Agricultural Systems Research Unit Site Logo
ARS Home About Us Helptop nav spacerContact Us En Espanoltop nav spacer
Printable VersionPrintable Version     E-mail this pageE-mail this page
Agricultural Research Service United States Department of Agriculture
Search
  Advanced Search
Programs and Projects
 

Research Project: OBJECT MODELING AND SCALING OF LANDSCAPE PROCESSES AND CONSERVATION EFFECTS IN AGRICULTURAL SYSTEMS

Location: Agricultural Systems Research Unit

Title: Simulated Effects of Nitrogen Management and Soil Microbes on Soil Nitrogen Balance and Crop Production

Authors

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 5, 2008
Publication Date: October 1, 2008
Citation: Ma, L., Malone, R.W., Jaynes, D.B., Thorp, K.R., Ahuja, L.R. 2008. Simulated Effects of Nitrogen Management and Soil Microbes on Soil Nitrogen Balance and Crop Production. Soil Science Society of America Journal. 72:1594-1603.

Interpretive Summary: System models are important tools in evaluating N loss from non-point agricultural sources in the Midwestern US. In this study, an agricultural system in central Iowa, managed using a corn-soybean rotation, were evaluated with the RZWQM-DSSAT4.0 for crop yield, grain N, annual N loss in tile drainage flow, and residual soil nitrate-N under a high (H, 199 kg N/ha), medium (M, 138 kg N/ha), and low (L, 69 kg N/ha) N application rate shortly after planting, and a split (S, 69 kg N/ha shortly after planting and at midseason) N treatment. The model adequately simulated the responses of yield and N loss to H, M, and L nitrogen treatments, but it failed to simulate the lower corn yield and higher N loss under the S treatment than under the M treatment, where both received the same amount of N applications.

Technical Abstract: Searching for environmental friendly nitrogen management practices in the Midwestern US is an on-going task in the agricultural community. Many practices have shown promise in reducing N in tile drainage that may contribute to hypoxia in the Gulf of Mexico. In this study, an agricultural system in central Iowa, managed using a corn-soybean rotation, were evaluated with the Root Zone Water Quality Model (RZWQM)-DSSAT4.0 for crop yield, grain N, annual N loss in tile drainage flow, and residual soil nitrate-N under a high (H, 199 kg N/ha), medium (M, 138 kg N/ha), and low (L, 69 kg N/ha) N application rate shortly after planting, and a split (S, 69 kg N/ha shortly after planting and at midseason) N treatment. The model adequately simulated the responses of yield and N loss to H, M, and L treatments, but it failed to simulate the lower corn yield and higher N loss under the S treatment than under the M treatment, where both received the same amount of N applications. Experimental differences in yield between the two treatments were statistically significant, whereas the differences in N loss were not significant experimentally. Further improvement on model responses to late fertilizer application in terms of yield and N leaching was needed before it could be applied to simulate other N scheduling, such as the late spring N test (LSNT). The study also showed that, with a constant soil microbial population implemented in RZWQM, the model produced very similar simulation results for crop production and soil N balances compared to a dynamic soil microbial population in RZWQM.

   

 
Project Team
Ascough, James
Green, Timothy
Ma, Liwang
McMaster, Gregory - Greg
Ahuja, Lajpat - Laj
Dunn, Gale
 
Publications
   Publications
 
Related National Programs
  Soil Resource Management (202)
  Integrated Farming Systems (207)
  Water Availability and Water Management (211)
 
Related Projects
   THE OBJECT MODELING SYSTEM (OMS): AN ADVANCED COMPUTER FRAMEWORK FOR NATURAL RESOURCES TECHNOLOGY MODELS AND TOOLS
   DEVELOP, TEST, AND IMPROVE THE NEEDED SCIENCE MODULES AND MODELS OF AGRICULTURAL SYSTEMS IN OMS FOR VARIOUS APPLICATIONS
   COMPLETE NEEDED ENHANCEMENTS OF OMS AND DELIVERY OF THE OMS-PROTOTYPE FIELD TO WATERSHED SCALE MODEL FOR CEAP
 
 
Last Modified: 11/05/2008
ARS Home | USDA.gov | Site Map | Policies and Links 
FOIA | Accessibility Statement | Privacy Policy | Nondiscrimination Statement | Information Quality | USA.gov | White House