Document Type

Thesis - Open Access

Award Date

2016

Degree Name

Master of Science (MS)

Department

Agronomy, Horticulture, and Plant Science

First Advisor

Sandeep Kumar

Keywords

cattle manure, corn-soybean rotation, greenhouse gas emissions, soil hydrological properties, soil organic carbon, soil quality

Abstract

Dairy and beef manure have been used to enhance soil quality; however, their impacts under long-term application in corn-soybean rotation need to be evaluated. Nutrient based recommended rates of manure applications on soils are important and also need to be monitored. This study, therefore, was conducted at two long-term sites to assess the impacts of manure and inorganic fertilizer application rates on some of the soil quality indicators and greenhouse gas emissions (GHGs) in a corn (Zea mays L.) - soybean (Glycine max L.) rotation system located at Beresford and Brookings in Eastern South Dakota. Study treatments included: three manure [phosphorus (P) based recommended manure application rate, nitrogen-based recommended manure application rate (N), nitrogen-based double of recommended manure application rate (2N)], and two fertilizers; recommended fertilizer (F) and (HF) high fertilizer and a control (CK) with no manure management. Soil samples were extracted in four replicates under randomized complete block design from 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm depths to analyze selected soil quality indicators, and intact core samples were taken from 0-10 and 10-20 cm depths to measure soil hydrological properties in 2015. Soil GHG fluxes were observed once a week from June 2015 through October 2015 and May 2016 to August 2016 depending on the climatic conditions. Results showed that manure maintained the soil pH for 0-10 cm depth and inorganic fertilizer decreased it compared to the control treatment at either site. Manure improved soil organic carbon (SOC), total nitrogen (TN), soil aggregate stability (WAS), soil water retention (SWR), water infiltration (qs) but decreased the soil bulk density (BD) in comparison with inorganic fertilizer and control. The CO2 fluxes were significantly impacted by manure application, whereas, there were insignificant impacts on CH4 flux. Soil surface nitrous oxide (N2O) fluxes were significantly impacted by inorganic fertilizer in 2016, whereas, there were nonsignificant differences in 2015. Air temperature and soil moisture content were strongly correlated with soil CO2 fluxes. As a result, this study concluded that manure produced better soil quality by improving soil properties and developing better soil structure, whereas, manure also increased soil surface GHGs emission. The rate of manure application is consequently important for use in agriculture to offer better environmental quality.

Library of Congress Subject Headings

Cattle -- Manure -- South Dakota.

Farm manure -- South Dakota.

Fertilizers -- South Dakota.

Soils -- Quality -- South Dakota.

Agricultural wastes -- Environmental aspects.

Corn.

Soybean.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

214

Publisher

South Dakota State University

Rights

Copyright © 2016 Ekrem Ozlu

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