Nutrient Cycling in Agroecosystems
1573-0867
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The long-term effects of manures and fertilisers on soil productivity and quality: a review
Tập 66 Số 2 - Trang 165-180 - 2003
The results from 14 field trials comparing the long-term (20 to 120 years) effects of fertilisers and manures (farmyard manure, slurry, and green manure) on crop production and soil properties are reviewed. In total there were 24 paired comparisons of the effects of manure and fertiliser. Some of the trials also contained a control (no nutrient inputs) treatment. The input of nutrients as either f......
Contribution of livestock excreta to nutrient balances
Tập 66 Số 2 - Trang 119-131 - 2003
Livestock excreta make an important contribution to soil nutrient inputs and in many developing countries are the only significant input. However, there is little quantitative information available on excreta, manure production, and application and this makes it difficult to obtain meaningful soil nutrient balances. A model has therefore been developed to calculate the excreta produced and manure ......
Emissions of NH3, N2O and CH4 from dairy cows housed in a farmyard manure tying stall (housing, manure storage, manure spreading)
Tập 60 Số 1 - Trang 103-113 - 2001
Emission measurements from dairy cows housed in a tying stall were carried out with the aim of finding factors that influence the amount of emissions and means to reduce emissions. All sectors of animal husbandry were investigated. This enabled calculations of emissions for the whole management system including housing, storage and spreading of manure. Emissions during aerobic composting and anaer......
Comparing a process-based agro-ecosystem model to the IPCC methodology for developing a national inventory of N2O emissions from arable lands in China
Tập 60 Số 1 - Trang 159-175 - 2001
Nations are now obligated to assess their greenhouse gas emissions under the protocols of Article 4 of the United Nations Framework Convention on Climate Change. The IPCC has developed `spreadsheet-format' methodologies for countries to estimate national greenhouse gas emissions by economic sector. Each activity has a magnitude and emission rate and their product is summed over all included activi......
Modeling Trace Gas Emissions from Agricultural Ecosystems
Tập 58 Số 1 - Trang 259-276 - 2000
A computer simulation model was developed for predicting trace gas emissions from agricultural ecosystems. The denitrification-decomposition (DNDC) model consists of two components. The first component, consisting of the soil climate, crop growth, and decomposition submodels, predicts soil temperature, moisture, pH, Eh, and substrate concentration profiles based on ecological drivers (e.g., climat......
Canadian greenhouse gas mitigation options in agriculture
Tập 60 Số 1 - Trang 317-326 - 2001
In 1991, on farm management practices contributed 57.6 Tg CO2 equivalent in greenhouse gas emissions, that is, about 10% of the anthropogenic GHG emissions in Canada. Approximately 11% of these emissions were in the form of CO2, 36% in the form of CH4 and 53% in the form of N2O. The CO2 emissions were from soils; CH4 emissions were from enteric fermentation and manure, and N2O emissions were prima......
Comparing measured and Expert-N predicted N2O emissions from conventional till and no till corn treatments
Tập 66 Số 2 - Trang 107-118 - 2003
Agricultural soils are a major source of the greenhouse gas nitrous oxide (N2O). Nitrous oxide emission models can be used to predict the effectiveness of N2O mitigation strategies; however, these models require rigorous testing before they can be used with confidence. Expert-N, a modular process based N2O emission model, was tested to determine its ability at predicting nitrogen (N) cycling in th......
Nutrient cycling in organic farms: stall balance of a suckler cow herd and beef bulls
Tập 64 Số 3 - Trang 225-230 - 2002
In organic agriculture, the internal farm nutrient cycle must bequantified to ensure high system productivity accompanied by environmentallysound production processes. In contrast to common farm-gate and field balances,budgeting at the stall level is seldom undertaken. When budgeting mixed farmingsystems, a substantial lack of nutrients can be detected in the “forageand straw input – stall – manur......
Quantitative dependence of methane emission on soil properties
Tập 64 Số 1 - Trang 157-167 - 2002
To identify the key soil parameters influencing CH4 emission from rice paddies, an outdoor pot experiment with a total of 18 paddy soils was conducted in Nanjing Agricultural University during the 2000 rice growing season. The seasonal average rate of CH4 emission for all 18 soils was 6.42±2.70 mg m−2 h−1, with a range of 1.96 to 11.06 mg m−2 h−1. Correlation analysis indicated that the seasonal a......
Amelioration of Al toxicity and P deficiency in acid soils by additions of organic residues: a critical review of the phenomenon and the mechanisms involved
Tập 59 Số 1 - Trang 47-63 - 2001
High rates of lime and fertilizer-P are characteristically required to obtain high crop yields on highly weathered acid soils. Much of the agriculture in the southern tropical belt, where acid soils predominate, is carried out by resource-poor, semi-subsistence farmers who are unable to purchase large quantities of lime and fertilizer. There are, however, a number of reports that additions of orga......