Denitrification and nitrous oxide emissions from riparian forests soils exposed to prolonged nitrogen runoff

Compared to upland forests, riparian forest soils have greater potential to remove nitrate (NO3) from agricultural run-off through denitrification. It is unclear, however, whether prolonged exposure of riparian soils to nitrogen (N) loading will affect the rate of denitrification and its end products. This research assesses the rate of denitrification and nitrous oxide (N2O) emissions from riparian forest soils exposed to prolonged nutrient run-off from plant nurseries and compares these to similar forest soils not exposed to nutrient run-off. Nursery run-off also contains high levels of phosphate (PO4). Since there are conflicting reports on the impact of PO4 on the activity of denitrifying microbes, the impact of PO4 on such activity was also investigated. Bulk and intact soil cores were collected from N-exposed and non-exposed forests to determine denitrification and N2O emission rates, whereas denitrification potential was determined using soil slurries. Compared to the non-amended treatment, denitrification rate increased 2.7- and 3.4-fold when soil cores collected from both N-exposed and non-exposed sites were amended with 30 and 60 μg NO3-N g-1 soil, respectively. Net N2O emissions were 1.5 and 1.7 times higher from the N-exposed sites compared to the non-exposed sites at 30 and 60 μg NO3-N g-1 soil amendment rates, respectively. Similarly, denitrification potential increased 17 times in response to addition of 15 μg NO3-N g-1 in soil slurries. The addition of PO4 (5 μg PO4–P g-1) to soil slurries and intact cores did not affect denitrification rates. These observations suggest that prolonged N loading did not affect the denitrification potential of the riparian forest soils; however, it did result in higher N2O emissions compared to emission rates from non-exposed forests

Uso de la técnica de canciones en el aprendizaje de inglés para elevar el rendimiento académico en el segundo semestre de los estudiantes del tercer grado del nivel secundario de la institucion educativa Augusto Salazar Bondy - Nuevo Chimbote 2010

TesisEl presente trabajo de investigación titulado “Uso de la técnica de canciones en el aprendizaje del Inglés para elevar el rendimiento académico en el segundo trimestre de los estudiantes de tercer grado del nivel secundario de la Institución educativa “Augusto Salazar Bondy” - Nuevo Chimbote – 20i0”, tuvo como objetivo general conocer si el uso de la técnica de canciones eleva el rendimiento académico en el aprendizaje del idioma inglés para los alumnos de tercer año de educación secundaria de la Institución Educativa “Augusto Salazar Bondy”. La población estuvo constituida por 90 alumnos (2 secciones), de las cuales la muestra estuvo constituida por 45 alumnos, 3”A” nuestro grupo de control y 3 “B” nuestro grupo experimental. Para la investigación se empleó la técnica cuasi - experimental de dos grupos paralelos con medición previa y posterior, debido a que un grupo estuvo bajo la influencia de la técnica de canciones y el otro grupo con los métodos tradicionales

Gender roles and greenhouse gas emissions in intensified agricultural systems in the mid-hills of Nepal

This paper assessed gender differences in agricultural activities that have a potential effect on N2O emissions from agricultural soils in the Ansikhola watershed of the mid-hill region of Nepal. Multiple methods were used to collect data, including a questionnaire survey (310 households), six focus group discussions, five key informant interviews and field gas flux measurements over a year. Results indicate that women are involved in farmyard manure (FYM) collection, transport and application. Decisions regarding which crops to plant and about purchases of chemical fertilizers have changed over the last 20 years, with women now being more included in such decisions, although this is happening more among higher and middle caste groups than in the lower castes. Involvement of women in community-based agriculture-related institutions has also increased, regardless of caste. Field flux measurements show variation in N2O emissions depending on the type of land use (e.g. Khet versus Bari), cropping system (traditional versus intensified) and across seasons (e.g. higher during the rainy season). The results show that increased fertilizer applications over 20 years has resulted in higher intrinsic propensity of the soil to emit N2O. Therefore the ongoing intensification of agriculture in South Asia may result in increasing N2O emissions

Assessment of the redistribution of soil carbon using a new index—a case study in the Haihe River Basin, North China

Abstract Soil carbon redistribution is an important process in the terrestrial carbon cycle. This study describes a new index, soil carbon redistribution (SCR) index, that can be used to assess long-term soil carbon redistribution at a large watershed scale. The new index is based on the theoretical preconditions that soil carbon redistribution is mainly controlled by vegetation type, precipitation, topography/slope, and soil carbon concentration. The Haihe River Basin served as an example for this analysis. The SCR index was calculated, and a GIS-based map shows its spatial patterns. The results suggested that soil carbon was usually prone to being carried away from mountainous regions with natural vegetation, while it was prone to deposition in the plain and plateau regions with cultivated vegetation. The methods in the paper offer a tool that can be used to quantify the potential risk where soil carbon is prone to being carried away and deposited in a large watershed