at the same time decreasing the environmental pollution. These systems could be fabricated from both synthetic and natural sources, such as wheat gluten proteins, polysaccharides, and composites (polymeric matrix, wheat‐gluten‐urea mix, among others). This review gives a sustainable agriculture approach in the application of CRF and PRF using inorganic and organic raw materials, focusing on the use of wheat gluten proteins and urea for the development of these systems.

Fertilización de dos grupos genéticos de Pinus patula Schiede ex Schltdl. &amp; Cham. en un ensayo de progenies de cuatro años

Introduction: Genetic improvement and nutritional management are used to increase productive capacity. Objective: To analyze the effect of traditional and controlled-release fertilizers, as well as the way to define the doses (technically or empirically), on growth of 20 tree families of Pinus patulaSchiede ex Schltdl. &amp; Cham. Materials and methods: Four fertilization treatments were applied: 1) control; 2) “technical”, based on foliar analysis; 3) controlled release (18-6-12 + 2CaO + 3.5 Mg + 2.1 Si + microelements); and 4) mixture of agricultural fertilizers in nutrient concentrations similar to the controlled-release treatment. Height, diameter, biomass index, number of whorls, leaf mass, and growth initiation and cessation were evaluated in a group of 10 superior and 10 inferior three-year old families in Chignahuapan, Puebla. Data were analyzed with the MIXED procedure of SAS. Results and discussion: Trees showed no significant differences in growth, biomass production and growth initiation by fertilization effect, but showed significant differences by genetic quality (P ≤ 0.05). The genotype*fertilization interaction was significant; after one year of controlled-release fertilizer application, inferior genotypes had the highest values of relative rates of biomass production, diameter at root collar and height. Conclusions: Controlled-release fertilizers at appropriate doses and environmental conditions are a viable option to promote growth of young P. patula trees in the field.

The long-term effects of microplastics on soil organomineral complexes and bacterial communities from controlled-release fertilizer residual coating

Controlled-release fertilizer (CRF) was applied widely in China as an efficient utilization strategy for improving grain yield and reducing the nitrogen contamination. However, it was indeterminate to know the impacts of inevitably imported plastic into the soil on sustainable development. After ten-year fixed-site experiment, the visible residual coating microplastics were separated from the soil to measure their changes, then the long-term effects of CRF application (theoretical microplastic content 0.018–0.151 g kg−1 soil) on soil architecture and bacterial communities were evaluated. Based on soil organomineral complexes (OMC) distribution experiments and soil 16S rRNA sequence analysis, residual coating microplastics had no significant impact on soil architecture and limited effects on soil bacteria, but became the specific microbial habitat. The nitrogen rate and nitrogen release mode affected sand- and silt-grade OMC, and nitrogen rate impacted soil bacteria communities. The residual coating, small inert particles, is safe for soil OMC and bacterial communities in agricultural soil. Due to the effectiveness of CRF on reducing environmental pollution, CRF is considered as a favorable measure to the sustainable agricultural development in Shandong Province, China.

Effects of Different Fertilization Patterns on Nitrogen Leaching Loss from Paddy Fields Under Reduced Nitrogen

Nitrogen leaching loss in paddy fields is one of the main ways of farmland non-point source pollution. To explore the suitable fertilization of rice fields in the Erhai Lake Basin and reduce the nitrogen loss from paddy fields, a field experiment was conducted by setting single applications of chemical or organic fertilizer, combined organic and inorganic application, and single application of controlled release fertilizer under reduced nitrogen conditions. The results showed that, compared with the conventional fertilization treatment(CF), there was no significant difference in rice grain and straw yield between the single chemical fertilizer treatment(T1) and the organic-inorganic combined treatment(T3); the single organic fertilizer treatment(T2) decreased the rice grain yield by 13.0%, and decreased straw yield by 17.1%; single application of controlled-release fertilizer(T4) increased rice grain and straw yield by 15.7% and 21.0%, respectively. Further, compared with CF, the single application of chemical fertilizer(T1), organic fertilizer(T2), and organic-inorganic combined application(T3) reduced the total nitrogen leaching loss at 30 cm depths by 26.9%, 18.0%, and 33.9%, respectively. The loss of ammonia nitrogen leaching with T1, T2, and T3 decreased by 24.4%, 36.9%, and 36.6%, respectively, and the loss of nitrate nitrogen leaching decreased by 40.2%, 4.8% and 46.4%. The total nitrogen leaching at 60 cm soil depths was reduced by 34.2%, 26.3%, and 42.1%, the loss of ammonia nitrogen leaching was reduced by 31.4%, 35.7%, and 46.6%, and the loss of nitrate nitrogen leaching was reduced by 8.0%, 10.1%, and 23.9% for T1, T2, and T3, respectively. The total nitrogen loss at 30 and 60 cm depths increased by 41.6% and 14.0% in the single application of controlled release fertilizer(T4) treatment. Considering factors such as agronomic and environmental benefits of different fertilization modes, T1 and T3 are suitable environmentally friendly alternative fertilization modes.

Controlled release fertilizer: A review on developments, applications and potential in agriculture

Controlled release fertilizer (CRF) plays a crucial yet necessary part in the sustainable agriculture industry. An alarming rise in call for crop production directly influences the increasing need for synthetically derived fertilizers and pesticides production. The application of CRF has been a gamechanger as an environmentally sustainable pathway to increase crop yields by paving desired phase of plant growth via a direct or indirect mechanism. The mechanism of CRF does not only decreases nutrient dissipation due to volatilization and leaching, but also provides a precisely appropriate nutrient release design that is suitable in the physiological and biochemical aspect of the plant growth. However, CRF is not deployed on larger scale of commercial agriculture practices due to being expensive, has relatively low efficiency in releasing nutrients and its coatings are largely composed of petroleum-based synthetic polymers. Alternatively, there are many polymers derived from renewable and biodegradable sources that can be used as coating material for CRF in the form of bio-nanocomposites. Having said that, there is an apparent gap between the mechanism of the CRFs for promoting plant growth and the prominent role of the nanocomposites especially bio-nanocomposites as coating material for CRF synthesis, thus the importance of nanotechnology application in enhancing the effectiveness of CRF. Therefore, this review attempts to bridge the stated gap and summarizes the comprehensive developments, application mechanisms and future potential of CRF as a fertilizer for crop sustainability.