Which of the following practices is least likely to contribute to reducing emissions in agriculture?

Expanding fossil fuel use is least likely to contribute to reducing emissions in agriculture. This practice directly increases emissions as the burning of fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere. In contrast, the other practices mentioned, such as crop rotation, optimizing water use, and implementing precision agriculture, are geared towards enhancing sustainability and reducing the overall carbon footprint of agricultural operations.

Crop rotation helps in maintaining soil health and can enhance the efficiency of nutrient use, which can lead to lower emissions of nitrous oxide, a potent greenhouse gas. Optimizing water use can reduce energy demand for irrigation and improve water efficiency, thereby reducing the emissions associated with water transport and application. Precision agriculture utilizes technology to optimize inputs like fertilizers and pesticides, which can minimize waste and lower emissions as well. All these practices contribute positively to reducing emissions, making the expansion of fossil fuel use a clear outlier in this context.