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21.
G.I. Nyadzi B.H. Janssen R.M. Otsyina H.W.G. Booltink C.K. Ong O. Oenema 《Agroforestry Systems》2003,59(3):215-229
The objective of this study was to compare the effects of woodlots of five tree species, continuous maize (Zea mays L.) and natural fallow on soil water and nitrogen dynamics in western Tanzania. The tree species evaluated were Acacia crassicarpa (A. Cunn. ex Benth.), Acacia julifera (Berth.), Acacia leptocarpa (A. Cunn. ex Benth), Leucaena pallida (Britton and Rose), and Senna siamea (Lamarck) Irwin & Barneby). The field experiment was established in November 1996 in a completely randomized block design
replicated three times. Maize was intercropped between the trees during the first three years after planting and thereafter
the trees were allowed to grow as pure woodlots for another two years. Transpiration by the trees was monitored when they
were 3 years old using sap flow gauges. Soil water content was measured using the neutron probe approach between November
1999 and March 2001. Soil inorganic N profiles were measured when the trees were four years old in all treatments. The results
indicated that the trees transpired more water than natural fallow vegetation during the dry season. The difference was apparent
at a depth of 35 cm soil, but was more pronounced in deeper horizons. The water content in the entire soil profile under woodlots
and natural fallow during the dry period was 0.01 to 0.06 cm3 cm−3 lower than in the annual cropped plots. This pattern was reversed after rainfall, when woodlots of A. crassicarpa, A. leptocarpa, A. julifera, S. siamea and L. pallida contained greater quantity of stored water than natural fallow or continuous maize by as much as 0.00 to 0.02, 0.01 to 0.04,
0.01 to 0.04, 0.01 to 0.03 and 0.00 to 0.02 cm3 cm−3, respectively. Natural fallow plots contained the lowest quantity of stored water within the entire profile during this period.
Transpiration was greatest in A. crassicarpa and lowest in L. pallida. All tree species examined were `scavengers' of N and retrieved inorganic N from soil horizons up to 2-m depth and increased
its concentration close to their trunks. This study has provided evidence in semi-arid environments that woodlots can effectively
retrieve subsoil N and store more soil water after rains than natural fallow and bare soil.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
22.
Nutrient losses from manure management in the European Union 总被引:4,自引:0,他引:4
Manure management systems are conducive to nutrient and carbon losses, but the magnitude of the loss highly depends on the nutrient element, the manure management system and the environmental conditions. This paper discusses manure management systems in the 27 Member States of the European Union (EU-27) and nutrient losses from these systems, with emphasis on nitrogen (N). In general, losses decrease in the order: C, N >> S > K, Na, Cl, B > P, Ca, Mg, metals. Assessments made with the integrated modeling tool MITERRA-EUROPE indicate that the total N excretion in 2000 by livestock in EU-27 was 10,400 kton. About 65% of the total N excretion was collected in barns and stored for some time prior to application to agricultural land. Almost 30% of the N excreted in barns was lost during storage; approximately 19% via NH3 emissions, 7% via emissions of NO, N2O and N2, and 4% via leaching and run-off. Differences between Member States in mean N losses from manure storages were large (range 19.5–35%). Another 19% of the N excreted in animal housing systems was lost via NH3 emissions following the application of the manure to land. The results indicate that maximally 52% of the N excreted in barns was effectively recycled as plant nutrient. Various emission abatement measures can be implemented and have been implemented already in some Member States to reduce the emissions of NH3 and N2O, and the leaching of N and P. There is scope to reduce NH3 emissions by 30% relative to the reference year 2000, although the uncertainty in estimated emissions and in the estimated effects of emission abatement measures is relatively large. 相似文献
23.
Effects of nitrogen input and grazing on methane fluxes of extensively and intensively managed grasslands in the Netherlands 总被引:5,自引:0,他引:5
A. van den Pol-van Dasselaar M. L. van Beusichem O. Oenema 《Biology and Fertility of Soils》1999,29(1):24-30
Generally, grasslands are considered as sinks for atmospheric CH4, and N input as a factor which reduces CH4 uptake by soils. We aimed to assess the short- and long-term effects of a wide range of N inputs, and of grazing versus mowing,
on net CH4 emissions of grasslands in the Netherlands. These grasslands are mostly intensively managed with a total N input via fertilisation
and atmospheric deposition in the range of 300–500 kg N ha–1 year–1. Net CH4 emissions were measured with vented, closed flux chambers at four contrasting sites, which were chosen to represent a range
of N inputs. There were no significant effects of grazing versus mowing, stocking density, and withholding N fertilisation
for 3–9 years, on net CH4 emissions. When the ground-water level was close to the soil surface, the injection of cattle slurry resulted in a significant
net CH4 production. The highest atmospheric CH4 uptake was found at the site with the lowest N input and the lowest ground-water level, with an annual CH4 uptake of 1.1 kg CH4 ha–1 year–1. This is assumed to be the upper limit of CH4 uptake by grasslands in the Netherlands. We conclude that grasslands in the Netherlands are a net sink of CH4, with an estimated CH4 uptake of 0.5 Gg CH4 year–1. At the current rates of total N input, the overall effect of N fertilisation on net CH4 emissions from grasslands is thought to be small or negligible.
