Greenhouse gas emissions from solid and liquid organic fertilizers applied to lettuce

Improper application of nitrogen (N) fertilizer and environmental factors can cause the loss of nitrous oxide (N2O) to the environment. Different types of fertilizers with different C/N ratios may have different effects on the environment. The focus of this study was to evaluate the effects of environmental factors and four organic fertilizers (feather meal, blood meal, fish emulsion, and cyano-fertilizer) applied at different rates (0, 28, 56, and 112 kg N ha−1) on N2O emissions and to track CO2 emissions from a lettuce field (Lactuca sativa L.). The study was conducted in 2013 and 2014 and compared preplant-applied solid fertilizers (feather meal and blood meal) and multiple applications of liquid fertilizers (fish emulsion and cyano-fertilizer). Three days a week, N2O and CO2 emissions were measured twice per day in 2013 and once per day in 2014 using a closed-static chamber, and gas samples were analyzed by gas chromatography. Preplant-applied solid fertilizers significantly increased cumulative N2O emissions as compared with control, but multiple applications of liquid fertilizers did not. Emission factors for N2O ranged from 0 to 0.1% for multiple applications of liquid fertilizers and 0.6 to 11% for preplant-applied solid fertilizers, which could be overestimated due to chamber placement over fertilizer bands. In 2014, solid fertilizers with higher C/N ratios (3.3–3.5) resulted in higher CO2 emissions than liquid fertilizers (C/N ratio, 0.9–1.5). Therefore, organic farmers should consider the use of multiple applications of liquid fertilizers as a means to reduce soil greenhouse gas emissions while maintaining high yields

Determination of cation exchange capacity of natural zeolite: a revisit

Natural zeolite has been widely used as an ion exchanger since the 1950s. The purpose of this study was to quantify the cation exchange capacity (CEC) of natural zeolite from different locations (Bayah and Cikembar in West Java, Indonesia) based on particle sizes of 0.15 and 0.079 mm, using different displacement solutions of 0.5M cesium chloride (CsCl) and 0.5 M potassium chloride (KCl). Higher CEC was observed in Cikembar100 compared to Bayah100 due to its higher surface area (31%) and total pore volume (11%) compared to Bayah100. Cikembar100 had 11% higher clinoptilolite mineral content compared to Bayah 100. The low CEC measured for Bayah100 and Bayah200 may be due to the lower percentage purity of the clinoptilolite mineral content in those samples. The natural zeolite samples displaced with 0.5M CsCl had 6% higher CEC compared to 0.5M KCl, which means that Cs+ had more strength compared to K+ in displacing NH4+ into the solution from the nanocavity site of the zeolitic framework into the solution. In both displacement solutions (0.5M CsCl and KCl), Cikembar100 had 10% more net negative charge compared to Bayah100 due to its isomorphous substitution properties in natural zeolite. Isomorphous substitution in natural zeolite affects its negative charge and the capacity to retain NH4+ in the zeolitic framework, thus increasing its CEC and making natural zeolite with the particle size of 0.079 mm (Cikembar100) a promising material for cation removal, particularly Cs from aqueous solution

Gaseous nitrogen losses from tropical soils with liquid or granular urea fertilizer application

Gaseous loss of N leads to lower nitrogen use efficiency (NUE) of applied urea and N content of the soil. This laboratory study was conducted to compare the nitrogen losses from two tropical soil series (Bungor sandy clay loam and Selangor clay) incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400, or 500 mg/kg of soil for thirty days. The NH3 volatilization, N2O emission, and N content in the soils were measured throughout the incubation period. For the same application rate, the total NH3 volatilization loss was higher in GU-treated soils than the LU-treated soils. NH3 volatilization loss continued up to the 15th day in the Selangor soil, while in the Bungor soil series it continued up to the 26th day. Higher amounts of N2O emissions were recorded in GU-treated soils than the LU-treated soils, and N2O emission increased with increasing rate of GU and LU applications in both soils. The N2O emission was higher only in the first few days and then tapered off at the seventh and eighth day in Bungor and Selangor soil series, respectively. The total N2O emission was higher in the Selangor soil series than that of Bungor soil series. The total N content that remained in the LU-treated soils after 30 days of incubation was higher than the GU-treated soils. The total N loss from applied urea was higher in the sandy clay loam Bungor soils than that of clayey Selangor soil series. The results suggest that the LU may be a better N fertilizer source than GU due to lower N loss from NH3 volatilization and N2O emission

Organic fertilizer source and application method impact ammonia volatilization

Ammonia (NH3) volatilization from fertilizer applications reduces efficiency and poses environmental hazards. This study used semi-open static chambers to measure NH3 volatilization from organic fertilizers (feather meal, blood meal, fish emulsion, cyano-fertilizer) to evaluate the impacts of fertilizer source, application method, and rate on NH3 volatilization. In 2014, two application rates (28 and 56 kg N ha−1) were applied to lettuce (Lactuca sativa L.). Solid fertilizers (feather meal, blood meal) were preplant applied in a subsurface band, whereas liquid fertilizers (fish emulsion, cyano-fertilizer) were applied weekly through drip irrigation beginning two weeks after transplanting. In 2015, a single application rate (28 kg N ha−1) was applied to cucumber (Cucumis sativus L.). Solid fertilizers were applied in either subsurface or surface bands. There was a significant difference in NH3 volatilization among fertilizers, but there was little difference between application rates. Liquid fertilizers had lower NH3 emissions than solid fertilizers due to their timing and placement. In 2014, blood meal at 56 kg N ha−1 and feather meal at both rates had the highest NH3 fluxes. In 2015, surface-banded blood and feather meal had the highest NH3 fluxes. Fertilizer decisions for organic systems should consider NH3 emission losses and practices for their reduction

Effects of Gliricidia sepium residue vermicompost on the yield and dry matter biomass of organic choy sum mustard

As the population grows and resource consumption increases, waste management has become a significant environmental challenge. A more sustainable approach to waste management is essential to maximize the recovery of materials acquired from nature. Vermicomposting is one of the answers to sustainable waste management. A study was conducted to determine the viability of vermicomposting Gliricidia sepium leaves and office scrap paper with matured compost as feedstock and to determine the vermicompost characteristics and suitability as potting mixtures for vegetable cultivation. The choy sum mustard was selected as the test crop. The plants were grown in the pots in a netted nursery in Serdang, Selangor. Treatments were mixtures of vermicompost to soil ratio by volume: control (0% no vermicompost), T1 (20% vermicompost), T2 (40% vermicompost), T3 (60% vermicompost), T4 (80% vermicompost) and T5 (100% vermicompost). Physicochemical properties of the potting media mix were determined and compared to an established growth media concentration and other ASEAN standards. Crop growth was evaluated by measuring plant height, the number of petioles, and fresh and dry weights at harvest. A significant improvement in the physicochemical properties of the media was observed, where the optimum ratio of potting media was 60% to 80% (T3 & T4). The number of petioles was 20-46% higher, plants were 39-46% taller, and dry matter accumulation was three-fold higher than controls. Crop yields were 200% higher in media treatments consisting of 60-80% vermicompost. In conclusion, G. sepium based vermicompost could be used in media mixtures for potting plants

Split application of liquid urea as a tool to nitrogen loss minimization and NUE improvement of corn - A review

Nitrogen loss minimization is the main challenge to sustainable crop production and reducing environmental and economic losses. There is a new approach to urea application in liquid form (LU) so that the NH4 + can be evenly distributed throughout the soil profile, soil particles adsorb it and reduce the local substrate concentration inhibiting further transformation. Liquid urea has been hydrolyzed even prior to soil a pplication, whereas the urea in granulated urea (GU) must be hydrolyzed after application before it can be transformed to NH4 +. Increased urea application frequency with lower doses can lower the NH4 + concentration in soil compared to a single application. These mechanisms reduce the N loss potential and increase the N crop uptake potential of applied N by conforming to the proper synchronization between N availability and crop N demand as well as reduce N loss potential as NH3 volatilization, NO3 - leaching and N2O emission. The inconsistent results and clarifications from various studies highlight the importance and benefits of relating the effect of LU application on N loss minimization, N availability and corn (Zea mays L.) yield. This review summarizes the potential ways of N losses and their management and provides the scientific reference to achieve sustainable corn yield and reduce N losses

Nitrogen dynamics in tropical soils applied with liquid and granular urea fertilizers

The mineralization of urea fertilizer mostly regulates the nitrogen dynamics in the soil. A laboratory-scale study was conducted to compare the nitrogen dynamics in two tropical soil series incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400 or 500 mg/kg of soil. The soils samples used in the experiment were the Bungor and Selangor soil series which have a sandy clay loam and clay texture, respectively. The NH4 + -N, NO3 −-N concentration in the soils were measured for four weeks to determine the urea-N mineralization while ten pore volumes of water were used for the NH4 + -N and NO3 −-N leaching loss. At the same application rate, higher NH4 + -N and NO3 −-N concentrations were recorded in the LU applied soils throughout the incubation period in case of N mineralization. Urea-N recovery was higher in GU than LU treated soils in the first two weeks while no urea-N was present in both GU and LU treated soils after the third week of incubation. The leaching of N (NH4 + -N and NO3 −-N) was higher in GU treated soils than that of LU and leaching was increased with increased application rate in both LU and GU in both soils. The NH4 + -N and NO3 −-N concentrations were higher in the Selangor soil whereas the total N leaching loss was higher in Bungor soil. The results suggest that the LU was a better N fertilizer source than GU for rapid mineralization, quicker N availability and lower N leaching loss

Nitrogen Dynamics in Tropical Soils Treated with Liquid and Granular Urea Fertilizers

The mineralization of urea fertilizer mostly regulates the nitrogen dynamics in the soil. A laboratory-scale study was conducted to compare the nitrogen dynamics in two tropical soil series incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400 or 500 mg/kg of soil. The soils samples used in the experiment were the Bungor and Selangor soil series which have a sandy clay loam and clay texture, respectively. The NH4+-N, NO3−-N concentration in the soils were measured for four weeks to determine the urea-N mineralization while ten pore volumes of water were used for the NH4+-N and NO3−-N leaching loss. At the same application rate, higher NH4+-N and NO3−-N concentrations were recorded in the LU applied soils throughout the incubation period in case of N mineralization. Urea-N recovery was higher in GU than LU treated soils in the first two weeks while no urea-N was present in both GU and LU treated soils after the third week of incubation. The leaching of N (NH4+-N and NO3−-N) was higher in GU treated soils than that of LU and leaching was increased with increased application rate in both LU and GU in both soils. The NH4+-N and NO3−-N concentrations were higher in the Selangor soil whereas the total N leaching loss was higher in Bungor soil. The results suggest that the LU was a better N fertilizer source than GU for rapid mineralization, quicker N availability and lower N leaching loss