U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Ma, Liwangitem
                                            Malone, Robert

                                                         - *Rob*item
                                            Jaynes, Danitem
                                            Thorp, Kellyitem
                                            Ahuja, Lajpat
  Submitted to: Soil Science Society of America Journal
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 5/5/2008
                                    Publication  Date: 10/1/2008
                                    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.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov