Application of the DNDC model to the Rodale Institute Farming Systems Trial: challenges for the validation of drainage and nitrate leaching in agroecosystem models

2010 ◽  
Vol 87 (3) ◽  
pp. 483-494 ◽  
Author(s):  
Christina Tonitto ◽  
Changsheng Li ◽  
Rita Seidel ◽  
Laurie Drinkwater
2014 ◽  
Vol 11 (1) ◽  
pp. 91-107 ◽  
Author(s):  
F. Cui ◽  
X. Zheng ◽  
C. Liu ◽  
K. Wang ◽  
Z. Zhou ◽  
...  

Abstract. Contemporary agriculture is shifting from a single-goal to a multi-goal strategy, which in turn requires choosing best management practice (BMP) based on an assessment of the biogeochemical effects of management alternatives. The bottleneck is the capacity of predicting the simultaneous effects of different management practice scenarios on multiple goals and choosing BMP among scenarios. The denitrification–decomposition (DNDC) model may provide an opportunity to solve this problem. We validated the DNDC model (version 95) using the observations of soil moisture and temperature, crop yields, aboveground biomass and fluxes of net ecosystem exchange of carbon dioxide, methane, nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3) from a wheat–maize cropping site in northern China. The model performed well for these variables. Then we used this model to simulate the effects of management practices on the goal variables of crop yields, NO emission, nitrate leaching, NH3 volatilization and net emission of greenhouse gases in the ecosystem (NEGE). Results showed that no-till and straw-incorporated practices had beneficial effects on crop yields and NEGE. Use of nitrification inhibitors decreased nitrate leaching and N2O and NO emissions, but they significantly increased NH3 volatilization. Irrigation based on crop demand significantly increased crop yield and decreased nitrate leaching and NH3 volatilization. Crop yields were hardly decreased if nitrogen dose was reduced by 15% or irrigation water amount was reduced by 25%. Two methods were used to identify BMP and resulted in the same BMP, which adopted the current crop cultivar, field operation schedules and full straw incorporation and applied nitrogen and irrigation water at 15 and 25% lower rates, respectively, than the current use. Our study indicates that the DNDC model can be used as a tool to assess biogeochemical effects of management alternatives and identify BMP.


Soil Research ◽  
2014 ◽  
Vol 52 (7) ◽  
pp. 621 ◽  
Author(s):  
Lucy L. Burkitt

This paper reviews the literature on nitrate leaching and nitrogen (N) runoff under intensive dairy pasture systems in Australia and draws comparisons with research undertaken under similar climates and farming systems internationally, with the aim to inform future research in this area. An Australian nitrate-leaching study suggests that annual nitrate-leaching loads are lower (3.7–14.5 kg N ha–1 year–1 for nil N and 6–22 kg N ha–1 year–1 for 200 kg N ha–1 applied) than the range previously measured and modelled on New Zealand dairy farms (~18–110 kg N ha–1 year–1). It is likely that nitrate-leaching rates are higher in New Zealand because of the prevalence of free-draining soils and higher average stocking rates. However, this review highlights that there are insufficient Australian nitrate-leaching data, particularly following urine application, to undertake a rigorous comparison. Median N surpluses on Australian dairy farms are higher (198 kg N ha–1) than values for an average New Zealand farm (135 kg N ha–1). Given the facts that many soils used for intensive pasture production in Australia are lightly textured or free-draining clay loams receiving average rainfall of >800 mm year–1, that herd sizes have risen in the last 10 years and that water quality is a concern in some dairy catchments, nitrate leaching could be an issue for the Australian dairy industry. Australian data on surface runoff of N are more available, despite its overall contribution to N losses being low (generally <5 kg N ha–1 year–1), except under border-check flood irrigation or hump-and-hollow surface drainage (3–23 kg N ha–1 year–1). More research is needed to quantify surface N runoff and leaching following effluent application and to examine dissolved organic forms of N loss, particularly in view of the continued intensification of the Australian dairy industry.


Geoderma ◽  
2014 ◽  
Vol 223-225 ◽  
pp. 108-118 ◽  
Author(s):  
Hu Li ◽  
Ligang Wang ◽  
Jianjun Qiu ◽  
Changsheng Li ◽  
Maofang Gao ◽  
...  

2001 ◽  
Vol 136 (3) ◽  
pp. 271-281 ◽  
Author(s):  
J. ERIKSEN

Intensive dairy farming with low N use efficiencies may have adverse environmental impact through nitrate leaching. The residual effects of six different temporary grasslands (1994–96) on yield and nitrate leaching in the following cereal crops (1997–99) were investigated on a loamy sand in central Jutland. The grasslands were unfertilized grass–clover and fertilized ryegrass subject to cutting or continuous grazing by dairy cows with two levels of N in feed supplements. In the first year there was sufficient residual effect of the grazed grasslands to obviate the need for supplementary fertilizer, but in the following years gradually more fertilizer N was required to obtain optimal yields. Nitrate leaching decreased as a function of time after cultivation of grassland, but grassland management had little effect on the subsequent nitrate leaching (6 to 36 kg N/ha in unfertilized plots). Application of cattle slurry to cereals influenced nitrate leaching more than the history of the grassland and caused the annual mean nitrate concentration to exceed the EU Drinking Water Directive upper limit in most cases. Presumably, large differences in N-input during the grassland phase of the crop rotation had relatively little effect on the subsequent N release because of variable N losses during grazing. Possibilities for further improvement of the utilization of grassland N following cultivation are limited when the current knowledge has been implemented. If the N use efficiency of dairy farming systems is to be further improved the utilization of N during the pasture phase is crucial.


Sign in / Sign up

Export Citation Format

Share Document