Received: 27 January 1998 相似文献
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C. L. van Beek P. Droogers H. A. van Hardeveld G. A. P. H. van den Eertwegh G. L. Velthof O. Oenema 《Water, air, and soil pollution》2007,182(1-4):291-301
In many peat land areas in The Netherlands target concentrations for nitrogen (N) and phosphorus (P) in surface water are exceeded. A considerable, but poorly quantified, fraction, of the N and P loading of surface water in these areas originate from the subsoil. Waterboards, responsible for the water management, are currently exploring options to improve surface water quality, whilst sustaining agricultural production. Therefore, insight into dynamics of nutrient pools in peat soils is required. The aim of this study was to measure concentration profiles (0–12 m) of the soil solution in an intensively managed grassland on peat soil and to explore the effects of a rise in surface water level on N and P loading of surface water, using budgeting approaches and two dimensional simulation modeling. The concentration profiles of N, P and Cl reflect by the presence of nutrient-rich anaerobic peat and a nearly impermeable marine clay in the subsoil. Concentrations of N, P and Cl tended to increase with depth till about 6 m and then decreased. In the top soil, inputs of N and P via fertilizers and animal manure were only partly retrieved in the soil solution, suggestion that biogeochemical processes, uptake and lateral transport processes had a dominant influence on dissolved N and P. Exploring scenario simulations showed that major drainage fluxes passed through the peat layer that transported nutrients to adjacent surface water. Raising surface water levels with 20 cm suppresses this kind of nutrient loading of surface water by more than 30%, but nutrient rich peat layers will remain persistent as a potential source of nutrients in surface water in many peat polders in the western part of The Netherlands. 相似文献
27.
C.?L.?van?BeekEmail author E.?W.?J.?Hummelink G.L.?Velthof O.?Oenema 《Biology and Fertility of Soils》2004,39(5):329-336
In this study spatial and temporal relations between denitrification rates and groundwater levels were assessed for intensively managed grassland on peat soil where groundwater levels fluctuated between 0 and 1 m below the soil surface. Denitrification rates were measured every 3–4 weeks using the C2H2 inhibition technique for 2 years (2000–2002). Soil samples were taken every 10 cm until the groundwater level was reached. Annual N losses through denitrification averaged 87 kg N ha-1 of which almost 70% originated from soil layers deeper than 20 cm below the soil surface. N losses through denitrification accounted for 16% of the N surplus at farm-level (including mineralization of peat), making it a key-process for the N efficiency of the present dairy farm. Potential denitrification rates exceeded actual denitrification rates at all depths, indicating that organic C was not limiting actual denitrification rates in this soil. The groundwater level appeared to determine the distribution of denitrification rates with depth. Our results were explained by the ample availability of an energy source (degradable C) throughout the soil profile of the peat soil.This revised version was published online November 2003 with corrections to Figure 4 and in February 2004 with corrections to Figure 2. 相似文献
28.
Nitrous oxide emission from animal manures applied to soil under controlled conditions 总被引:6,自引:0,他引:6
Gerard?L.?VelthofEmail author Peter?J.?Kuikman Oene?Oenema 《Biology and Fertility of Soils》2003,37(4):221-230
Animal manures may differ strongly in composition and as a result may differ in the emission of N2O following application to soil. An incubation study was carried out to assess the effects of type of mineral N fertilizer and manure, application technique and application rate on N2O emission from a sandy soil with low organic matter content. Fluxes of N2O were measured 30 times over a 98-day period. The total N2O emission from mineral N fertilizer ranged from 2.1 to 4.0% of the N applied. High emissions were associated with manures with high contents of inorganic N, easily mineralizable N and easily mineralizable C, such as liquid pig manure (7.3-13.9% of the N applied). The emission from cattle slurries ranged from 1.8 to 3.0% and that of poultry manures from 0.5 to 1.9%. The total N2O emission during the experimental period tended to increase linearly with increasing N application rate of NH4NO3 and liquid pig manure. The N2O emission from surface-applied NH4NO3 was significantly smaller than that following the incorporation of NH4NO3 in the soil. The N2O emission from pig manure placed in a row at 5 cm depth was significantly higher than from surface-application and other techniques in which manure was incorporated in the soil. The results show that modification of the composition and application technique may be tools to mitigate emission of N2O. 相似文献
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What root traits determine grass resistance to phosphorus deficiency in production grassland?
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Mart B. H. Ros Gerlinde B. De Deyn Gerwin F. Koopmans Oene Oenema Jan Willem van Groenigen 《植物养料与土壤学杂志》2018,181(3):323-335
Grasslands are a major form of agricultural land use worldwide. Current and future declines of phosphorus (P) inputs into production grasslands necessitate a shift towards selecting grass species based on high efficiency under suboptimal, rather than optimal P conditions. It is therefore imperative to identify key root traits that determine P acquisition of grasses in soils with a low P status. In a 9‐month greenhouse experiment, we grew eight common grass species and cultivars on a soil with a low P status and related root morphological traits to their performance under P‐limiting conditions. We applied (P1) or withheld (P0) P fertilization while providing adequate amounts of all other nutrients. Omitting P fertilization greatly reduced yield and nutrient acquisition for the various grass species. Biomass production differed significantly (P < 0.1%) among species and P fertilization treatments, varying from 17.1 to 72.1 g pot?1 in the P0 treatment and from 33.4 to 85.8 g pot?1 in the P1 treatment. Root traits were species‐specific and unresponsive to P fertilization, but overall we observed a trade‐off between root biomass and specific root length. Structural equation modeling identified total root length as key factor with respect to resistance to P deficiency, especially when roots explored the subsoil. Optimizing root length and subsoil exploration could be the key to maintaining high productivity of production grasslands with decreasing P availability. This is relevant for both plant breeding programs and for composing seed mixtures. 相似文献