Date of Award

2024

Publisher

North Dakota State University

Document Type

Dissertation

Degree Awarded

Doctor of Philosophy (PhD)

Department

Natural Resources Management

College

Agriculture, Food Systems and Natural Resources

Faculty Advisor

DeSutter, Thomas

Description

Crop production in North Dakota covers nearly 64 million ha, playing a crucial role in the state’s economy. However, wide-spread agriculture also poses environmental risks resulting from soil erosion and loss of N to ground and surface water. To address these concerns, agriculturists must adopt practices to decrease soil erosion and responsibly manage N. Between 2020 and 2024, several studies in North Dakota focused on improving N management in two-row malting barley (Hordeum vulgare L.), explored opportunities for cover crop integration, and assessed the rotational impact cover crops on crop productivity and soil factors. Research indicated N recommendations ranging from 89 to 190 kg available N ha-1 could optimize profitability and barley quality while reducing fertilizer requirements compared to yield-goal based recommendations. Although cover crops planted following barley harvest sequestered N in the biomass preventing leaching, the subsequent two cropping years of corn (Zea Mays L.) and wheat (Triticum aestivum L.) showed no significant yield response from the cover crop. It did appear the cover crop had an impact on the wheat yield response to N, indicating a potential long-term benefit. In addition to cover crops, managing barley residue resulted in significant soil temperature differences in the spring, with greater mean daily temperatures measured where residue was removed compared to residue-mulched or cover cropped treatments; these temperature differences were attributed to increased absorption of solar radiation. The absence of mulch or cover crops, however, caused greater fluctuations and lower minimum temperature in the bare-soil treatment. Additionally, integrating interseeded cover crops into wide-row (152-cm) corn was determined to be a viable option for adding diversity to the cropping system without impacting corn yield. Through responsibly managed N recommendations in North Dakota cropping systems, dependence on N fertilizers can be reduced. The integration of cover crops can sequester N and provide erosion control without a significant impact on rotational crop yield.

Rights

NDSU policy 190.6.2

Rights Link

https://www.ndsu.edu/fileadmin/policy/190.pdf

Handle Identifier

https://hdl.handle.net/10365/33964

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