Document Type

Conference Proceeding

Conference

2008 ASABE Annual International Meeting

Publication Date

6-2008

City

Providence, RI

Abstract

Nitrate-nitrogen (NO 3 -N) loading from subsurface drainage is an environmental concern in the Midwest. The majority of NO 3 -N loading occurs in April, May and June when the crops are not planted or just establishing. In this study, NO 3 -N leaching was monitored under alternative land covers and in a corn-soybean rotation. Land cover treatments in a 2-year field experiment included: 1) corn-soybean rotation initiated with corn in 2006 and fallow in late fall and early spring (fallow-Corn-fallow-Soybean, fCfS); 2) corn-soybean rotation initiated with soybean in 2006 and fallow in late fall and early spring (fallow-Soybean-fallow-Corn, fSfC); 3) corn-soybean rotation initiated with corn in 2006 with rye cover crop (rye-Corn-rye-Soybean, rCrS); 4) corn-soybean rotation initiated with soybean in 2006 with rye cover crop ( rye-Soybean-rye-Corn, rSrC); 5) Corn with established kura clover as a living mulch (kura-Kura-kura-Corn, kKkC); and 6) Pasture as a perennial grass treatment (PP). Subsurface drainage volume and NO 3 -N concentration were monitored. Suction lysimeters were installed to extract the soil water solution for NO 3 -N analysis. Biomass of spring cover crops was sampled to analyze nitrogen (N) content. The objectives of this study were: 1) to determine NO 3 -N loss through subsurface drainage as affected by different land covers; 2) to investigate the NO 3 -N concentrations in the soil water under different land covers and 3) to quantify the nitrogen uptake by different cover crops in the spring. The results from the two-year study indicated that the annual average NO 3 -N loss for fCfS and fSfC treatments was 37.5 kg N ha -1 and that the rCrS and rSrC treatments reduced NO 3 -N leaching by 3.8 kg N ha -1 during April, May and June. kKkC and PP treatments resulted in 39.7% and 59.9% annual NO 3 -N leaching reduction, respectively, when compared to the average NO 3 -N loss of fCfS and fSfC treatments. Rye followed by soybean reduced the NO 3 -N concentration in the soil solution significantly (56.4%) at the 30- and 60-cm depths, and PP treatment showed the lowest NO 3 -N concentration at those two depths. The average nitrogen uptake by rye was 33.3 kg N ha -1 at growth termination, and the average N uptake was 59.9 kg N ha -1 for kura clover and 33.2 kg N ha -1 for pasture in early June. This study suggested that winter rye cover crop, kura clover as a living mulch and perennial pasture land covers have positive effects on NO 3 -N loss reduction under the weather condition encountered during this study period in Iowa.

Comments

This is an ASABE Meeting Presentation. Paper No. 084806.

Copyright Owner

American Society of Agricultural and Biological Engineers

Language

en

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