Core Ideas Nitrite concentration was highly correlated with N2O emissions within two distinct water content ranges. Soil moisture was the most important environmental factor affecting N2O emissions. Nitrous oxide emissions increased exponentially as the N application rate increased. Biochar and N transformation inhibitors showed great potential to reduce N2O emissions. A better understanding of the factors and processes affecting N2O emissions is essential for developing mitigation strategies. This research aimed to examine the factors and processes affecting N2O emissions and N dynamics. Laboratory incubation experiments examined the effects of N (urea) application rate (0ā150 mg N kgā1); soil water content (5ā30%, w/w); temperature (10ā40Ā°C); and incorporation of biochar (1%, w/w), a urease inhibitor (Agrotain Ultra), and a nitrification inhibitor (NāServe 24) on N2O emissions and N transformation dynamics in a Hanford sandy loam soil. Nitrous oxide emissions, soil pH, and mineral N species were monitored for 35 d. Peak emission rates and cumulative losses of N2O increased more than the N application rate increased. Soil water content at 20 and 30% [above the water holding capacity (WHC) of 12%] resulted in much higher total N2O emissions (9.3 and 8.0% of total soil inorganic N, respectively) than that from 5 and 10% water content (0.2 and 0.3%, respectively). Increasing soil water content above WHC caused higher N2O emissions than increasing the soil temperature, which demonstrates that soil moisture is more significant in affecting the process. Nitrite concentration was highly correlated with N2O emissions within two water content ranges (above or below WHC). Amendment with biochar, Agrotain Ultra, and NāServe 24 reduced N2O emissions by 74, 78, and 74%, respectively. This research provide further understanding of the processes affecting N2O emissions from soil, which can assist in developing management practices.
Soil fertilization is one of the major sources for nitrous oxide (N 2 O) emissions and soil moisture is among the most important factors affecting its production. Thus, one of the important mitigation strategies in semiarid or arid regions is through irrigation and/or fertigation management. The objective of this research was to evaluate the effects of different drip irrigation methods and N application levels on N 2 O emissions. Nitrous oxide emission flux and N 2 O concentration in soil profile were measured in a pomegranate field for two growing seasons under two irrigation systems [subsurface drip irrigation (SDI) at ~0.5 m depth and traditional surface drip irrigation (DI)], and three N application rates (50%, 100%, and 150% of current practice rate). Both years' data showed that N 2 O emissions has a high and positive correlation with N fertilization events and application levels. Nitrous oxide emissions from DI at 100% and 150% N levels were over an order of magnitude higher compared to those from SDI based on the data of the first year. Data from the second year confirmed the first year's findings of high emissions from DI. A positive linear correlation between the N 2 O emission flux and N 2 O concentration in soil-gas phase was identified that supported emission data. This research demonstrated that although N fertilization is a major cause for N 2 O emissions, subsurface drip irrigation/fertigation can lead to a significant emission reduction in addition to other benefits, such as increased water and nutrient use efficiencies, and reduced weed pressure.Index Terms-Chemical nitrogen fertilizer, greenhouse gas emission, high-frequency drip irrigation.
Abstract-Static flux chambers are often used to determine emission flux of gases such as greenhouse gas nitrous oxide (N 2 O). However, the sampling process is laborious especially when many treatments/plots are included for measurements to compare treatment effects in the effort to develop mitigation strategies. To solve this problem, we constructed an automatic sampler (autosampler) at low cost, simple to operate, and easy maintenance and used it with static chambers to sample N 2 O emissions. The construction involves mechanical work including mainly woodworking for building a chassis (mounting board), syringe mounting block, and servo mounting block, and electronics for the controller involving hardware assembly, soldering, and programming to control the operation of the sampler. This paper provides the detailed information and instructions as well as price of materials for the construction of the sampler with the flexibility for modification to meet various research needs. The samplers were used to measure N 2 O emissions in a pomegranate field demonstrating improved sampling efficiency. The results illustrated treatment differences with much higher flux from surface drip irrigation than that from subsurface drip irrigation.Index Terms-Greenhouse gas, emission flux, nitrogen fertilizer, drip irrigation.
Mitigation of greenhouse gas emissions is essential to combat climate change, and also for sustainable agriculture. Agriculture is facing a growing number of challenges including water shortage and environmental degradation that threaten crop production. In this research, field monitoring was carried out to evaluate the effects of drip irrigation methods and nitrogen (N) fertilization level on carbon dioxide (CO 2 ) emissions in a 5-year old pomegranate orchard. Surface drip irrigation (DI) and subsurface drip irrigation (SDI) were tested as main treatments. Three N application rates (50%, 100%, and 150% in reference to current practices) were applied as sub-treatments. CO 2 emission data were collected during the growing season. The CO 2 flux near the irrigation line was significantly higher from DI (ave. 2.67 Āµmol m -2 s -1 ) than SDI (ave. 1.74 Āµmol m -2 s -1 ). There were significant spatial variations surrounding a tree from DI but much less from SDI. However, no significant differences in cumulative CO 2 emissions were determined between DI (7.5-9.5 Mg ha -1 ) and SDI (7.7-9.0 Mg ha -1 ) due to small wetting areas under DI. These values may subject to error due to the limited number of sampling times in spatial variations. The higher DOC and water content in surface soil from DI contributed to the higher CO 2 emissions in comparison to SDI. The spatial variation should be considered to accurately estimate CO 2 emissions in orchard settings especially with irrigation systems. The SDI provides overall benefits of water savings, improvement on nutrient use efficiency, and reduction in total greenhouse gas emissions.Index Terms-Greenhouse gas emission, high-frequency drip irrigation, surface drip irrigation, subsurface drip irrigation, fertigation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citationsācitations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright Ā© 2024 scite LLC. All rights reserved.
Made with š for researchers
Part of the Research Solutions Family.