Emission of nitrous-oxide from some grazed pasture soils in New Zealand

Soil Research ◽  
1995 ◽  
Vol 33 (2) ◽  
pp. 341 ◽  
Author(s):  
RA Carran ◽  
PW Theobald ◽  
JP Evans

Nitrous oxide emissions from grazed pastures were measured at four sites for a 2 year period. Sites differed in drainage class and N cycle characteristics. At two intensively farmed sites on Kairanga silt loam, which is poorly drained, daily emissions ranged from 0 to 100 g N ha-1 day-1 and annual emission was in the range 3-5 kg N2O-N ha-1. Emissions occurred when the soil was near or above field capacity indicating denitrification is the probable source of N2O. Multiple regression analysis, using soil water content, NO3-, NH4+ and temperature, gave r2 = 0.44 and 0.57 at sites 1 and 2 respectively. Soil water content and NH4+ were significant variables. Emissions at a low fertility hillside site were very low and an annual emission of 0.5 kg N2O-N yr-1, or less, was indicated. The highly fertile hillside site also showed low emission values. It is suggested that grazing animals may have a large impact on emissions through hoof damage on wet soils.

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 810 ◽  
Author(s):  
Iris Vogeler ◽  
Rogerio Cichota

Despite the importance of soil physical properties on water infiltration and redistribution, little is known about the effect of variability in soil properties and its consequent effect on contaminant loss pathways. To investigate the effects of uncertainty and heterogeneity in measured soil physical parameters on the simulated movement of water and the prediction of nitrous oxide (N2O) emissions, we set up the Agricultural Production Systems sIMulator (APSIM) for different soil types in three different regions of New Zealand: the Te Kowhai silt loam and the Horotiu silt loam in the Waikato region, and the Templeton silt loam in the Canterbury region, and the Otokia silt loam and the Wingatui silt loam in the Otago region. For each of the soil types, various measured soil profile descriptions, as well as those from a national soils database (S-map) were used when available. In addition, three different soil water models in APSIM with different complexities (SWIM2, SWIM3, and SoilWat) were evaluated. Model outputs were compared with temporal soil water content measurements within the top 75mm at the various experimental sites. Results show that the profile description, as well as the soil water model used affected the prediction accuracy of soil water content. The smallest difference between soil profile descriptions was found for the Templeton soil series, where the model efficiency (NSE) was positive for all soil profile descriptions, and the RMSE ranged from 0.055 to 0.069m3/m3. The greatest difference was found for the Te Kowhai soil, where only one of the descriptions showed a positive NSE, and the other two profile descriptions overestimated measured topsoil water contents. Furthermore, it was shown that the soil profile description highly affects N2O emissions from urinary N deposited during animal grazing. However, the relative difference between the emissions was not always related to the accuracy of the measured soil water content, with soil organic carbon content also affecting emissions.


Author(s):  
MUHAMMAD ASLAM ALI ◽  
SANJIT CHANDRA BARMAN ◽  
MD. ASHRAFUL ISLAM KHAN ◽  
MD. BADIUZZAMAN KHAN ◽  
HAFSA JAHAN HIYA

Climate change and water scarcity may badly affect existing rice production system in Bangladesh. With a view to sustain rice productivity and mitigate yield scaled CH4 emission in the changing climatic conditions, a pot experiment was conducted under different soil water contents, biochar and silicate amendments with inorganic fertilization (NPKS). In this regard, 12 treatments combinations of biochar, silicate and NPKS fertilizer along with continuous standing water (CSW), soil saturation water content and field capacity (100% and 50%) moisture levels were arranged into rice planted potted soils. Gas samples were collected from rice planted pots through Closed Chamber technique and analyzed by Gas Chromatograph. This study revealed that seasonal CH4 emissions were suppressed through integrated biochar and silicate amendments with NPKS fertilizer (50–75% of the recommended doze), while increased rice yield significantly at different soil water contents. Biochar and silicate amendments with NPKS fertilizer (50% of the recommended doze) increased rice grain yield by 10.9%, 18.1%, 13.0% and 14.2%, while decreased seasonal CH4 emissions by 22.8%, 20.9%, 23.3% and 24.3% at continuous standing water level (CSW) (T9), at saturated soil water content (T10), at 100% field capacity soil water content (T11) and at 50% field capacity soil water content (T12), respectively. Soil porosity, soil redox status, SOC and free iron oxide contents were improved with biochar and silicate amendments. Furthermore, rice root oxidation activity (ROA) was found more dominant in water stress condition compared to flooded and saturated soil water contents, which ultimately reduced seasonal CH4 emissions as well as yield scaled CH4 emission. Conclusively, soil amendments with biochar and silicate fertilizer may be a rational practice to reduce the demand for inorganic fertilization and mitigate CH4 emissions during rice cultivation under water stress drought conditions.


