Smart climate initiatives for United States cropland

Introduction

The US Department of Agriculture’s initial climate-smart projects (USDA 2023) will be only as good at reducing greenhouse gases (GHGs) as the practices they support. Project summaries choose cover crops, reduced tillage, and nutrient management to reduce GHGs from crop farms and from mixed crop and livestock farms.

Challenges occur in the design and implementation of the above GHG reduction cover crop, reduced tillage, and nutrient management practices. USDA cover crop practices achieved considerable success in addressing nutrient pollution in the Chesapeake Bay, but GHG reduction (Basche et al. 2014; Abdalla et al. 2019) and economic impacts vary; USDA experts need to document cover crop practice designs and locations for cost-effective GHG reductions on climate-smart farms. No-till offers a more straightforward, top-tier GHG reduction practice design (Pape et al. 2016); the challenge is to persuade periodic no-till practitioners instead to practice it continuously, without any interruption, and persuade more reduced tillage and continuous tillage farmers to switch to continuous no-till. Nutrient management practices’ effectiveness varies from one location to the next, with the important exceptions of fertilizer soil testing (Williamson 2011) and timing of fertilizer applications. USDA’s climate-smart initiative needs to narrow its focus so that its nutrient management projects emphasize fertilizer soil testing and fertilizer timing practices.