2002 ◽  
Vol 82 (4) ◽  
pp. 855-859 ◽  
Author(s):  
M. L. Leblanc ◽  
D. C. Cloutier ◽  
C. Hamel

A 2-year field study was conducted in corn to determine the influence of rainfall, irrigation and soil water content on common lambsquarters and barnyardgrass emergence. Rainfall or irrigation had no influence on the final weed density and little on the pattern of weed emergence because the soil water content was at or greater than field capacity during the main weed emergence period. Irrigation may hasten the first weed emergence by warming the soil when temperature is limiting for germination. In southwestern Quebec, temperature appears to be the most important factor regulating germination in the spring since soil moisture is normally at field capacity for a long period, in part because of the melting of snow. Key words: Irrigation, weed emergence, soil moisture


2012 ◽  
Vol 9 (11) ◽  
pp. 16565-16588 ◽  
Author(s):  
S. Castaldi ◽  
T. Bertolini ◽  
A. Valente ◽  
T. Chiti ◽  
R. Valentini

Abstract. Most recently atmospheric studies have evidenced the imprint of large N2O sources in tropical/subtropical lands. This source might be attributed to agricultural areas as well as to natural humid ecosystems. The uncertainty related to both sources is very high, due to the paucity of data and small frequency of sampling in tropical studies. This is particularly relevant for the African continent. The principal objective of this work was to quantify the annual budget of N2O emissions in an African tropical rain forest. Soil N2O emissions were measured over 19 months in Ghana, National Park of Ankasa, in upland and lowland areas, for a total of 119 days of observation. The calculated annual average emission was 2.33 ± 0.20 kg N-N2O ha−1yr−1, taking into account the proportion of upland vs. lowland, as the two areas showed significantly different fluxes, the lowland being characterized by lower N2O emissions. N2O fluxes peaked between June and August and were significantly correlated with soil respiration on a daily and monthly basis. No clear correlation was found in the upland areas between N2O fluxes and soil water content or rain whereas in the lowland soil water content concurred with soil respiration in determining N2O flux variability. The N2O source strength calculated in this study, very close to those reported for the other two available studies in African rain forests and to the estimated mean derived from worldwide studies in humid tropical forests (2.96 ± 2.0 kg N-N2O ha−1 yr−1), supports the concept that tropical humid forests represent the strongest natural source of N2O emissions, most probably the strongest source of N2O in the African continent.


2013 ◽  
Vol 33 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Adão W. P. Evangelista ◽  
Luiz A. Lima ◽  
Antônio C. da Silva ◽  
Carla de P. Martins ◽  
Moisés S. Ribeiro

Irrigation management can be established, considering the soil water potential, as the limiting factor for plant growth, assuming the soil water content between the field capacity and the permanent wilting point as available water for crops. Thus, the aim of this study was to establish the soil water potential interval during four different phenological phases of coffee irrigated by center pivot. The experiment was set at the experimental area of the Engineering Department at the Federal University of Lavras, in Brazil. The coffee variety planted is designated as Rubi, planted 0.8 meters apart, with rows spaced 3.5 meters apart. The treatments corresponded to the water depths applied based on different percentages of Kc and reference evapotranspiration (ET0) values. Sensors were used to measure the soil water potential interval, installed 25 centimeters depth. In order to compare the results, it was considered as the best matric potential the one that was balanced with the soil water content that resulted in the largest coffee productivity. Based on the obtained results, we verified that in the phases of fruit expansion and ripening, the best results were obtained, before the irrigations, when the soil water potential values reached -35 and -38 kPa, respectively. And in the flowering, small green and fruit expansion phases, when the values reached -31 and -32 kPa, respectively.


2002 ◽  
Vol 6 (3) ◽  
pp. 325-338 ◽  
Author(s):  
S. E. Machefert ◽  
N. B. Dise ◽  
K. W. T. Goulding ◽  
P.G. Whitehead

Abstract. The results of a literature study examining quantitative estimates of N2O emission rates are presented for a range of land-uses across Europe. The analysis shows that the highest N2O emission rates are for agricultural lands compared to forests and grasslands. The main factors regulating these rates are available mineral nitrogen, soil temperature, soil water content and the available labile organic compounds. These controls operate across different time-scales, all must exceed a certain threshold for N2O emission to occur. The results support the need for an emission factor function of land-use and climate within models describing nitrogen dynamics in catchments. This would allow the assessment of the net N2O emission within catchments in terms of current levels and potential changes associated with climate variability, climate change and land use change. Keywords: nitrous oxide, soil water content, inorganic N, soil temperature, ecosystems, land-use management, soil type


1972 ◽  
Vol 79 (1) ◽  
pp. 75-81 ◽  
Author(s):  
F. A. Langton

SUMMARYPotato varieties were grown in the field in soil uniformly infected with Streptomyces scabies. In 1969 tubers were severely and evenly infected but in 1971 infection was slight and not uniform. Agreement of varietal ranking with agricultural experience was good in 1969 but poor in 1971.In 1971, plots protected from rainfall after planting were dry enough at the start of tubering for severe infection; covering the plots for a further 6 weeks followed by irrigation to field capacity resulted in good yields of evenly and severely scabbed tubers. Irrigation during this period suppressed scabbing. The results were easily interpreted in relation to fluctuations in soil-water content measured by a neutron moisture-meter.The efficiency of using only one site and the need to reduce variability in scab screening tests are discussed.


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